What would YOU do with this transformer

taj · 21st August 2009, 10:22 PM

I'm just lookin for ideas...

I have a pair of 44VCT Plitron transformers that look like 700-1kVA judging by the physical size. They suggest a class A amplifier project, but with 30+ VDC rails a class A amp would require more heatsink than I am willing to buy, lift and suffer the home heat with.

What else makes sense?

..Todd

wg_ski · 21st August 2009, 10:37 PM

Put 'em in series and build a Leach (or similar power level) amp which will double into 4R and darn near again into 2R.

They wouldn't happen to the the 'Phast Microsystems' trafos, would they? I have 3 of them left. I think they were supposed to be for a 6x LM3886 amp.

Andersonix · 21st August 2009, 10:38 PM

Are there choices on how to wire up the primaries to give you other secondary voltages?

Wavebourn · 21st August 2009, 10:46 PM

A bridged amp would be fine, with plenty of output power.

taj · 11:38 PM

Good input. Keep the ideas coming...

wg_ski: I have a couple of Leach variations already, but the general idea is worth considering for other amp circuits that use 60V rails. I'm sure there are a few circuits here that qualify. (DX Precision I think; Citation 16 clone; a Quasi Nxxx).

I'm not sure where I got these transformers, it was a couple years ago, from some surplus sale somewhere.

Tosh: I can't recall if these have dual primaries. I'll look when I see them next. But if I use them in 220V mode on my 110v power, I'd end up with ~15VDC rails. That's pretty low for an amplifier.

Wavebourn: Another good idea. My DIY speakers tend to be low impedance (4-ohm-ish) so a bridged amp would be a bit stressful on the all the hardware (I think).

..Todd

Wavebourn · 22nd August 2009, 12:07 AM

Quote:

Originally Posted by taj

Wavebourn: Another good idea. My DIY speakers tend to be low impedance (4-ohm-ish) so a bridged amp would be a bit stressful on the all the hardware (I think).

What do you mean? Still the same current, the same power, like in case of non-bridged one, but with +/-60V on rails. And you can use cheaper lower voltage devices there, including filtering reservoirs.

taj · 22nd August 2009, 12:12 AM

Quote:

Originally Posted by Wavebourn

What do you mean? Still the same current, the same power, like in case of non-bridged one, but with +/-60V on rails. And you can use cheaper lower voltage devices there, including filtering reservoirs.

I guess I don't understand that configuration. Can you give more basic details or show me a simple diagram?

..Todd

Wavebourn · 22nd August 2009, 12:21 AM

Quote:

Originally Posted by taj

I guess I don't understand that configuration. Can you give more basic details or show me a simple diagram?

2 identical amps per channel, phase splitter on input, speaker between outputs.
You may use a line input transformers to get counter - phase signals, and get balanced inputs so no ground loops will be possible.

taj · 22nd August 2009, 12:36 AM

I understand that part. Isn't a 4-ohm load impedance a problem in that configuration? (2-ohm for each amp circuit?)

How do you configure the power for 60v rails and still use lower voltage parts? There's something basic I'm not understanding. Maybe I just need more sleep. It's Friday.

..Todd

Wavebourn · 22nd August 2009, 12:45 AM

Actually, there are 2 amps working with +/-30V rails each, in counter-phase, with a speaker between their outputs. For speaker's side it looks like it is driven by an amp with +/-60V rails, so 200W/channel is easy. That means, 6 Amp peak current is needed. The same, like in case of a single power amp with +/60V rails.

21st August 2009, 10:22 PM	#1
taj diyAudio Member Join Date: Feb 2005	What would YOU do with this transformer I'm just lookin for ideas... I have a pair of 44VCT Plitron transformers that look like 700-1kVA judging by the physical size. They suggest a class A amplifier project, but with 30+ VDC rails a class A amp would require more heatsink than I am willing to buy, lift and suffer the home heat with. What else makes sense? ..Todd

21st August 2009, 11:34 PM	#5
taj diyAudio Member Join Date: Feb 2005	Good input. Keep the ideas coming... wg_ski: I have a couple of Leach variations already, but the general idea is worth considering for other amp circuits that use 60V rails. I'm sure there are a few circuits here that qualify. (DX Precision I think; Citation 16 clone; a Quasi Nxxx). I'm not sure where I got these transformers, it was a couple years ago, from some surplus sale somewhere. Tosh: I can't recall if these have dual primaries. I'll look when I see them next. But if I use them in 220V mode on my 110v power, I'd end up with ~15VDC rails. That's pretty low for an amplifier. Wavebourn: Another good idea. My DIY speakers tend to be low impedance (4-ohm-ish) so a bridged amp would be a bit stressful on the all the hardware (I think). ..Todd Last edited by taj; 21st August 2009 at 11:38 PM.

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21st August 2009, 10:37 PM	#2
wg_ski diyAudio Member Join Date: Oct 2007	Put 'em in series and build a Leach (or similar power level) amp which will double into 4R and darn near again into 2R. They wouldn't happen to the the 'Phast Microsystems' trafos, would they? I have 3 of them left. I think they were supposed to be for a 6x LM3886 amp.

21st August 2009, 10:38 PM	#3
Andersonix diyAudio Member Join Date: Jan 2004 Location: Silicon Valley	Are there choices on how to wire up the primaries to give you other secondary voltages?

21st August 2009, 10:46 PM	#4
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	A bridged amp would be fine, with plenty of output power.

22nd August 2009, 12:36 AM	#9
taj diyAudio Member Join Date: Feb 2005	I understand that part. Isn't a 4-ohm load impedance a problem in that configuration? (2-ohm for each amp circuit?) How do you configure the power for 60v rails and still use lower voltage parts? There's something basic I'm not understanding. Maybe I just need more sleep. It's Friday. ..Todd

22nd August 2009, 12:45 AM	#10
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Actually, there are 2 amps working with +/-30V rails each, in counter-phase, with a speaker between their outputs. For speaker's side it looks like it is driven by an amp with +/-60V rails, so 200W/channel is easy. That means, 6 Amp peak current is needed. The same, like in case of a single power amp with +/60V rails.

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