I'd go with 300-400 VA for a mono block.
Those who wish to build dual mono amps ought to consider a mains transformer with four secondaries. 4x25 VAC @ 600-800 VA. Then use a Power-686 per channel. Even the theoretical difference in performance between two separate transformers and one transformer with four secondaries is pretty darn small. After all, to transformers will "talk" through the primary connections. The Modulus-686 isn't sensitive to power supply perturbations anyway. The benefit of only having to deal with one transformer is substantial, though.
I'm pretty sure Antek has some options at 4x25 VAC. If not, Toroidy in Poland will happily wind a transformer for you. Their cost is very reasonable.
Tom
Those who wish to build dual mono amps ought to consider a mains transformer with four secondaries. 4x25 VAC @ 600-800 VA. Then use a Power-686 per channel. Even the theoretical difference in performance between two separate transformers and one transformer with four secondaries is pretty darn small. After all, to transformers will "talk" through the primary connections. The Modulus-686 isn't sensitive to power supply perturbations anyway. The benefit of only having to deal with one transformer is substantial, though.
I'm pretty sure Antek has some options at 4x25 VAC. If not, Toroidy in Poland will happily wind a transformer for you. Their cost is very reasonable.
Tom
The main difference between the Power-86 and the Power-686 is that the '686 has twice the capacitance. I designed it for use in a stereo Modulus-686 amp.
With the Power-86 the output voltage of the supply will droop a bit more than for the Power-686, so you won't reach the full 360 W into 4 Ω, but you'll probably get well past 300 W. I honestly wouldn't worry too much about it.
Tom
With the Power-86 the output voltage of the supply will droop a bit more than for the Power-686, so you won't reach the full 360 W into 4 Ω, but you'll probably get well past 300 W. I honestly wouldn't worry too much about it.
Tom
@zman01
You probably recall I used an 800VA Toroidy with quad 25V secondaries. Works perfectly. I have yet to measure the amp to the point at which the voltage rails droop ;-)
If I were to build with dual toroids I would go for full monoblocks in separate enclosures but other than curiosity I have no need at this point.
Best,
Anand.
You probably recall I used an 800VA Toroidy with quad 25V secondaries. Works perfectly. I have yet to measure the amp to the point at which the voltage rails droop ;-)
If I were to build with dual toroids I would go for full monoblocks in separate enclosures but other than curiosity I have no need at this point.
Best,
Anand.
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I agree. If you're going through the expense of double everything you might as well use two chassis. ModuShop has some nice mono block chassis for that purpose.
Tom