Efficiency of various projects here

[Eric_C]

I looked through a lot of the threads but could not find this info.

I was looking for efficiency of the various speakers. I just finished up the rough setup on my Gainclone amp and am going to test it out on my Deftech 7002's which at 92db it should drive well but also on the BR-1's which at 85db, not so well.

These will be for the bedroom, 70-75db listening level and if I get motivated maybe a small 8-10 inch sub to sit in the corner.

Just trying to do some planning, 4 days left of vacation and I'm working away

[cjd]

which chip is in your amp? Not that it really matters, should have NO trouble with anything anywhere except perhaps if it's a LM3875 and you're driving 4ohm speakers - and even then it's dependent on the power supply rail voltage.

for 70-75dB it will take 1W of power on an 8ohm speaker with a 75dB sensitivity... The Modula MT is one of the lower sensitivity options at about 81-83dB/1W guesstimate. BR1 must have very little BSC if it's rated 85dB.

C

[Eric_C]

I have a 3886, pair of them actually for stereo.

The transformer is a 25v/25v 330a.

I take it you have a Gainclone, what do you think of it?

I have tested it to make sure it works but haven't mounted in a case so no listening time as of yet.

[cjd]

Have a gainclone? no... Not a gainclone (and given my disagreements with 47labs I don't consider any clones of their amp - they, in fact, are simply following the datasheet - nothing worth giving them any accolades for).

I have 2 working chip-amps and other experiments in various stages of needing more parts to continue working on them.

25v trafo is ~34v at the chip unregulated (~35v before counting loss through diodes and whatnot) - if you were using the 3875 it would have trouble on some of the lower impedance projects. But the 3886 is ideal for 4ohm use and will do fine. You should have more than enough power by boatloads for anything under 90dB levels. Above that may depend more on the speakers and to a very large extent, the quality of the power supply topology and rating of the transformer (ability to deliver current on demand without significant sag).