aleph 5

[BillyD]

i am building aleph 5 plese help me i have
1000va/30/30
> > transformer with dual bridges and 6/ 44000uf caps,when i take voltage
> > readings i get 44v with no load .Will this work with aleph 5,i also have
> > .3ohm 250watt dale resistors maybe i can use crc to lower voltage.Thanks
> > Bill.

[Netlist]

Hi Bill
You have the perfect voltage to build something in between an Aleph4 and Aleph5. It will take too much power and thus heat to convert from 44V to 34V.

/Hugo

[wuffwaff]

Bill,

what you could try is an L-C power supply. This would give you around 27-28 volts. Depending on the impedance of your speaker you could choose on way or the other.
If the heatsinks are big enough you could also stay with the 44volts, ad two fets per channel and up the bias to 2.8-3A. This means around 500 watts dissipation for a stereo amp.
If not it would be cheaper to buy a new transformer

william

[nobody special]

How about a pi filter?

bridge- (2) 44000µF caps- 2.5mH .360 ohm 14 ga. inductor- (1)44000µF cap. With 5 amps (total) bias from both channels (not sure how much bias you plan on running) you would be down around 35 volt, with very little ripple. Does that help any?

[Brian Donaldson]

Put the coil before the first caps to lower the voltage (and increase the current)

[BillyD]

Thank you for your help. My transformer is a Plitron 1000v amp with 30/30 secondaries. When I take a voltage reading after the bridge, I get 32v. When I hook up secondaries to the caps and take a reading, I get 45v. Can I use a resistor to lower the voltage? I have high power dale resistors. Any other suggestions that would help me out, I would be very grateful. This is my first diy project and it would be finished if it weren't for this hurdle.
I will post pics soon.
Thanks!

[GRollins]

Resistors will work, but you're going to create an awful lot of heat.
LCLC or LCRC would be better, meaning more efficient.
Or...you could just go ahead and build a pair of Aleph 2s. One of my pairs is running off of that same transformer. (I'm assuming that you meant 1000VA and dual 30V secondaries.) Use plenty of heat sinking and you'll be fine.

Grey