I have built a regulated split rail supply 24+ Ov 24- to power an old Exposure Pre Amp. This is dual mono with a board for both channels. The boards are marked DC input 24vdc for a split rail supply. The boards also have an LM317 and 337 after the DC input.
The pos rail of the PS is drooping to around 10v and the negative rail to around 2 volts. I did make a supply for this years ago and from memory it was an unregulated supply and it worked fine. Any ideas anyone?
The pos rail of the PS is drooping to around 10v and the negative rail to around 2 volts. I did make a supply for this years ago and from memory it was an unregulated supply and it worked fine. Any ideas anyone?
I have built a regulated split rail supply 24+ Ov 24- to power an old Exposure Pre Amp. This is dual mono with a board for both channels. The boards are marked DC input 24vdc for a split rail supply. The boards also have an LM317 and 337 after the DC input.
The pos rail of the PS is drooping to around 10v and the negative rail to around 2 volts. I did make a supply for this years ago and from memory it was an unregulated supply and it worked fine. Any ideas anyone?
One immediate thing you can check is whether the input to those regulators also sag. Diagnose.
Jan
Ok, some pics and a part schematic. This is all there is on the sellers page. This was an ebay buy at not much money. I tested everything after I had built it with a DBTester and it was good. When I put the full fat mains through it it blew one of the rectification IN4007 diodes. I replaced the diode, but it didn't want to work, so I bypassed the on-board regulation with a bridge rectifier (seen in the pic) it tested all ok at +/- 24v.
This is a pic of one of the pre-amp boards.

This is a pic of one of the pre-amp boards.


The PSU is a LM317 wired as current source plus a shunt regulator. Unnecessary in my opinion. A simple LM317 as series regulator will be better.
Yes, I made one of these recently for a Diamante (Twisted Pear) Pre-Amp and it works well. I should trust in my own DIY skills!
I didn't doubt in your skills nor that the circuit will not work, I only say that simple things usually do its job better than complex solutions.
No, I didn't read it that way. I should not look at the parts count on the stuff on ebay and think it is good value for what the parts would cost me to make it myself.
I am thinking of ditching the current limiting and modifying the board. In the past I have had success with adding a power transistor to the circuit to boost the current as in the link below.
https://www.eeweb.com/extreme-circuits/ampere-or-current-booster-circuit
https://www.eeweb.com/extreme-circuits/ampere-or-current-booster-circuit
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