OK straight AC bad how about this? 8000kva

Hi,
the 0-208-240Vac input would suit the 220Vac you have at your distribution board.

If you feed in 120Vac you will get the half voltages (44 & 60) you are looking for AND you will get the same maximum secondary current i.e. 4000VA.

This would probably be more suited to provide balanced output for the whole music system.
The dual secondaries could be wired for balanced output, either 120Vac by 2 or 60Vac by 2 depending on whether the input is 110 or 220Vac.
 

wg_ski

Member
2007-10-10 5:21 pm
ben62670 said:
http://cgi.ebay.com/Amveco-120V-8KV...oryZ4660QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

If this was wired for 120 in what would the output be?
44ac, and 60ac?
I am seriously looking for 2500va with 85dc output. Same as my Adcom GFA-585.

Ben

Unfortunately, you need +/-85V to make an Adcom clone. You got no center tap so you either need *two* 130# trafos (and even I'm not that crazy) or you need to build each channel as a bridge amp off the single 85V rail. That's plenty doable. Use a voltage divider to make a pseudo-ground that's only used for the input signal reference. Then stack up as many channels off that supply as you want. Each will be about 200-250W /8R.
 

ben62670

Member
2006-12-27 7:58 am
OK rectified DC voltage from a 60vac would be about 75vdc correct? I could share the two 75vdc outputs for many channels correct? How about the two 44vac outputs. Could they be combined to equal 88vdc? I have played with a few different power supplies with different results. Rectifying has given the same volts on some trans formers, and more on others. I don't see where there is no center tap on the outs. Please forgive my ignorance. Most of my experience is hands on, and Randy Slone amp book. I could also do a GFA-55 clone much easier than a GFA-585, and just increase the output transistors. I have about 200 Toshiba's in my possession.
Thanks
Ben
BTW any amp ideas with pcb's that could use the Toshiba's sd424, and 554's would be nice.
Thanks again
Ben
 

ben62670

Member
2006-12-27 7:58 am
OK.
Sorry guys I am trying to do this on the cheap here. I may have found a solution locally.
Here is an isolation transformer. I was wondering if I wired the 2 primaries in series if I would have 2 separate 60vac secondaries. Would it still be a 1kva output? I'm thinking it might halve due to decreased output vac.

Also can you guys recommend a good book on Power supplies for audio, amps, and pre-amps for someone with decent comprehension, but no EE training.

Thanks
Ben
trans120to120.jpg
 

poobah

Member
2005-11-15 7:24 pm
Yes... that would work...

When using a transfomer off its intended design voltage... you have to keep max winding currents the same... so, you will wind up with half the original kVA rating... basically.

You can push it... but is ill advised... losses in the winding are about current squared... I^2 * R.


:)