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PaX amplifier: invitation to discussion

HiFi, LoFi, Tubes, Transistors, ICs, Commercial, DIY

Postby janneman01 » Sat Jun 25, 2011 12:00 am

Sorry I do not understand your question and what you mean by 'reflected'.
From the article you can see that the amplifier has 1 PCB for 1 channel (mono) so for stereo you need 2 amplifier PCBs.
The protection system has also 1 PCB for one channel, for stereo you need 2.
So in total for stereo you need 4 PCBs.

jan didden
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Postby pat75 » Sun Jun 26, 2011 12:00 am

dear jan,
here is these pcb
Attachments
071085-PCB.pdf
(522.51 KiB) Downloaded 195 times
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Postby janneman01 » Sun Jun 26, 2011 12:00 am

This is a double-sided PCB.

jan didden
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Postby kioseusznook » Sun Jun 26, 2011 12:00 am

Hi Jan,

Your comment re a new design of protection board has got me piqued as I had recently noticed that U2 is incredibly hard to source. In fact after extensive searching I failed to locate a supplier anywhere. Does this issue have any bearing on the new design, and if so will you issue it to elektor so that those like me who purchased the article can download it? Thanks.

Robbie.
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Postby linn-fan » Sat Nov 12, 2011 12:00 am

Dear Jan and all,

I build up your PAX-amp. During test the transistors of the voltage amplifier are getting quite hot on both channels. When estimating the power loss I got around 300mW which can explain the heating. Is it really safe to run the amp at this temperature or is it better to add a cooling to the transistors?

Thank you for answers
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Postby linn-fan » Sun Nov 13, 2011 12:00 am

Does any one who has build the PAX-amp made the same observation as me that the six transistors of the voltage amplifier are getting quite hot?
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Postby mick.carrick » Mon Nov 14, 2011 12:00 am

Hi

Yes they do get hot and I believe Jan has comments on this on his Linear Audio website. I think he specified the higher power version (TO220) in the AudioXPress article. Jan says they have caused no problems running hot and that has been my experience also.

Enjoy the amps.

Mick
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Postby linn-fan » Mon Nov 14, 2011 12:00 am

Thanks Mick that helps me to be sure everything is o.k. )
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Postby linn-fan » Thu Nov 17, 2011 12:00 am

which replacement transistors with TO-220 case does Jan use for the voltage amp in this article. I can't find any hints on his homepage.

Thanks for answering
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Postby mick.carrick » Sat Nov 19, 2011 12:00 am

Finally dug it up!

The higher power (TO126) transistors were specified as:
2SA1209 and 2SC2911.

Good luck

Mick
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