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Hi!

Welcome to my DIY audio forum.

Cheers
Per-Anders Sjöström

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#71
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - May 21, 2019, 11:03:53 PM
I have measured all the electrolytics in the psu, and all the resistors. When still on the pcb, they all measure the same.

When I watch the amp power up with a termal camera, the only thing really different is the rectifiers. The two in the middle (the two failing ones) gets really hot. When I measure resistance across these, I get almost a short between the ac and the positive on the two failing ones, but the working ones show several megaohms.

Should I simply order new ones, or do you think these are only symptoms for another error?


Thank you for following me through this so far!
#72
Headphone amplifiers / Re: QRV-08 power up
Last post by peranders - May 15, 2019, 06:30:01 AM
One positive regulator works the other doesn't afters one time. It means that most parts are in the right place. The two halves of the pub's are indentical so compare especially how electrolytic caps are mounted. You have probably made same mistake for the negative regulator.
#73
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - May 13, 2019, 01:34:24 PM
This is at the output of the lines from the psu that i have cut previously.

I will have a look with a thermal camera.
#74
Headphone amplifiers / Re: QRV-08 power up
Last post by peranders - May 03, 2019, 06:57:28 AM
Is this the output from the regulators? Is the voltage at each amplifier zero(should be since you have cut the connection)? Can you notice any heated component?
#75
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - May 02, 2019, 08:18:30 PM
These are the values. I noted the fuse number on the rails i measured. (In parenthesis the values after some seconds, when the amp fails)

F1 +13,8v (5v)
F2 - 13,8v
F3 +13,8v
F4 -13,8v (-5,5v)
#76
Power supplies / (Solved): Voltage drop on SSR0...
Last post by zidor28 - April 07, 2019, 02:54:21 PM
Per Anders, here is what was at play. The DAC board was actually drawing more than 100mA. The choke was designed for this rating, which wasn't enough. Hence the choke saturated and behaved as a resistance. Installing a choke with higher current capacity has solved the issue. Thanks again for your support and for the regulator.
#77
Headphone amplifiers / Re: QRV-08 power up
Last post by peranders - March 25, 2019, 06:53:29 PM
What is the values of the output voltages?
#78
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - March 25, 2019, 06:30:28 PM
The two in the middle. The leds stop shining after about five seconds.
#79
Power supplies / Re: SSR01 - substitute H1 with...
Last post by tk-don - March 24, 2019, 09:55:15 PM
Great, thanks P-A. I found a rubber cap for a rocker switch which fit perfectly ontop of the LED. Otherwise the assembled SSR01 works excellently it seems - 6.97V output spot on with the calculations.
#80
Power supplies / Re: Voltage drop on SSR01 unde...
Last post by zidor28 - March 23, 2019, 02:41:31 PM
This is a good point. I will try and let you know. In the meantime, thanks for your support.