This my power supply.
http://img.villagephotos.com/p/2003-4/144711/DOS317.gif
15 - C is my buffer
http://www.borbelyaudio.com/adobe/ae699bor.pdf
So I thought I had it all plugged in and the right channel sounded correct at good. I could not test to see if it sounded better with it because the left channel made weird noises like it was not plugged in, a small zapish sound and mostly buzzing. Apparently the RCA cord fell off when I put the buffer into my little wood stand thing.
When I plugged the left channel in and fired it up again I get really bad distortion and static? The right channel is no longer clear?
The only other details of this setup are thus... all grounds from RCA's are running to system ground. The two shunted resistors for input are going to earth ground. Earth ground is connected to chassis from plug.
http://img.villagephotos.com/p/2003-4/144711/DOS317.gif
15 - C is my buffer
http://www.borbelyaudio.com/adobe/ae699bor.pdf
So I thought I had it all plugged in and the right channel sounded correct at good. I could not test to see if it sounded better with it because the left channel made weird noises like it was not plugged in, a small zapish sound and mostly buzzing. Apparently the RCA cord fell off when I put the buffer into my little wood stand thing.
When I plugged the left channel in and fired it up again I get really bad distortion and static? The right channel is no longer clear?
The only other details of this setup are thus... all grounds from RCA's are running to system ground. The two shunted resistors for input are going to earth ground. Earth ground is connected to chassis from plug.
I have concluded these means the + and - power do work.
The right channel works by itself. Power is happening, signal is moving. The question is just why the left when powered is causing a problem. Could it be a bad JFET? I still have like 15 so I could test new ones. I tried not to over heat them. However would one bad JEFT make both channels sound distorted?
The right channel works by itself. Power is happening, signal is moving. The question is just why the left when powered is causing a problem. Could it be a bad JFET? I still have like 15 so I could test new ones. I tried not to over heat them. However would one bad JEFT make both channels sound distorted?
hi, my idea is there is something wrong on the power supply.
for the negative(-24) you must to use the LM337.
then the LM317 provide the +24v and the LM337 the -24v.
or the drawing of the power supply schematic is wrong.
for the negative(-24) you must to use the LM337.
then the LM317 provide the +24v and the LM337 the -24v.
or the drawing of the power supply schematic is wrong.
Hm this shows either, http://www.national.com/images/pf/LM337/00906701.pdf
My understanding was to get -24v I just reverse the output leads, like in the picture. A friend helped me with this, who is extremely good with electronics, but could of been wrong.
The other question would be why did it work on one channel but not with both plugged in?
My understanding was to get -24v I just reverse the output leads, like in the picture. A friend helped me with this, who is extremely good with electronics, but could of been wrong.
The other question would be why did it work on one channel but not with both plugged in?
Two pieces of 317 will also do without trouble, just don't screw them uninsulated on the same heatsink, that will short circuit...
I did not mount them to a heatsink considering the amount of power in this circuit is a couple of mvs. There is definitely power going. It worked before with power but due to bad PDF instructions I had the JFET's reversed and they blew up. That is fixed but now the noise issue is baffling.
I have been reading up on negative voltage... the way it is setup is correct.
At the moment I am realizing having the grounds on the RCA jacks tied into "system ground" seems unnecessary. From what I can tell the +24 and -24 circuits complete eachother... so long as the JFET's are switching then +24 and -24 rails should make a complete circuit. The problem lies in the fact that they must reference to ground. I wonder if this means that I need to make the shunted inputs (500k I think I have them at) go to "system ground" in order to give +24 and -24 reference points to ground, in affect giving them their voltage.
The grounds from RCA's and the signal should be it's own circuit, especially to keep DC out of everything.
I guess I will have to try this soon.
At the moment I am realizing having the grounds on the RCA jacks tied into "system ground" seems unnecessary. From what I can tell the +24 and -24 circuits complete eachother... so long as the JFET's are switching then +24 and -24 rails should make a complete circuit. The problem lies in the fact that they must reference to ground. I wonder if this means that I need to make the shunted inputs (500k I think I have them at) go to "system ground" in order to give +24 and -24 reference points to ground, in affect giving them their voltage.
The grounds from RCA's and the signal should be it's own circuit, especially to keep DC out of everything.
I guess I will have to try this soon.
Ok I the power normal now by switching the ground from the resistor shunts to the system ground. However even without the buffer on I get buzzing through my little test amp and speakers. I am going to put capacitors on the inputs, already tried outputs... I was thinking DC is feeding back into it but I am not sure?
It sure sounds like a ground loop hum or some sorta disconnect, but how it is happening is behind me unless my RCA's do need to be touching system ground inside of the buffer, as well.
It sure sounds like a ground loop hum or some sorta disconnect, but how it is happening is behind me unless my RCA's do need to be touching system ground inside of the buffer, as well.
If I so much as plug in the power cord with the amp on I get noise. I got no idea why. That is with the power off.
I have no idea what is wrong, I give up. I am just going to have to wait who knows how much time and get a PASS B1 I guess.
I have no idea what is wrong, I give up. I am just going to have to wait who knows how much time and get a PASS B1 I guess.
robertor, I disagree with you, it IS possible to create a positive and a negative voltage with 2 pieces of LM317. It would be nicer to use LM337 instead, but it should work without trouble.
I think since it is a shared power supply for both channels, the problem isn't in the power supply, it must be in that left channel. You should check the circuit board for bad ground connections.
You could also try to swap the amp inputs, so left channel becomes the right and the right becomes the left, this eliminates any doubts about the amp itself.
Could you post me a picture? So I have a clue what we're talking about exactly..
Best regards
I think since it is a shared power supply for both channels, the problem isn't in the power supply, it must be in that left channel. You should check the circuit board for bad ground connections.
You could also try to swap the amp inputs, so left channel becomes the right and the right becomes the left, this eliminates any doubts about the amp itself.
Could you post me a picture? So I have a clue what we're talking about exactly..
Best regards
If I understand it correctly, you get noise when you plug in the power cord of the amp that is connected to your circuit? If that's true, you certainly have a ground loop.
Yeah well I put the whole thing into the closet until I need the box again... I can not even imagine how a ground loop was being created without the circuit even on.
re-build the power supply with 317/337 and try another time.
don't work fine?
search for another problem.
must to go for exclusion: that work fine and the problem persist? check the fet or buy some j-fet buffer PCB come from china.
jims-audio have the borbely.
p.s.: i'm not able to build a power supply work fine then i buy from some Chinese ebay seller. the price is absolutely absurd and make their work.
don't work fine?
search for another problem.
must to go for exclusion: that work fine and the problem persist? check the fet or buy some j-fet buffer PCB come from china.
jims-audio have the borbely.
p.s.: i'm not able to build a power supply work fine then i buy from some Chinese ebay seller. the price is absolutely absurd and make their work.
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