If You apply emitter follower between the 2 stages, will increase the performance. Most of the distortion resulted by the nonlinear Cdg capacitance of the output devices.
sajti
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Zenotron is a power amp with only 2 JFET and 2 MOSFET.
It has lots of distortion.
Can it be improved, maybe?
Link: 2A & DIY
Schema:
If you want to minimize the number of active components, how about two? Is it too many?
Zero Feedback Transformer Audio Power Amplifier
The Transformer audio Power amplifier...has not two but four active devices....
where especially the last High Current transformer is a limiting factor...
besides it has really nothing to zenotron...
I agree with Saity... A Stage in between the input and output would do some good....Some better drive of the mossfets would be good...
Thinking something like the current mirror in your J-fet-amplifier (mirrored to each rail and ...made from 2SA970 SC2240) with a resistor in the center to give the right bias spreading....
where especially the last High Current transformer is a limiting factor...
besides it has really nothing to zenotron...
I agree with Saity... A Stage in between the input and output would do some good....Some better drive of the mossfets would be good...
Thinking something like the current mirror in your J-fet-amplifier (mirrored to each rail and ...made from 2SA970 SC2240) with a resistor in the center to give the right bias spreading....
MiiB.
I did a mirror.
It is absolute the perfect solution. Gives easier load onto JFETs.
The distortion became better with a factor of more than 10 times.
See Image.
Attachments
With this action You increase the open loop gain. So more feedback, means less THD.
Sajti
Unfortunately adding drivers too, did not improve.
THD 0.017% vs THD 0.014% without drivers.
Do you mean Zen variation 5.
I know Pass has done two HEXFET with output from Drain.
The complementary Zen.
http://www.passdiy.com/pdf/zen-v5-hires.pdf
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EDIT.
Yes, I see F5 is like you say.
http://www.dms-audio.com/system/files/F5-Nelson.pdf
.
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Here I have feedback to each JFET.
LIke Nelson Pass in his F5.
It does not change much. Same level of THD.
Like with normal feedback.
And as good and low as 0.011%
The dist spectrum is interesting.
Image shows Fourier at 8 Watt and 0.041% THD
LIke Nelson Pass in his F5.
It does not change much. Same level of THD.
Like with normal feedback.
And as good and low as 0.011%
The dist spectrum is interesting.
Image shows Fourier at 8 Watt and 0.041% THD
Attachments
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Zenotron is a power amp with only 2 JFET and 2 MOSFET.
It has lots of distortion.
Can it be improved, maybe?
Link: 2A & DIY
Schema:
Topology looks more like Hiraga's "le monstre" topology about the URLs
Amplificateur DIY - Le monstre 8W
http://belinfabien.free.fr/amplificateur/le monstre/schema/schema_ampli.png
http://www.diyaudio.com/forums/solid-state/32611-le-monstre-2.html
http://www.diyaudio.com/forums/solid-state/5462-hiraga-le-monstre-4.html
and not as a combination consisting of the "ZEN" - and the "CSPP/Circlotron topology.
How can I transform it in the totem pole topology about
http://www.susan-parker.co.uk/zeus.htm
but with transistors instead a phase shift transformer?
And how can I transform it in a real circlotron topology also without transformer (but with four supply rails - two for the input stage) ??
For the last case there is already a thread:
http://www.diyaudio.com/forums/solid-state/146586-conversion-hiragas-le-monstre-circlotron.html
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