PSU for lm3886

[soren_jepsen]

What does your psu's look like? I've surfed around the net, looking at different peoples take on this. It seems the amp is quite sensible to this.

BrianGT uses those diodes in his psu, but I can't find them here (Denmark). Can u suggest some good alternatives (also to the circuit)?

[joecool85]

Well you have to use diodes to rectify the AC to DC, Brian's PSU is arguably the best design possible for the amp, so that is the one I recommend.  I'm sure there are other options however, I just don't know what they are. 

[soren_jepsen]

I was probably not formulating myself too well 


I realize the need for diodes (or a bridge). But those MUR860 are impossible to find i Denmark. Are there any good alternatives? What about bridges?

[teemuk]

"Are there any good alternatives?"

Yes, there are. In fact, I think any diode/bridge rectifier with proper voltage and current rating should be fine. That supply is not like a SMPS or something where the switching speed becomes a major concern. For instance, I don't even know the model names of the rectifiers my amps use. Worrying about something like that seems a bit vain - just give the clerk at the component store the specs for current and voltage and ask what they have in stock. If you wish to hunt for specs then by all means type rectifier (or diode) xA xV to google and see what it brings up (replace x with proper number). However, bear in mind that there's no way to make sure that a certain model is more commonly available than some other.

"It seems the amp is quite sensible to this." [power supply]

If you worry about "switching noise", which I believe was the reason MUR860s were used in the first place (besides adequate current rating), fit some capacitors in parallel with the diodes. You could also ask if the store has MUR820 or MUR840. Anyway, I believe the main issue why amps are even troubled by diode noise is a bad layout: For example, never feed the circuit directly from the rectifier. The amplitude of switching noise is already significantly lower at the legs of the filter capacitors.

[joecool85]

I was probably not formulating myself too well 


I realize the need for diodes (or a bridge). But those MUR860 are impossible to find i Denmark. Are there any good alternatives? What about bridges?

Ah, I didn't get that part.  Well, you could (as teemuk mentioned) get some other diodes that fit the bill, or you could pay me shipping and I could send you a few MUR860 diodes.  I have four of them sitting around from a group buy I did a while ago where I had some extra parts.