GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Melquiades Amplifier
In the Thread: Single-stage Melquiades vs. DHT amps

Post Subject: Swimming the ocean at night?Posted by Romy the Cat on: 12/28/2008

drdna wrote:
I think this 2A3 must have a specific set-up to sound its best. You have not found it yet. To begin with and familiarize yourself with the sound of it, I suggest sticking with the topology that has been tested by amplifier designers, since they have tried many configurations before releasing their design. Let them do the work for you. Get to know it before a lot of experimenting. It is like swimming in the ocean at night.

I am not sure where this comment comes from. The 2A3 might need a specific set-up to sound its best but I do not violate the way how it was for years “tested by amplifier designers, since they have tried many configurations before releasing their design”. I you paid attention my 2A3 us use as it was for many years – with cathode bias and 275V in plate. I do not know what you mean by “specific set-up” and what San Audio did is very orthodox use of 2A3 and I did not change it.

The only change that I made (and I do not know at this point if it was a good change) was the change of the driver tube from 6SN7 to 6E5P. Objectively the 6E5P is way better driver then driver. In fact of you insist that I need to “sticking with the topology that has been tested by amplifier designers, since they have tried many configurations before releasing their design” then the 6E5P way more used tube then 6SN7 as a driver. The 6SN7 is used since 1940 and there were tones of amps built with it where the 6SN7 was a driver, mostly in 3 stages design. When 6E5P was “discovered” for audio use in 1999 than it would be very educational to look what Russians designer and DIYer use as driver. (I say Russians become 6E5P is very popular in there and conceded the king of the drivers). Since 1999-2000 no one use 6SN7 type tube anymore as everyone switched to 6E5P. The 6E5P is objectively ultimate 2 stage driver. It has 10 times more gain then 6SN7 (30 vs. 20 on 6SN7) it can push much more current (3.5W of max single plate dissipation on 6SN7 vs. 8.5W), has much lover plate impedance (7kOhm for 6SN7 vs. 1kOhm), and has higher bias that is very important for sources that swing a lot of voltage foe 2-stage amps. I mean objectively the 6SN7 is not even a competition for 6E5P as they are different level of drivers. Interesting that they were used for the very same purpose – vertical-deflection for TVs and oscilloscopes – it was exactly where Dima discovered it. Anyhow, I think if the 6E5P-class tube was able since WWII as 6SN7 then you would never see the 6SN7 to drive 2A3.

Saying all above I have to aphesis that I DO NOT MAKE ANY CLAIMS about sonic characteristics of 6SN7 vs. 6E5P. I know the 6E5P/6E6P very well but I never played with 6SN7. In fact it shell be a good tube and I heard a lot of good sounding devises with it. Still, as an universal driver and using the only objective data the 6SN7 is different class of driver that not even rivalry with 6E5P/6E6P. It would be interesting is somebody do sonic comparing of the 6E5P/6E6P vs… anything else indirect-heated out there.

Rgs,
The caT

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