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With much thanks and help from Mike Samra, my newly installed ECC99 drivers are working nicely. In my 2A3 amps, I have wanted to try out some triode drivers. Recently many of you volunteered ideas for triode drivers, little did I realize that I had 2 of the ECC99 tubes already at home. So, it was easy to install the 9-pin sockets and the tubes.
The optimal operating points for the ECC99 are not final, but with some help from Mikey we were able to get very close. The ECC99s have led bias (5V+) and are running at 180V, but more to come soon as I need a few higher wattage resistors.
Once I installed the ECC99 drivers, the sound was much warmer and fuller, which is what has been elusive for me. The ECC99s seem to be a nice match with the JJ 2A3-40 output tubes which are dialed in at 12.1W dissipation. Very happy with the sound for now.
Follow Ups:
Is the ECC99 doing both voltage amplification and driver functions? If so, I would understand better that Mike says you can tweak the settings to get more power. Thanks.
The ECC99 is serving a driver function only. I believe Mikey was referring to a higher B+ to get the most out of the JJ 2A3-40 output tubes.
Pat
You can dial that JJ tube in for a lot more power if we raise the B+ to around 450v.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
What's the operating conditions you suggest for a lot more power? I have JJs too, may want to try the maximum power condition some day .
The JJ 2A3-40 can handle 450v as I recall and boosting the B+ is the first thing he would have to do.The other night when I was helping him,the ECC99 was drawing 35ma.That told me we had to raise the cathode voltage by adding more LEDs and then it dropped to 21ma but also,he was only running 243v between the plate and cathode of the 2A3 so we had to raise the B+ to at least get it to a 250v potential which he did.The first choke went to the 2hy 35 ohm tap and that helped with that.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
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