I'd like some ideas please for my next PP amp. The ingrediants I want to use are Sovtek 2a3s and 2C22/7193, which is a 6J5GT equivalent, so basically for a pair, think 6SN7. I guess choices are a) some kind of cascode, SRPP or Mu stage. If so, do I use 2C22 top and bottom or some other combination? There are some 6J5GT values in Morgan Jones' book
b) One diff pair (and a high output preamp)
c) Two diff pairs
d) Direct coupled
e) Transformer coupled (I'm pretty happy with teflon caps.....)
f) Other
Sound quality is the main concern - whatever sounds best.
I mention the 2C22 because so far it's the cleanest most detailed valve I've used for input stages. I have some older valves I haven't used yet if that helps - 76, 56, 37, 27, 26. I also have 6C45 but haven't used that yet, likewise 8532. I have loads more valves if you want to make any other suggestions. I don't mind any kind of overkill on this project, since the idea is to have a reference amp. Smallish room, lowish sound levels, jazz and classical. Two monobloks. Power supply will have damper diodes, a number of chokes and all polypropylene caps. OPTs are Lundahl 6K PP. Andy
b) One diff pair (and a high output preamp)
c) Two diff pairs
d) Direct coupled
e) Transformer coupled (I'm pretty happy with teflon caps.....)
f) Other
Sound quality is the main concern - whatever sounds best.
I mention the 2C22 because so far it's the cleanest most detailed valve I've used for input stages. I have some older valves I haven't used yet if that helps - 76, 56, 37, 27, 26. I also have 6C45 but haven't used that yet, likewise 8532. I have loads more valves if you want to make any other suggestions. I don't mind any kind of overkill on this project, since the idea is to have a reference amp. Smallish room, lowish sound levels, jazz and classical. Two monobloks. Power supply will have damper diodes, a number of chokes and all polypropylene caps. OPTs are Lundahl 6K PP. Andy
I agree with your comments about the 2c22 / 7193 having used these in linestages and preamp applications. A cleaner and more detailed 6SN7 really but lets keep that quiet before the prices start going up! If you don't already have curves for the 7193, you can find a datasheet at Gary Kaufman's site - http://www.the-planet.org/ in the linestages section.
When it comes to power amplifiers my ears prefer single ended to push-pull designs. The main differences for me are resolution of low level detail and ability to preserve rhythm and timing. Given the choice, I would prefer a SE 211 over the PP 2A3.
If you prefer the sound of PP, then I would consider using an interstage transformer to do the phase splitting as in my experience, the reduced component count and shorter signal path does improve resolution.
When it comes to power amplifiers my ears prefer single ended to push-pull designs. The main differences for me are resolution of low level detail and ability to preserve rhythm and timing. Given the choice, I would prefer a SE 211 over the PP 2A3.
If you prefer the sound of PP, then I would consider using an interstage transformer to do the phase splitting as in my experience, the reduced component count and shorter signal path does improve resolution.
Two diff pairs for sure. Current source cathode loads. Direct coupling.
If you use a transformer for a phase splitter, do it right at the input; low level signals are easiest to transform and galvanic isolation is a benefit.
If you use a transformer for a phase splitter, do it right at the input; low level signals are easiest to transform and galvanic isolation is a benefit.
I was just looking at Jeremy Epsteins direct coupled SET 2a3 amp with 8532 input. It would be interesting, though would tax my skills a bit, to double this up for PP starting with a diff pair of 8532. Easier not to direct couple - that would be a simple two stage design. A thought..........
http://db.audioasylum.com/cgi/m.mpl?forum=bottlehead&n=512&highlight=8532&r=&session=
http://db.audioasylum.com/cgi/m.mpl?forum=bottlehead&n=512&highlight=8532&r=&session=
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