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VSE PP1 driver stage

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Andrewbee

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Joined 2002
#1
Does anyone in diyAudio land have any knowledge as to how well the driver stage from this amp would drive a pair of 2a3's?
I am lashing up the front end in the next few weeks (if I get the parts before the Christmas rush) and was going to try it first with el84's in U.L. mode and fixed bias then the 2A3's also with fixed bias.

Thanks

Andrew
 
#2
Hi,

Does anyone in diyAudio land have any knowledge as to how well the driver stage from this amp would drive a pair of 2a3's?
Click to expand...

It would work but there's better to be had for driving 2A3s.
The input stage is a cascode (a bit like a small signal penthode minus the noise) which has high gain but unfortunately also rather high output impedance.
For penthodes such as EL84s, EL34 etc. it should work fine.

You could turn the cascodes into mu-followers to drive the 2A3s if you want to stick with a similar hook-up.

Cheers,😉
 
#3
Andrewbee said:
Does anyone in diyAudio land have any knowledge as to how well the driver stage from this amp would drive a pair of 2a3's?
I am lashing up the front end in the next few weeks (if I get the parts before the Christmas rush) and was going to try it first with el84's in U.L. mode and fixed bias then the 2A3's also with fixed bias.

Thanks

Andrew
Click to expand...
Works fine. For EL84's be warned that it will have a heap too much gain.
 
#4
Andrewbee said:
Does anyone in diyAudio land have any knowledge as to how well the driver stage from this amp would drive a pair of 2a3's?
I am lashing up the front end in the next few weeks (if I get the parts before the Christmas rush) and was going to try it first with el84's in U.L. mode and fixed bias then the 2A3's also with fixed bias.

Thanks

Andrew
Click to expand...


If I'm not mistaken(guessing 😉 ), he may have switched to 6H30's or ECC99's, still in his favorite cascode implementation, for 2A3's, 300B's, etc.,... this is from different correspondences on the tube DIY asylum.

The latest schematics haven't been published.
 
#5
vse pp1 driver stage

Thanks guys.

I heard about a newer version, in fact Allen told me about it, a pp2c but well, you know Allen, it "might" be a while before he sends it to me🙂

I suppose I could replace the 6922's with 6h30's, less gain and maybe a little more omph for the 2A3's.
I have el34's, kt66's (real ones) and kt88's so could keep the triode wired pentode / tetrode but prefer to use a real triode, I also have the 2a3's as well as 300b's but the 300b's are not my cup of tea, at least the ones I have.

On a slightly different note but still related, I have a pair of 100W U.L. Massicore output transformers which I believe were made by G.E.C., huge heavy beasts which were rewound but the bakelite plates with the markings were replaced and I do not have a clue how to connect the secondaries, the primaries were marked. Anyone familiar with them?

Maybe I should try the kt66's triode wired with the Massicores?
I think they have 4300R primaries.

Thanks again

Andrew
 
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