Whooah..!
Now I'm getting lost...
I recall the EF II from D. Self, but I can't recall what DFP and SS amps stand for, and which "de Haan" refers to...
I guess I'm down to choosing between something inspired by D.Self's EF2, or the Stasis design (if I can avoid it's oscillations)
Pro's and cons of these two in class AB operation would be appreciated.
Jens
Now I'm getting lost...
I recall the EF II from D. Self, but I can't recall what DFP and SS amps stand for, and which "de Haan" refers to...
I guess I'm down to choosing between something inspired by D.Self's EF2, or the Stasis design (if I can avoid it's oscillations)
Pro's and cons of these two in class AB operation would be appreciated.
Jens
"I recall the EF II from D. Self, but I can't recall what DFP and SS amps stand for, and which "de Haan" refers to... "
CFP is figure 3 from D.Self, the Stasis is a variation of this. SS is short for 'solid state', deHaan is the author of the two FET amps I linked to for the DC off-set scheme.
"I guess I'm down to choosing between something inspired by D.Self's EF2, or the Stasis design (if I can avoid it's oscillations)"
If you split the collector load resisor for the driver transistor it acts like a base resistor for the output transistor, a small base resistor may be needed for the driver(both of these might need to be done for the EF stage as well).
Threshold sold thousands of amplifiers that worked, as did Nakamichi.
The basic CFP output stage was used for many years by Marantz, Harman Kardon, Bryston, etc.
"Pro's and cons of these two in class AB operation would be appreciated."
The EF is easier to construct, but is not unity gain. The CFP will take a little more effort, but I think sounds better open loop. You can construct both with the same transistors, why not give them both a listen?
A nice DC servo schematic from Hawk:
http://www.tnt-audio.com/gif/a18a.gif
Another follower:
http://www.audiodesignguide.com/my/Hot_Follower1.GIF
CFP is figure 3 from D.Self, the Stasis is a variation of this. SS is short for 'solid state', deHaan is the author of the two FET amps I linked to for the DC off-set scheme.
"I guess I'm down to choosing between something inspired by D.Self's EF2, or the Stasis design (if I can avoid it's oscillations)"
If you split the collector load resisor for the driver transistor it acts like a base resistor for the output transistor, a small base resistor may be needed for the driver(both of these might need to be done for the EF stage as well).
Threshold sold thousands of amplifiers that worked, as did Nakamichi.
The basic CFP output stage was used for many years by Marantz, Harman Kardon, Bryston, etc.
"Pro's and cons of these two in class AB operation would be appreciated."
The EF is easier to construct, but is not unity gain. The CFP will take a little more effort, but I think sounds better open loop. You can construct both with the same transistors, why not give them both a listen?
A nice DC servo schematic from Hawk:
http://www.tnt-audio.com/gif/a18a.gif
Another follower:
http://www.audiodesignguide.com/my/Hot_Follower1.GIF
Thank you to all who've helped me on this output stage issue
*doing the happy man's dance for office chairs*
I think it's time to temporarily withdraw from this chat, and hide behind my 'puter to do some simulation, and hopefully end up with something useful.
It's not too important if the output is exactly unity gain, or has a little less output swing than input, as I got plenty of voltage gain in my first stage.
If I can turn my Stasis "oscillator" into a power follower of some sort, then I'm a happy man for sure
I need to give those last comments about the split collector resistors a second thought, but enevtually I hope to see the light.
Jens
*doing the happy man's dance for office chairs*
I think it's time to temporarily withdraw from this chat, and hide behind my 'puter to do some simulation, and hopefully end up with something useful.
It's not too important if the output is exactly unity gain, or has a little less output swing than input, as I got plenty of voltage gain in my first stage.
If I can turn my Stasis "oscillator" into a power follower of some sort, then I'm a happy man for sure
I need to give those last comments about the split collector resistors a second thought, but enevtually I hope to see the light.
Jens
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