Hey, I'll let you guys in on a little secret. I've been buying KLH 2400 receivers off of ebay for $20.00 each not working($0.99 plus $18.00 shipping) They have a nice little 2x40V 400va toroid with a 5.2V and 15v-0-15v secondary for pre and logic, heat sink and case etc. Most of them only have a shorted rectifier snubber.
So I fix half and sell for $40.00 and gut the other half and get the goodies for free.
Nice for parts or something to play around with and give as gifts.
So I fix half and sell for $40.00 and gut the other half and get the goodies for free.
Nice for parts or something to play around with and give as gifts.
A quick update.
I have now auditioned two SMPS, ie one per channel. No apparent improvement in sound quality but the negative regulator that got a little warm using just one SMPS is now quite cool. In fact I played a bit of rock at louder volumes than I have before and there is nothing at all wrong with the deep clean bass.
Secondly, I have modified one of these SMPS so that the 0 volt rail is isolated from mains ground (fairly straight forward once I looked at the underside of the PCB). So next step is to modify a second and then connect them together.
I have now auditioned two SMPS, ie one per channel. No apparent improvement in sound quality but the negative regulator that got a little warm using just one SMPS is now quite cool. In fact I played a bit of rock at louder volumes than I have before and there is nothing at all wrong with the deep clean bass.
Secondly, I have modified one of these SMPS so that the 0 volt rail is isolated from mains ground (fairly straight forward once I looked at the underside of the PCB). So next step is to modify a second and then connect them together.
Nuuk said:Secondly, I have modified one of these SMPS so that the 0 volt rail is isolated from mains ground (fairly straight forward once I looked at the underside of the PCB). So next step is to modify a second and then connect them together.
Ok. If you need me, I'll be right over here behind this bunker...
se
Nuuk said:Yeah - I do need you Steve! To turn on the power while I hide behind the next town!
Oh no fair, man!
If anybody gathered here knows just impediment why I may not now apply power to the afore mentioned SMPS, please speak now or forever hold your peace.
Yeah. Don't want the next post to begin with "We are gathered here today..."
Oh what the hell. Just go ahead and flip that little chromium switch.
se
Nuuk said:Secondly, I have modified one of these SMPS so that the 0 volt rail is isolated from mains ground (fairly straight forward once I looked at the underside of the PCB). So next step is to modify a second and then connect them together.
Nuuk said:If anybody gathered here knows just impediment why I may not now apply power to the afore mentioned SMPS, please speak now or forever hold your peace.
I'm against that marriage.
Nuuk, look closer.
What have you disconnected?
Is the PCB completely isolated from the chassis of the PSU?
Also, where does the earth wire connect?
The zero volt rail was connected by a single track to a metal tab that is connected to a metal pillar when the PCB is screwed to the chassis. I removed the metal tab and put an insulator between the PCB and metal pillar.
The mains earth is still connected to the chassis but not the zero volt rail.
Nuuk said:The zero volt rail was connected by a single track to a metal tab that is connected to a metal pillar when the PCB is screwed to the chassis. I removed the metal tab and put an insulator between the PCB and metal pillar.
The mains earth is still connected to the chassis but not the zero volt rail.
Ok, put that in series with the other PSU and switch them on.
SY said:
WHAT!?!? You mean there are people out there now who are going to think that I look like THAT disgusting thing!? That's really low, Stuart. I didn't think you'd ever stoop that low. Even as a joke.
Just to set the record straight, THIS is me. Not that... thing in Stuart's avatar.
An externally hosted image should be here but it was not working when we last tested it.
Heh. The gorilla their dreams, eh?
se
I thought it only fair to tell Steve he can come out of the bunker now!
Yes, two of the SMPS are connected together and working at present. I cannot honestly say there is any difference in the sound from using one SMPS per channel but of course, I have removed the potential bottleneck of the negative regulators (only capable of supplying 1 amp).
Now the next step is to convert (isolate) the other two SMPS and then connect them all together to get +/-24volts. But how do I do that exactly?
Yes, two of the SMPS are connected together and working at present. I cannot honestly say there is any difference in the sound from using one SMPS per channel but of course, I have removed the potential bottleneck of the negative regulators (only capable of supplying 1 amp).
Now the next step is to convert (isolate) the other two SMPS and then connect them all together to get +/-24volts. But how do I do that exactly?
Nuuk said:
Indeed.
Nuuk said:Now the next step is to convert (isolate) the other two SMPS and then connect them all together to get +/-24volts. But how do I do that exactly?
You have +12V, GND and - 12V now, right?
If you use +12 and -12V wires and leave the GND floating you have 24V.
You just need to make the same on another pair of PSUs.
Btw, I would "isolate" them all.
Like this uncle C?
An externally hosted image should be here but it was not working when we last tested it.
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