Transformer question

[Ardvaark]

Hi folks!:music:

I have a large transformer that has two taps (+35 0 -35)(+45 0 -45). In this circuit, the unit has an 8 amp fuse. The 35v tap is driving 5 2SA1943/2SC5200 output device pairs for a total of 10 devices or five channels out. The 45v tap is driving 3 pairs of the same output devices for that total of 6 output devices in that stage for one channel out.
My question is, if I disconnect the 45v tap, will that make more current available to the 35v tap? Unfortunately, I do not have the specs on the transformer, other than theres an 8 amp slow blow fuse on the way into the transformer.
Search here for(RMDS-1) for the unit I'm messing with.
Thank you!

Ardvaark:music:

[Nakdoc]

Yes. The power is in watts, or volt-amps. A transformer's capacity is limited by the strength of its magnetic field below core saturation, so shifting power from one set of secondaries to the other will deliver the same total power, but out of one secondary. In other words, you could switch to the 45-0-45 sec. and get more power from that pair. There would be an absolute current limit for the wire in the secondary, but with an 8 amp primary fuse it is a big piece o' iron. The actual RMS power will change a bit, but the effective music power will change a lot.

[Ardvaark]

Thank you very much for that! :banana:

I am trying to utilize this circuit pretty much as is. I mean, without gutting the board and starting from scratch. I do not have enough training for that. I would like to make a nice little 2 channel amp at least out of it.
Thanks Again!

:thmbsp:

[bricktop]

Careful! You can't always pull more current out of one winding because the other is unused. Read my post in this (http://www.audiokarma.org/forums/showthread.php?t=158076) thread for an explanation. The core actually has nothing to do with how much power you can get out of it, given the primary is designed correctly for the line voltage, frequency, and full power load (quite unintuitive actually). If the one winding you are trying to pull more power out of can't handle the current draw, then that will be the power limiting factor. The primary winding resistance should already be low enough to handle the full power load, but make sure you don't overheat the secondary winding! :thmbsp:

[Ardvaark]

Thank you for the heads up!:thmbsp:
Is there an easy way to find out what the current capability is of a given transformer when one does not have the specs handy? What would be your best guess for this transformer? I feel like I'm going to ask you like 50 questions right now, but until I have a better idea about what I want to use or convert this circuit to, I won't ask you a bunch of questions. I want to post the schematic in pdf form but it is about 100k to big to be allowed. Its 1073k.

[Wigwam Jones]

Thank you for the heads up!:thmbsp:
Is there an easy way to find out what the current capability is of a given transformer when one does not have the specs handy? What would be your best guess for this transformer? I feel like I'm going to ask you like 50 questions right now, but until I have a better idea about what I want to use or convert this circuit to, I won't ask you a bunch of questions. I want to post the schematic in pdf form but it is about 100k to big to be allowed. Its 1073k.

Yes, there is. Run it until it blows up. Then back it down a bit.

:banana::banana::banana::banana::banana:

[Tom Bavis]

Those amps are class AB - they don't draw much current unless they're delivering power. So I think the extra available current will be minimal.

The 8 amp fuse is a clue, but not 100%... the transformer might have internal overload protection too - then the fuse is only to protect against a complete short.