Upgrade my power supply

[steven2583]

I'm just starting in DIY, I'm reading electronic books and reading forum threads. Thus I barely know I'm doing. My sound processor is currently using a 12v/200mA Symmetrical Regulated Power Supply (12V / 200 mA Symmetrical Regulated Power Supply - Cana Kit) from CanaKit to power the OPA627 op amps for the R/L front two channels. I had it modded.



I'm thinking that if I update the caps in the PS I might bet a better DC feed and thus better performance. I thinking that I really just need to change the caps on the DC side to get better performance. Is that true? The blue caps on the right side say 220 uF. Any recommendations on caps. I was looking at some high end film caps. Like the Mundorf Silver Oil series. I heard good things about them but looking at the ratings nothing goes to 220uF. I see a 0.22uf or a 2.2uf. Should I be adding two decimal places to the number? capacitor_film_mund_sgo.html

Does anyone know of a better design PS to replace this canakit?

Any help with this would be appreciated.

[Frank Berry]

The blue caps are 220 microfarad.
The basic problem with this circuit is that each rail is fed by a half-wave rectifier.
I'm not sure that there is anything that you can do to improve the performance of this power supply.
There are better designs which use center-tapped transformers which feed a full-wave bridge rectifier. It looks like the regulators are 7812 and 7912. There are regulators which have better noise performance.

Are you having any particular problem with this supply? Improving the noise performance of the power supply might not make any measurable difference on the performance of your opamps.

[Mooly]

As long as the regulators are not dropping out... meaning that the DC input to them is high enough (and that the AC ripple troughs don't go below the drop out threshold) then you won't gain anything tbh. Low noise is all well and good but the wiring from the PCB to the reg board alters that figure many times over.

The secret to good supplies is to do it at a local level on the board where it's needed. Opamps are supremely tolerant of noise on supplies anyway.

[steven2583]

I'm not have any particular problem. I just had the unit modded replacing the R/L op amps to the BB OPA627 and changed the Attenuator to the PGA2310 from PGA2311. The PGA2310 requires a higher voltage to get the added benefits. The mod company added a new power supply and this regulated DC power supply in addition to the original PS in the unit. The original feeds everything except the R/L outputs.. The sound is more detailed but the sound stage has shrunk. Depth isn't as good as it use to be. Bass is alright but it doesn't really have strong force. I can't feel it. I read that caps are very important in the PS and changing them can improve things. I looked up the PS on the internet and it looked like it was fairly cheap PS. I figured get this another one of these PS and change a few things and see what happens. So I was thinking slightly larger caps 330 microfarad and at better quality and I may get my bigger and deeper sound stage back with stronger bass.

[steven2583]

I'm not having a specific problem. I had my Anthem D2v modified a month ago and the depth of the sound stage shrank. The midrange and highs details are a lot better. Ideally I want all the details and want my sound stage depth back. If I can get some stronger bass then great. I had them add OPA627 for the front R/L channel and PGA2310 for the attenuators for the right and left. To benefit from the 2310 the voltage had to go up to +/-12 from +/-5 volts. Thus a new power supply was added and the PS board that I have listed above for the +/- 12 volts. I've read that the caps in the PS change have quite the affect on the sound quality. I figured I buy another board in a kit and change a few things and see how the sound changes. I figured a if I can keep it under $100 it would be a fun little project. What would your recommendation be to try and get a bigger sound stage.

[Wirehead.be]

I think you're better off creating a new PSU - fed by a center-tap transformer; using LM317/LM337. Put the buffer caps in front of the reg's - decouple the reg's with 100nF; and if you'ld like to spice things up, you could use something like a capacitance multiplier behind the regulators for added filtering.

[AndrewT]

Keep your existing PSU as an experimenter's supply for your future builds.

Buy a new transformer that suits dual polarity supplies and make up a new dual polarity regulator, much as suggested above.

Pay particular attention to decoupling the opamp at the opamp. This will repay if there is any hint of feedback, oscillation, etc.

At this stage in development, both you and the circuit, do not waste your money on exotic components. Standard components used properly in the correct location do a very good job of transmitting the wanted audio signal.

[sreten]

Hi,

Silver and Gold foil oil capacitors in a power supply ? Your having a laugh .....
220uF of the above ? I'd leave things well alone until you understand them.

rgds, sreten.

[Ron AKA]

If you can increase the uF capacity of the 4 electrolytics while keeping the physical size the same or similar enough to fit, you may smooth the voltage ripple some. When choosing a new electrolytic make sure the voltage is the same or higher, and also try to find ones that have as low an ESR as is reasonable.

In my opinion audio quality capacitors are not necessary, and are more hype than anything else, especially in a power supply application.

Check out Panasonic FR Capacitors as an example of what may work for you. Shouldn't be more than a buck or so per capacitor.

[steven2583]

Does any one have any schematics on a good power regulated power supply using the LM317/LM337 chips fixed at +/-12v.