Would it be nice to have constant current on the output transistors ?

Bernhard · 10th April 2009, 07:33 PM

No current swing = less distortion ?

woody · 10th April 2009, 07:55 PM

How were you thinking of doing this?

Bernhard · 10th April 2009, 07:58 PM

Quote:

Originally posted by woody
How were you thinking of doing this?

I mean in theory, would it be... ?

Frank Berry · 10th April 2009, 07:58 PM

No current swing = no output power.

woody · 10th April 2009, 08:01 PM

Doesn't Nelson do this in his Stasis amplifiers?

Bernhard · 10th April 2009, 08:02 PM

Quote:

Originally posted by Frank Berry
No current swing = no output power.

Please somebody could answer my question.

Bernhard · 10th April 2009, 09:12 PM

Same question from me > three years ago

const. voltage & const. current on output FET ?

Just made a circuit that keeps the current swing of the gain device around 10mA @ a bias of 1,1A.

I would like to implement constant current in a circlotron.

fotios · 11th April 2009, 04:20 AM

IMHO the main beneffit that offers a CCS it is the absolute rejection of the power supply ripple remaining after the reservoir capacitors, which in practice translated in better "hum" rejection. It is ucefull from the input stage up to the voltage gain stage because the common emitter arrangements.
I had an idea in the past (maybe like your?) to buffer each output transistor from the supply rail with another one (same) transistor, like in cascading form. After experimenting, the result was a loss of p-p voltage arround 5V in output, thus reduction of power, in the same time time that i had not any improvement in output noise.

Fotios

Wavebourn · 11th April 2009, 05:41 AM

Quote:

Originally posted by woody
Doesn't Nelson do this in his Stasis amplifiers?

I did that as well, many times, from line drivers to power amps. Also, I kept both current and voltage almost stable.

Bernhard · 12th April 2009, 09:49 AM

I tried it now in a simulation with a circlotron that has distortion cancellation.
After adjusting the X resistor, THD figures stay exactly how they were around -123 dB for +/-10V swing..

10th April 2009, 07:33 PM	#1
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	Would it be nice to have constant current on the output transistors ? No current swing = less distortion ?

10th April 2009, 07:58 PM	#4
Frank Berry diyAudio Member Join Date: Sep 2003 Location: Midland, Michigan	No current swing = no output power. __________________ Frank

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10th April 2009, 07:55 PM	#2
woody diyAudio Member Join Date: Jan 2002 Location: Tyrone Ga. U.S.A.	How were you thinking of doing this?

10th April 2009, 08:01 PM	#5
woody diyAudio Member Join Date: Jan 2002 Location: Tyrone Ga. U.S.A.	Doesn't Nelson do this in his Stasis amplifiers?

10th April 2009, 09:12 PM	#7
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	Same question from me > three years ago const. voltage & const. current on output FET ? Just made a circuit that keeps the current swing of the gain device around 10mA @ a bias of 1,1A. I would like to implement constant current in a circlotron.

11th April 2009, 04:20 AM	#8
fotios diyAudio Member Join Date: Feb 2007 Location: ΔΡΑΜΑ - North Greece	IMHO the main beneffit that offers a CCS it is the absolute rejection of the power supply ripple remaining after the reservoir capacitors, which in practice translated in better "hum" rejection. It is ucefull from the input stage up to the voltage gain stage because the common emitter arrangements. I had an idea in the past (maybe like your?) to buffer each output transistor from the supply rail with another one (same) transistor, like in cascading form. After experimenting, the result was a loss of p-p voltage arround 5V in output, thus reduction of power, in the same time time that i had not any improvement in output noise. Fotios

12th April 2009, 09:49 AM	#10
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	I tried it now in a simulation with a circlotron that has distortion cancellation. After adjusting the X resistor, THD figures stay exactly how they were around -123 dB for +/-10V swing..

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