SE Triode amp for a newbie

[tta60]

They both appear to be reasonable designs, the 6SL7 based design does not use global feedback, which to me is an advantage.

Both the 6J5 and 6SL7 are good sounding tubes.

The 6J5 version seems to be configured for lots of voltage gain, the 6SL7 is not, but will still have a full power sensitivity of less than 1Vrms I would guess.

I terms of reliability issues I am not sure there is a significant difference.

In terms of driving the 6C33 the 6SL7 CF will have lower source impedance than the 6J5, but due the relatively low operating current will probably have less large signal power bandwidth than the 6J5 which can be operated at much higher currents.

Could you tell me please what power (how many watts) I can get from each version?
Thanks a lot,
TTA

 

[kevinkr]

Actually I can only hazard a guess, but typical 6C33 designs running off of 200V rail will produce something on the order of 12 - 15W. I should think both of these designs will fall into that range. FWIW in terms of output power there will probably be little audibly discernable difference between them.

I would probably favor the 6SL7 design based on the lower tube count and the fact that it does not use global feedback.

Note that you can subsitute a single 6SN7 for a pair of 6J5 as the 6J5 is exactly equivalent to 1/2 of a 6SN7.

It's a matter of taste and whether or not you want to use global feedback.

 

[tta60]

Actually I can only hazard a guess, but typical 6C33 designs running off of 200V rail will produce something on the order of 12 - 15W. I should think both of these designs will fall into that range. FWIW in terms of output power there will probably be little audibly discernable difference between them.

I would probably favor the 6SL7 design based on the lower tube count and the fact that it does not use global feedback.

Note that you can subsitute a single 6SN7 for a pair of 6J5 as the 6J5 is exactly equivalent to 1/2 of a 6SN7.

It's a matter of taste and whether or not you want to use global feedback.

What happens if I remove the feedback from the 6J5 based schema?

 

[planet10]

It is possible to put together a nice SE amp for not much more than the cost of a pair of 2A3s -- especially if you are good at scrounging. Eli suggested 6AQ5/12AQ5 -- those can be lumped into a whole family of possibilities including 6BQ5/EL84, 6V6, 6BM8/ECL82, SV83, 6GW8/ECL86, 6DL5/EL95, ELL80.

I've heard Gregg's 6FD7 amp. It is good. Good enuff that i've scared up 4 idential Tamura OEM OPTs to build up a 4-channel version.

The required iron seems to be one of the most common vintage variants around and can be had cheaply. These are at the lowish end of the spectra (and even surface post from NA to Asia would close to double the cost) but give an idea.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9722391493

dave

 

[tta60]

Actually I've built some trial circuits (one channel) and now am listening to the 6SL7-6C33C-B, happy enough with the sound from my ML TL Fostex FE 206E, built after a design by MJ King. I use James JS 6130H OPT and DIY PSU transformers . Just wanted to be sure the used schema is the right one to start building the real amp (monoblocks).
Thank you for your thoughts shared to me. Sure I'm for any improvement you'll suggest for my amp.
TTA