Kt88 Bias Chart

fixed bias 0,1 0,1 mΩ Self bias 0,5 0,5 mΩ Substitutes: 5871 6aY5 6p6C 6V6G 6V6Gt 6V6Gta 6V6GtY 6V6Y 7184 CV509 CV510 CV511 oSW3106 Vt107 Vt227 Wt2100082 Wtt123 7408 Capacitances: Cg1 = 9 pf Ca 8,5 pf Ca/g1 = 0,7 pf. CHARTS, - total value $3. "You measure the output transformer's voltage drop and. A KT88 production line of a large factory is always automated. Adjust the bias pots slowly. SEPTEMBER PROJECT SALE - take 11% off all Amp Kits with coupon code SPS20 (starting September 1, 2020). The new $10,000 Sigma 170i iQ represents the lowest cost VAC amplifier to date but includes the company’s continuous automatic bias system and can deliver a healthy 85W per channel from its quartet of KT88 power tubes. If you buy a new Fender amp the first thing you must do is bias it as they set them really cold at the factory for the 5 year warranty. (pour autre chose, il faut tout réajuster !) Tu sais qu'une KT88 dissipe une puissance maxi de 42W à l'anode (si tu ne le sais pas, cf datasheet ). • STAX Pro Bias 5-pin EarSpeakers output x 2 • XLR input x 2, RCA input x 1 • Auricap capacitors for interstage and output coupling • Mills and Kiwame resistors • Balanced smooth potentiometer • Anodized aluminum chassis, available in black or silver • Self-biasing with compatible tubes [chart]. Sold from 1961-1971. Power tubes can have a dramatic effect on your amplifier’s sound. I have been enjoying for more than a year now the Amphion Argon 3L (floorstanders, but otherwise extremely similar to the Argon 3 bookshelves), driven by a Copland CTA-405 (full tube, KT88, 50 wpc), and all I can say is that the result is simply amazing (specially considering the price when compared to some more. Since the top output pentode's cathode follows the output signal, the screen capacitor must terminate into the output, which the bottom pentode's screen capacitor must. Re: Twin Jet EL34/KT88 Bias Mod Fri, Jun 14, 2013 10:41pm leib10 wrote: So I got my Twin Jet back from the local tech here in St. LM317HV Regulators are used for the cathode CCS. In the JD-1000P Level-2 mod we do the following [retrofit $1,000 + frt to your amp, New modified units are $2,790 + frt]:. Wide asortment and models up to 560 V. Building a Loop Bias Amplifier. About Connecting the dots between internal knowledge and real-time market information. Go and see the doctor: Find all of our products here: our newest product line of high-end blackplate tubes, our famous premium selected tubes, and the equipment we manufacture like our Class A Converters, the Bias Master or the Silencer. KT88-STR is the model. This electrical spec enables to design powerful amplifiers without parallel connection. That's twice the output of an average pair of 6L6 tubes. This meant that each tube could output more power before risking meltdown and, more importantly for the circuit, could operate more efficiently. Created Date: 4/12/2011 11:26:41 AM. Now that being said the 6550 and the KT88 are similar electrically and people inter-change them quite often. Speaker: 13. Their sales pitch is that they spec them tightly from their suppliers, and match/code power tubes to that if you replace like with like you can in theory get away without re-biasing the amp. A Tale of Two Bias Settings. 0520 or 52 milliamps X. Vacuum tubes are an older technology not often used today, but they still show up in some amplifiers and other devices. Findchips Pro brings fragmented sources of data together into a single platform and delivers accurate and contextual answers to your most strategic questions. Re: Biasing KT88's and/or KT120's in a VTA ST-120 - The. Tubes: The 2150 tube complement consists of four VHT Special Design KT88/6550As, two 12AX7s, and two 12AT7s. EL34, EL37, EL84, KT77, KT88, 6550, 7027, 8417 comes to mind. You check the bias on the EL34s, swap in the KT77s and adjust to match, or a little hotter if you want. I have used a tube chart designed for the Hickok 6000 dated 1971. Single-ended EL34 amps are fairly rare in the guitar world, for a couple reasons (one being SE amps are usually designed to be less powerful so it makes sense to use a smaller tube, and also output transformer for SE are much heavier and expensive so the smaller the "better"). JJ-Electronic Valve ecc83s Is great for blues/rock players, good fat base. Single Ended 2 x 8 Watt Class "A" (KT88) Uses push-pull 6SN7, then KT88. Please note that the reading is the sum of 2 power tubes. The maximum value is always lower for fixed bias (a separate negative supply) than for self bias using a cathode resistor and a grid resistor that connects to earth. With a gold-plated molybdenum alloy grid and carbon -coated screen grid, the Svetlana KT88 is the finest power tube of its type be ing manufactured today. Please see the substitutes at the top of the page for more details. I have been enjoying for more than a year now the Amphion Argon 3L (floorstanders, but otherwise extremely similar to the Argon 3 bookshelves), driven by a Copland CTA-405 (full tube, KT88, 50 wpc), and all I can say is that the result is simply amazing (specially considering the price when compared to some more. 20th Anniversary Shiva - comes with a pair of KT88’s and the amp is rated at 90 watts. Bias: Fixed bias Rectifier: solid state Phase Inverter: Cathodyne type: 1/2 x 12ax7 The F. Of course the adapter you are using should work using this chart also. 3 HS-5348-1 Bias 1. Rotate all four bias adjust controls located on the rear of the chassis (V7, V8, V9 and V10) fully clockwise for maximum bias. The Eurotubes "Pro One" Bias Probe is an "all in one" bias probe for octal tubes including 6V6's, 6L6's, KT66's, EL34's, E34L's, KT77's, 6CA7's, 6550's and KT88's. Lots of people hold the view that you should not use chinese KT88 tubes and that their use leads to different problems in many units. According to the manufacturer, the input stage’s four inputs are designed for use with sources of 250mV. It is a mid-range sweep that offers many variations on the Orange sound. RE: my bias is running away on one side even with the bias backed all the way off on that side! - Jonesy 05:46:38 07/24/20 RE: my bias is running away on one side even with the bias backed all the way off on that side! - immatthewj 10:35:27 07/24/20 RE: my bias is running away on one side even with the bias backed all the way off on that side!. Lots of electricity still consumes though. Vacuum tubes are an older technology not often used today, but they still show up in some amplifiers and other devices. That is the result of the combination of moderate soybean prices and the collapse of the real. Later in the 1970s, EL34 tubes became hard to get. Remember VAC’s Phi 200 amplifier, the one whose KT88 tubes range in price from $40 to $400 each? The EAT tube is the one at the high end of that spectrum. 495,-- SPIRIT III Integrated or Power amplifier; 2x55W Pentode or 2x35W. This banner text can have markup. (Order nr: 380-080-67) Final inspection in tube factories is really a weakness. They use a fixed resistor soldered into the. For the tubes, I decided to use some KT88. Jim Jones' Bias Tables Click here to vist the "House of Jim" Website. For 420 to 440V dc B+ (required for cathode-bias amps: 350V anode voltage, + 70-90V of cathode bias voltage) then the power transformer secondary must be about 460V rms for choke-input design. I do know the bias current requirements for the 6550's, KT88's & KT90's when I was using Manley monoblocks, which required individual biasing. NOT EVEN CLOSE. An alternative, which I have used in some of my designs, is to apply a high negative bias to the grid during warm-up, then after a delay, drop the bias to the normal level. (read chart). If you are uncertain that you are experienced enough to work on a live high voltage amp, please take your amp to a professional to get it biased. Finding the right amp for your bedroom and smaller clubs, can be a challenge. Run in class AB1 push/pull, a pair of KT88's are capable of producing 100 watts at 2. 31 1 speaker load 680Ω, 2W 282-680-RC 0. It was originally produced for players who needed more stage volume and sported a full 200 watts powered by KT88 power tubes. thetubestore. Ditto for Mesa. How to Test Vacuum Tubes. The M-3000 MK II monoblock amplifier is Allnic Audio’s top of the line, parallel push-pull power amplifier model. Update December 3rd 2019: Added example valves Type 80, ATP4, 6V6G and 6SQ7. Adjust the bias pots slowly. In our previous article, we have introduced you to amplifiers and its types. Then, use ohm. web; books; video; audio; software; images; Toggle navigation. C5 is fine just where it is! R5 and R7 puts the grid at 0-volt potential. Speaker: 13. It never let me down, always remained stable despite my novice attempts at tuning up,but has one big fault. Introduction. Page 12: Troubleshooting Guide. The Tube Type parameter allows you to select from common power tube types: 6AQ5, 6L6/5881, 6V6, 300B (triode), 6550, 6973, EL34/6CA7, EL84/6BQ5, KT66, KT77, KT88, 5881 and 6L6GB. The HiFi Engine library database contains model information, images and free, downloadable owners manuals, service manuals and product catalogues for amplifiers, pre-amplifiers, power-amplifiers, equalizers, processors, tape decks, tuners, CD players and loudspeakers etc. 3 or Current Chart Conversions from Manual- the chart number corresponds to the setting of lever "S" 7581A 7027A KT88 KT66 1, 3, 5, 8 Rs1 Rs2 Rs3 Rs4 Rpot Ω Rmeter A Rs5 Rs total Imeter Waveform factor "S" lever Range, mA Reading % Imeter140 Vmeter Ishunt, mA Mostly change this. Bias Settings For Safe Plate Dissipation - Class AB 70% Class A 90% Explain This: Class. If the idle current of a KT88 output tube drops below nominal limits, the LED corresponding to that tube will light green. TUBES To create a push pull amplifier is possible to use triode and pentode but obviously to test many configurations like the ultra linear we need a pentode. Tube Bias Online Calculator. Audio Compressor Schematic. Amptata T4 Vacuum Tube Tester EL34 KT88 6L6 6550 Bias Current Checker Match Tool £33. Each stage can be eitehr single ended or push-pull and bias can be adjusted on the fly to generate different levels of odd/even harmonics. 0: 12AX7, 6V6: 231: DIY Plasma-Tweeter: Looks better than the other one. That's twice the output of an average pair of 6L6 tubes. The EZ bias system uses LEDs so no meter is required. SEPTEMBER PROJECT SALE - take 11% off all Amp Kits with coupon code SPS20 (starting September 1, 2020). TV and RADIO Scopes enable you to spot all tube troubles in a jiffy. *IMPORTANT NOTE: All work carried out on your Blackstar amplifier must be done by a qualified technician. I would hazard a guess that a KT120 tubes bias is 500mv, but I cannot confirm this. Rebranded tubes just means that they will be more expensive. Use this as a guide for setting your bias. basically more powerful versions of KT88 and 6550 tubes. What has to do with bias is that there's a non-stock adjustment pot on the back panel clearly labelled "HUM". If memory serves, the difference was the first two letters in the set up--for the filament. KT88-STR is the model. The M-3000 MK II monoblock amplifier is Allnic Audio’s top of the line, parallel push-pull power amplifier model. (KT88, KT120, and KT150 pentodes can also be used, to respectively provide 40Wpc, 44Wpc, and 48Wpc). This is the Groove Tubes reference chart from www. As this can be hard to quantify, most premium preamplifiers in this price range simply reveal a level of musical nuance that lesser models do not. a push-pull amp. What sound characteristics do the KT88s have? The KT88 is known for its incredible clarity in the mid-range frequencies. Last Update: Description. The KT88 audio tube is considered to be one of the best sounding power tubes for hifi tube audio amplifiers. It has even less distortion and an even cleaner tone then the 6L6 or even the 6550. This page is my attempt to correct the general lack of schematics and technical information about Hiwatt amplifiers. A KT88 tube has a recommended bias at around 380mv-420mv. "Bias" in this context refers to the amount of voltage held on the grids of the output power tubes. PDF format. 8Pin Valve Tube Socket Cathode&Plate Bias Current Probe Tester for 6L6 EL34 KT88. B iasing by negative grid voltage is highly inaccurate because the same grid voltage can produce drastically different plate currents in different tubes of the same type. RE - 1992-09 - Free ebook download as PDF File (. the chassis is setup for 4 6l6 tubes. com provides easy to find states, metro areas, counties, cities, zip codes, and area codes information, including population, races, income, housing, school. Plate Voltage mA: Calculate Plate Dissipation Based On Plate Voltage And Cathode Current Readings. Back panel has external switching jacks for channel-solo-reverb (footswitch included), parallel effects loop with "mix" control, Bias Switch for EL34 and 6L6 power tubes (a new feature added with the Series 2 models), 8-4-4 ohm output jacks, and slave output. In this article, the 6550 is used in a clean, sweet-sounding, single-ended design. KT88 Quad vacuum tubes are highly sought-after tubes with an amazing sound profile that will please even the pickiest of audiophiles. We believe that this is the most complete, highest resolutio. In this article a typical single ended tube amplifier circuit has been conversed. One of the members had suggested building a Super Simple Single Stage Preamp (“4S” Preamp for short) and there was much discussion concerning various tubes, gain, noise, etc. To make an adjustment, slightly loosen the outer locking nut. According to OSHA, any exposure in excess of these permissible limits could result in some hearing loss. 495,-- SPIRIT III Integrated or Power amplifier; 2x55W Pentode or 2x35W. The chart also lists the 6AG7 as good for 7. Kt88 Amplifier Schematic Our simple bias circuit means kt77 kt88 if you are new to valves the stereo 25 mk ii is an excellent starting point with ample power its affordable price and excellent power make it an The ergonomically integrated amplifier as well comes with three various kinds of power tubes which comprise eh el34 and kt88 an. Designed for endurance and longevity for application in the audio industry. The 6L6 in class A should have a maximum plate current of 75mA @ 250 volts on the plate. au Electronic Components Electronic Components PCB Br ead Boar ds Cr oss-R ef er ence Da ta SEMICONDUCT OR WORLD DA T A BOOKS T able comparison chart for easy referenced data Listing is Alpha. Supplier of vacuum tubes for guitar, audio, and recording applications. Valuable Repair Aids: TV, RADIO, and - whether - THREE you keep nnazing DETECT -O -SCOT' E Charts. KT88: pdf Bold designators are close or identical, Italic designators are different ratings, different pinouts or different filament voltages. and British musicians in favor of which are modified and uprated in power dissipation rating from their KT88 and EL34 prototypes. Its exclusive screen-grid radiator fins reduce a major source of. Type III/FeCr was a combination of ferric oxide and chromium dioxide, while Type IV/Metal had a non-oxide metal particle coating and could take higher peak levels prior to saturation. For the tubes, I decided to use some KT88. When replacing tubes, remove only the rear cover. If they are 1% resistors then one of them could be 1% high and the other 1% low so there can be a variation of 2% just due to the resistors that. Sound I am emphasizing again that my impression is based on SR1a which Aegir isn’t recommended to drive (even Jason mentioned so!). Update December 3rd 2019: Added example valves Type 80, ATP4, 6V6G and 6SQ7. Thank You Sam, that's really interesting! But why this bias range doesn't fit any chart/calculator? (take ANY found on the web. Sold from 1961-1971. 5% total harmonic distortion or up to about 50W at low distortion in hi-fi applications. The citation, while lovely, sounded almost flat and uninvolving compared to this KT88 amp with the fully regulated high voltage supplies for each channel and the adaptive bias system. The basis for this amp started out as a post in a thread on the DIY Audio Projects Forum site. The chart shows that the current price of soybeans of nearly 35 reais per bushel is greater than all of the previous price spikes -- including the 2007/08 and 2012/13 Everest-like peaks. 70) Hello all! Hopefully someone out there will be able to help. This page is my attempt to correct the general lack of schematics and technical information about Hiwatt amplifiers. Many articles have appeared regarding projects using one of the most sturdy, versatile, and trustworthy audio tubes ever made — the 6550. are common guitar amplifier power tubes, and are all easily biased with this method. Valve amp bias. 6SC7 For Resistance CoupledAmplifier Chart, see 6SL7-GT,below Page 1 Page 2. Factory settings for 6L6 at either TEST POINT is 72mV, EL34 = 76mV, 6550/KT88 = 84mV. LM317HV Regulators are used for the cathode CCS. It has even less distortion and an even cleaner tone then the 6L6 or even the 6550. com - Your online source for audio vacuum tubes. It looks like that particular amp was intended for KT88 with a hot-ish bias; the grid leak resistors look to be 100k, which complies with the Penta limit, but not other makes, eg EH, but it isn't usually a problem unless the tubes are run very hot. Pat was blown away with the build quality on these amps, and looking at the plate voltage which was running at 780volts, thought it would be cool to put some KT88s in. The output stage is a Class-A UL SIPP using KT88 tubes. Surprisingly, the 6AQ5 is good for 54 MHz and 11 Watts Output. later i might try a 6sl7 im not very familiar with those. An icon used to represent a menu that can be toggled by interacting with this icon. This form of bias is called cathode bias. 9 thoughts on “ Build a DIY vacuum tube amp ( EL34 / KT88) ” Jkx on October 11, 2006 at 1:16 am said: Caution Unlike said on the HackAday post, the pic isn’t my Amp, since it’s not finished yet, but this come for "Consonance". *Please Note – All fixed bias amps will need biasing by a qualified technician when the output valves are changed. It isn’t used in guitar amps as often as it is in hi-fi audio amps, but that being said, I know a few guys who totally swear by the KT88. 1317 Ross Street Petaluma, CA 94954 United States of America. 5% total harmonic distortion. Then I put the fully regulated version of my KT88 amp back in. AMPLIFIER KT88 SERIES ORION II Integrated amplifier; 2x50W Pentode or 2x30W Triode - switchable, 4x Ayon KT88s, 3x12AU7, 0dB NFB, 3 x Line-In, 1x USB-In, 1x Pre out, 1 x Direct in, RC, Auto-Fixed-Bias system& Tube test program, PPP; N E W € 2. We accept credit cards via Paypal including Visa, Mastercard, Maestro, American Express. JTM-45 Series The 1st Marshall 1961 Lead 45w 1962 Bass & Lead 45w (Bluesbreaker) 1963 PA 45w 1985 PA 45w 1986 Bass 45w 1987/T Lead 45w 1989 Organ 45w. Handy chart. Negative bias supply is used to supply the 20v 125mA filament power to the C3m, then a doubler boosts this to 140v DC for use of negative bias to the 300B's. TUBES: 2-KT88/6550 output, 12AX7, 12AU7, 12BH7, 12AT7/12AZ7. Hi, and first of all, congratulations for this nice blog that I just discovered. Make fix -it jolis easier, faster. Plus, Mesa amps don't have bias pots, so you can't rebias them to deal with tube variability (unless you modify the amp). (KT88, KT120, and KT150 pentodes can also be used, to respectively provide 40Wpc, 44Wpc, and 48Wpc). The SLI-80HS integrated stereo amplifier operates in a Class AB1 mode utilizing a negative fixed bias supply. Update December 3rd 2019: Added example valves Type 80, ATP4, 6V6G and 6SQ7. Life Test button; Terminals for attaching external self-bias resistor. Tube type: ----Choose---- 6V6 EL84/6BQ5 5881 EL34 KT66 6L6GC KT88/6550. A nice complete Allen push-pull 6550 tube power amp Looks nice and was not long ago removed from service All complete 2 original 6SN7 s and a wonderful Mullard 6267 / EF86 -- all there except for 2 missing needed 6550 tubes This is Model 75 and features a versatile Acro output better known as -- Acrosound. The KT88 is based on the 6550 but even more refined and boosted. As in its other amps, PrimaLuna's Adaptive Auto-Bias circuitry is used to monitor power-tube performance and eliminate the need to buy tubes in matched pairs. 6SC7 For Resistance CoupledAmplifier Chart, see 6SL7-GT,below Page 1 Page 2. The KT88 audio tube is considered to be one of the best sounding power tubes for hifi tube audio amplifiers. I received email from a person who tried 32 mA with EL 34's with no ill effects. The amp is in the highly desirable chrome finish and is 6 years old. I mentioned KT88 and EL509 tubes, both of which are pentodes. It will also work for different types of output tubes, including 6550, KT88, KT90, KT120 or KT150. They made the Marshall amps sound different. Right bias adjustment: Controls the bias of the right output tube, V4 (See tube chart on pg. bias; BIAS Amp; BIAS Amp 2; Bias Amp 2 LE; BIAS AMP 2 Mobile; BIAS FX 2; Bias FX Mobile; BIAS FX2; BIAS Head; BIAS Modulation; biasing; Biffy Clyro; Big Dist; Big Fella; Big Fish Audio; big goat; Big Muff; Bigsby; Bigsby B-50; Bigsby B5; Bill Finnegan; Bill Lawrence L-500; bill putnam mic collection; Bill Ruppert; Billie Joe Armstrong; Billy. WRONG!!! From a tube-only perspective, this might fly, but your clean head room goes right out the window!. —more about the bias laterThe Rogers EHF-100 is a fully Class A amplifier. Use this as a guide for setting your bias. SE with Grundig AT3 transducers; KT88 Endröhren and EF800: DE : Roehrensockel Scheamtic link is at bottom of page. This form of bias is called cathode bias. Hickok always listed the 6550 under KT88. Hiwatt DR-201 KT88 bass amp finished Post by doctord02 » Thu Jul 16, 2009 6:38 am Thanks to both Mark Huss and Skyboltone for their advice during the planning and construction on this guy - as a result other than some buzz/noise reduction tweaking, this baby is finished!. Non-Adjustable Fixed Bias: This category can be the most labour intensive when it comes to setting the correct bias. A amp biased too cold sounds worse than one biased too hot IMO. 0: 3750 Again, this is the weakest one. In that chart we have 415V for the Va and 300V Vg2(screen), which no one seems to respect If you're going cathode bias 425V on plates, 390V on Screens, 8K. Set up chart for the 7-A and accompanied 10-D loudspeaker. The bias measuring resistor in the cathode is safe and sits at a few volts. The calculator will give you the bias current for each tube. What are you talking about? We are talking a EL34 to KT77 switch. Supplied complete with all parts, wire. Re: Biasing KT88's and/or KT120's in a VTA ST-120 - The. 1 bias supply KT88 22K, 1/2W 71-RN65D-F-22. Hot (70%) Avg (60%) Cool (50%) 200V. --The Cathode bias resistor (Rk) All tubes require the grid (signal input) to be negative in respect to the cathode. The HiFi Engine library database contains model information, images and free, downloadable owners manuals, service manuals and product catalogues for amplifiers, pre-amplifiers, power-amplifiers, equalizers, processors, tape decks, tuners, CD players and loudspeakers etc. Vacuum tubes are an older technology not often used today, but they still show up in some amplifiers and other devices. Rebranded tubes just means that they will be more expensive. Last Update: Description. Run in class AB1 push/pull, a pair of KT88's are capable of producing 100 watts at 2. Before insert KT88 check the bias voltage on grid setting the trimmer for the max negative voltage. The setting is locked in place by the outer locking nut. The plates feed the bridge directly. Tubes are tested either in the upper “quik-check” section using multiple tube sockets wired in the most popular pinout arrangements, allowing the mutual conductance (Gm) of most common “TV type” tubes to be measured; or the lower “switch” section allowing other less common tubes to be tested in. Both have electronically balanced inputs and outputs (there are no transformers), but the Dbx 386 employs a 12AU7 (ECC82) triode valve running with a 200V anode supply voltage as part of its gain stage, while the AEA TRP is a DC‑coupled, JFET, solid‑state design. It looks like that particular amp was intended for KT88 with a hot-ish bias; the grid leak resistors look to be 100k, which complies with the Penta limit, but not other makes, eg EH, but it isn't usually a problem unless the tubes are run very hot. So far i have tried GL KT88, JJ6550, Tung-Sol 6L6G, and SED Winged C EL34. 7 ma U g1 = -15 V S = 11,5 ma/V R i = 12 kΩ µ-g1-g2 = 8 Triode Connected U a, g2 = 250 V I a+g2 = 147 ma U g1 = -15 V S = 12 ma/V R i = 670 Ω µ = 8 Red/Blue versions available max 125,0 max 52,0 max 110,0. (261-262 Series) "Tube Guitar Amp "Replacement Output, Power & Chokes (1750, 290 & 194 Series) Price Books - Refer Back To. The 5F1 Champ Amplifier Clean Schematic. ) My point is, the bottle shape has MUCH less to do with the sound of the finished amp than does the circuit as a whole. Re: 6550/KT88 bias - [email protected] 4 could be used to indicate a quiescent bias current indication. As a result, KT88's and 6550's are produce cleaner tones and have low distortion, making it popular amongst bass amplifiers and high end audio applications. "You measure the output transformer's voltage drop and. PDF format. Enter the KT120, the most powerful tube in the 6550/KT88/KT90 family. - Maybe I should divide this "chart-calculator settings" by 2? But why?. --The Cathode bias resistor (Rk) All tubes require the grid (signal input) to be negative in respect to the cathode. The chart also lists the 6AG7 as good for 7. B&K “Dyna-Quik” model 700 combination mutual conductance and emissions tube tester. But switching the KT88's for the 6550's isn't going to help the bias issue, but it will sound different. The fully regulated version outputs 65 watts/ch from about 26. 495,-- SPIRIT III Integrated or Power amplifier; 2x55W Pentode or 2x35W. Most tubes are somewhere in between. In the JD-1000P Level-2 mod we do the following [retrofit $1,000 + frt to your amp, New modified units are $2,790 + frt]:. The KT88 also can handle larger plate voltages, up to 800 volts. It is one of the largest tubes in its class and can handle significantly higher plate voltages than similar tubes, up to 800 volts. There are many pentode good for audio amplifiers but the most common in the current. It was originally produced for players who needed more stage volume and sported a full 200 watts powered by KT88 power tubes. It is a mid-range sweep that offers many variations on the Orange sound. 495,-- SPIRIT III Integrated or Power amplifier; 2x55W Pentode or 2x35W. Hickok always listed the 6550 under KT88. Browse Gallery of Mcintosh 6l6 pictures, images, photos, GIFs, and videos on imgED. 95 11 product ratings - Dual Bias testing probe tool 1968 Marshall Major Plexi 200 Watt KT88 Genelec. As a drop-in to existing 6550/KT88 amps, the KT120 is impervious to overload, delivering peak power with extreme reliability and almost infinite tube life. So use that setting as your base. You want to bias so that the tubes are running between 50% and 70%. The KT88 is based on the 6550 but even more refined and boosted. There are two reasons for the specified value of the grid resistor under the two different operating conditions - one that is described in most comprehensive texts about valve amp. Typically this is negative 12volts for a EL84, -35 for a EL34 and -50 volts for a KT 88. Variation in bias voltage at a given plate voltage really doesn’t have a great effect on peak RMS power output. Before insert KT88 check the bias voltage on grid setting the trimmer for the max negative voltage. Factory settings for 6L6 at either TEST POINT is 72mV, EL34 = 76mV, 6550/KT88 = 84mV. Each tube sample used for comparison was chosen because it measured in the middle range of idle plate current draw at the same operating point set by a Maxi. Groove Tubes Cross Reference Chart Groove Tubes Part Number Original Part Number GT-6L6B Sovtek 5881WXT GT-6L6S JJ 6L6GC GT-E34LS JJ E34L GT-EL34R Electro-Harmonix EL34. When replacing tubes, remove only the rear cover. Specially designed heat dispersion wings on the plate add more performance, stability and allow plate dissipation up to 50 watts. 6SL7-GT (same basic data applies to6188, 6SL7-WGT, also, except for filament voltage, 12SL7-GT) ForResistance Coupled Amplifier Chart, click here Page1, Page2, Page3. If you buy a new Fender amp the first thing you must do is bias it as they set them really cold at the factory for the 5 year warranty. The amp tech asked what I'd like the amp to be biased to. Rebranded tubes just means that they will be more expensive. You can find kits in the online store! In case you have heard horror stories about the metal bases being connected to a pin and causing shorts, the culprits are the sovtek KT88 and KT66 tubes. The Tube Type parameter allows you to select from common power tube types: 6AQ5, 6L6/5881, 6V6, 300B (triode), 6550, 6973, EL34/6CA7, EL84/6BQ5, KT66, KT77, KT88, 5881 and 6L6GB. If you care about tone, re-tube with Tung-Sol. Tubes are tested either in the upper “quik-check” section using multiple tube sockets wired in the most popular pinout arrangements, allowing the mutual conductance (Gm) of most common “TV type” tubes to be measured; or the lower “switch” section allowing other less common tubes to be tested in. control stands for Frequency Analysing Control. Class A operation is often found in high-end. These are the older cousins of today's MC-275s, which Mac has just re-introduced as a set with a 60th aniversary C-22 preamp. It looks like that particular amp was intended for KT88 with a hot-ish bias; the grid leak resistors look to be 100k, which complies with the Penta limit, but not other makes, eg EH, but it isn't usually a problem unless the tubes are run very hot. Unique multi-section design. a push-pull amp. Plate Voltage mA: Calculate Plate Dissipation Based On Plate Voltage And Cathode Current Readings. 5 Watts out up to 10 MHz. wagneronline. Sound I am emphasizing again that my impression is based on SR1a which Aegir isn’t recommended to drive (even Jason mentioned so!). KT88-STR is the model. Guitar amplifier parts, guitar amplifier tubes and guitar amp tubes 12ax7, 6v6gt, EL84. It is unique in the fact that it shows you both the plate current and plate voltage simultaneously and it is completely self-contained with no switches, knobs or batteries. As this can be hard to quantify, most premium preamplifiers in this price range simply reveal a level of musical nuance that lesser models do not. 845 Tube Amplifier Schematic. Most manufacturers state the maximum power the valve can dissipate is 30 watts. When the grid bias is properly set, the tubes are balanced in the circuit and produce a clean, powerful signal. There are many pentode good for audio amplifiers but the most common in the current. TV and RADIO Scopes enable you to spot all tube troubles in a jiffy. Most of them show these audio beauties used in the push-pull configuration in order to obtain the greatest efficiency and the most power output. What has to do with bias is that there's a non-stock adjustment pot on the back panel clearly labelled "HUM". ” For full knowledge go through this tutorial of amplifiers. kt88/6550 is a different animal, look for a little over 80 watts a pair. 1kHz distortion reaches 1% @ ≈55W. --The Cathode bias resistor (Rk) All tubes require the grid (signal input) to be negative in respect to the cathode. are the KT88, KT100, KT120 and KT150 Tubes safely interchangable generally speaking in a well built tube amplifier? The KT120 and KT150 are both pentode devices and the KT88 and KT100 are described as beam tetrodes so no, I wouldn't think these can be easily interchanged even though the data sheets have the same "pin-out". I do know the bias current requirements for the 6550's, KT88's & KT90's when I was using Manley monoblocks, which required individual biasing. When driven close to its maximum output, the bias will change several volts, becoming more negative by roughly four to six volts. Lee's board "Tube Circuits" on Pinterest. 8Pin Valve Tube Socket Cathode&Plate Bias Current Probe Tester for 6L6 EL34 KT88. The item “Vintage McIntosh MC-275 Stereo KT88 Tube amp with a cage” is in sale since Monday, May 11, 2020. If memory serves, the difference was the first two letters in the set up--for the filament. Size 8-3/4"H, 19"W (for rack mounting) and 7-3/4"D. Many affordable options are available on eBay. By using a very high value grid resistor and a coupling capacitor from the previous stage, stray electrons from the space charge surrounding the cathode are collected by the grid, and cause a voltage to appear. Back panel has external switching jacks for channel-solo-reverb (footswitch included), parallel effects loop with "mix" control, Bias Switch for EL34 and 6L6 power tubes (a new feature added with the Series 2 models), 8-4-4 ohm output jacks, and slave output. My recommended bias measurement method is the "Output Transformer Resistance Method. As a result, KT88's and 6550's are produce cleaner tones and have low distortion, making it popular amongst bass amplifiers and high end audio applications. kt88/6550 is a different animal, look for a little over 80 watts a pair. CHARTS, - total value $3. 0 Reviews Poster/Wall Chart;. For 420 to 440V dc B+ (required for cathode-bias amps: 350V anode voltage, + 70-90V of cathode bias voltage) then the power transformer secondary must be about 460V rms for choke-input design. Audio Compressor Schematic. Meter and roll chart are backlit…. The Tube Type parameter allows you to select from common power tube types: 6AQ5, 6L6/5881, 6V6, 300B (triode), 6550, 6973, EL34/6CA7, EL84/6BQ5, KT66, KT77, KT88, 5881 and 6L6GB. Lots of people hold the view that you should not use chinese KT88 tubes and that their use leads to different problems in many units. The 6V6 is only good for 11 Watts up to 10 MHz, like the 6L6. B iasing by negative grid voltage is highly inaccurate because the same grid voltage can produce drastically different plate currents in different tubes of the same type. The new KT120 has 50% more power than the KT88 tube. Also the most common electrical circuits are given for KT88 and 6550. Although a fair amount of detail is included, this is more a summary of the major developments rather than an exhaustive list of every project covered by the specialist press over the years. STANDBY, measure and set BIAS INSIDE 2 or BIAS OUTSIDE 2 located below the test points. SCHEMATICS AND LAYOUT DIAGRAMS Here are hundreds of original Fender schematics and layout diagrams, available for free viewing and download. This amp does not have user-adjustable bias settings, a common feature of most all Mac amps. The KT88 was invented by Marconi-Osram Valve Co. These are invaluable reference tools if you are digging around inside of your vintage Fender amplifier. 42 mV is within the bias range for 6550s. Facebookpräsenz zum Blog philosophia-perennis. RE: my bias is running away on one side even with the bias backed all the way off on that side! - Jonesy 05:46:38 07/24/20 RE: my bias is running away on one side even with the bias backed all the way off on that side! - immatthewj 10:35:27 07/24/20 RE: my bias is running away on one side even with the bias backed all the way off on that side!. I've been using the EH KT-88s and the older EI KT-90 Type IIs in my Mac MC-75 monoblocks. Search the history of over 446 billion web pages on the Internet. ” Example: the Euro Blue and Red models are based on the Bogner Ecstasy 20th Anniversary model, which is an amplifier with 6L6 tubes. The purpose of this KT88 / KT66 /6550 / KT90 / KT120 page is to give an overview about what KT66, KT88. Bias is a negative voltage applied to a power tube's control grid, to set the amount of idle current the tube draws. It was originally produced for players who needed more stage volume and sported a full 200 watts powered by KT88 power tubes. This paper charts the course of Do-It-Yourself hi-fi in the UK. (KT88, KT120, and KT150 pentodes can also be used, to respectively provide 40Wpc, 44Wpc, and 48Wpc). The KT88 is based on the 6550 but even more refined and boosted. The new $10,000 Sigma 170i iQ represents the lowest cost VAC amplifier to date but includes the company’s continuous automatic bias system and can deliver a healthy 85W per channel from its quartet of KT88 power tubes. Readouts come via two high-quality 3" diameter metal and glass analog milliamp meters (100mA max). They use a fixed resistor soldered into the. The latest Lifestyle | Daily Life news, tips, opinion and advice from The Sydney Morning Herald covering life and relationships, beauty, fashion, health & wellbeing. Vintage McIntosh MC-275 Stereo KT88 Tube amp with a cage Up for sale is an excellent original condition McIntosh MC-275 Stereo Tube Amp. 036 or 36 milliamps Most 50 and 100 watt amps using these tubes will have between 450 to 480 plate volts so even if you do not measure your plate voltage you will find that a setting between 35 to. Tech stuff aside, the KT88 is a gorgeous sounding tube. KT88 Author: M-O Valve Subject: JA-FP-2000-10-01 Created Date: 10/1/2000 7:35:29 PM. Ditto for Mesa. The OP’s amp can accommodate either an El34 or Kt88 tubes and these aforementioned bias setting are also quoted in the OP. The purpose of this KT88 / KT66 /6550 / KT90 / KT120 page is to give an overview about what KT66, KT88. This calculator is for a single tube. "Bias" in this context refers to the amount of voltage held on the grids of the output power tubes. This article describes the basic functional principles of valves, as they developed from the discovery of the behaviour of free electrons in a vacuum, to devices that could amplify and generate electrical signals, coming into mass market use in the early 20th century. STANDBY, measure and set BIAS INSIDE 2 or BIAS OUTSIDE 2 located below the test points. As this can be hard to quantify, most premium preamplifiers in this price range simply reveal a level of musical nuance that lesser models do not. According to the manufacturer, the input stage’s four inputs are designed for use with sources of 250mV. The Naylor amps were all designed around the Sovtek 5881 and 12AX7WB tubes so if you use those tubes you will get the true original Naylor tone. 6550/KT88 SET amp aka "Uber Beam Machine" current and bias voltage) from other diy'ers. txt) or read book online for free. In our previous article, we have introduced you to amplifiers and its types. McIntosh amplifiers blend eye-catching aesthetics, power and sonic integrity in a way that has been capturing the imagination of music lovers and home theater enthusiasts for decades. Back panel has external switching jacks for channel-solo-reverb (footswitch included), parallel effects loop with "mix" control, Bias Switch for EL34 and 6L6 power tubes (a new feature added with the Series 2 models), 8-4-4 ohm output jacks, and slave output. What has to do with bias is that there's a non-stock adjustment pot on the back panel clearly labelled "HUM". Power/Bias - 115 V Pri. The Misner Factor by Robert Alexander. 5% total harmonic distortion or up to about 50W at low distortion in hi-fi applications. A GZ34 rectifier tube was added which dramatically improved sustain. a push-pull amp. Tubes: The 2150 tube complement consists of four VHT Special Design KT88/6550As, two 12AX7s, and two 12AT7s. A Dr Z Route 666 uses an EF86 in V1, and LTP and a pair of KT66 (UL, fixed bias with 440 on the plates, grids @ -50V) with a GZ34 rectifier. All of my measurements (as well as those shown on the chart) suggest that the power tubes are rated based on the Grid voltage required to obtain and maintain a constant 16. Name Last modified Size Description; Parent Directory - qso-dp1pol-antarctica-2359ut-7mar2003-14253khz. A small Fender amp with one 6V6 and 3 watts is operating in class A. the chassis is setup for 4 6l6 tubes. Kt88's usually have 100k bias resistors for a pair. As a result, KT88's and 6550's are produce cleaner tones and have low distortion, making it popular amongst bass amplifiers and high end audio applications. What are you talking about? We are talking a EL34 to KT77 switch. Alas, the amps were not up to the task of driving the low impedence load of the stats and have since been sold. Set up chart for the 7-A and accompanied 10-D loudspeaker. Single-ended EL34 amps are fairly rare in the guitar world, for a couple reasons (one being SE amps are usually designed to be less powerful so it makes sense to use a smaller tube, and also output transformer for SE are much heavier and expensive so the smaller the "better"). The plates feed the bridge directly. • STAX Pro Bias 5-pin EarSpeakers output x 2 • XLR input x 2, RCA input x 1 • Auricap capacitors for interstage and output coupling • Mills and Kiwame resistors • Balanced smooth potentiometer • Anodized aluminum chassis, available in black or silver • Self-biasing with compatible tubes [chart]. How to Test Vacuum Tubes. Surprisingly, the 6AQ5 is good for 54 MHz and 11 Watts Output. It is also worth remembering that the 1 ohm resistors will not be exactly the same value as they have a tolerance on them. In German: Single Ended: 48. 12AU7 tube is a medium gain dual triode. For example, suppose the grid bias is -12 volts at no signal. Wide asortment and models up to 560 V. The basis for this amp started out as a post in a thread on the DIY Audio Projects Forum site. A Wrong Way to The Top. Just something to consider. , 572B-TAY-VERT - Transmitting Tube, Taylor (Vertical Mount Only), 572BMP-RFP Transmitting Tube, SELECT Matched Set of 2, RF Parts, SPRCLP-L Spring clip, large. TY - paper TI - Complete Journal: Volume 27 Issue 5 SP - EP - PY - 1979 JO - Journal of the Audio Engineering Society IS - 5 VO - 27 VL - 27. 31 1 speaker load 680Ω, 2W 282-680-RC 0. I have seen 150k and 220k as well. 9780781773478 0781773474 Hip and Knee Inflammations Anatomical Chart, Anatomical Chart Company 9780697216229 0697216225 Fundamentals of Chemistry Tr, Goldberg 9780321437105 0321437101 Amer Govt - Policy & Divider Not Uniter Pkg 9780790101316 0790101319 Screech! (Guider USA), Jennifer Beck 9780131502093 0131502093 Legl Termlgy&Flash Crds, Brown. 4 volts press P4. Like the reverb, it is not in the signal path, manipulating the bias voltage on the power tubes instead. 5 Watts out up to 10 MHz. A amp biased too cold sounds worse than one biased too hot IMO. An icon used to represent a menu that can be toggled by interacting with this icon. The Naylor amps were all designed around the Sovtek 5881 and 12AX7WB tubes so if you use those tubes you will get the true original Naylor tone. ) will change optimum plate to plate load impedance. The module doesn’t “know” is if it’s adjusting the bias on a 6L6, 6550, KT150 or any other tube. Tube Type. Type II/High/CrO2 was coated with chromium dioxide particles and was used with a higher bias setting. Sound I am emphasizing again that my impression is based on SR1a which Aegir isn’t recommended to drive (even Jason mentioned so!). Some amazing amps from Blackstar from Winter NAMM'18. In this article, the 6550 is used in a clean, sweet-sounding, single-ended design. This banner text can have markup. Biasing an amp requires some knowledge of tube amp circuits and experience with high voltage. Amplificatore a valvole - Italian DIY SE amp with EL34 or KT88 AWG to Metric Conversion Chart - For converting speaker cable Self Bias- DIY Ultra-Fi Audio. This feature really makes the tester a joy to use in darker rooms. Readouts come via two high-quality 3" diameter metal and glass analog milliamp meters (100mA max). Enter the KT120, the most powerful tube in the 6550/KT88/KT90 family. The shield of the 6V6's is connected through a resistor to the anode, so that it has a fraction of the anode voltage. It looks like that particular amp was intended for KT88 with a hot-ish bias; the grid leak resistors look to be 100k, which complies with the Penta limit, but not other makes, eg EH, but it isn't usually a problem unless the tubes are run very hot. Now that being said the 6550 and the KT88 are similar electrically and people inter-change them quite often. NOT EVEN CLOSE. This would give about 6 watts output but the load needs to be around 2500 ohms. For a quick test, inspect the tube for signs of damage and listen to the sound it makes. Specially designed heat dispersion wings on the plate add more performance, stability and allow plate dissipation up to 50 watts. The line-only integrated amp can also be supplied with an optional phono stage. Bias is a negative voltage applied to a power tube's control grid, to set the amount of idle current the tube draws. If you have a replacement application in mind, a really, really good guess is the size that is in there now, plus a bit if you want to make it better some way. Kessler is not exaggerating. 15A 291FX: GENERIC 120V @ 60 Hz 640Vct @ 518 mA 60V Bias 6. A small Fender amp with one 6V6 and 3 watts is operating in class A. Re: 6550/KT88 bias - [email protected] Name Last modified Size Description; Parent Directory - qso-dp1pol-antarctica-2359ut-7mar2003-14253khz. The new KT120 has 50% more power than the KT88 tube. SEPTEMBER PROJECT SALE - take 11% off all Amp Kits with coupon code SPS20 (starting September 1, 2020). I also read somewhere that EL34's should dissipate 15-18 watts at idle (the math for 545 volts of B+ equates to 30 mA of plate current). bias; BIAS Amp; BIAS Amp 2; Bias Amp 2 LE; BIAS AMP 2 Mobile; BIAS FX 2; Bias FX Mobile; BIAS FX2; BIAS Head; BIAS Modulation; biasing; Biffy Clyro; Big Dist; Big Fella; Big Fish Audio; big goat; Big Muff; Bigsby; Bigsby B-50; Bigsby B5; Bill Finnegan; Bill Lawrence L-500; bill putnam mic collection; Bill Ruppert; Billie Joe Armstrong; Billy. Bias is the negative voltage we put on the control grid of a tube to make the tube conduct the current we desire. The Eurotubes "Pro One" Bias Probe is an "all in one" bias probe for octal tubes including 6V6's, 6L6's, KT66's, EL34's, E34L's, KT77's, 6CA7's, 6550's and KT88's. Making a B+ using raw dc with no choke, and using electrolytic capacitors is not good enough, and again 300B will give no real improvement over KT88. The Rolodex-style tube chart inside the unit has no listing for either KT88 or 6550. Tested for shorts, balanced triods, audio test so you get the best of the best. control stands for Frequency Analysing Control. au Electronic Components Electronic Components PCB Br ead Boar ds Cr oss-R ef er ence Da ta SEMICONDUCT OR WORLD DA T A BOOKS T able comparison chart for easy referenced data Listing is Alpha. SEPTEMBER PROJECT SALE - take 11% off all Amp Kits with coupon code SPS20 (starting September 1, 2020). beam pentode Base: OCTAL Uf = 6,3 V If = 1,6 a Typical Characteristics: U a = 250 V U g2 = 250 V I a = 140 ma I g2 = max. A KT88 push-pull pair in class AB1 fixed bias is capable of 100 watts of output with 2. A Dr Z Route 666 uses an EF86 in V1, and LTP and a pair of KT66 (UL, fixed bias with 440 on the plates, grids @ -50V) with a GZ34 rectifier. MESA/Boogie Ltd. The clean channel has an entire new boost circuit. Bias refers to the adjustment (generally in the power tube section) that controls the voltage of the grid of a tube. The maximum value is always lower for fixed bias (a separate negative supply) than for self bias using a cathode resistor and a grid resistor that connects to earth. KT90 and types and brands exist, and what you can do with the this tube. B iasing by negative grid voltage is highly inaccurate because the same grid voltage can produce drastically different plate currents in different tubes of the same type. The award winning Cronus Magnum has garnered an enviable reputation in the high end audio world. are common guitar amplifier power tubes, and are all easily biased with this method. Weight 135 lb. Make fix -it jolis easier, faster. Posted on December 1, 2001 February 5, 2015. The simplest way to achieve this "negative bias" is to raise the cathode voltage sightly--that's the job of the cathode-bias resistor. 66: JTM45 MKIV 1962: 7304: Black Levant: 784-103: 1202-55: U Frame: Aluminum (End Blocks) Bulgin: 8,16,100V Jumper Style: Yes. I have used a tube chart designed for the Hickok 6000 dated 1971. balance potentiometers between KT88/6550’s should be set in the mid-position. KT88 BEAM POWER TETRODE T he Svetlana™ KT88 is a beam power tetrode having a large standard octal base and glass envelope. 3 mA DC (0 mA AC) cathode current flow for the KT88 and 6550 tests (and 18. A small Fender amp with one 6V6 and 3 watts is operating in class A. Illuminated roll chart features a smooth action thumbwheel drive. The shield of the 6V6's is connected through a resistor to the anode, so that it has a fraction of the anode voltage. ) My point is, the bottle shape has MUCH less to do with the sound of the finished amp than does the circuit as a whole. When driven close to its maximum output, the bias will change several volts, becoming more negative by roughly four to six volts. com 19:39:47 01/10/06 (1) Re: 6550/KT88 bias - Kajtsu 05:36:06 01/11/06 ( 0) Looking for Tungsram 6922's - jim94025 09:42:57 01/07/06 ( 1). i for now want to use a 12ax7 since there is a 9 pin socket already. There are two reasons for the specified value of the grid resistor under the two different operating conditions - one that is described in most comprehensive texts about valve amp. If you care about tone, re-tube with Tung-Sol. I would hazard a guess that a KT120 tubes bias is 500mv, but I cannot confirm this. It reduces the available power of the amp and runs the tubes hard, meaning shorter tube life and failures via "shorts". Make fix -it jolis easier, faster. If you are uncertain that you are experienced enough to work on a live high voltage amp, please take your amp to a professional to get it biased. Supplier of vacuum tubes for guitar, audio, and recording applications. Set up chart for the 7-A and accompanied 10-D loudspeaker. The amplifier class is selected by biasing the control grid of the output tube into the range to select the appropriate conduction cycle. SE 6L6 Schematic. It's still valid to try a cooler bias and so benefit from a longer tube life etc. the chassis is setup for 4 6l6 tubes. It is important to bias a tube to stay within its rated dissipation. TV and RADIO Scopes enable you to spot all tube troubles in a jiffy. Measuring Device For Bias Four octal socket adapters, For the control of the retirement, At 6L6GC, 6550, EL34, 6V6 GT, 5881, KT88, KT66, KT90, KT100, 7027A, With illuminated display, Made in Germany. Preamp being RCA MR 6SJ7GT, Sylvania 6SJ7WGT, RCA red can 5693. The basis for this amp started out as a post in a thread on the DIY Audio Projects Forum site. Bias adjustments Left bias adjustment: Controls the bias of the left output tube, V5 (See tube chart on pg. The simplest way to achieve this "negative bias" is to raise the cathode voltage sightly--that's the job of the cathode-bias resistor. 5A FUSES: Fusing for the two inside pair and two outside pair of output tubes. This article describes the basic functional principles of valves, as they developed from the discovery of the behaviour of free electrons in a vacuum, to devices that could amplify and generate electrical signals, coming into mass market use in the early 20th century. are common guitar amplifier power tubes, and are all easily biased with this method. com provides easy to find states, metro areas, counties, cities, zip codes, and area codes information, including population, races, income, housing, school. Single-ended EL34 amps are fairly rare in the guitar world, for a couple reasons (one being SE amps are usually designed to be less powerful so it makes sense to use a smaller tube, and also output transformer for SE are much heavier and expensive so the smaller the "better"). 20th Anniversary Shiva - comes with a pair of KT88’s and the amp is rated at 90 watts. If the bias is set too low the sound will be distorted, but the tubes will last a long time. This webpage offers two ways to calculate tube bias and plate dissipation. If we set the bias so the tubes are at their upper limit, the sound quality might be lovely, but the tubes won’t last very long. Make fix -it jolis easier, faster. The new $10,000 Sigma 170i iQ represents the lowest cost VAC amplifier to date but includes the company’s continuous automatic bias system and can deliver a healthy 85W per channel from its quartet of KT88 power tubes. I'm not going to go into the full rundown here, especially with plenty of info on Louis' Site ( click here ) and a review by Guitar Player mag. The chart shows that the current price of soybeans of nearly 35 reais per bushel is greater than all of the previous price spikes -- including the 2007/08 and 2012/13 Everest-like peaks. txt) or read book online for free. Speaker: 13. They made the Marshall amps sound different. It's still valid to try a cooler bias and so benefit from a longer tube life etc. My recommended bias measurement method is the "Output Transformer Resistance Method. 100 watts with two KT88 is also push-pull. Run in class AB1 push/pull, a pair of KT88's are capable of producing 100 watts at 2. Size 8-3/4"H, 19"W (for rack mounting) and 7-3/4"D. Search the history of over 446 billion web pages on the Internet. are the KT88, KT100, KT120 and KT150 Tubes safely interchangable generally speaking in a well built tube amplifier? The KT120 and KT150 are both pentode devices and the KT88 and KT100 are described as beam tetrodes so no, I wouldn't think these can be easily interchanged even though the data sheets have the same "pin-out". PDF format. A KT88 tube has a recommended bias at around 380mv-420mv. and several designs were presented using various dual triode tubes. Its exclusive screen-grid radiator fins reduce a major source of. When replacing tubes, remove only the rear cover. See more ideas about Valve amplifier, Vacuum tube, Electronic schematics. Of course the adapter you are using should work using this chart also. Bias Oscillator: 65 kc (voltage or current internally adjustable to match any head). This is the perfect table for vinyl newcomers; anyone can set it up. If you want to bump the bias up a little higher, you are welcome to do so but the amp won't really sound any better and tube life will go down. Each tube sample was installed in the same custom built, fixed bias single-ended guitar amplifier (see schematic) with a Fender black face style preamp circuit. You'll need a 1-ohm resistor for each power tube in the amp. Solid state rectifier bridges. ALL THREE (worth $2. Another interesting "feature" is the way the 6N7 is used in the input circuit. The real cure would be to change out the BIAS range resistor so you could set the bias properly. Otherwise, you DO NOT need to worry about small deviances from the manufacturer's recommendations. Soon after came the late ‘50s Gibson-inspired bias-vary tremolo, which begs the question why anyone would ever use any other method. Now that being said the 6550 and the KT88 are similar electrically and people inter-change them quite often. I would hazard a guess that a KT120 tubes bias is 500mv, but I cannot confirm this. Run in class AB1 push/pull, a pair of KT88's are capable of producing 100 watts at 2. thetubestore. A98 11A I believe is just manufacturing and batch number data. ram: 2015-06-03 22:43. the chassis is setup for 4 6l6 tubes. I have been enjoying for more than a year now the Amphion Argon 3L (floorstanders, but otherwise extremely similar to the Argon 3 bookshelves), driven by a Copland CTA-405 (full tube, KT88, 50 wpc), and all I can say is that the result is simply amazing (specially considering the price when compared to some more. I am wondering what is the problem with using 220k since my current build uses a LARMAR Master which is just over 225k. It reduces the available power of the amp and runs the tubes hard, meaning shorter tube life and failures via "shorts". By using special explosion–forged plate material, GE was able to increase the 6550As rating from 35 to 42 watts of dissipation, matching the British KT88. 06% and 20 HZ being. The chart below compares the distortion ratio at 50Hz of two mic preamps: a Dbx 386 and an AEA TRP. "Bias" in this context refers to the amount of voltage held on the grids of the output power tubes. Due to the combination of low grid-plate capacitance and medium gain, 12AU7 is well suited for use in audio voltage amplifier with an extended frequency range. Jumper Style: Perforated: Chrome Bat. As a drop-in to existing 6550/KT88 amps, the KT120 is impervious to overload, delivering peak power with extreme reliability and almost infinite tube life. Hickok always listed the 6550 under KT88. Humble Beginnings. Designed for endurance and longevity for application in the audio industry. An icon used to represent a menu that can be toggled by interacting with this icon. Their sales pitch is that they spec them tightly from their suppliers, and match/code power tubes to that if you replace like with like you can in theory get away without re-biasing the amp. The difference in sound between a conservative setting and ~28W dissipation is pretty huge in my opinion. If they are 1% resistors then one of them could be 1% high and the other 1% low so there can be a variation of 2% just due to the resistors that. "You measure the output transformer's voltage drop and. Groove Tubes Cross Reference Chart Groove Tubes Part Number Original Part Number GT-6L6B Sovtek 5881WXT GT-6L6S JJ 6L6GC GT-E34LS JJ E34L GT-EL34R Electro-Harmonix EL34. Meter and roll chart are backlit…. Also the most common electrical circuits are given for KT88 and 6550. In this article a typical single ended tube amplifier circuit has been conversed. Evatco an help you find the right valve / tube for you amplifier, We carry thousands of tubes and all the parts you would ever need to design and build a new valve amp. I don't know what's a good bias, but I suggested 44 mA, as that's lower than some 6550 bias settings I've seen online, and at the same time isn't very low. Right bias adjustment: Controls the bias of the right output tube, V4 (See tube chart on pg. A98 11A I believe is just manufacturing and batch number data. Positive Grid BIAS Mini 300W Bass Amp Head. Pat was blown away with the build quality on these amps, and looking at the plate voltage which was running at 780volts, thought it would be cool to put some KT88s in. Each stage can be eitehr single ended or push-pull and bias can be adjusted on the fly to generate different levels of odd/even harmonics. Search the history of over 446 billion web pages on the Internet. To create a push pull amplifier is possible to use triode and pentode but obviously to test many configurations like the ultra linear we need a pentode. The simplest way to achieve this "negative bias" is to raise the cathode voltage sightly--that's the job of the cathode-bias resistor. New high. If you are uncertain that you are experienced enough to work on a live high voltage amp, please take your amp to a professional to get it biased. and British musicians in favor of which are modified and uprated in power dissipation rating from their KT88 and EL34 prototypes. The basis for this amp started out as a post in a thread on the DIY Audio Projects Forum site. In general, the KT88 tube has a magical mid-range similar to the smaller EL34 tube , but with low and high end extremes that reach much further. How to Test Vacuum Tubes. Bias controls: (left and right sides) TUBES: 8-KT88/6550 output, 4-12AX7A, 2-12AT7. KT88 Author: M-O Valve Subject: JA-FP-2000-10-01 Created Date: 10/1/2000 7:35:29 PM. 0: 6SN7 (2), KT88 (2) 230: Audio Amplifier with transistor [In Dutch] Schematic Only. Tubes: The 2150 tube complement consists of four VHT Special Design KT88/6550As, two 12AX7s, and two 12AT7s. 42 mV is within the bias range for 6550s. The KT88 also can handle larger plate voltages, up to 800 volts. 550 VDC bias point (for each output tube) for the ST-120 is a nice compromise for good sound and good tube life. The article also discusses a few enhancements in the form of. Run in class AB1 push/pull, a pair of KT88's are capable of producing 100 watts at 2.
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