PSU Design help

wildbill · 9th March 2006, 10:05 PM

Hi to all, reading lots of stuff on PSU's and i find it difficult to decide on which components to use for my PSU's. I intend building esp's P3a amps for a tri-amped project, so, i need around 35 - 0 -35 for the power amps and i intend to use a separate toroid and bridges etc for each amp. (six in total plus 1 for pre-amp and LR crossover) If it were your project, what manufacturer of toroid and smoothing caps would you use ? lets say for the time being, price of parts doesn't matter. Hope this will generate a few replies. Thank you all in advance.

Wildbill.

lndm · 9th March 2006, 11:33 PM

If you need electrolytics, start with Rubycon Black Gate Elna. This choice may be more significant than your choice of toroid.

gp4Jesus · 16th March 2006, 03:36 PM

Do you plan to have 2 or channels share one chassis? Consider one toroid and one rectifier bridge (RB) for each chassis.
or
If any of your power amp(s) will share a chassis, say 3 P3As for the left side and 3 for the right side, consider one larger toroid and RB for each side.

The add'l cost and space requirements for dedicated toroids and RBs far from justsifies the almost nonexistant performance gains. One larger, oversized toroid & RB is cheaper than three smaller, barely adequate ones. Triple Rod's biggest VA suggestion along with a 50+ amp RB and you can't go wrong!

On the other hand, dedicated capacitor banks* (CB) for each amp Pand/or frequency range, yes 6 separate CBs, will be a whole lot closer to the multi-mono design you seek**without going to extremes.

* your highs will likely need a less robust CB than your mids. Here focus on quality. By the same token, bass demands quantity; current is king here! Mids fall in between.

** I'm doing something similar with 6 ESP P101s on three chassi (bi-amped left, centre, and right channels) and 8 toned-down*** 3As on one chassis (bi-amped side & rear channels) plus two hot rodded**** Hafler XL-280s for 2 subs for a home theatre 7.1 system
*** lower PS rail voltages, about 30V
**** modified Power Supplies and heavier internal wiring

Interesting reading on power supplies
http://www.tnt-audio.com/clinica/ssps1_e.html
http://www.tnt-audio.com/clinica/ssps2_e.html
http://www.tnt-audio.com/clinica/ssps3_e.html

cheers

tony

AndrewT · 17th March 2006, 07:02 PM

Hi Wildbill,
no thoughts on manufacturer recomendation.

But common chassis to multi channel amps. Two or three to each case.

I think a common transformer followed by a dedicated rectifier for each channel then adequate smoothing to suit the amplifier duty may produce an economic assembly and yet still use quality parts.

If you know that each amp will only ever be used with bass, mid or treble then the PSU to each and the amplifier can be designed specifically for that duty.

Eg. bass PSU and amp of high current ability and DC connected.
Treble PSU and amp of high peak voltage from fast caps and high pass filtering engineered into the input and NFB loop to limit response to three or four octaves below what you actually need. This may allow exclusive use of film caps or better throughout.

As an example my Conrad Johnson pre-amp has no electrolytics anywhere.

9th March 2006, 10:05 PM	#1
wildbill diyAudio Member Join Date: Feb 2006 Location: Bonnie Scotland	PSU Design help Hi to all, reading lots of stuff on PSU's and i find it difficult to decide on which components to use for my PSU's. I intend building esp's P3a amps for a tri-amped project, so, i need around 35 - 0 -35 for the power amps and i intend to use a separate toroid and bridges etc for each amp. (six in total plus 1 for pre-amp and LR crossover) If it were your project, what manufacturer of toroid and smoothing caps would you use ? lets say for the time being, price of parts doesn't matter. Hope this will generate a few replies. Thank you all in advance. Wildbill.

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9th March 2006, 11:33 PM	#2
lndm diyAudio Member Join Date: Mar 2006 Location: nsw	If you need electrolytics, start with Rubycon Black Gate Elna. This choice may be more significant than your choice of toroid.

16th March 2006, 03:36 PM	#3
gp4Jesus diyAudio Member Join Date: Jan 2006 Location: Crawford, Georgia, US	Do you plan to have 2 or channels share one chassis? Consider one toroid and one rectifier bridge (RB) for each chassis. or If any of your power amp(s) will share a chassis, say 3 P3As for the left side and 3 for the right side, consider one larger toroid and RB for each side. The add'l cost and space requirements for dedicated toroids and RBs far from justsifies the almost nonexistant performance gains. One larger, oversized toroid & RB is cheaper than three smaller, barely adequate ones. Triple Rod's biggest VA suggestion along with a 50+ amp RB and you can't go wrong! On the other hand, dedicated capacitor banks* (CB) for each amp Pand/or frequency range, yes 6 separate CBs, will be a whole lot closer to the multi-mono design you seek*without going to extremes. your highs will likely need a less robust CB than your mids. Here focus on quality. By the same token, bass demands quantity; current is king here! Mids fall in between. I'm doing something similar with 6 ESP P101s on three chassi (bi-amped left, centre, and right channels) and 8 toned-down* 3As on one chassis (bi-amped side & rear channels) plus two hot rodded** Hafler XL-280s for 2 subs for a home theatre 7.1 system * lower PS rail voltages, about 30V **** modified Power Supplies and heavier internal wiring Interesting reading on power supplies http://www.tnt-audio.com/clinica/ssps1_e.html http://www.tnt-audio.com/clinica/ssps2_e.html http://www.tnt-audio.com/clinica/ssps3_e.html cheers tony

17th March 2006, 07:02 PM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi Wildbill, no thoughts on manufacturer recomendation. But common chassis to multi channel amps. Two or three to each case. I think a common transformer followed by a dedicated rectifier for each channel then adequate smoothing to suit the amplifier duty may produce an economic assembly and yet still use quality parts. If you know that each amp will only ever be used with bass, mid or treble then the PSU to each and the amplifier can be designed specifically for that duty. Eg. bass PSU and amp of high current ability and DC connected. Treble PSU and amp of high peak voltage from fast caps and high pass filtering engineered into the input and NFB loop to limit response to three or four octaves below what you actually need. This may allow exclusive use of film caps or better throughout. As an example my Conrad Johnson pre-amp has no electrolytics anywhere.