Upupa Epops has been displaying his opinion to some amps for some time here. He had been criticized that he did not show his own. Now an interesting discussion has started at http://www.diyaudio.com/forums/showthread.php?s=&postid=330991#post330991 regarding Steven's design, a bit similar to Pavel Dudek's ones. Pavel Dudek decided to release two of his amps developed in 1992. Here they are:
http://web.telecom.cz/macura/dpa_386.pdf (mosfet)
http://web.telecom.cz/macura/dpa_222.pdf (bipolar)
with PCB's as well. The amps serve as reference power amps in our country, compared with most of the well known amps and beating them in clarity, purity and resolution. Some minor improvements have been recently made in the input stages, not shown at linked schematics.
http://web.telecom.cz/macura/dpa_386.pdf (mosfet)
http://web.telecom.cz/macura/dpa_222.pdf (bipolar)
with PCB's as well. The amps serve as reference power amps in our country, compared with most of the well known amps and beating them in clarity, purity and resolution. Some minor improvements have been recently made in the input stages, not shown at linked schematics.
Resistors
Parallel connection of small resistors ( 0207 ) have several advantages against bigger ones : they are problemloss to buy, summary price ( per wattage ) is lowest, have standardly 1 % tolerance, thanks parallel connection is reliability very good and, what is for me very important, PCB looks nice 😉 .
Parallel connection of small resistors ( 0207 ) have several advantages against bigger ones : they are problemloss to buy, summary price ( per wattage ) is lowest, have standardly 1 % tolerance, thanks parallel connection is reliability very good and, what is for me very important, PCB looks nice 😉 .
I have seen these layouts before, and I must admit that I'm very fond of the beautiful and compressed layout 
i would give the layout a "fair" rating, i seldom find that all my 2 legged critters just happen to want to be scrunched up together shoulder-to shoulder in parallel rows for best electrical performance but the lack of squirrelly tracks snaking between and around parts does show the care put into parts placement - the layout may get better than fair marks for ease of assembly
and as always power/signal ground and supply rail routing can really only be evaluated and perfected within the context of the whole chassis and power/signal i/o connections
and as always power/signal ground and supply rail routing can really only be evaluated and perfected within the context of the whole chassis and power/signal i/o connections
Thanks jcx
for your nice words 😎 . Outside of this PCB are only toroid, input connector, protection circuit and output binding posts. True this extremly short rail ways have amp very good SNR ( more than 122 dB, refered to full output, IHF - A, or 117 dB linear).
for your nice words 😎 . Outside of this PCB are only toroid, input connector, protection circuit and output binding posts. True this extremly short rail ways have amp very good SNR ( more than 122 dB, refered to full output, IHF - A, or 117 dB linear).
DPA
Hello,
I see that Pavel Dudek's amplifiers are still better, I remember that few years ago magazine called "Amaterske Radio" had few of them on theis pages.
But I don't like one thing, overall negative feedback (I'm one of guys that don't like overall negative feedback).
Tak nech vam to pekne hraje aj s tou spetnou vazbou.
Hello,
I see that Pavel Dudek's amplifiers are still better, I remember that few years ago magazine called "Amaterske Radio" had few of them on theis pages.
But I don't like one thing, overall negative feedback (I'm one of guys that don't like overall negative feedback).
Tak nech vam to pekne hraje aj s tou spetnou vazbou.
To DarkOne
386 is eight years old and newest will be still better 😉 - and they will have feedback too 😀 . Thanks.
386 is eight years old and newest will be still better 😉 - and they will have feedback too 😀 . Thanks.
Re: Resistors
Do you always use the third person when you talk about yourself? 😉
You have maybe forgotten one thing about using small resistors, which may or may not be important: Transient handling capability.
Nice job, PavelUpupa Epops said:
Do you always use the third person when you talk about yourself? 😉 You have maybe forgotten one thing about using small resistors, which may or may not be important: Transient handling capability.
The amp looks very good Pavel, I suppose it is a commercial amp?
Although just a minor detail, I do like that clever idea of etching
warning signs on the mains (?) PCB.
Although just a minor detail, I do like that clever idea of etching
warning signs on the mains (?) PCB.
Warning signs
This is little PCB above main PCB. Below are mains inlet ( Schurter ), mains fuses and WAGO's for connecting of trafos. Little PCB also fixed mains wires from power switch against releasing. This amp I had try made as comercial product and in our country is well known. In Poland was by one magazine declared as " Power amp of the year '98 ( ? ) ".
This is little PCB above main PCB. Below are mains inlet ( Schurter ), mains fuses and WAGO's for connecting of trafos. Little PCB also fixed mains wires from power switch against releasing. This amp I had try made as comercial product and in our country is well known. In Poland was by one magazine declared as " Power amp of the year '98 ( ? ) ".
Upupa Epops said:
Nice tablecloth! 😀
Impressive work!
Only the output connectors (?) looks a bit exaggerated.
Common emmitter, floating cooler...any specs?
Heinz!
Pavel. i wish i was able to do it like that 😎
Probably takes a lifetime to learn though
Greetings,
Klaas
Probably takes a lifetime to learn though
Greetings,
Klaas
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