Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects

[JR.]

wereoflu used the TPA7AXX-series in his minimixer which is where I found it: viewtopic.php?f=6&t=882#p10291

There's another ripple eater I recall from a Design Idea.
I'll dig, scan and post.

My goal is to have something that plugs in and works without any additional filtering.
Most of the Meanwell and TDK models I tested are great.
The simple RC required for the 24V and 48V supplies aren't a deal-breaker.
In the case of the 24V for powering relays external filtering may not be needed at all.
I haven't tried the 24V yet.

When I designed the PS for my last (big) console I used double regulation, so 3-terminal regulators on each strip and a several amp master power supply that was a glorified ripple filter using a simple pass element to put out roughly +/-19V, but that voltage was a fraction of the unregulated voltage to scrap off ripple.

If the mains sagged, this pre-regulator would sag too, to stay comfortably below the ripple.

JR

[mediatechnology]

"Feed-forward cancellation rejects supply noise by 26 dB," Ken Yang.

This is one of the ripple-rejection circuits I was thinking about: https://www.eetimes.com/document.asp?doc_id=1272276

[JR.]

"Feed-forward cancellation rejects supply noise by 26 dB," Ken Yang.

This is one of the ripple-rejection circuits I was thinking about: https://www.eetimes.com/document.asp?doc_id=1272276

This sucker has been bugging me for several days... when I first looked at it with my beer goggles on I thought hey that's NF not FF, but looking at it later through coffee goggles reveals the FF, but I still see NF.

If current draw from the output causes C2 to sag, NF will cause current drawn from that output node to be reduced presumably helping lift the output, but the availability of current through that vector is modest (limited by class A bias).

Designing a PS with intentional 100 mOhm source impedance is not great, but I appreciate this is a specialized circuit.

Next if we add a capacitor to the output the RC from Rs and this output cap will cause phase shift that could interfere with the FF cancellation current.

This is cute but I might be tempted to just use the mosfet as a pass element (in fact I did use one that way to make a pre regulator for my battery powered tuner to deal with fresh battery voltage hotter than my audio power chip could handle.)

Interesting way to showcase some components but I question the utility..

JR

PS: As usual let me apologize in advance, for being a negative nellie.

[mediatechnology]

I had wondered about this one too.

There is another circuit I'm looking for that the author specifically called a ripple eater.
IIRC it used a series pass element and had much deeper attenuation.

[Gold]

Here is a power supply to test console units on the bench. I got tired of the rats nest that was the HP units and a million banana plugs.

This power supply has separate Modulation and Preview bipolar 15VDC and bipolar 24VDC. There is an On-Off-On selector switch for Modulation and Preview. There is also +12VDC for lamps and relays. There will be a +5VDC eventually that won’t get a current meter. The whole thing cost less than $100 to make not including the case which I had.

[mediatechnology]

Nice!

It's been awhile since I made some metal shavings.
I'm itching to rack up my PTS EQ monitor switcher.
The flat preamp has been done for years now.

The Pico build seems almost a year ago now.

[Gold]

Thanks. Having to test the test setup every time I wanted to work on something was a psychic barrier to getting stuff done. Even though it only took a minute or so to check it.

I’ve always been curious to watch current draw when playing program material. With a current meter on each rail I can watch them bounce up and down. Now that the PSU is neat and tidy Its easier to modify the setup investigate things like the effects of PSU source impedance.

[mediatechnology]

I found that a 3.9 mH common mode choke works wonders on the Meanwell RS-25-48 48V supply: https://www.proaudiodesignforum.com/for ... =16&t=1016