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Cheers
Per-Anders Sjöström

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#91
Power supplies / Re: Voltage drop on SSR01 unde...
Last post by peranders - March 20, 2019, 11:04:56 AM
How much current are you able to take out before you'll get a voltage drop?
#92
Headphone amplifiers / Re: QRV-08 Place to connect PW...
Last post by peranders - March 20, 2019, 11:03:23 AM
I'll recommend that you connect to the unregulated voltage in order to avoid unnecessary heat in the voltage regulator. Adjust the resistor value so the light is enough.
#93
Power supplies / Voltage drop on SSR01 under lo...
Last post by zidor28 - March 17, 2019, 02:18:54 PM
Per Anders,

I have installed a +12V SSR01 regulator to power up a DDDAC board. At no load, the regulator provides 12.3V but when the DAC board is connected, the output voltage from the regulator drops to 2.5V.

I was wondering if other users have already faced this issue, and how to solve it. Thanks for any input you could provide!

Operation conditions are as follows:
On the SSR01 board, both J1 and J2 are bridged.
The DAC board should be drawing around 100mA.
Input voltage is 30VDC
There is a large heatsink over the LM317
Upfront DC regulation is done with a LC circuit (diode bridge, 17H in series, 100uF polypro in parallel)
#94
Power supplies / SSR01 - substitute H1 with zen...
Last post by tk-don - March 10, 2019, 09:38:51 PM
Hi,

I'm building a 7V SSR01 using a 9V AC supply, which when rectified and accounting for losses should give nearly 12V output, which should be ok with the SSR01 with AD825 I hope.
The PCB will be partly visible through a perforated cardboard inside an old tube radio, and would like avoid any shining LEDs if possible.

Would it thus be possible just to use a 2.4V zener diode instead of H1, and just leave R3 at 2.2k? Or is the base current of the BC556B negatively affected by this (as I-V characteristics of zeners and LEDs are not the same)
Or would it be possible to even use a 3.3V zener like used as DZ1, possibly lowering the value of R3?
#95
Headphone amplifiers / Re: QRV-08 Place to connect PW...
Last post by chinook9 - February 27, 2019, 05:58:04 PM
heaveno P-A!

I have been enjoying my QRV-08 for a long time now but I still have not finished enclosure installation with power LED.  I have been afraid of damaging something if I mess up the LED wiring. I understand very little electronics and would not be able troubleshoot if I cause a problem.

I understand how to measure the LEDs I have and calculate the required resistor, however I have not found a specific location on the PCB that I like for the connection.

My friend Keith connected a 1000 ohm resistor to the + side of G31 but I am not comfortable with this location. it is 25V which requires a larger resistor (1500 ohm 2 Watts) and the way I have G31 soldered I have very little space.

Is there a spot you could suggest that would provide 15V and possible is a through the board hole that would be easier to make a good and safe connection.

Thank you P-A I appreciate your help.
#96
Headphone amplifiers / Re: QRV-08 power up
Last post by peranders - February 26, 2019, 09:33:31 PM
Which power supply doesn't work?
#97
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - February 26, 2019, 02:27:42 PM
Ok, the power supply is not working when i cut the four lines. Where do I go from here?
#98
Headphone amplifiers / Re: QRV-08 power up
Last post by peranders - February 09, 2019, 09:19:36 AM
I'll suggest that you try to get a working power supply first. Then you'll have to cut four traces, the power lines to each amp.
#99
Headphone amplifiers / Re: QRV-08 power up
Last post by svarthvitt - February 08, 2019, 05:46:04 PM
Hi again,

Yes, the electrolytics are mounted correctly.

The supply lines seems to go to a lot of components in the amplifier, could you tell me the part numbers to remove and where to measure the voltage?


Thank you again!
#100
Headphone amplifiers / Re: QRV-08 power up
Last post by peranders - January 02, 2019, 07:35:54 PM
Are all electrolytic caps mounted correctly? Both channels are dead? If yes, then it's not a random error.