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1
Headphone amplifiers / Re: QRV-08 gain reduction
« Last post by peranders on September 12, 2019, 07:30:03 AM »
No...
2
Headphone amplifiers / Re: QRV-08 gain reduction
« Last post by Hodgin on September 11, 2019, 03:42:45 PM »
Do 330 ohms impact anything else besides the gain?
3
Power supplies / Re: SSR03-15V LM431 Volt too low
« Last post by eloes51 on September 08, 2019, 05:16:26 PM »
Hi,

Thanks for the tip.

I did not think that the AGND have no mass !!!
4
Power supplies / Re: SSR03-15V LM431 Volt too low
« Last post by peranders on September 08, 2019, 04:14:04 PM »
Are the sense inputs connected? Have you tin drops on J1-4?
5
Power supplies / SSR03-15V LM431 Volt too low
« Last post by eloes51 on 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!! :-(
6
Headphone amplifiers / Re: QRV-08 power up
« Last post by svarthvitt on 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.

7
Headphone amplifiers / Re: QRV-08 power up
« Last post by svarthvitt on 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.

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Headphone amplifiers / Re: QRV-08 power up
« Last post by peranders on 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.
9
Headphone amplifiers / Re: QRV-08 power up
« Last post by svarthvitt on 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.
10
Headphone amplifiers / Re: QRV-08 power up
« Last post by peranders on May 22, 2019, 07:39:30 PM »
Switch over to "diode" on your DVM and measure the diodes in the rectifier bridges. If you read near zero, the you probably have broken diodes => change the parts.
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