[kipman725]

I am wondering if anyone knows where to get rear panel conectors capable of 20A per pin for connection of power supply to amplifier. Low cost is primary concern here as the amplifiers will be moved at most once or twice a year.

My basic problem is I want to build a 50W class A speaker amplifier and the only cheap decent cases I can get are 19" rack mounts. Therefore I need two cases to fit the beast in. However I need some way of connecting the power for each amplifier (left and right channel) from there respective power supply. I am not using one power supply for both amplifiers due to not been able to find 1000VA 25+25V transformers.

As for why such a crazy amplifier, because I have not seen such a powerfull class A amplifier before.

 

[luvdunhill]

Quote:

Originally Posted by kipman725 /img/forum/go_quote.gif capable of 20A per pin for connection of power supply to amplifier....My basic problem is I want to build a 50W class A speaker amplifier

sweet, so you're looking at like 1.0-1.5 V output?

 

[kipman725]

you misunderstand the amplifier is very ineffeciant due to operating in class A. The load is a 4ohm speaker. In an ideal case I would get from my +/-25V rails I would get 78.125W maximum transmited to my load however I only expect that I will be able to get within 5V of each rails without incuring unaceptable levels of distortion, therefore I say 50W. As the amplifier is class A the maximum current into the load is 6.25A however the impedance of the speaker will drop bellow 4ohms therefore I assume 7A. OK so this results in an amplifier that permenatly sinks 7A and with maximum output another 4.4A. As I would like to minimise resistive losses a 20A connector or greater seems to be the order of the day.

 

[TimmyMac]

I used a 6-pin DIN connector on my beta22 with dual power supplies. Cheap, but might not be good for 20A.

If you don't mind sharing ground you can get away with 5 pins.

 

[qusp]

yeah and with 5 pins you could use XLR I would think

 

[FallenAngel]

Mouser:
C016 30G006 100 12
C016 30H006 100 12

 

[luvdunhill]

If you're aiming for +/- 25 VDC rails, what are you going to do with the extra heat that's generated from the approximate 10 VDC you have to drop after the rectifier? That's ~115W wasted power that the PSU has to handle before it can start to supply the current demands of the power amplifier.

 

[kipman725]

Quote:

Originally Posted by luvdunhill /img/forum/go_quote.gif If you're aiming for +/- 25 VDC rails, what are you going to do with the extra heat that's generated from the approximate 10 VDC you have to drop after the rectifier? That's ~115W wasted power that the PSU has to handle before it can start to supply the current demands of the power amplifier.

You are correct and I was planning on just having a monster regulated supply. After all my amplifier is disipating aprox 350W per channel in heat at full output anyway. The output stage current consists of 4*IRF530 and 4*TIP120. I already have some 1.1c/W heatsinks and was planning on mounting them verticaly inside a 2u case with the top half of the heatsink pocking through the lid with 2 devices per heatsink. Hence the need for two cases. If heat disapation is an issue the top of the case shall have an MDF structure built ontop of it with ducted cooling (I am worried about room heating with aprox 900W of disipation total).

I managed to find these, they seem sturdy enough and as the distance between the PSU and AMP is non variable I only need one soccet plug and gland per amplifier. Rapid Electronics - Cables & Connectors

As for wiring power connections I planned on using 13A mains cable as that stuff can take far more than 13A.

 

[luvdunhill]

Quote:

Originally Posted by kipman725 /img/forum/go_quote.gif I already have some 1.1c/W heatsinks and was planning on mounting them verticaly inside a 2u case with the top half of the heatsink pocking through the lid with 2 devices per heatsink.

At what ambient temperate is the 1.1C/W number given at?