Steve Melkithesian (Angela Instruments) is promoting the Ei ECC83 tube from Yugoslovia as the best sounding preamp tube in current production. He is (was) selling them at $5 for shiny plate and $8 for gray plate versions. He admits they had bad microphonic problems in the past, but says the new production has much reduced microphonics. Watford Valves said the new production had improved, but were still inferior to Electro-Harmonix and JJ in the microphonics department.
I ordered one of each version from Steve. I installed the shiny plate in my dad's Tube 12 amp, and it gave a definite improvement over the Chinese tube that came in it. I installed the gray plate version in my Tube 12 amp, and it sounded about the same as the JJ ECC83S I was running. It was a tiny bit more microphonic, but not much. It was slightly brighter on the top end and slightly richer in upper harmonics. Nice tube!
My dad has run his every day for months and it has not become more microphonic that I can tell. He plays clean with the gain knob all the way down and disengaged. I rarely use my Tube 12 right now, but the Ei ECC83 does have plenty of gain for playing high gain rock music. The gain distortion is much smoother than the Chinese Ruby tube gave. It is similar to the JJ tube in that regard. I also tried an E-H 12AX7 in my Tube 12 and it sounded very good. Very high gain like the Ei ECC83 and a bit less microphonic. The E-H has a bit more midrange punch and less rich in upper harmonics. It is preferable for high gain rock music in my opinion. The JJ tries to be all things to all people. It did everything well, but was bettered in different areas by the other two tubes.
The Ei ECC83 was being sold for $45 for 10 from Angela Instruments. I bought a "10 Stash" and set them back for later. Steve is selling them cheap rather than charging what others do and offering a warranty against microphonics. Even if too microphonic for your combo amp, they should give excellent service in your stereo equipment, especially in line stages and buffers where microphonics are not too critical. It is a copy of the flat plate ECC83 Telefunken, so you know what that means as far as tone goes. It definitely has "the tone".
Ei ECC83 (12AX7 type) Preamp Tubes
Moderator: jingle_jangle
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toneman
Phillip; Have you tried the Ei Elite's w the gold pins? I find them to be an even better tube than the regular Ei's. I think most of the problematic Ei's were from before the UN trade embargo a few years ago(`97-98..). Since the embargo was lifted they seem to have provided a much better built tube. The Ei's in an old Vox AC15 or AC-30 sound wonderful! I've got the Ei EL-84 Elite's in my new Handwired AC-30 Limited Edt. I could've used Telefunken's or Mullard's but I think the Ei Elite's sounded very good.
Also, thanks for the heads' up on the new KT-66's and Mogami wire! I tried Aspen's KT-66's when the first came out and they would fail @ 450v & the chinese versions seem to put out around 10-12 watts less than the GEC's do.
Also, thanks for the heads' up on the new KT-66's and Mogami wire! I tried Aspen's KT-66's when the first came out and they would fail @ 450v & the chinese versions seem to put out around 10-12 watts less than the GEC's do.
I was told that the Ei Elites were just the gray plate version with gold plating on the pins. Therefore, I haven't bought any. Also, I can't tell any difference between the shiny plate version and gray plate version, soundwise. The gray coating is supposed to aid in heat dissipation, as they run a bit hotter than the short plate JJ and E-H tubes. Must be a reliability enhancer only. At $5 a pop, I'm not complaining if the shiny plates die a bit sooner.
I bought a quad of Ei EL84 tubes, but never got that Blues Junior amp, so never used them. I got an AVT20 instead because it has some serious bass due to the closed cab. It now has an Eminence B102 installed and never runs out of bottom end, or top end for that matter.
I actually heard somebody knock the Sovtek KT66, but I don't know why. Maybe it was because they don't suck about 1.5 amps per tube of heater current and aren't "real" KT66 tubes because of it. Mine tested good when set for the normal amount of emission that a standard KT66 is supposed to deliver. I think the Russians can deliver a much better product than the Chinese, and at $25 per tube, are much costlier than Russian 6L6GC or 5881 tubes.
There has been some problems with the Sovtek KT66 being in short supply, but supply seems OK now. I compared them to the Sovtek 6L6GB, and they have a similar plate structure. Mica spacers on both ends of the plate seem the same. The bases are different and the getter has been relocated. The KT66 has an additional mica spacer above the plate that mounts it within the much larger diameter tube. The emission tested much higher in the KT66 tube, but the 6L6GB has seen some use. It would be interesting to compare new copies of both. The KT66 is too large to fit in my Traynor amp, so can't try it there. It's a pretty tube, and looks good in an open chassis amp.
I bought a quad of Ei EL84 tubes, but never got that Blues Junior amp, so never used them. I got an AVT20 instead because it has some serious bass due to the closed cab. It now has an Eminence B102 installed and never runs out of bottom end, or top end for that matter.
I actually heard somebody knock the Sovtek KT66, but I don't know why. Maybe it was because they don't suck about 1.5 amps per tube of heater current and aren't "real" KT66 tubes because of it. Mine tested good when set for the normal amount of emission that a standard KT66 is supposed to deliver. I think the Russians can deliver a much better product than the Chinese, and at $25 per tube, are much costlier than Russian 6L6GC or 5881 tubes.
There has been some problems with the Sovtek KT66 being in short supply, but supply seems OK now. I compared them to the Sovtek 6L6GB, and they have a similar plate structure. Mica spacers on both ends of the plate seem the same. The bases are different and the getter has been relocated. The KT66 has an additional mica spacer above the plate that mounts it within the much larger diameter tube. The emission tested much higher in the KT66 tube, but the 6L6GB has seen some use. It would be interesting to compare new copies of both. The KT66 is too large to fit in my Traynor amp, so can't try it there. It's a pretty tube, and looks good in an open chassis amp.
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toneman
you don't want to put any shiny plate EL-84's in a Vox. They'll self-distruct. The Elite Series seem to be better built and sound better than the older grey plate tubes from Ei. The grey plating is a Mu-metal coating that does dissapate heat. It's also toxic as all get out but does the job it was intented to do.
The new Sovtek/Reflector KT-66 is great! I think G.T. has them packaged as KT-66HP(high power..) and have more output and can handle the a higher plate voltage of older amps much better. The first versions couldn't handle a lousy/wimpy 375v D.C. The chinese one's seem to put out around 10 watts less output.
The new Sovtek/Reflector KT-66 is great! I think G.T. has them packaged as KT-66HP(high power..) and have more output and can handle the a higher plate voltage of older amps much better. The first versions couldn't handle a lousy/wimpy 375v D.C. The chinese one's seem to put out around 10 watts less output.
My EL84 tubes may not get used. I am SERIOUSLY considering an Epiphone Galaxie 10 that uses a single 6L6 output tube. Reviews are extremely positive for it. I have some NOS RCA 6L6GC tubes that I need to buy an amp for. 
Used/exc-mint Peavey Classic 20 amps are going for around $200 on eBay, and I can get a new Galaxie 10 for that price.
I wonder how those Sovtek KT66 tubes are rearranged internally? They sure look a lot like Sovtek 6L6GB tubes internally as far as the plates go. Of course, certain internal parts could be used on several different tube variants. A KT66 is just a 6L6 with the kink taken out of the transfer curve, and much nicer looking as well. The 6L6/5881 "kink" is what gave old Fender amps their bark, from what I read.
But back to 12AX7 tubes. My Marshall AVT20 has been modified again. I installed a Scan-Speak 29001 flow resistance vent in the back panel and stuffed the cabinet with Acousta-Stuf nylon fiber damping material. It took out a lot of the peakiness at the box resonance frequency. The low frequency response is more linear and more extended. Now the main problem sounds like the preamp tube going into distortion differently at different frequencies. I'll have to try every type 12AX7 tube mentioned above, and maybe a few other NOS types I have laying around. I'll report my findings on my old post regarding the AVT20. The best part is that it just keeps improving as a practice amp for my 4004L. I'm getting some nice overdriven tube distortion tones now at very tolerable volume levels. I get tones I could only dream of with that old Peavey folded horn. I just need to find the right 12AX7 with smoother transition from clean to distorted tones. It's acting too much like "toggle switch tone" to suit me. I think Marshall sent it out with a Sovtek tube because of their high gain and reliability. It's not exactly a finesse tube. Or maybe the FDD circuitry is the problem. It DOES stand for Frequency Dependent Damping, and I changed the damping of the speaker quite drastically. Still, I got an overall improvement in the sound. The AVT20 shows a lot of potential, but nobody except me has given a hoot so far, as Marshall is not a traditional Rickenbacker type of amp.
Used/exc-mint Peavey Classic 20 amps are going for around $200 on eBay, and I can get a new Galaxie 10 for that price. I wonder how those Sovtek KT66 tubes are rearranged internally? They sure look a lot like Sovtek 6L6GB tubes internally as far as the plates go. Of course, certain internal parts could be used on several different tube variants. A KT66 is just a 6L6 with the kink taken out of the transfer curve, and much nicer looking as well. The 6L6/5881 "kink" is what gave old Fender amps their bark, from what I read.
But back to 12AX7 tubes. My Marshall AVT20 has been modified again. I installed a Scan-Speak 29001 flow resistance vent in the back panel and stuffed the cabinet with Acousta-Stuf nylon fiber damping material. It took out a lot of the peakiness at the box resonance frequency. The low frequency response is more linear and more extended. Now the main problem sounds like the preamp tube going into distortion differently at different frequencies. I'll have to try every type 12AX7 tube mentioned above, and maybe a few other NOS types I have laying around. I'll report my findings on my old post regarding the AVT20. The best part is that it just keeps improving as a practice amp for my 4004L. I'm getting some nice overdriven tube distortion tones now at very tolerable volume levels. I get tones I could only dream of with that old Peavey folded horn. I just need to find the right 12AX7 with smoother transition from clean to distorted tones. It's acting too much like "toggle switch tone" to suit me. I think Marshall sent it out with a Sovtek tube because of their high gain and reliability. It's not exactly a finesse tube. Or maybe the FDD circuitry is the problem. It DOES stand for Frequency Dependent Damping, and I changed the damping of the speaker quite drastically. Still, I got an overall improvement in the sound. The AVT20 shows a lot of potential, but nobody except me has given a hoot so far, as Marshall is not a traditional Rickenbacker type of amp.
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toneman
I haven't tried them yet in my guitar amps. I might try FRED's in the AVT20 after I take care of other issues. I'm fairly certain my C-J amps have them installed, after all they are loaded with polystyrene capacitors, separate regulated supplies on every tube, and oxide-on-glass resistors, etc. It would have been an oversight for them to have been left out. The latest C-J amps ARE smooth and detailed for sure.
I don't think FRED's would have much effect in an amp with a choke in the power supply. Chokes cost a LOT more than FRED's, however. Capacitor input power supplies could certainly use some help from FRED's, for sure. I don't expect many guitar amp manufacturers to rush back to the filter choke era anytime soon, and a lot of people would hate the extra weight. Putting a B102 in the AVT20 REALLY took out the midrange bump and increased the clarity. A 650D almost becomes a bass guitar when you hook the two together. The character of the distortion is really changed (harder edged), as almost none is now coming from the new speaker like it did from the Celestion.
I need to get an AVT20 schematic before I mess with the circuitry too much. I would like to study how the FDD circuitry works.
I don't think FRED's would have much effect in an amp with a choke in the power supply. Chokes cost a LOT more than FRED's, however. Capacitor input power supplies could certainly use some help from FRED's, for sure. I don't expect many guitar amp manufacturers to rush back to the filter choke era anytime soon, and a lot of people would hate the extra weight. Putting a B102 in the AVT20 REALLY took out the midrange bump and increased the clarity.
A 650D almost becomes a bass guitar when you hook the two together. The character of the distortion is really changed (harder edged), as almost none is now coming from the new speaker like it did from the Celestion. I need to get an AVT20 schematic before I mess with the circuitry too much. I would like to study how the FDD circuitry works.
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toneman
Phillip: a choke is about the same price as 4-FRED's. Especially if bought in bulk.
Alot of guitar amp manufactures don't have a clue about choke's. Not only does the Q factor make a difference but the way it's made and the way it's mounted play a big role in the way the amp's power supply works and it's tonal effects on the amp. FRED's will certainly help weather you have a choke or not.
My old 50 watt plexi Marshall head had a stupid(stock) choke that acted more like an air coil inductor. It looks like a "Partridge" made one that used a bracket on both sides and 4 screws to mount it to the chassis. I yanked it an put a 10H choke that solidly mounted to the chassis and used two screws/bolts. It made a drastic improvement. I have also replaced the two diodes in the 1/2 wave rectifier with two FRED's. I have a Radio Spares clone output tranny made by Mercury Magnetics in this amp and it uses M.O.Valve KT-66's. The amp sounds incredibly early JTM-45-ish. It was used recently in a comparison article in a Japanese guitar magazine. I thought these guys were going to start bowing to it when they played it..LOL!
any case, I think a good choke and FRED's will make a big difference in a guitar amp. I was a skeptic of both until I tried them in several different amps. I've got FRED's in all my old Fisher tube stereo's as well!
Alot of guitar amp manufactures don't have a clue about choke's. Not only does the Q factor make a difference but the way it's made and the way it's mounted play a big role in the way the amp's power supply works and it's tonal effects on the amp. FRED's will certainly help weather you have a choke or not.
My old 50 watt plexi Marshall head had a stupid(stock) choke that acted more like an air coil inductor. It looks like a "Partridge" made one that used a bracket on both sides and 4 screws to mount it to the chassis. I yanked it an put a 10H choke that solidly mounted to the chassis and used two screws/bolts. It made a drastic improvement. I have also replaced the two diodes in the 1/2 wave rectifier with two FRED's. I have a Radio Spares clone output tranny made by Mercury Magnetics in this amp and it uses M.O.Valve KT-66's. The amp sounds incredibly early JTM-45-ish. It was used recently in a comparison article in a Japanese guitar magazine. I thought these guys were going to start bowing to it when they played it..LOL!
any case, I think a good choke and FRED's will make a big difference in a guitar amp. I was a skeptic of both until I tried them in several different amps. I've got FRED's in all my old Fisher tube stereo's as well!
Actually, what I got to go in my old Heathkit amps is probably more expensive than either one. I bought a couple of Mullard CV378 (GZ37) rectifier tubes to replace the 5R4GY that came stock. Somebody put 5U4G rectifiers in and the B+ was way too high soon after turn on until the output tubes began to conduct. I got some Sovtek 5AR4 (GZ34 type) tubes to delay the application of plate voltage, but they have more conductance than 5R4GY tubes and still cause slightly high plate voltages. My solution was the GZ37 while I could get a pair of nearly new ones for $66. I actually fell for the killer looks. However, I discovered they take about 50% more heater current than a 5AR4, which is no problem with my new power transformers, and they also are supposedly limited to 4uF of input capacitance as they were primarily designed for choke input power supplies. I am running a 50uF 900V input cap on the amps, and that is much higher than the 20uF cap that was standard, but well within the capability of the 5AR4 to handle. Looks like I will have to reduce the capacitance, but I have seen an amp schematic that used a GZ37 and 22uF of input capacitance on Angela Instrument's website, which is way above spec. It could be that reducing the voltage allows increased input capacitance. The GZ37/CV378 was a military tube, and the design specs are considered very conservative. I am using a power tranny with 425V of B+ while my specs for the GZ37 says it can handle 500V. The 5R4GY was also rated at 4uF of input capacitance while Heathkit used 20uF of input capacitance. The 5R4GY was designed to handle 900V with an Imax of 150mA. The GZ37 can handle an Imax of 350mA. The filter choke is only rated at 150mA, so the Imax should be way below the limits of the GZ37.
Installing FRED's and a standby switch is also an option, but the turn-on surge would probably be hard on the transformer and I'm afraid it might blow the fuse unless some kind of soft start circuit was employed. I would like to be able to use the GZ37 rectifiers. They really look great standing next to the Sovtek KT66 tubes. However, I do not want to pay for replacements as they are getting rare and expensive. The Sovtek 5AR4 rectifiers are probably my best route right now.
Installing FRED's and a standby switch is also an option, but the turn-on surge would probably be hard on the transformer and I'm afraid it might blow the fuse unless some kind of soft start circuit was employed. I would like to be able to use the GZ37 rectifiers. They really look great standing next to the Sovtek KT66 tubes. However, I do not want to pay for replacements as they are getting rare and expensive. The Sovtek 5AR4 rectifiers are probably my best route right now.
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toneman
I bought a bunch of NOS Phillips(Mullard) GZ-37's about 6 years ago on one of my many trips to the U.K.
I think I paid the equivilant of $15.00 each for them. they came in the bright yellow Phillips boxes and the tubes were etched with the Mullard/Phillips date and factory code. these were made in Mullard's original Blackburn factory in Lancashire.
Great tubes if a GZ-34 is too much B+. Be fore warned though that they draw 3 amps of current so make sure your power tranny can handle that.
I think I paid the equivilant of $15.00 each for them. they came in the bright yellow Phillips boxes and the tubes were etched with the Mullard/Phillips date and factory code. these were made in Mullard's original Blackburn factory in Lancashire.
Great tubes if a GZ-34 is too much B+. Be fore warned though that they draw 3 amps of current so make sure your power tranny can handle that.