https://aliexpress.ru/item/1005005586448990.html?sku_id=12000033654044620 The best board for making an amplifier. It is better not to use a large capacitor. This thread has a list of parts and assembly recommendations.
Look carefully and compare the boards. Yours are close, but not the best. You can do it on them. If you want to get as close as possible to the original, you need to follow all the recommendations. Unfortunately, without studying the material, you may not get a good result. Repeat writing what has already been written, too not easy. I can publish photos, diagrams, tables. By the way, the last pages of my statements will help you.
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The diagram is original. Here is from different sites about Dartzeel.In the original, in a further upgrade, a supercapacitor was installed, which, according to reviews, worsened the sound but reduced the constant drift at the output. During cloning, many people removed it or did not install it. The input four transistors were selected and thermally connected. More than 20 mV did not rise, but even 100 mV does not affect sound.Drawing I posted it again.
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The schematic is very similar to what we used in the power amps of our old company, since end of the seventies.
Main difference is the use of additional emitter followers Q5, Q6. Not sure why 90% of the input stage gain is
wasted in R7, R8. Also noticeable is the lack of emitter resistors for Q11, Q12. The bias for drivers Q9, Q10 is
very high, more than 100 mA. What are diodes D3, D4 good for ? A slow dc servo should be added, no "super
capacitor". Maybe I wrote similar things before, sorry.
Main difference is the use of additional emitter followers Q5, Q6. Not sure why 90% of the input stage gain is
wasted in R7, R8. Also noticeable is the lack of emitter resistors for Q11, Q12. The bias for drivers Q9, Q10 is
very high, more than 100 mA. What are diodes D3, D4 good for ? A slow dc servo should be added, no "super
capacitor". Maybe I wrote similar things before, sorry.
Yes, you wrote about this. I agree with you, the scheme is not new. The whole trick is that Dartzeel probably simplified it, changed or added something, patented it. I think the patent would not have been issued if there had been plagiarism. I assure you, he plays better in this form old vintage expensive Japanese.
Depends on in which country it is patented. In USA you can get a patent for a dog stick.
https://www.freepatentsonline.com/D461025.html
https://www.freepatentsonline.com/D461025.html
But this is already a parody of Dartzeel. There was a lot of discussion about it on the Russian forum. It plays great on a couple of output transistors, why add more? It doesn’t need a zero-setting board. The very concept of this amplifier is lost. But in this thread there are a lot of improvements him, I don't mind.
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Then why are there so many sales in the USA? By the way, there is another foreign forum on it, which was opened a long time ago. There, too, it was remade on many different boards. If it were not interesting, no one would be interested in it. Not everyone succeeds, despite its simplicity scheme.
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Try it in this form, if you like it, you will assemble it on a good board and with good parts.
As experts told me, on your board the ground area is close to the contacts, which is not good (I, of course, don’t understand this either), but my boards are 1:1 from the original and this is not there. Look at the boards from the soldering side of the parts. A good board doesn’t have it. But for the first acquaintance, I think you can assemble it on it. I sold those that were in my amplifier and made all the good boards and parts. I have nothing else to exchange.
