Hello,

I had a Buffalo32s(v 1.0) that has been working great for years. Recently it developed a low level scratching/static noise in the right channel. I am only mildly experienced in the DIY world so I am not sure how I should go about troubleshooting it. This was built for me awhile back by a trusted, experienced builder but it just isn't cost effective to ship it out to have him address the issue so I would like to give it a shot with your folks help.

The noise sounds like tape hiss with a intermittent scratchy sounding noise almost like warbling tv static.
The noise is at a constant low level in the right channel.
The noise is present at the same intensity whether there is music playing or not, no matter what input I switch to and no matter where I turn the volumite.


What I have done:
I checked it in different rooms and different outlets/surge protectors.
I very scientifically "wiggled" all the wires to see if it was a loose/cold solder joint and the noise was unaffected.
I switched placid power supplies on the channels to see if the noise was coming from the power supply or the Buffalo32s board and the noise remained constant in the right channel.

Can anyone help? Is that noise indicative of a cold solder joint, a failing capacitor, or maybe an issue with the opamp?

Edited by user Friday, January 6, 2012 10:14:12 AM(UTC)  | Reason: Not specified

I guess you could try powering off the VD inlet.

That would halt the DAC section and give you a clue whether the noise comes from the DAC section - or the analogue section.

Tried listening to it with the power to the VD inlet unhooked and there was no noise coming through the right channel. When I hooked the placid back up to the VD inlet the noise returned in the right channel.

I unplugged the volumite and it had no effect on the noise in the channel.

One thing to note. I noticed that in these pics(from the builder while in progress) there is a chip in the ic8 slot. There isn't anything in there now.

I saw from another forum that someone had suggested removing the chip when using the volumite so I am assuming that is why mine doesn't have it in there but I figured I would bring it up. If it is helpful, I can take another picture of the internals as they sit now.

Thank you again for trying to help here.

Also, for further description on the behavior of the noise. It is very light but it is present at the same intensity whether there is music playing or not, no matter what input I switch to and no matter where I turn the volumite.

Edited by user Friday, January 6, 2012 10:13:36 AM(UTC)  | Reason: Not specified

I will give that a go tonight, thank you.

Pardon the newbie question but are you referring to the opamp in the IC2 slot?


EDIT: Actually I am now looking at this thread and following the advice given here:

Layout

Edited by user Friday, January 6, 2012 2:43:18 PM(UTC)  | Reason: Not specified

Hey Everyone, sorry for the delay, finally got some free time to measure the stuff. I went ahead and measured all of the opamps that the guy in the other thread tried.

LEFT:
IC3 (LME49710) output = 3.279V
IC13 (LM4562) output A (pin 1) = 3.8mV
IC13 (LM4562) output B (pin 7) = 1.636V

RIGHT:
IC2 (LME49710) output = 3.279V
IC14 (LM4562) output A (pin 1) = 3.8mV
IC14 (LM4562) output B (pin 7) = 1.637V

I also tried disconnecting the MUX and it had no effect.

I feel your pain, I have done the same thing before. You may possibly be able to just replace just that opamp. It is worth a shot.

If not then likely the DAC chip itself is dead, in which case you could replace it with a B-III.

Very sorry for your misfortune. I know it is frustrating.

Ok got home and took a look at things.

1) I believe the 15v supplies are LCBPS v 1.1b

2) My Case is pretty much right about 71mm high, will the IVY/B-III/Trident stack fit?

Replace R1 to R4 on the LCDPS with 1 ohm resistors.(or jumper)
-Yes

Get rid of the volumite and wire the pot directly to the dac.
-Yes

Drill new holes in the case for the different spaced stacking connectors.
-Yes

Use the I2S connection from the Mux instead of the consumer level s/pdif.
-Yes. Or get the new input boards.

Should I just jumper the one side of the LCDPS that feeds the B-III since the other side goes to the older mux?
-You could, but it doesnt hurt to change both sides.

Do I have to do anything prior to wiring the older LCBPSs to the IVY III?
-No, it works as is.

My Case is pretty much right about 71mm high, will the IVY/B-III/Trident stack fit?
-Yes. My stack measures less than 5 cm.

Seems like you have everything under control, and are ready to start building!
And dont be sorry for "newbie" questions. We have all been there, asking questions and getting help from more experienced DIY'ers.

Good luck!