DPA-222 BJT amp from Upupa Epops - diyAudio
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Old 3rd July 2004, 01:30 PM   #1
Electrons are yellow and more is better!
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Default DPA-222 BJT amp from Upupa Epops

Click the image to open in full size.

What do you think of this? Nice work but with unknown performance.

Schematics and pcb layout here
http://www.sjostromaudio.com/dudek/files/DPA-222.pdf
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Old 3rd July 2004, 02:29 PM   #2
UrSv is offline UrSv  Sweden
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Exceptional build quality and amazingly neat PCB design. IMHO, obviously the work of a cery experienced professional.

Simply wonderful to see something like that.

PCBs for sale?
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Old 3rd July 2004, 02:41 PM   #3
Rudy is online now Rudy  Belgium
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picture =/= schematic

but still very very very nice construktion, not only on a mechanical base

Question to pavel, is it realy neccesary all the diodes for softclipping ? or is it just becouse the outpust stage is on an lower voltage then the vas and diff pair, would you still use them if all the devices or on the same railvoltage.

is this a commercial produkt or just for diy ?
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Old 3rd July 2004, 05:48 PM   #4
Electrons are yellow and more is better!
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Quote:
Originally posted by Rudy
picture =/= schematic
I noticed that. Maybe Pavel can give me the newest schematics? I have sent him an email about it.

The amp hasn't any soft clipping... no? Some of the diodes are for fold back current limiting and some are for biasing.
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Old 3rd July 2004, 06:31 PM   #5
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it looks great.

has anyone heard it?
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Old 4th July 2004, 12:49 AM   #6
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I must little correct Per - Anders : it is pic of my amp DPA 222, which BJT, not MOSFET. This pic I was send him only as example of mechanical conception and, " mea culpa ", without name . 386 have the same construction, only PCB is little bit short. All my amps have now the same mechanical / electronic design and I'm ready to explain it step by step and I mean, that you will be agree with me. Rudy ask me, if is neccessary to use antisaturation diodes and my answer is " yes " - when all amps will have this circuit solution, talking about " high gain or low gain " and " feedback or feedbackless " will ended. Guys, now is too late here in Europe, bed is calling, but if you will to can, I will write more tomorrow.
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Old 4th July 2004, 07:04 PM   #7
Electrons are yellow and more is better!
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It's updated now, DPA-386 => DPA-222 Still, a nice looking amp

Technical data here
http://www.sjostromaudio.com/dudek
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Old 4th July 2004, 07:32 PM   #8
mikeks is offline mikeks  United Kingdom
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Most excellent handiwork..upapa epops...
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Old 6th July 2004, 02:32 PM   #9
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Default Fet power amplifier DPA 380

Birth date: Year 1992 ...

http://machalik.hi-end.org/temp/dpa380.jpg
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Old 6th July 2004, 06:04 PM   #10
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Default DPA 380

It is amplifier in which I was at the first use Cordell's error correction ( Per - Anders have scanned schematic from magazine, where I had published it, with measurig on Ap ). It was builded by maybe thousand people and still is, 'cos its parametres after twelve years don't lose excelent quality. In short : Output power - 130 / 8, 200 / 4. SNR - more than 124 dB ( IHF - A ), more than 120 dB linear. Fr. char. - 1 Hz - 300 KHz ( full power ). Distortion ( 1dB below full power ) 20 - 20 000 Hz below 0. 01 %. SR - more than 100 V / micro sec. Offset - below 1 mV. 2 Ohm stable. PCB's still available.
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