[UntilThen]

Do not ever try 6SL7 there (1W power dissipation per section). Of course nobody is crazy enough to put mu=70 on output but just saying. And of course, always check datasheet.

Of course.

I should stress this...

No high mu driver tubes on 6y6 socket... - 6SL7, 6FD7, 6DR7 are with higher mu driver.

 

[UntilThen]

I see you have 18mA on the 6J5 used directly in the power socket. This is ok? 6J5 has 2.5W plate dissipation. Math with Vplate around 200V takes to around 4W.

Eric has a clarification now.

I also note the the 6J5's dissipation is 2.5W, not as high as a single triode 6SN7 at 3.5W, so 6J5 may not be suitable for plugging on 6Y6 socket...

Anyway and in general, It is not recommended to use driver tubes on 6y6 socket - it will not damage the amp , but will hurt the tube, unless they are those high plate dissipation twin triodes like 6BX7, 6BL7, and marginally 6SN7.

 

[UntilThen]

So what can be used are:-

As power tubes
6EM7 using 6EM7 to 6J5 adapter in the 6y6 sockets.
6BX7 / 6BL7 / 6SN7 using 6SN7(P) adapter in the 6y6 sockets.

As driver tubes
6EM7 using 6SN7(S) to 6J5 adapter in the 6J5 sockets - ie using the 6EM7 driver section as driver tubes in Ultimate. This would be similar high gain as 6SL7 / 12AT7.

 

[OctavianH]

I also note the the 6J5's dissipation is 2.5W, not as high as a single triode 6SN7 at 3.5W, so 6J5 may not be suitable for plugging on 6Y6 socket...

6SN7 has 2.5W, see here. 6SN7 should be fine in (P) adapter with half current. I saw you measured 24mA in your (P) adapter. If both triodes are internally balanced you are around 12mA/section which goes around 2.4W. At the limit but well, should work.

 

[UntilThen]

Yup he did say

Anyway and in general, It is not recommended to use driver tubes on 6y6 socket - it will not damage the amp , but will hurt the tube, unless they are those high plate dissipation twin triodes like 6BX7, 6BL7, and marginally 6SN7.

So 6SN7 is marginal but it's ok to use it with P adapter.

What is more interesting to my ears are 6EM7 and 6BX7 / 6BL7 as power tubes in Ultimate.

 

[UntilThen]

What I have now is to use 6EM7 as both driver and power tubes in Ultimate.

Driver - 6FD7 > 6FD7 to 6EM7 adapter > 6SN7(S) to 6J5.

Power - 6EM7 > 6EM7 to 6J5 adapter.

Interesting way to split up the 6EM7 / 6FD7 tubes. The sound ? Unbelievable.

 

[rollinbr]

With 6FD7, you need 2 adapters. See picture. Biased similar to 6EM7. I was using these tubes as drivers in Eric's 300b amp. Glad I kept them when I sold off the amp. I am getting a pair of 6EW7 tubes of lower mu from Eric.

6EM7, 6FD7, 6BX7 and 6BL7 sound excellent as power tubes in Ultimate. In fact I can experiment using 6EM7 with the lower power section or the higher power section of the dissimilar triodes.

So with the 6EM7/6J5 I take it one can use 6EM7, 6GL7, 6EA7 or 6DN7 tubes. All of these tubes are Octal tubes. The 6EM7, 6GL7 and 6EA7 have the high mu while 6DN7 has medium mu.

With the 6FD7/6EM7, which don't seem to be available any longer from Mrs. X. But the 6CY7/6EM7 which appears to be the same as 6FD7/6EM7 adapter and can use 6FD7, 6DR7, 6CY7, 6EW7 or 6DE7. All of these tubes are 9 pin tubes. The 6FD7, 6DR7 and 6CY7 have high mu and 6EW7 and 6DE7 have medium mu.

If one wants to add another adapter, 6FY7/6EM7 the 6FY7 and 6FM7 tubes are both high mu tubes. These tubes are 12 pin tubes and will work just the same as the 6FD7/6EM7 adapter going into the 6EM7/6J5 adapter. I've never picked up this adapter or either of the tubes.

As you said, the 6EM7 is a driver tube along with the 6FD7 in Eric's 300B amplifier that you used to own. As you know those are the same driver tubes in my "Chameleon", KT150 Super Silk Amplifier that Eric built for me back in 2021. There are so many different tubes that the Super Silk UltimatE can use................

Eric had mentioned most of these tubes when we were corresponding with the build of Chameleon.

Chameleon - GZ34>6DR7>KT170>LCD-4

 

[UntilThen]

Alright let's not jump into every double triodes until it has been checked with Eric.

Eric specify 6FY7 to 6EM7 for his own purpose. So let's not confuse this with Ultimate.

There are only 4 tubes that I'm interested in as power tubes for Ultimate. They are 6EM7, 6FD7, 6BX7 and 6BL7. Of these 4, I like 6BX7 and 6BL7 and these use the 6SN7(P) to 6J5 adapters. The 6SN7(S) to 6J5 adapter and 6SN7(P) to 6J5 adapter are not listed on eBay yet. xulingmrs made them for Eric and I to test first.

I see that the 6EM7 to 6J5 adapters have sold quite a few. That is fine. They sound good as power tubes in Ultimate.

 

[UntilThen]

I measure the Test Point for 6EM7 again and the readout is 64 mA.

So I ask Eric if that is ok for Ultimate. I also ask him about the 6CY7 to 6EM7 adapter. https://www.ebay.com/itm/195986594867?

His reply...

Hi Matt,

Indeed!!! The new 6CY7 adapter can be used for all 6FD7..... 6DE7...For new entry to the game, buy 6CY7 adapter is all good.

The previous 6FD7 adapter is NOT for 6CY7, and moreover, there is NO 6FD7 adapter available now. that is why I design a 6CY7 adapter and it is good for all.

Since you have 6FD7 adapter, you don't need to buy 6CY7 adapter for 6FD7... etc tubes ( but not for 6CY7 OK ?)

Cheers

Eric

PS... I checked for 64mA current. Only 6EM7, 6FD7 and 6EW7 are OK, The others need less current, so do not try the others on UltimatE unless they are running at less current.

 

[Deleeh]

There is only one thing left to say,the super Ultimate was more of a pseudonym,but it lives up to the name,it is indeed a super Ultimate.
Maybe I'll have to think about it at the beginning of next year.
2 Ultimate's with different caps would be the icing on the cake.

 

[jonathan c]

There is only one thing left to say,the super Ultimate was more of a pseudonym,but it lives up to the name,it is indeed a super Ultimate.
Maybe I'll have to think about it at the beginning of next year.
2 Ultimate's with different caps would be the icing on the cake.

… your focus on caps ==> the most important part of h/p/a ?? ==>

 

[Deleeh]

… your focus on caps ==> the most important part of h/p/a ?? ==>

No, not at all.
If I had a second Ultimate built in the super version, then flexibility and choice would be good.
With a second Ultimate I would never have to look for another amplifier again, because 2 Ultimates would offer so much.
4 different caps, 4 different styles and directions where they would go, if that's not enough I don't know what is.
I would also have the 2nd one fitted with silktrafos,.

 

[jonathan c]

@Deleeh , then you need …

“Cap on, cap off … The ‘Capper’!!”

 

[UntilThen]

There is only one thing left to say,the super Ultimate was more of a pseudonym,but it lives up to the name,it is indeed a super Ultimate.
Maybe I'll have to think about it at the beginning of next year.
2 Ultimate's with different caps would be the icing on the cake.

6EM7, 6FD7, 6BX7, 6BL7 is now making an impact in Ultimate. It's not a one hit wonder. I have been listening since yesterday morning and I couldn't stop....

Not surprising because Eric does make optimised versions of amps using those tubes.

6FD7 / 6CY7 / 6DR7
https://www.ebay.com.au/itm/125792445361?

6BX7 / 6BL7
https://www.ebay.com.au/itm/115705270686?

During my evaluation in March 2023, when I was deciding on Ultimate, 6BX7 amp, 6FD7 amp, I almost went with 6BX7 amp. I chose Ultimate because it is quieter and can use more tubes. All 3 sound very good.

So now Ultimate can use 6EM7, 6FD7, 6BX7, 6BL7 and it's so quiet, I'm stoked ! I'm tripping with excitement. Tonally these power triodes sound as good as my NOS pentodes in strapped triodes.

 

[UntilThen]

Ultimaters, get yourself a pair of 6EM7 and the 6EM7 to 6J5 adapters and listen to Ramble On by Led Zep. The best bass lines in history.