[doggie]

Hi Kevin et Al,

One more question. Any recommendations for the transformer for a stereo UCD amp. I was thinking either 250VA or 330VA at 2x30 volts. Can I go to 35v or is that pushing it?

I ordered the UCD180AD modules and HG power supply today from DIYCable  

Best,

Paul

[Kevin Haskins]

Paul,

It depends on your line voltage.   With the 30V secondaries you won't run into overvoltage protection until you hit a line voltage of about 140V.    The highest line voltage I've seen is around 130V but you have to plan for the worst in order to keep the amps from shutting down via the overvoltage protection.     With the 35V secondaries you would be going into overvoltage protection with 121V on the mains.   I wouldn't do it.   Max I'd recommend is with 115V primaries is 32V which gives you up to 132V on the mains before entering overprotection.    

You won't notice the few watts difference in output for riding the bleeding edge so go with the 30V and you will never have a problem.

[doggie]

How about the VA? I mostly play "accoustic" and vocal music at moderate volumes. Would 250 be enough for a stereo amp?

Thanks again for your help...

[Kevin Haskins]

Sure... absolutely.   What you get is better regulation and less voltage sag under load with a larger transformer.   You could use a 100VA transformer on a stereo pair and few people would notice with a nominal 8 ohm load and moderate listening volumes.   You will notice there is little difference in cost by oversizing the transformer though so most people will upsize.

I'm getting custom 630VA units that I plan on using for everything from 2-5 channels of UCD180.    A smaller transformer would work just fine for 2-channel applications but I only want to stock one unit.