15V SMPS enough for Gainclone?

[sharpi31]

I have found a reasonably cheap (£37.00) SMPS with +/-15V output (3.9A continuous on both positive and negative legs). While this is quite low voltage for a Gainclone, will this work well with high efficiency speakers (FE207e etc.)?

I have the Audiosector LM3875 dual mono kit. If this supply is sufficient, I intend to use one per channel with a snubberized 10,000uF cap. I have lots of small value <0.1uF russian teflon capacitors I intend using. I plan on making a ladder arrangement of these brilliant caps.

Thanks.

[phn]

Just a thought. Over here you can easily find used laptop SMPSs for €10-15. Some of them have +/-19 or 20V. Why not checking out eBay UK and get two of those for the same price?

Somebody else will have to answer your question.

[sharpi31]

As I understand it, the problem is this:

An SMPS can only be used if it has equal current available to both the positive and negative legs. The vast majority offer a fraction of the current available to the positive leg to the negative leg.

If I'm wrong please let me know and I'll happily save the $$$$

[cpemma]

Originally posted by sharpi31
As I understand it, the problem is this:

An SMPS can only be used if it has equal current available to both the positive and negative legs. The vast majority offer a fraction of the current available to the positive leg to the negative leg.

If I'm wrong please let me know and I'll happily save the $$$$

No, you're essentially right if the -12V line is truly inadequate. One system with the unequal PC supplies is to isolate any common ground and connect the two 0V & +12V outputs in series, as shown by Nuuk.

The NS Overture design spreadsheet says you'll get 10.7W (1%THD) into 8R from +/-15V, datasheet will give a graph.

[Nuuk]

I can confirm that the Skynet 8080 SMPS works well with high-efficiency drivers even though the -12 volt rail is only rated at 1 amp (+12v is rated at 6 amp).

I use one module per channel and it sounds beautiful!