• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Problems with Chinese PP kit

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Rallyfinnen

Rallyfinnen

Member
Joined 2017
I'm thinking about getting a cheap valve amp to play around with, what would you recommend in this price range? Any specific amp/seller, based in Europe?
I have not played around with tube amps, but built and modified a number of solid state amps, so looking to learn something about valve amps with a cheap project, measure, and maybe listen if I like the sound of it..
 
oemcar

oemcar

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Joined 2020
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Rallyfinnen said:
I'm thinking about getting a cheap valve amp to play around with, what would you recommend in this price range? Any specific amp/seller, based in Europe?
I have not played around with tube amps, but built and modified a number of solid state amps, so looking to learn something about valve amps with a cheap project, measure, and maybe listen if I like the sound of it..
Click to expand...
I built the PP amp in this thread 3 yrs ago. It was a good starting point to enter the tube amp field.
The amp in thread below has good specs- 20-28k, but @ what dB is unknown. IMO price is reasonable-

https://www.aliexpress.us/item/3256802532801472.html

Post #242 builder is happy with the results, otherwise I would not mention for consideration.

https://www.diyaudio.com/community/...e-i-build-maybe-during-if-i-do.394962/page-13

Jim
 
Rallyfinnen

Rallyfinnen

Member
Joined 2017
Thank you for the replies! The amp in this thread seems to be the cheapest to buy and available in Europe, but maybe there is a lot to be spent to get it performing well? Seems a lot is wrong with the original design.
Maybe getting a used amp locally would be a better alternative?
I have too many projects, it might be left sitting in a box and never finished too :) I need to think about it a bit, too easy to press the 'buy' button!
 
S

snapper

Member
Joined 2007
unbekannter Röhrentyp: E27 :D:LOL::ROFLMAO:

https://www.ebay.com/itm/275755500514

s-l1600 (8).jpg
 
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S

snapper

Member
Joined 2007
Rallyfinnen said:
Thank you for the replies! The amp in this thread seems to be the cheapest to buy and available in Europe, but maybe there is a lot to be spent to get it performing well? Seems a lot is wrong with the original design.
Maybe getting a used amp locally would be a better alternative?
I have too many projects, it might be left sitting in a box and never finished too :) I need to think about it a bit, too easy to press the 'buy' button!
Click to expand...
In Germany this amplifier is available again with a big discount, which makes the offer almost irresistible (it is also available for shipping to Sweden but with slightly different conditions) ;)

pay.JPG
 
S

snapper

Member
Joined 2007
I have to ask DOUKMALL directly about an advertising commission :LOL:
"and the voltages are a bit scary too.."
a 100K 2w discharge resistors across the 330µf in the power supply circuit works wonders, at least when the power plug is disconnected ;)
https://www.digikey.de/en/resources...version-calculator-capacitor-safety-discharge
And I would definitely install series resistors in the heating system. This protects the tubes and limits the load on the power transformer !
https://www.diyaudio.com/community/threads/problems-with-chinese-pp-kit.353111/page-5#post-7473748
 
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jcalvarez

jcalvarez

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Joined 2021
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DC voltages look close in simulation, the input pentode voltages are a bit off, I use a 6U8 (ECF82), not sure how close is to the Chinese 6F2, and for the 6P1 I use a 6P1P-EV model found here in the Spice models' thread. I also used an 8K:8 OPT, not sure which one is required.
1699919177504.png
 
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