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#1 Voltage regulation

Posted: Sat Dec 11, 2021 11:24 am
by Daniel Quinn
I’ve got a myriad of phono boards I’m playing with.

Some need for the voltage stepping down. So I’ve got several voltage regulators for single and split rail boards.

I bought the cheapest of eBay .

Are they all created equal or do they effect sound and what should I be looking out for.

#2 Re: Voltage regulation

Posted: Sat Dec 11, 2021 11:55 am
by ed
you don't say which version you bought, so a bit tricky to answer.
I use this one for testing, can't speak to quality of supply though. You can be sure they're not all created equal though. If you've got a noisy one you can always filter some more. The one shown is long in the tooth but I still think you can find similar for a couple of pounds.
dc-dc.jpg
dc-dc.jpg (63.12 KiB) Viewed 6946 times

#3 Re: Voltage regulation

Posted: Sat Dec 11, 2021 12:33 pm
by Nick
But adding filtering will increase the supply impedance so will partly defeat the point of regulating. Arguably shunt regulation is better all things being equal. But if it's just a case of too much voltage consider adding bucking windings to the transformer if you can.

#4 Re: Voltage regulation

Posted: Sat Dec 11, 2021 12:56 pm
by Daniel Quinn
I’ve got about 20.

Currently I’m using them to step down the 42 v power to 24v to power a + dual rail.

I remember reading something about bucking windings. More reading .

Thanks gents

#5 Re: Voltage regulation

Posted: Sat Dec 11, 2021 1:22 pm
by Daniel Quinn
So if I have understood advise in this post and my original one correctly , I would be better of using a transformer which gave me 18v .

18x 1.41 =25.3 volts

This should be fine fine for a board which needs 24v

In this way I would just need a bridge rectifier and caps and thus I wouldn’t increase the inpedance

#6 Re: Voltage regulation

Posted: Sat Dec 11, 2021 3:05 pm
by Nick
That would be where I would start. You could try regulation later, but most of the other suggestions (IMHO) are trying to work out solutions to the problem caused by a initial wrong choice of transformer.

#7 Re: Voltage regulation

Posted: Sat Dec 11, 2021 5:13 pm
by Daniel Quinn
On a point of clarification 😂 it wasn’t a choice , it what I had lying about. A 500va 30v transformer.

#8 Re: Voltage regulation

Posted: Sat Dec 11, 2021 5:29 pm
by Nick
Yes, I see your point, but you did chose to use what you had laying about :-)

#9 Re: Voltage regulation

Posted: Sat Dec 11, 2021 7:45 pm
by Ray P
Daniel Quinn wrote: Sat Dec 11, 2021 1:22 pm This should be fine fine for a board which needs 24v
You'll also need to factor in the voltage drop across the rectifier diodes and regulator.

And remember there are no free lunches - when you multiply 18V by 1.414 you reduce the DC current capacity - if you need 24VDC @ 1A you would want something like a 36VA transformer (assuming an 18V secondary).

#10 Re: Voltage regulation

Posted: Sat Dec 11, 2021 7:49 pm
by pre65
Oh, I think it will be a tad bigger than 36VA. :wink:

#11 Re: Voltage regulation

Posted: Sat Dec 11, 2021 7:56 pm
by Daniel Quinn
Indeed.

If it wasn’t for the fact others have tried it , I would begin to think it was all in my mind. But then I remember Richard spent decades selling hifi were the only difference was the size and no of power supplies.

As far as phono amp are concerned my theory revolves around the fact that Richards phono stage are 4 op amps one for each stereo channel .

Which I can’t find in a commercial stage but there is one in diy audio forum with 4

#12 Re: Voltage regulation

Posted: Sat Dec 11, 2021 9:28 pm
by Nick
I do one like that. 4 op amps the PH-1. £200.

#13 Re: Voltage regulation

Posted: Sat Dec 11, 2021 9:30 pm
by Nick
Ray P wrote: Sat Dec 11, 2021 7:45 pm
Daniel Quinn wrote: Sat Dec 11, 2021 1:22 pm This should be fine fine for a board which needs 24v
You'll also need to factor in the voltage drop across the rectifier diodes and regulator.
I went through that earlier and there is no regulator.

#14 Re: Voltage regulation

Posted: Sat Dec 11, 2021 9:51 pm
by Daniel Quinn
Nick wrote: Sat Dec 11, 2021 9:28 pm I do one like that. 4 op amps the PH-1. £200.
I might have known😉 but doesn’t it have a power supply I would find poor and only mm


I’m looking at discrete phono amps at present.

#15 Re: Voltage regulation

Posted: Sat Dec 11, 2021 10:35 pm
by Nick
Daniel Quinn wrote: Sat Dec 11, 2021 9:51 pm
Nick wrote: Sat Dec 11, 2021 9:28 pm I do one like that. 4 op amps the PH-1. £200.
I might have known😉 but doesn’t it have a power supply I would find poor and only mm
It has a different approach to the power supply, and yes, MM only.