Class D Audio power supply upgrade

[Feanor]

For the heck of it I decided to try an upgrade on my Class D Audio SDS-258 amp. I'm replacing the standard, Class D Audio "Heavy Duty" linear supply, HERE, with Connexelectronic's linear supply, HERE.

Here's the "before" picture with the CDA power supply ...



And here's the two power supplies side by side ...



The CDA has 6x 4,700 uF capcitors, the Connexelectronic has 6x 10,000 which more than doubles the capacitance.

I don't have an "after" picture yet. The new PS is working fine, though I haven't decided yet whether it has made very much difference.

[blackraven]

Which power transformer do you have? I hear the larger ones offered by Class D Audio improve dynamics and bass.

[Feanor]

Which power transformer do you have? I hear the larger ones offered by Class D Audio improve dynamics and bass.

I have the standard transformer for the SDS-258 kit. I'm not sure of the the power capacity, maybe 400VA. The VAC output is +/- 47 volts. Of course, the new power supply puts out the same rail voltages as the old, about +/- 64 VDC according to my mulitmeter.

The supposed advantage of higher capacitance is greater instantaneous power and dynamics, not higher sustained power which depends on the rail voltages. So far I'm not convinced that I'm hearing this, but then again I rarely listen a very high volumes where it would presumably make the most difference.

Transformers are pretty expensive to buy -- and expensive to ship on account of the weight, so I wasn't thinking of replacing the current one at this time.

[Feanor]

At the same time I ordered the power supply from Connexelectonic, I also ordered an IEC power connector with integrated RFI/EMI filter, fuse holder, and on/off switch. See HERE.



I haven't installed this yet because it will be a fussier operation, requiring me to cut the metal back panel to size.

Class D amps, by many reports, are more susceptible than most to degradation due to RFI/EMI, so this filter might help. On the other hand my power Belkin power filter already has isolated outlets with RFI/EMI filters, and I use a shielded power cord to the amp, so the new connector might make no difference. Once installed, though, it will make for a tidier interior for the amp

[E-Stat]

For the heck of it I decided to try an upgrade on my Class D Audio SDS-258 amp. I'm replacing the standard, Class D Audio "Heavy Duty" linear supply...

It's a shame you didn't have the room to add the new one and parallel them together.

When I replaced the Mallory electrolytics in the Threshold a couple of years ago, I had a bit of a height clearance issue with the new higher value caps. Just to be sure, I added some teflon washers between the chassis and top plate.

[harley .guy07]

I have been loving my amp and really haven't thought of any upgrades to it but it does look like it could help adding capacitance for dynamics but like you said you don't listen very loud so you might never notice the difference unless you run into a song or a part of a song that is very dynamic and really push your speakers.

[Feanor]

I have been loving my amp and really haven't thought of any upgrades to it but it does look like it could help adding capacitance for dynamics but like you said you don't listen very loud so you might never notice the difference unless you run into a song or a part of a song that is very dynamic and really push your speakers.

True, I still don't think I'm hearing any real difference.

[Feanor]

It's a shame you didn't have the room to add the new one and parallel them together.

When I replaced the Mallory electrolytics in the Threshold a couple of years ago, I had a bit of a height clearance issue with the new higher value caps. Just to be sure, I added some teflon washers between the chassis and top plate.

Interestingly I once asked Tom at Class D Audio whether he though two of their "Heavy Duty" power supplies, paralleled, would be any improvement; he said No.

[blackraven]

The upgrade for the larger power transformer is about $75 according to Tom.

I am still thinking about buying one of the 600 wpc Class D audio amps to replace my Parasound A21. It's too bad they don't have a 30 day return policy.

[Feanor]

The upgrade for the larger power transformer is about $75 according to Tom.

I am still thinking about buying one of the 600 wpc Class D audio amps to replace my Parasound A21. It's too bad they don't have a 30 day return policy.

The A21 is a pretty nice amp but then the SDS amps are pretty nice too.

I think you have a CDA amp, how does it compare with the A21? If my recollection is right, you said you preferred the A21 for tonal balance, but that the CDA had less grain. It seems likely that the SDS will be tonally more like the CDA but a bit more refined. Does Tom have any opinion on this?

[E-Stat]

Interestingly I once asked Tom at Class D Audio whether he though two of their "Heavy Duty" power supplies, paralleled, would be any improvement; he said No.

Now you can call him back and tell him he's right!

Perhaps now you can go in the other direction with the old one. Remove a bank of caps at a time until you hear a difference.

[Feanor]

Now you can call him back and tell him he's right!

Perhaps now you can go in the other direction with the old one. Remove a bank of caps at a time until you hear a difference.

In fact CDA recommends a single "Heavy Duty" to run multiple amp modules.