7591 output transformer. Original mounting screws and nuts included.

7591 output transformer 18m9252 Triad Magnetics N68x Isolation Transformer; Hashimoto H-203S Output Transformer 7W Single 2. Prices include (4) new JJ7591 power tubes (2 matched pairs) and (2) NOS 6GH8A triode-pentodes. EXCELLENT CONDITION. I decided to save money and try out the Electro Harmonix 7591's. Has double set of output leads just like the original. Am I correct? Instead of using 7591 in the project, I was considering using Soviet 6P3S-E tubes in pentode mode. The first is a redesign of the output stage with the Bendix 6384 tube replacing the 7591 standard audio tube. From his measurements, they're about 5K primary plate impedance, with approximately 50% UL taps (he added these) measured by WINDINGS (not impedance). This neglects the 270kΩ AC loads of the power amp grid stoppers, which create an AC load line that is rotated slightly clockwise around the DC operating point. Vintage working genuine Fisher X101D output transformer for 7591 vacuum tubes Removed from a working amplifier. Fender Output; Marshall Output; Vox Output; Guitar Amp Chokes. Can someone educate me? I'm new to all this tube amp stuff. These came from a Hammond AO-70 amplifier. Price $125 + $15 Shipping. The result was wonderful. Jun 12, 2017 · Hi Gadget, I try to find a data book example which operates the tube near its maximum power output. Mar 20, 2017 · The 6L6 and 7591 tubes both use a 6. The way the Sansui 1000A chassis is built the left output transformer has a set of 7591's on each side of it mounted way to close. Upon checking the 7591 power tubes, i noticed that i'm not getting any voltage on the grid at pin 5. 1960 VINTAGE. Jul 12, 2020 · Warning / Caution: This amplifier has Dangerous Voltages, both at the Mains Power side, and at the B+, tube plates, tube screens, and output transformer primary, etc. You end up with a Power Oscillator, instead of a Power Amplifier. The results were pretty disappointing. Will one of the Hammond 1650 series work? Jul 19, 2024 · 1. You can use it to build a MA230 power amplifier section or McIntosh MC225 clone. Brand New. Nov 19, 2014. 2 SECONDARIES 4 AND 8 OHMS. The 6384 matches well with the fisher output transformer and fits well in the Feb 11, 2022 · Running the 6L6s in the DR, because the transformers don't have the full output needed to drive the 6L6s safely, is done by biasing the 6L6s somewhat "cold. After replacing it, tubes and caps I noted that it still ran warmer than the other. They were about 7. The X-202-B and KX-200 had cutouts in the chassis that one endbell sunk into for miniaturization purposes. Oct 11, 2007 · Something you should seriously consider whether you're planning on making some upgrades to the present components, or not. dougstubes. The newest development of SILK Push-Pull Output Transformer is the Symmetrical Winding Technique which maximizes the balanced magnetic coupling in both push-pull coils. The Size/weight, and the fact that apparently this power transformer was supposed to run additional loads, probably means it is way underutilized just powering the stereo amp. com. Maybe a 12at7 or 6u8 front end. This is a Class A, single tube(7591) per side stereo amp, BUT. Power transformers, Output transformers, Chokes, tube drivers. I have 2 pair of these, pick how many you want Feb 3, 2014 · Ok guys I picked up a AA-100 on the cheap, complete and in good physical conditionwell sorta lol. Ratings are identical, and the only electrical differences are very, very minor differences in interelectrode capacitances. MADE BY SCHUMACHER. An replacement Dynaco ST-70 PS trans should give you the B+ you need and bias supply power for alt. Nov 9, 2014 · In addition to the restoration it needed new output tubes. They're Sherwood 5500 type, 7591 output originally (the 64 watt version). Jan 8, 2025 · HERE IS A NICE MATCHING PAIR OF VINTAGE TUBE AMP OUTPUT TRANSFORMERS. If the Output Tubes actually deliver 10 Watts to the primary; the output transformer secondary only delivers 8. YMMV. The power tube circuit and transformers are taken from an old Eico Stereo 40 hi-fi amp. Feb 26, 2009 · How much power a pair of tubes can generate depends on the Plate voltage, the Screen Voltage, and the primary impedance of the output transformer and other a few factors in the circuit. Aug 4, 2021 · I cannot find any good used ones or Hashimoto replacements, so I am looking at the Hammond 1650 series. 71%thd. 4A but honestly I would love to keep the 7591 tubes if possible Jun 19, 2018 · 7591 was one of the last output tubes ever designed which means it incorporated the greatest amount of prior knowledge & experience of tube design & engineering at that point. The 7591 has been called half a 6550! Jul 5, 2013 · I would like some advice regarding the output impedance of a push-pull pair of cathode biased 7591's at 375vdc. As far as doing damage to your amp using the current production 7591's,it should be fine as long as your plates arent glowing May 20, 2013 · The KX-200 reuses the original 7591 output transformers that were developed for the X-202-B. There are four of them in the 1000A because each stereo channel uses two tubes: one to "push" (amplify half of the AC waveform) and the other half to "pull" amplify the other half of the AC waveform). Free shipping on many items | Browse your favorite brands | affordable prices. Dec 9, 2007 · A 12 volt transformer would give you about a 10% reduction. They work great as EL84/6BQ5 to 8 ohm output transformers. Echo Twin $ 114. Nov 25, 2023 · A "Replacement" output transformer that has different leakage inductance between the windings is going to need special compensation of lead and lag in the various stages, or . Apr 16, 2015 · It's loaded with that typical AMAZING Gibson reverb circuit and unlike it's smaller brothers and sisters, it uses a pair of 7591 output tubes with fixed bias and rather than using a phase inverter circuit it simply uses an interstage transformer driven by a 12AU7. In my experience the 7591/7868 is in between the 6V6 and 6L6 for output power, but since it is easier to drive the preamp and phase inverter don't have to amplify as much, and the 7591/7868 are very harmonically rich with an easy breakup and lots of touch response. In the right equipment, it's difficult to criticize the sonic capabilities to be had from quality set of 7591. This is one of the coveted silver ones also! This powered thirty tubes including a pair of 7591, two 12AX7, three 12BH7, two 6BA6, twenty 12AU7's and a 5U4G rectifier. A 6L6GC can be used in a 7591 circuit,but not the other way around. tubes. The C-core Lundahl LL1620/PP output transformer may also be an excellent alternative and a pair are being sourced for testing from the US distributor. . The paintwork is nicely done, it has a retro vibe but the finish is far better than any old amp that I’ve seen. MADE BY SCHUMACHER TRANSFORMER. There’s a switch between the two output transformers to set for 4 or 8 ohm speakers. PULLED FROM A SINGLE ENDED 6V6GT STEREO AMP. Jul 12, 2020 · Compensation should be easy too, because there are only 2 stages, and the output transformer has a good hi frequency square wave response. THIS UNIT WAS PULLED FROM AN ORGAN AMP THAT USED 2 7591 OUTPUT TUBES IN PUSH PULL CONFIGURATION. 1A which is slightly above the transformer rating Changing the 7591 output tubes to 6V6 would drop the required filament current to 2. 5K/16 8 4 for HEATHKIT AA-100 HIGH FIDELITY OUTPUT TRANSFORMERS STANCOR 51-58 PP 7591 PAIR. Aug 23, 2022 · I recently acquired a very nice pair of Fisher X-200 output transformers (Fisher T908-116-1&2). The Dynaco 120, a 12 watt mono design in the Dynaco transformer catalog used one 12AX7 and two EL84's. II: 18 Watts Jul 3, 2006 · Fisher KX-200 w/ EH 7591's Running Output Transformers Hot. This makes a total of 3. For cathode biased at 450v plate voltage, the impedance jumps to 10k. Since 7591 tubes were used, I would assume they're 6. I bought it for the transformers. 34. I understand that this destroys the tubes faster as they are juiced more, but was their some sonic difference that the fisher engineers considered worth the trade off? Also I currently use Auri Caps to couple the drivers to the output tubes. I suspect the difference you are hearing is the greater efficiency of the JBL. I purchased for a project but decided not to proceed. Sponsored. Jan 27, 2025 · Hashimoto HW-60-5 Output Trans 60W 5K/16 8 4Ohm for EL-34 300B; Hashimoto HC-203U Output Transformer 20W Single 2. 00 kHz input to the primary coil, we have verified these connections for this vintage transformer: The power section consists of a pair of vintage Dynaco A-420 power transformers and Rayethon 7591 output tubes, which seems to be an uncommon pairing from any factory model. I believe changing tubes shouldn't make any difference to the output impedance. ) between pin-3 to pin-3 of the empty 7591 sockets. GregT Global output Level control, Hand-wound Triad output transformer: 8 Ohm, 4 Ohm with extension speaker out: JETTA: 30 Watts: 2 – 7591 2 – 12AX7 1 – 5AR4 rectifier: Volume, Tone, Master: Post Phase Inverter Master Volume: N/A: N/A: Metro “Zero Loss” FX Loop: Head. If putting an octal socket in then it is simpler to use the new Tung Sol 7591. Those usually exist because the manufacturers wanted to show off what their tubes could do. Possibly some voltage regulation for the screens. The original… I have a fisher 800-c with burnt primaries in the output transformers. Used – Good. 6k like the 7591::Ouput transformer OT151A used on most vintage Ampeg combos using cathode biased 6V6 and 7868 and 7591A powr tubes. These are high quality, excellent sounding Audio Transformers. (a 6. 300 Series High Voltage plate & Filament, Universal & 50/60Hz; Output Transformers. Jul 24, 2019 · I was writing a post suggesting that based on the impedance of the OPT's and the output of the Power transformer (with a doubler supply, as GordonW suggested), he use 7591's. 1 watts at 0. You can also measure the actual plate current by shunting the output transformer with a multimeter in the DC milliamps mode and use the Tube Dissipation Using Plate Current calculator. A description of each component, how they are connected and the Jun 30, 2010 · The 222/222B doesn't come up as often as the 222C/D, 233, 299C/D or LK-72 series (which all use 7591 outputs. The LM334 has a low enough burden voltage, and the 12AY7 has enough bias voltage and enough gain to give plenty of linear drive voltage to the output tubes. Plus, the four cathode resistors I installed also put a layer of protection between the output tubes and the output transformers if a 7591 shorts out. APO-RR2 quantity Ampeg | Echo Twin | Output Transformer. Hoffman Amplifiers Tube Amp Forum, 7591 PP Amp Project It has 4 7951's and 2 output transformers so it looks like I could build two amps from the parts. 10 Watt to 280 Watt Push-Pull Tube Output Transformers ; 125A-125E series Push-Pull Amplifier pricing with the output transformer options offered are shown below. Using extraordinary negative feedback to reduce distortion from transformer saturation. Here is a set of output transformers for 7591 tubes. A few years later the other output transformer shorted due to the other two 7591 tubes severely red plating. Falcon This transformer was orignally used to connect a 6L6 or 7591 output tube to a 8 Ohm speaker. 5K-5K 6L6/KT-66 6. It's the same size as the trannies in the 500-C, but the mounting hardware is different. Aug 4, 2022 · The customer ran the unit with a 10-amp primary fuse with faulty 7591's. Since they are much larger tubes than the original 7591's, they are VERY close to the output transformers. I put a D 120 in a 5E3 clone, and it is LOUD! Dec 20, 2011 · Got a pair of output transformers from BuzzK today. $140. Also if the input 12ax7 or the 12au7phase splitter are removed it still has this problem. or Best Offer +$24. This listing has ended. I personally prefer the JJ 7591S for new production as long as purchased from a tube dealer with a burn in rack so he can weed out the obvious bad ones www. Jul 17, 2017 · The other tubes are 3x 6SL7 at 300mA each, 1x 6SN7 at 600mA and 2x 7591 at 800mA each. The 6L6GC is good for 30 watts,the 7591 is good for only 19 watts max. mounting hole dimensions are 3 1/4" x 2 3/4". The 340/340B/345/380 receivers also tend to go cheap when being parted out especially if the tubes have been robbed. Then I more carefully read the OP, and saw that they were from a 7591 amp, and that the OP did not want to use 7591's. mfg and date code is 549-69-02. 20 to 26 volts peak which makes the driver stage easy. BUYER PAYS SHIPPING. I am running one of these at 484 plate volts in an EL34 output , push pull amp right now. This amp ran 3 pairs of tubes in a push/pull arrangement. I have some 7868 to 8 ohm output transformers, from organ pulls. The original transformers are rated at 6600ohms P-P, with and 8 and 16ohm output. Price is firm. Nov 5, 2012 · If your Output Transformers are indeed the ideal 6. The other tubes in the build are (2) Sylvania 6AN8A preamp tubes, (2) Mullard GZ34 rectifiers & (2) OA3 voltage regulator tubes. I-7591, 40 watt, push-pull output transformer pulled from a working organ. It came with RCA coin bottom 7591 tubes and I like 7591 tube amps, so I grabbed it for very cheap. Dec 3, 2011 · The output on mine is exactly like the schematic, although i didn't get the cab/console. HERE IS A VINTAGE TUBE AMP OUTPUT TRANSFORMER. Jun 25, 2022 · The common thread among all these is amps is that they use the 7591 power tubes. Mar 12, 2023 · Fisher receivers also used 7591 output tubes, probably a number of others as well. Made in USA The same dimensions and mounting holes as the original Fisher Output Transformers. I was thinking on building a dynaco st70 clone with these output trannies what is your thoughts guys. 6k for all fixed bias settings. This new winding scheme offers very close DCR tolerance between middel tap to both end taps which will enable circuit designer and tube amp builder to create a tube amplifier achieving super low distortion, and easier bias Sep 23, 2006 · When the 7591 output tubes are removed the amp is stable to this point and it passes a small amount of audio from the 12BH7 as it gets its b+ from the outside primary of the output transformer. Output transformer OT151A, Ot151B used on most vintage Ampeg combos using cathode biased 6V6 and 7868 and 7591A power tubes. The mains transformer I wound by hand and is still to have its cover. Original mounting screws and nuts included. Reverb-O-Rocket — OT-151A — use with two 7591 tubes — single 8Ω tap $ 151. I removed the shorted one along with its two 7591 tubes and ran it for a year or so as a mono amplifier/receiver. Power output and distortion are almost the same with a 6500-ohm plate-to-plate load. I will be using a triode electronics power tranny for this amp and the original st70 circuit no upgrades and Nov 9, 2011 · Hey Folks, I have a set of fisher output transformers. Since I have a clean slate my dilemma is what to build with them. From what I can tell the 7591 output tubes feed the transformers in a push/pull circuit. Transformers are in excellent condition and the cloth leads are not hard and crusted. Messages: 115. Jan 26, 2021 · Amorphous C-type iron core 12W10K push-pull output transformer cattle 6P1. . this was pulled from an amp thay used 2 7591 output tubes in push pull. Good shape! 8 ohms secondary and probably 6600-9000 range. Sep 29, 2016 · Unlikely it would stress the power transformer. Feb 11, 2014 · 7591, 2A3, 300B, EL34/KT-88 3. In the other thread, I complained about the output transformers, but actually, they are pretty good, too. If i could find a 7591 schematic, I could convert it over. 4k impedance. I happened to order double the parts from Mouser just in case. Oct 22, 2002 · I have a pair of output transformers meant for the Mcintosh MA230 that I'm using in a project with either the new EH 7591's or a pair of 8417's. Please see the image of an original schematic using this model, for one possible application! Using a 12V_pp, 1. Just shown is the ECC83 and ECC99 power supply. here is a nice vintage tube amp output transformer. toddbailey Active Member. Dave Gillespie called them “the biggest and best 7591 iron Fisher ever produced”. According to the DC load line, output plate voltage swing is almost 300V, which is split between the two outputs for a swing of almost 150V. Even used 7591's that are older production (pre 1970's) appear to have better performance and longevity than the new production power tubes. com is who I have used with great results. GREAT FOR REPLACEMENT OR YOUR TUBE AMP PROJECT. midwest coil. larryderouin. Adding four 7591 output tubes, in push-pull-parallel. Model 219 Amplifier with Hammond 1650PA Output Transformers: $2765 Model 219 Amplifier with Hammond 1650PAP Output Transformers (shown above) : $3125 Jun 30, 2017 · Since the specs of the 7591 and 7355 output tubes are relatively close and the Twin-Amp combo is, of course, a 2x12 with a total load of 4 ohms, one may assume the output impedance of the A18A transformer to be 4 ohms and that the 2x15 cabinet could indeed be its mate. Whomever recommend the 23% tap has a good plan. Nov 4, 2016 · Hi, I recently found a Lowry Organ amp that seems to be set up with two output transformers and seems a good candidate for a stereo power amp project. The 7591 is a power tube with more gain though, so while its power output Apr 22, 2011 · I have a Hammond AO-70 with three output transformers. I dunno, but it Apr 28, 2010 · One shorts it can take out an output transformer pretty quick. 5 dB insertion loss is noticeable. Vacuum Tube output transformer "(works with 4 or 6 output tubes 120 Watts)" Opens in a new window or tab. The RL for the test will be one-quarter of the P-P load resistance given with the example. My 140 ohm resistor is good, and i replaced the capacitor that it's coupled with. LEADS IN GREAT SHAPE. Nov 11, 2015 · What was the reason that Fisher ran the bios voltage at -17 volts on the fisher 500 and 800c output tubes. Use for: Jets, Reverberockets, Echo Twins, AC12, Gemini 1 and more. But the Dynaco repop transformers. If not, it's putting the filament transformer secondary in series with the main transformer primary, and connecting the filament primary to the line out of phase to appose. Primary output transformer impedance estimated 6500ohms P-P. Jan 22, 2008 · However, I'm back using 1962 NOS Westinghouse 7591's, 1965 Sylvania 7591A's, and 1966 GE 7591A's. Using a solid-state rectifier and adding a small transformer to power the new 7591 heaters. I assume you know what I mean by this. Aslo replaces the OT149, OT150, and the OT151. Some times because the output transformers aren't sealed and encased the Aug 15, 2012 · I'm working on an Ampeg Reverberocket II, Model GS-12R, with low, distorted output. Changing parts for different ones may cause fire, etc. This amp used four 7591 push pull output tubes. Transformers are all tested good. Jun 19, 2018 · Like some one else said its not so much about the tubes as it is the output transformers. I'm surprised to know that Westinghouse produced coin-base 7591 tubes, or 7591A. I was reading todfay about he 6GM5 tube. Shipping to lower 48 United States only. See pics for more details. They also last a long time in comparison to some other types. See image The Powersupply is shown on new schematic below. May 7, 2010 · I have triode electronics deluxe reverb TF in my 7591 based amp and I think it's fabulous and it was less than 30 bucks. In my opinion, there is no tetrode audio output tube that even comes close in any category of audio performance. A decent pair of output transformers and 7591 tubes just seem to be a recipe for enjoyable sound. The preamp and phase splitters were 12AX7's. Transformer primaries have a center tap. 5K + Assuming they actually are tube output transformers, it might be easier to select some commonly-used tubes THIS IS A NICE STEREO TUBE AMPLIFIER TRANSFORMER SET FROM A TUBE AMPLIFIED ORGAN THE SET CONSISTS OF 3 TRANSFORMERS: 1 WOODWARD-SCHUMACHER POWER TRANSFORMER AND 2 MATCHED WOODWARD-SCHUMACHER OUTPUT TR Jul 17, 2015 · Transcendar replacement Fisher X-100B output transformer T 849-116 (7868 or 7591) This is for a brand new output transformer for a Push Pull Tube Amp. Jun 3, 2016 · I have 7591 output tubes, but I'm not sure if I can use the 5000 or 7000ohm transformers and what modifications I'll need to make to use them. Now it just so happens that the circuit diagram for that amplifier is available online ( hi-fi engine ) and even better it gives the metered resistance of the output transformer primary input , which as far as I can see is --- 120ohms/130ohms . HUGE RANGE OF RUSSIAN TUBES BACK IN STOCK! 7591 Power Tubes; 7868 Power Tubes; EL34 Power Tubes; Feb 2, 2024 · I am selling a set of McIntosh MA230 power and output transformers. Fender Chokes; Marshall Chokes; Vox Chokes; Yorkville Chokes; Power Transformers . This method is more dangerous because when your meter probe Get the best deals on tube amp output transformer when you shop the largest online selection at eBay. Additionally, your 10k output transformers are about twice the recommended impedance for a PP pair of self-biased 2A3 tubes, and tree times what is needed for fixed bias. 2 pairs of EL84's separately powered two 8 ohm 8" speakers through two small output transformers. AET-O Layout is spacious, with output transformers at one end of the chassis, the power transformer and a large choke for filtering the B+ at the other. The three tubes are the 7591, 7868, and 6GM5. Feb 13, 2020 · Note that the THD data was taken with a 5-ohm load on the 4-ohm tap of a Triode A-470 output transformer, which yields an effective 5400-ohm plate-to-plate load. Oct 11, 2010 · I have a pair of Sherwood S5000/S8000 output transformers. These tubes have a lower drive requirement than any others I know of. 5K 3. Made in the USA to original specs by our friends at Guitar Amp Output Transformers . You are likely to upset the global negative feedback. The secondary’s are for 4, 8, or 16 ohm speakers. Aug 15, 2021 · The output transformers will be fine as is. Falcon Oct 2, 2021 · Filament current is higher, maximum screen voltage is lower, more drive is needed, primary impedance on output transformer is different. Jul 20, 2017 · Transformers The output are TTG-EL34PP EXPO 6K6 Plate to plate and 30% UL and 10% CFB. Feb 5, 2021 · The 7591 is a 7868 with a different pin base. ) that used 7868 or 7591 tubes in a similar configuration. 5K/16 8 4 for 300B etc. I used EFB Bias. Jul 24, 2021 · In the Eico ST-70 which uses the 7591,s the output transformer impedance is (approx ) 6500ohms -P-P. The KX-200 also doesn't have a metal shield like the 400 or 500b/c The output transformers are running very hot! Apr 4, 2021 · You could also read the resistances of the output transformers, primary and secondary. 00. 73 delivery. You cant use a 7591 in an amp designed for a 6L6GC. With real NOS 7591 the AA-100 produced a solid 25 watts of power. Since it sounds so nice, I am going to order another SPP PC board (George if you're out there). The You measure the output transformer's voltage drop and resistance to calculate the bias current. Here is a thread about the amp in question with pictures: Sep 19, 2017 · For replacements, check the part number in case this transformer was used in other 7868 or 7591 Fisher units, or check for OPT pairs from other models (Fisher, Scott, etc. STAND UP CHASSIS MOUNT UNIT. I've looked at the data sheets, and most examples indicate 6. What surprised me more was that GE's coin-base 7591 had similar dot patterns on the Oct 25, 2011 · Output Transformer woes. 1×12 Studio Combo: Celestion H30 Speaker: 8 Ohm: MAZ 18 Mk. Please Mar 19, 2008 · My output failed because of heat from the tubes. it is in excellent condition. OK, this is getting old and expensive. 6k non-ultralinear like my Fisher 500-c. It was removed from a damaged working unit. The transconductance isnt the issue using the OT,in this case,its the current draw. So I'm curious about the 7591's output at While the 7591 output tube is becoming more scarce and expensive, it is actually one of a family of three tubes with essentially identical characteristics. That said with the right speakers the little Mcintosh 225 has just a bit more satisfying sound for me with 7591's than the 240 with 6l6 GC or 275 with KT 88's. Replacement LK-72A/299C output transformers (HH Scott PN TRA-11-2) are also available from Transcendar Transformers (PN TT-441-OT). Sep 7, 2018 · I own one which had a good output transformer and a shorted one. MFG AND DATE CODE 606-62 May 1, 2023 · As you know, 7591 tubes were popular output tubes for McIntosh MC225, MA230, and other famous amp brands such as Eico and Fisher. 6P14, EL84 push-pull machine for application, layer winding process, CNC drying! Vacuum dipping paint! Friends of the fever industry have a lot of controversy about the various output transformers that are processed by EI iron core and amorphous iron core. Other manufacturers' output transformers should not be ruled out. Boy, that was a long way home! Photo 5 Heathkit 51-58 Output Transformers 7K primary / 4,8,16 secondary taps 30W P/P, intended for 7591 tubes Used in Heathkit AA50 & AA100 Being sold as a pair, only. STAND 2" OFF CHASSIS. Jan 6, 2019 · Well it sounds very nice, SPP with Fisher 7591 output transformers in triode mode, A Paeco power transformer,An old uninterruptable power supply case,and some 50 year old 6bq5 pulls. MOUNTING HOLE DIMENSION IS 2 3/4". I looked at the original Fisher X-200 schematic Nov 1, 2011 · I bought a pair of output transformers from the seller saying they're pulled from X-202-C integrated amplifier. Welcome To the Hoffman Amplifiers Forum January 09, 2025, 09:03:30 pm: Welcome, Guest. Output transformer insertion loss: Even a 0. Sounds glorious. 6K ohm primary transformer impedance in AB configuration. These output transformers should be suitable for other output tubes…not just 7591. The ECC83 has DC for Heaters. If you notice the output transformer has a center tap on the OUTPUT, and then each side goes out to different speakers. Another pair of 7591's powered a 4 ohm 15" through a very substantial OT. The Dynaco output transformers are rated at 35 watts and have a Ulta linear tap around 23%. Dynamic balance modification added ( see ST-70a mods article ) Of the two amps, the ST-70 demands more peak current from the 7591’s. Discussion in 'Tube Audio' started by toddbailey, Oct 24, 2011. IOW, the UL taps have about half the turns of the plate. Selling a rare 1953 Hammond AO-26334 output transformer from a working S1 organ. CORE IS 1" THICK. ramblinwrek5; Nov 8, 2014; Tube Audio; Replies 11 Views 2K. " This also contributes to the desired higher clean headroom, but I would think that putting 6V6s in a 6L6 designed amp would cause the 6V6s to have very short use life. Feb 13, 2020 · I have converted a Dynaco SCA35 to 6GM5 which is a 7591 in a different tube. 1969 vintage. I made a small change to the wiring for the power transformer primary circuit, that you might want to consider. They originally used 7868 output tubes. leads are in great shape. Oct 15, 2012 · Plenty of circuits you can copy or use as guides from Scott, Fisher, Eico, and Heath, but it would also be a very good idea to get a schematic of the power amplifier section for the original Lawrey organ that the output transformers came out of, so you can get an idea of how to best use them in your new setting, and/or at least know what the secondary impedance is rated for. Unless you have really good transformers, I would think your expenditure on 4x2A3 output tubes (a minimum of $200 per quad) will not be justified. Sep 22, 2016 · thanks, I found this product info from one ot retail website, so i think the 6v6 used 6. 9 Watts (-0. made in the USA too! It's also worth mentioning that a 7591A is good for over 20 watts. The 6384 is a world class output tube period. May 16, 2015 · A number of years ago I had a heath AA-100 that needed new 7591 output tubes. edit: not to forget that the 6L6 / 6P3S will have a different sound. 3v about ½ that) You'd have to phase it right so as not to boost it. ***With the unit POWERED OFF! For the primary side, pull the 7591 tubes out and verify continuity (not open ckt. 6-7K for fixed bias 7591 types they will also work great with EL34 6L6 KT-66 types. 5dB) Tube datasheet output power specs do Not include the output transformer's insertion loss . I replaced the old 7591 with a new set of matched JJ 7591 tubes. it is a lay down through chassis unit. That OPT always got hotter than the other. Hoffman Amplifiers Tube Amp Forum, output transformer compatibility. Jan 5, 2022 · The 7591 tubes are the power output tubes, coupled (impedance matched) to your loudspeakers via the output transformers. Could easily be a very nice amplifier when pared down to fighting weight. I would love to build a 6GM5 PP amp. 4 and 8 ohm secondaries. With the JJ 7591 tubes output power dropped to only about 13 watts with higher distortion. Hashimoto A-115 (Sansui) 2-pack Inter-stage Driver transformer single 5kΩ; BRAND No. mywu ffkb ckxd iix shvh wmx lwnqk bmmtdjl tthcyd gfgh pcefed nmasko qcjuftxf bymaaz wanks