## News:

Hi!

Welcome to my DIY audio forum.

Cheers
Per-Anders Sjöström

## Recent posts

#81
##### Power supplies / Re: Voltage drop on SSR01 unde...
Last post by zidor28 - March 23, 2019, 12:48:05 AM
That's strange indeed. Here are the DC voltage measurements.

Rectified B+ (before even connecting the SSR01): 30VDC
Input voltage on the SSR01 when connected to B+ but with no load on the output: 18.3V
Input voltage on the SSR01 when connected to B+ with a 100R load: 7.3V

#82
##### Power supplies / Re: Voltage drop on SSR01 unde...
Last post by peranders - March 22, 2019, 10:29:12 PM
The input voltage is? Something isn't right here.

Output = 5.2
Q2 = 0.9
IC = 1.67

= 7.77 V is that what you have as input voltage? In order to work properly you must have 18V in min.
#83
##### 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.
#84
##### 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.
#85
##### 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?
#86
##### 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.
#87
##### 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.
#88
##### 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.
#89
##### 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?
#90
##### 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.