ETALON-schematics?

Kal · 24th April 2004, 10:38 PM

Hello,

has somebody any schematics of Etalon Acoustics from Hungary?

Their Amps sound great - one league with Ayre, Pass, ML...

Thanx

Highlander · 24th April 2004, 11:59 PM

I found this one here:

Kal · 25th April 2004, 09:05 AM

Thank you!

Etalon seems to be quite uncommon and that is a pity, because their sound is very transparant, detailed AND MUSICAL!

Charles Hansen · 25th April 2004, 08:12 PM

I've never heard of this design, but appears to be a zero-feedback front end connected to an error-correction type of output stage. Jam should be interested in this one....

Steven · 25th April 2004, 08:36 PM

Nice design, using Hawksford's error correction around the output stage. Some months ago, I thought there were not many amplifiers using this technique, but it seems they are just good sounding secrets

.
For those who are interested in other designs using this technique (both with and without overall feedback):
http://www.diyaudio.com/forums/showt...446#post330446
http://www.diyaudio.com/forums/showt...997#post330997
http://wes.feec.vutbr.cz/~gratz/Download/Hawksford.ZIP
http://wes.feec.vutbr.cz/~gratz/Download/Cordell.ZIP

Steven

Steven · 25th April 2004, 08:44 PM

I'm a bit surprised though by the triac at the output of the Etalon amplifier. This must be to short circuit the output in case of DC on the output if anything goes wrong with the amplifier. Quad uses the same approach to avoid relay contacts in the output.
But the Quad amplifier uses current limiters in the output stage, while the Etalon amplifier has not. I hope the power supply is current limited... or else a DC-error might blow the output stage.

Steven

PMA · 25th April 2004, 09:07 PM

Yes, the triac is sometimes used as an output DC protection. Usually the fuse is connected between the output and the triac and the triac blows it when activated. Omitted here probably for the reason of fuse resistance.

lumanauw · 27th April 2004, 12:52 PM

There are 2 pots in the schematic. One is attached to base of BD139-BD140 pairs, I think it is Vbe multiplier for adjusting bias, and one is attached to its emitors, parrarel with 1kresistor. What is the second pot for? How to adjust to get the desired function?

Steven · 27th April 2004, 06:21 PM

The one on the left across the bases of the combined Vbe multiplier/error correction amplifier is for bias current adjustment.
The one on the right connected to the emitters of the Vbe multiplier/error correction amplifier is to adjust exact error cancellation. In that case the output impedance of the amplifier will be zero! Adjustment is easy: just connect a load resistor to the amplifier intermittently and look at the ouput voltage (sine wave) of the amplifier. Normally the output voltage will slightly decrease when loaded, but now adjust the preset such that the voltage will not drop. If you continue to change the preset, then the voltage will even increase when loaded (negative output resistance). The beauty of this preset arrangement is that the bias current and the error correction adjustment is independent of each other: it is (almost) free of interaction. Furthermore both adjustments operate for both halves of the output stage simultaneously, i.e. the positive half and the negative half.

Steven

jam · 28th April 2004, 02:56 AM

Charles,

Wow! You are right. I much like the buffer between the first two stages. Aragon used in their amps. I wonder if replacing the 1k resistor with a current source would help? ( Rhetorical question......

)

Regards,
Jam

P.S. The servo has got to go......................

24th April 2004, 10:38 PM	#1
Kal diyAudio Member Join Date: Aug 2003 Location: Germany	ETALON-schematics? Hello, has somebody any schematics of Etalon Acoustics from Hungary? Their Amps sound great - one league with Ayre, Pass, ML... Thanx

25th April 2004, 08:36 PM	#5
Steven diyAudio Member Join Date: Oct 2003 Location: The Netherlands	Nice design, using Hawksford's error correction around the output stage. Some months ago, I thought there were not many amplifiers using this technique, but it seems they are just good sounding secrets . For those who are interested in other designs using this technique (both with and without overall feedback): http://www.diyaudio.com/forums/showt...446#post330446 http://www.diyaudio.com/forums/showt...997#post330997 http://wes.feec.vutbr.cz/~gratz/Download/Hawksford.ZIP http://wes.feec.vutbr.cz/~gratz/Download/Cordell.ZIP Steven __________________ The Analog Art shows no sign of yielding to the Dodo's fate. The emergence and maturation of monolithic processing finesse has perhaps lagged a bit behind the growth of the Binary Business. But whereas digital precision is forever bounded by bits, there is no limit excepting Universal Hiss to the ultimate accuracy and functional variety of simple analog circuits. - Barry Gilbert, 1973

25th April 2004, 08:44 PM	#6
Steven diyAudio Member Join Date: Oct 2003 Location: The Netherlands	I'm a bit surprised though by the triac at the output of the Etalon amplifier. This must be to short circuit the output in case of DC on the output if anything goes wrong with the amplifier. Quad uses the same approach to avoid relay contacts in the output. But the Quad amplifier uses current limiters in the output stage, while the Etalon amplifier has not. I hope the power supply is current limited... or else a DC-error might blow the output stage. Steven __________________ The Analog Art shows no sign of yielding to the Dodo's fate. The emergence and maturation of monolithic processing finesse has perhaps lagged a bit behind the growth of the Binary Business. But whereas digital precision is forever bounded by bits, there is no limit excepting Universal Hiss to the ultimate accuracy and functional variety of simple analog circuits. - Barry Gilbert, 1973

27th April 2004, 06:21 PM	#9
Steven diyAudio Member Join Date: Oct 2003 Location: The Netherlands	The one on the left across the bases of the combined Vbe multiplier/error correction amplifier is for bias current adjustment. The one on the right connected to the emitters of the Vbe multiplier/error correction amplifier is to adjust exact error cancellation. In that case the output impedance of the amplifier will be zero! Adjustment is easy: just connect a load resistor to the amplifier intermittently and look at the ouput voltage (sine wave) of the amplifier. Normally the output voltage will slightly decrease when loaded, but now adjust the preset such that the voltage will not drop. If you continue to change the preset, then the voltage will even increase when loaded (negative output resistance). The beauty of this preset arrangement is that the bias current and the error correction adjustment is independent of each other: it is (almost) free of interaction. Furthermore both adjustments operate for both halves of the output stage simultaneously, i.e. the positive half and the negative half. Steven __________________ The Analog Art shows no sign of yielding to the Dodo's fate. The emergence and maturation of monolithic processing finesse has perhaps lagged a bit behind the growth of the Binary Business. But whereas digital precision is forever bounded by bits, there is no limit excepting Universal Hiss to the ultimate accuracy and functional variety of simple analog circuits. - Barry Gilbert, 1973

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25th April 2004, 09:05 AM	#3
Kal diyAudio Member Join Date: Aug 2003 Location: Germany	Thank you! Etalon seems to be quite uncommon and that is a pity, because their sound is very transparant, detailed AND MUSICAL!

25th April 2004, 08:12 PM	#4
Charles Hansen diyAudio Member Join Date: May 2003 Location: Colorado	I've never heard of this design, but appears to be a zero-feedback front end connected to an error-correction type of output stage. Jam should be interested in this one....

25th April 2004, 09:07 PM	#7
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	Yes, the triac is sometimes used as an output DC protection. Usually the fuse is connected between the output and the triac and the triac blows it when activated. Omitted here probably for the reason of fuse resistance.

27th April 2004, 12:52 PM	#8
lumanauw diyAudio Moderator Emeritus Join Date: Oct 2002 Location: Bandung	There are 2 pots in the schematic. One is attached to base of BD139-BD140 pairs, I think it is Vbe multiplier for adjusting bias, and one is attached to its emitors, parrarel with 1kresistor. What is the second pot for? How to adjust to get the desired function?

28th April 2004, 02:56 AM	#10
jam diyAudio Member Join Date: May 2001 Location: Charlotte,NC,USA	Charles, Wow! You are right. I much like the buffer between the first two stages. Aragon used in their amps. I wonder if replacing the 1k resistor with a current source would help? ( Rhetorical question...... ) Regards, Jam P.S. The servo has got to go......................

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