system troubleshooting (white noise?)

beat · « **on:** 14 Mar 2005, 04:18 pm »

Hi guys,
I cant figure out why this system does this. I thought I had it figured out but I guess I don't. It consists of monoblock tube amps, ird purist pre, jolida cdp. I tried swapping different amps, different pre, different sources, and switching r for l. I thought I had it narrowed down to something from the pre but alas, no....

The deal is there is what sounds like a white noise hiss from one channel. Could this be static build up or something of that nature?

thanks for any input,
beat

_scotty_ · « **Reply #1 on:** 14 Mar 2005, 05:13 pm »

How loud is it and is it always in the same channel? Does the volume ever change? How old are the tubes in your Jolida CDP or your tube monoblocks.Could one of the tubes be loose in its socket. I would try to make some shorting plugs out of cheap RCAs and plug them into the power amp and see if the noise is still present. Good luck,Scotty

Occam · « **Reply #2 on:** 14 Mar 2005, 05:22 pm »

No soulution, but more confusion......

Another potential source for the noise you describe could be the interconnect cables themselves, a poor ground connection can manifest itself as white noise. When you thought you'd narrowed it down, are you sure that the interconnect weren't swapped. Are they somehow identified as to R & L? If they are labeled and you've eliminated them as a potential source, then......
nevermind, I gots nutt'n.

PS- doesn't the Purist have 2 seperately buffered sets of outputs? If so, you could check if the hiss came from a specific buffer.... and at least eliminate that as the source.

beat · « **Reply #3 on:** 14 Mar 2005, 06:02 pm »

Ok,
Thanks guys.

1) I swapped the output cable from the pre to the other amp, the sound went with it. So it isnt the amp.

2) New set of cables. no change. not the cables

3) swapped R+L from the source to the pre, No change..not the source

4) moved the output cable from the out1 to out2 on the pre and it went away.

survey says? problematic out on the pre eh?

Occam · « **Reply #4 on:** 14 Mar 2005, 09:30 pm »

Quote from: beat

....moved the output cable from the out1 to out2 on the pre and it went away.....

Once, while quite inebriated, a friend asked me why I was searching for my lost keys only under the parking lot's sole light. 'The lights better here.', I replied, and then vomited on his shoes.

All things being equal, check what is easiest to check first.

meby · « **Reply #5 on:** 14 Mar 2005, 09:48 pm »

Occam that is great

beat · « **Reply #6 on:** 14 Mar 2005, 10:26 pm »

Quote from: Occam

Quote from: beat
....moved the output cable from the out1 to out2 on the pre and it went away.....

Once, while quite inebriated, a friend asked me why I was searching for my lost keys only under the parking lot's sole light. 'The lights better here.', I replied, and then vomited on his shoes.

All things being equal, check what is easiest to check first.

that is on spot occam and hilarious

but DAMN, I have gone over this before and narrowed it down to the same thing (out1 is bad) but the sound re-appeared in out2 later on so dismissed it as something else. I have gone over this with Curt already, and at the time it seemed something more peripheral (sp?) than the acutal hardware itself but maybe the linkage betwixt it all. The thing about the purist is that they are bulletproof, but I suppose it is possible that there is a problem. I will take it up with Curt again...I will try not to puke on his shoes though.

avahifi · « **Reply #7 on:** 14 Mar 2005, 10:30 pm »

http://www.avahifi.com/root/ordering_info/troubleshooting_flow_chart.htm

I suspect many of you might find this useful in tracing down a fault in your audio system.

Of course, you can always call me for help at 651-330-9871.

Frank Van Alstine

Occam · « **Reply #8 on:** 14 Mar 2005, 10:58 pm »

Beat - Dunno, but given this from the Purist description -
" 2 Line level dual mono outputs (separate line drivers)"
http://www.ird-thailand.com/products/purist/purist.htm
I assume that if it indeed has separate buffers, that you can pretty conclusively confirm whether its something betwixt and between where the two ouputs divide, or not.
Verify that the noise is from a specific output# and side, and not specific to a certain source or input channel selection.
Make sure the noise doesn't 'travel' with any specific cable.

If it walks like a duck, talks like a duck.....
most likely, its a duck

EDIT - I'm not sure what you mean by '"but the sound re-appeared in out2 later on so dismissed it as something else." Do you mean that that noise also appeared on the previously noise free ouput channel? and it wasn't tied to a specific input selection choice, cable, or source component(s)? If so.... beats the heck outta me.

beat · « **Reply #9 on:** 14 Mar 2005, 11:35 pm »

Occam, you said
"I'm not sure what you mean by '"but the sound re-appeared in out2 later on so dismissed it as something else." Do you mean that that noise also appeared on the previously noise free ouput channel?"
Yes, in past tense, this happened. The noise was not there at first but later on it surfaced again. I am hoping it doesnt come up again. If so, I think we could still asssume it is coming from the pre, right?

Thanks Occam and Frank for the awesome help.
beat

beat · « **Reply #10 on:** 9 Apr 2005, 03:28 pm »

Hey guys,
It took me a while to actually contact IRD about this issue. As soon as I did though, Curt emailed me back and wanted a phone number to reach me at. He called me within like 15 minutes! Walked me through the problem and we got it rectified. Great service!

markC · « **Reply #11 on:** 9 Apr 2005, 04:27 pm »

So, what did it end up being? Could help others with similar problems in the future.

beat · « **Reply #12 on:** 9 Apr 2005, 08:02 pm »

Not sure as of yet.
Being skilled with a soldering iron he walked me through the obvious cold solder joint at the rca out..alas, no. If you have ever seen inside one of these things (and understand it's manifesto) it is immediately obvious that there is serious attention to every detail in layout and execution. However, I seem to be the lucky one who recieved a cap that went bunk prematurely. I'm keeping it and just using the outputs number two until the new run hits shore and then I will recieve a replacement. Being in the independent (and high end) restaurant business I understand the problems inherent in purchasing "ingredients" in bulk. I can spend fair money on a pound of shallots from the best dealers in town but it is not uncommon to find a bad one in the bunch. Unfortunately for the audio biz, caps and other things are supposed to last years but one can still go out on you prematurely even after bench testing each unit before shipping. Shallots on the other hand are also screened at least twice (once by the packager and again by the chef) and if one had the propensity to go bad prematurely and got in the mix (and it will but then it is referred to as extra ripe!) it is consumed that day and all is forgotten or never seen. My hat goes off to all small audio companies who provide excellent customer service such as IRD.