"Traditional" driver circuit designs versus "modern" all-triode designs

Hi Gentlemen

I came across this posting on the web: http://santafemusic.blogspot.com/2008/09/tube-be-or-not-tube-be.html and as you can see, the author pooh-poohs modern driver circuit designs and claims that the original Hafler designs are superior. This is not the first time I have come across this line of thought.

You opinions?
-- 'Jan

Bob, I was wondering the same thing - the common opinion over at DIYAudio and Audiokarma is "Before going to the trouble of replacing your VTA / Poseidon / whatever board with the original Hafler board, you want to go listen to an original ST-70 - sure it sounds good, but in a 'Fuzzy blanket' sort of way - it sounds DEAD".

Sorry, but I choose Accuracy and Detail over colouration and fuzziness - even if it means that it exposes weak components in the rest of the system.

Regarding NFB: I always wanted to ask about Negative Feedback (but were too scared in case it leads to a Religious War)! Bob, seems to me there was a line of thought in the Audiophile world in the 1990s/early 2000s that NFB is a BAD THING and should have been banned by the Pope, the UN Council on Human Rights as well as the SPCA. I therefore find it VERY interesting to know that the VTA board will still stay (relatively) stable when the NFB line (the 16 Ohm output on the OPT IIRC) is disconnected.

Supposedly, running without NFB should have the same effect as running in Triode mode (versus Pentode/Ultralinear mode), and I have been meaning to try it. I don't think I will bother now....

Thanks!
-- 'Jan

Bob, I was wondering the same thing - the common opinion over at DIYAudio and Audiokarma is "Before going to the trouble of replacing your VTA / Poseidon / whatever board with the original Hafler board, you want to go listen to an original ST-70 - sure it sounds good, but in a 'Fuzzy blanket' sort of way - it sounds DEAD".

Jan,

Younger listeners who grew up with solid state throw a stock ST-70 tube amp into their system. Their music system had a solid state amp in there and all of a sudden their "ears don't bleed" anymore from the hardness of their SS amp. They think they have found the holy grail of amps - an original Dynaco ST-70! What they have done is gone to the other end of the spectrum because an original ST-70 IS very listenable and smooth. The stock ST-70 doesn't give them the listening fatigue after 1/2 hour like their SS amp did. They also have a larger and deeper soundstage now that they didn't get with their SS amp. They may think they have found audio nirvana but there are are better tube audio amp designs out there that can give a more accurate music listening experience than a stock Dynaco amp.

Bob

I kind of disagree with the premise that modern amps have triode front ends and classic amps use pentode stages in the front end. There are several current marques that use pentodes in the front end, Shindo and Yamamoto come immediately to mind. Likewise many "traditional" amps had all triode front ends. It's more a design decision than it is a matter of tradition or currency.

As mentioned, the traditional Dyna circuits can sound quite fine, but there are better circuits available now, and different sounds to suit ones taste, from the more analytical sound of the Curcio boards to the more fluid sound of the VTA board. It doesn't seem that the blogger is really poo pooing (love that turn of phrase) modern circuits, but the Curcio circuit is clearly not to his taste and does not suit his system. Not surprising to someone who has heard Thiels.