Whitigir

Ah, these are Philips gawd, a lot of confusion. I guess, the T2 really plays nicer with 6922 rather than 6dj8 ?

I tried the Green label JAN 6dj8, and eventhough it was Balanced from the store. It was no good. The balances went crazy from -2V to +3V in a blink that the DMM couldn’t even keep up. The offset on Left channel was reading 25V and the one in the right channel was reading 177V....holy cow. I turned off and took them out as soon as I could.....luckily....no smell... Stuck back on the JJ goldpin ECC88 and the Balanced started right out below 500mV and keep going down steadily into +30 and -30mV on Left, and +150 to -150mV on right. Balances was dropping steadily when started out 4.5V on Left, and 6.5V on right and drop quickly, probably within couple minutes and it dropped to 0.8V on Left and 1.5V on right, and keep dropping down. I think these JJ goldpin are meant to be in there. Better stick to what works as T2 is not something to be playing around with. The next thing is probably a quad of Xf2 as everyone is saying they sound beautiful. I have no choice but to get a Quad to get the best out of my T2 and while sticking to what work best.

Okay, going to swap out these JJ and put them in together with Winged C el34, and no more tube rolling! Thank you so very much

Is Sylvania ECC88 NOS recommended ? I read Amperex was giving people problem and killing Transistors ?

In a sense, EL34G is the real EL34 and is Pentode, and not Beam Triode ? Ouch....I run that beam triode for a few hours

Well, it seems I better be safe than sorry. Only go for true EL34 from now on.

I think you just perfectly explained why my T2 cooked my JJ 6CA7, and not the EH 6CA7, while GG played real nice with JJ6CA7 and I loved it it also seems the explanation, the Beam Tetrode has the second harmonic minimized. Hence why I am hearing the EH6ca7 more balanced than any of the EL34 I threw on the T2

You did use 6922 in Kg T2 successfully ? Which one are you using. Many tube retailers list 6922/6dj8/ECC88 in the same category

I guess the EL35 Pentode was really intended for the T2 and not the Beam Tetrode. There are 5 connections in the scheme ? While the Beam Tetrode has only 4 elements ? Speaking of which, better turn of T2 until KG confirm about this

Indeed this EH6ca7 is more balanced and neutral tonal body. But really, many of the 6ca7 is just Pentode, and this one is Beam Tetrode. They gotta affect somehow to the Circuit ? Does it matter ? The GG was a much friendlier amp in comparison to the T2 and it Power though. I have no clues regard tubes :(....a disadvantage for being younger generation

Ouch...and I am using JJ ECC88. Will Sylvania do better ? How about those Beam Tetrode or Pentode ?

Where would you recommend to get these tubes ? Yes, and same here. May be sir KG can answer which one is intended more for T2 Not sure if it will blow up the T2, but so far she is singing. You did have a tube that took out some part in the T2 before right ? What was it ?

Nice! I tried these on, and they have “blue / purple hue fluorescent” or so I was told.....lol, never seen it in GG. Anyways, these sound so nice! Surprisingly the balances was dead-on around below 0.5V at cold start on both channel and offset is 5-6V on both channel. When Hv kicked in, she gave a quick snap, but even lower than RFT I hope this will be a reliable choice

I have a quad of these Electro Harmonix 6ca7. If it is safe, I would put it on :). Thanks ! these ? Best NoS I have is rft and Winged C. I refuse to go further the NOS road

So, I now learned my lesson to be very careful with T2 and tubes. I couldn’t deal with Groove tubes EL-34 sounds, and while I liked the JJ on the Grounded Grid, it was too fragile to stand with T2. Never again to stuck any JJ in the T2 anymore. Then nervously sticking in my next favorite in-line from GG tube rolls, the Quad RFT Vintage EL-34. Didn’t dare to swap tubes without checking the balances and offset. So balances was sitting at below 0.5V on both channel, and Offset was 5-6V on both channel. The one thing I always noticed about GG and the T2 is that these output tubes affect the “turned on” to the 009. The Groove tubes did an echo sound when Hv kicked on, and quick crack when turned off. The RFT has a quick snap which is lower in volume than Groove tubes, and echoes when turned off. In the GG quad Apex matched from JJ was dead quiet on turning on/off. Sadly, it is not a brand to stick into the T2. Now, why would they behave that way ? I have no clues. anyways, I am enjoying the T2 with Quad matched ECC88 goldpin from JJ...again, love those JJ signatures. Cross my fingers, and pray that they don’t give problems, and now RFT Vintage EL-34. I just had to get away from bad tubes Signature, but also so much respect to how powerful T2 is, and that she can cook tubes easily. So far, T2 is awesome!!! Wooooo By the way, if any long time T2 owners can please share the experiences of reliables tubes, and bad tubes. I think it would be excellent !

Yay ! I got music, and no background noises even at max volume. No Hums, no hiss !! Oh my gawd! I am blessed by Dr. Kevin Gilmore!. I appreciate it so much sir Dr. Gilmore! Finally, I have reached my “ultimate dream goals!” With very limited knowledges. Thank you to George for making this Build a possibility!! Thank you so much to the community as a whole. The best Stax community out there ! Finally, some pictures, herself and in all her glory. Pure solid silver for wires . I am big fan of it I am smiling like a maniac! Yayyyyy! stacking up, and Amp is 130F, the PsU is 141F after 2 hours. Pretty warmth ! Can’t imagine the original The most beautiful amp I have ever had! Period. Time to “burn-in”

I am getting very close! Thanks god that @Kevin Gilmore , @Georgep , @Soren, Birgir, Mike, and the whole community here. Especially thanks to Kevin for taking up your time and advises, and thanks George for the chassis, some obsolete sands and sharing hard to find Xicon. I finally realized that adjusting the batteries with 10k pots is wrong, and it will in the end make 1 battery stuck. Have to measure 22k resistor to 6.5V and then dialing with 2k pot to 740V . Thanks George for the method and it worked to unstuck my battery Now, I can have all 4 batteries at 740V, O+/O- is -100mV to +50mV on right channel. -200mV to +12mV on Left channel. This is cold start O+ to Ground References is R (2.2V and dropping steadily) and L (4.5V and dropping steadily) I think my next step is to plug in the 009 and try to observe noises **my Tube arcing problem turned out to be that JJ 6ca7 was pretty fragile, and couldn’t handle the T2. I was sweating and checking everywhere to realize it was a ghost, until KG confirmed that JJ are junk. I stuck in Groove tubes EL34, and it got to this result.

So, after thinking about why arcing happened for a while and sweating my brain out for no reason. Pulling parts, and measuring with all kind of tests, I was chasing a ghost. Thanks to George and I was getting the battery responding to reading the 22k resistor. It was simply 8.5V to 9.5V prior, and now 10k pot turned it down to 6.5V, then the other battery is the same reading across 22k. The output LED clicked on. Now, another ghost appeared, the 6CA7 would arc when HV is kicked on, and will only continue to flicker together with it LED after the HV is off for another second . It appeared that this Tube-arcing problems persists, and has Now attached itself to the 6CA7 black square is where the 6ca7 would arc and the led would be blinking, and Red square is the stuck battery. *there is 1 Led now on the other side of the board due to pad fell off* The method of dialing 2k and 10k pot to mid value prior to soldering, then using 10k pot to dial in 740V was working. On my working channel, the 22k resistor measured 6.85V which dialed into 740V. However, on the stuck battery, the 22k resistor had 8.5V while the battery next to it had 6.85V or so, which is similar to the good working 2. After proceeding to adjust the 10k pot to get 6.5V across the R22k, my 6ca7 Started Arcing. Spent many hours to diode and short measures all the active parts, and I believe that now I am still chasing a ghost....a pretty good one at haunting my brain

I was thinking that dialing while measuring the 22k resistor in the battery was just another way to do it ? I tried to set 2k pot in the mid value of 1k before soldering on, and then adjusting to 740V with 10k pot. This way I was able to set all 3 batteries, and the Left channel is fully lit up. Only the right channel that has one battery refuse to respond regardless of what I do. Unless I turn the pot on the battery next to it, then it will be affected together. This is the Channel I had the input tube arced very sparkly before. I am trying to chase down collateral somewhere, but it seems I am chasing a ghost ATM The stuck battery differences to the one responsive one is around 40V.

So, my active battery on one channel is perfectly responsive. I could adjust it from 700 to 740+ with every turn on 10k pot. However, the other channel has 1 stuck battery, no pot turning can affect it at all. All LED in the battery is on, but not the output 4 LED, the other LED out of the battery are dim. If I adjust the one responsive battery on that channel to 740, the stuck battery is at 780. Or if I turn the other one to 699, the stuck one goes to 740. it seems the stuck battery is 40V off and away from the responsive battery. What do I look for

That would come in extremely handy

The relay coil is running 12V DC into ground. If you want to run any LED indicator, tap directly into the regulated supply +12 and -12 output. Luckily it was not “pure catastrophic”.

Thanks you Kevin, it was sparkling and Led was blinking. So now, back to my little delay Circuit. After pulling many active parts, and ended up checking out “working”, but replaced anyways. I remembered that I hooked up the front Led power switch into the coil supply with a resistor before (45 seconds delay), and then I became a smartass and took the resistor out, just leaving the Led directly Tap into the coil +12V and Ground.......didn’t even check it as I overlooked it as it wouldn’t affect anything and forgot about it. Then I hooked up the amp board, and HV came in immediately to result in this Sparkling crazy light show. My apologies to Kevin, Soren, George that my dumb mistake happened and took up your time. Lesson learned. 1/ Defintely don’t hook up the LED (any kind) directly into the Coil Supply. The regulator won’t work without load anyways, so better hook LED into the 12V output 2/ Defintely Have to have the Delay Circuit working before hooking up your amp board.......otherwise, the freaky light show happen, cooking tubes, and possibly giving you a heart attacks and possibly collateral damages. I cross my fingers that nothing is wrong as I measured and read around on board, and they turned out “ok”.....until next power up. * for all that said * my PSU is working correctly once again, relay clicked on at 60 seconds timed. Though strangely my High Bias is at 563 and low Bias is at 273 which is lower than last time measured. the 7912 definitely overshoot the regulated negative rail without anything hooked up, it read -16.40. Now, when hooking LED into it, it read -11.96V

Yes, the filaments on J&J e88 is flashing and the led does too, the only thing burn constantly is el34 filaments. This is first turned on without HV kicked in. Is this because the tubes ? Or did SummR messed up my Fillament amperage Details again

Does the LED supposed to be flashing together with the filaments on e88 ? When I tried turning it on and the low voltage kicked in, the led are flashing and the filaments too, but no smoke or anything. So I turned it off before HV kick in as I want to make sure. Also, under load, now the negative 12 is reading -11.96V