The TAD 6V6GT-STR “Redbase” Premium tubes showed up and I got them installed in the 6V6 Curly Maple amplifier. I took new voltages and have been listening to the tubes with a variety of music. These tubes are very detailed and musical. They produce a stronger bass than the 6V6Gs and a very even tonality in the ultra linear topology. I would consider these a nice upgrade for any 6V6 amplifier.
The TAD Redbase 6V6GT-STRs are not quite as warm as the old 6V6Gs, but they are very musical and I believe very neutral in tone. They really let the music come through.
They also run at slightly higher current than the old 6V6Gs which is not surprising given the age of the old tubes. And at about a 5V lower plate voltage. Here are the measured voltages with the new tubes.
I’ll take the distortion measurements later. After I get done listening to the amplifier (which is playing in the background as I type). Till then I have to say that this amplifier just continues to impress with how it performs. It is definitely the upgrade it was intended to be.
As always, comments and questions are welcome.
A bit late but Happy holidays/ Christmas and New Year to you Matt and readers.
Thank you. And Merry Christmas to all.
Any update on the EL84 optimization with the new output transformer?
Not yet unfortunately. I’ve had some other matters pulling me away from the tube amplifier work.
This 6L6 is the most tempting project you have shared yet. Looking forward to your writeup and I’m inclined to follow it– make it.
I can’t wait for this baby to have its own page.
I actually have the write-up mostly complete. However, some other things have been keeping me from getting it finished. But it shouldn’t be too long now.
Ciao Matt, sono in trepida attesa per il servizio dell’amplificatore.
Angelo
> Hi Matt, I’m eagerly awaiting the amplifier service.
I’ll try and get to the Curly Maple project page soon.
…toc toc…
È permesso?
Angelo
Comments are always welcome.
Those are impressive plate dissipation numbers – Thanks for sharing!
I’m not quite sure what you mean by impressive plate dissipation numbers. 11.4W is below the 12W limit (about 95%) for the baseline 6V6G operation and far below the 14W limit (about 81%) for 6V6GC tubes. These numbers are very close to the amplifier design point.
Not offended or anything, just curious exactly what you mean. 🙂
Sorry for the confusion. You ended the post with “this amplifier continues to impress,” and I used “impressive” to mean it matched design predictions. I can see, though, that it would make more sense to use the word if the results were a lot higher than expected. I should avoid writing post replies like Instagram reactions. However, I am very excited to see the numbers you shared – Thanks again!
Matt,
Until this post, I never heard of 6V6GC. Looked ’em up, I’ll be darned – Tung Sol makes them.
Sorry, I should have said 6V6GTA. I believe I was thinking about some 6L6s at the time I wrote that comment. The 6V6G and 6V6GT are 12W maximum anode dissipation, the 6V6GTA are 14W maximum anode dissipation.
Anode – now you are talking my language! Industrial tubes don’t have plates, they have anodes. Whether it is a 12AX7 error amplifier or a 1,000 Amp ignitron, the most positive electrode is the anode.
BTW – the published ratings of the 6V6 family are very conservative – they can take a real beating and survive.
I agree about the 6V6 dissipation ratings. My experience is that they can generally dissipate steady state above their dissipation rating without any significant shortening of tube life. Except for the metal can versions which can overheat rapidly if dissipation limits are exceeded.