• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

Scalable PSU/regulator GB

Status
Not open for further replies.
Jump to Latest
#564
Problem with regulator startup.

Finally getting around to putting everything together, but now I'm having a problem with the (mostly) negative regulator starting up.

Powering 2 filter boards with 12 Op amps (NE5532) should draw roughly 120mA - 200mA.

My transformer is a dual 15V 17VA, maybe a little under powered but I happen to have a bunch of them. I measure 18.6 VAC on both inputs, but they just wont both start up reliably. Everything is fine without a load.

Suggestions ?

Double up the transformers to supply 34 VA to the regulators ?

Thanks.
 
#566
Argo - Jens suggested R4 and R19 could be increased to 1k2 or 1k5 to reduce startup latching. Another solution would be eliminate R4 and R19 altogether. This makes the LM4040 supply a little noiser, but if you bump R3 and R18 to 20-100K it ought to be pretty darned quiet. Just watch the startup delay.

Korben, Due to the underwhelming response, I decided to wait for the large sinks. If they shipped as scheduled, Mouser should have them next week, and I should have them 4-5 days later.
 
#570
Success !

BobEllis said:
Jens suggested R4 and R19 could be increased to 1k2 or 1k5 to reduce startup latching. Another solution would be eliminate R4 and R19 altogether.
Click to expand...

Well, I tried with 1k7 (that's the closest I had) but still couldn't get it to start reliably. Final resort was to eliminate R4 and R19 as suggested.
Powers up nicely every time now.

Thanks again for your help.
Argo.
 
#572
Re: Problem with regulator startup.

argofanatic said:
Finally getting around to putting everything together, but now I'm having a problem with the (mostly) negative regulator starting up.

Powering 2 filter boards with 12 Op amps (NE5532) should draw roughly 120mA - 200mA.

My transformer is a dual 15V 17VA, maybe a little under powered but I happen to have a bunch of them. I measure 18.6 VAC on both inputs, but they just wont both start up reliably. Everything is fine without a load.

Suggestions ?

Double up the transformers to supply 34 VA to the regulators ?

Thanks.
Click to expand...

looks like your transformer is indeed small, here's mine, the traffo is good for about 50va....

here is full load testing at 500mA using dummy load(not shown)
CIMG3249.jpg
 
Status
Not open for further replies.
Top Bottom