## News:

Hi!

Welcome to my DIY audio forum.

Cheers
Per-Anders Sjöström

## Recent posts

#91
##### Power supplies / Re: Voltage drop on SSR01 unde...
Last post by zidor28 - March 22, 2019, 05:48:08 PM
With a 100 ohm resistor, I get a 0.9V difference on Q2 (pins 2 and 3), and a 1.67V difference on IC1 (LM317, pins 2 and 3). Thanks again.
#92
##### Power supplies / Re: SSR01 - substitute H1 with...
Last post by peranders - March 21, 2019, 07:23:19 PM
I'll suggest that you take three 1N4148 in series instead or put the led in a shrink tube or paint it black. If you increase the H1 voltage, then the drop out voltage will increase and then you'll need to adjust the voltage of the IC1.
#93
##### Power supplies / Re: Voltage drop on SSR01 unde...
Last post by peranders - March 21, 2019, 07:19:53 PM
When you load with 100 ohm, what is the voltage between emitter and collector of Q2? Voltage between in and out of IC1?
#94
##### Power supplies / Re: Voltage drop on SSR01 unde...
Last post by zidor28 - March 21, 2019, 02:45:27 AM
I've taken some measurements and with a 100 Ohm resistor, the voltage drops from 12.3V to 5.2. With a 1k resistor, then there is no drop.
#95
##### Power supplies / Re: Voltage drop on SSR01 unde...
Last post by peranders - March 20, 2019, 04:35:30 PM
I'll suggest that you try with 120 ohm or something. This would create 100 mA.

If the regulator works you should have a voltage drop of a few millivolts only and the voltage at pin 2 and 3 on the opamp should be within 1-2 mV, and that is 6.25V if the output voltage is 12.5 V.
#96
##### Power supplies / Re: Voltage drop on SSR01 unde...
Last post by zidor28 - March 20, 2019, 03:06:37 PM
Well, I don't know how much current can I draw before voltage drops. What would be the best way to actually measure this (variable CCS, resistor, ... )?. Thanks.
#97
##### 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?
#98
##### 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.
#99
##### 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)
#100
##### 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?