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Per-Anders Sjöström

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#51
Power supplies / Changing output voltage on SSR...
Last post by zidor28 - February 04, 2020, 02:45:51 PM
Am sure (and sorry if) this question has been dealt with before. I would like to change the output voltage of the SSR01 from 12V to 6V. I would just want to validate which resistor(s) needs to be changed and what kind of values would work. Thanks for this.
#52
Headphone amplifiers / Re: QRV-08 gain reduction
Last post by peranders - September 12, 2019, 07:30:03 AM
No...
#53
Headphone amplifiers / Re: QRV-08 gain reduction
Last post by Hodgin - September 11, 2019, 03:42:45 PM
Do 330 ohms impact anything else besides the gain?
#54
Power supplies / Re: SSR03-15V LM431 Volt too l...
Last post by eloes51 - September 08, 2019, 05:16:26 PM
Hi,

Thanks for the tip.

I did not think that the AGND have no mass !!!
#55
Power supplies / Re: SSR03-15V LM431 Volt too l...
Last post by peranders - September 08, 2019, 04:14:04 PM
Are the sense inputs connected? Have you tin drops on J1-4?
#56
Power supplies / SSR03-15V LM431 Volt too low
Last post by eloes51 - September 08, 2019, 11:42:53 AM
Hi,

SSR03 board with OP, the rest soldered itself.
Plus volts 13.4V, minus volts 10.4V.
OP From PIN6 + V -6.5V
OP from -V + 3.5V.

All components checked twice.
Maybe components defective?

Please help!! :-(
#57
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - June 13, 2019, 09:11:47 PM
Hi,
E29 is fine. Have a look at a thermal photo of the amp. Does it look fine?

What can I measure to confirm that it is working properly now, amd how do I adjust the pots correctly?

Thank you again, it would have been really great to get this amp working properly.

#58
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - May 28, 2019, 12:30:36 PM
Ok, it could be something close to it that is heating up, but I will have a look.

#59
Headphone amplifiers / Re: QRV-08 power up
Last post by peranders - May 28, 2019, 07:01:10 AM
R29 should be 470 kohm. Impossible to get it heated for any value more or less. Check the resistance and the voltage across it.
#60
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - May 27, 2019, 11:12:08 PM
With new rectifiers, the psu seems ok. I soldered the amp section in, and it does not shut down like before. It makes a mechanical 50hz humming sound, and e29 lights up with the thermal camera.

What should I measure next to make sure it is ok? I sort of assume that this is a temporary thing until the new rectifiers brake down.