Buzzzzzzzz

[patm]

Getting a variable buzz from my speakers. System is two years old. Mac mini, halide dac hd, FP III, Paramounts  orcas and subs. Cleaned tube pins (p&p 5 times). Disconnected Mac Mini, Dac, sub Amps. Don't know if this helps but noise not present with FP III turned off. Turned FP III over and all I can see is cap on OD3 socket appears to be bulging on one end. Only recent change is Mac Mini but unplugged and disconnected all of the related computer equipment. Help

[Doc B.]

It's either a power supply issue like a bad cap, a loose solder joint somewhere, or a ground loop. SOP - check voltages first. What type and rating is the cap that looks bulged? Also check and reheat any suspicious solder joints. If fixing that stuff doesn't solve it you might want to try a cheater plug on the end of the Foreplay power cord to see if that stops it. If you have made any recent changes to interconnect cables you may need to change them back to what you had before to see if that is the problem.

[patm]

The bulging cap is a Mundorf SO .1uf 800 vac 1200vdc that goes from r3 to r5 on the OD3 socket. Will check voltages. Only new cabling is a new set of speaker cables that I got when I got the Orcas (2 pair).

[Doc B.]

Well, 800V rated cap certainly shouldn't fail there. But not having the part in front of me I can't say for sure if it's messed up. Assuming that it's OK I would suggest checking over the solder joints thoroughly, and think about whether something new has been added to your home that might put noise on the power line or radiate EMI into the environment.

[patm]

Well all voltages check out good. Plugged the FPIII in with a cord with gnd cut off, same noise. Plugged in the BH cable and no noise? (The cable I started with)Hooked everything back up and powered up system. Now I have a small buzz nothing like it was. A few seconds after power up, a high pitched wine that fades into the low level buzz but as I said not as loud as before, can't here it from my listening chair. May try replacing the suspect cap later.

[earwaxxer]

hey patm - could you post a picture of the bulging cap. Just curious as to what that would look like with a film cap. I have seen electrolytics do that. I also have a bunch of the Mundorf s/o's.

[Paul Birkeland]

A few seconds after power up, a high pitched wine that fades into the low level buzz but as I said not as loud as before, can't here it from my listening chair.

You might swap the 0D3 too if you have access to a spare. 

[patm]

Problem appears to be the power supply in the Mac Mini I was using for a music server with an external FW800 hd. Removed music server from the system an plugged in the CD player and dead quiet. All is well, maybe an external ps mod for the mini in the future.

Thanks all.

Pat

[earwaxxer]

I dont doubt that! - My Quickie was picking up crap from my t-amp SMPS.

[Laudanum]

I dont know about the Mundorf silver/oils, but I have some standard film caps (MKP's) that you could describe as having a bulge on the lead end/ends.   I have/have had new caps like this and just chalk it up to the way they were manufactured.  The end "caps" look like they were molded with the bulge, one side may be worse than the other.   I wonder if this could be what patm is seeing.

[patm]

Alas I was premature in pronouncing the noise gone. It truly is a lot quiter after the CD player, but it took several hours to return. Earwaxxer, I will post a picture of the so cap later, I am overseeing the construction of my new house and it was a hard day so I will post the photo later. So the quest continues for the source of the buzz. You guys are going to ban me if I keep flip flopping on a cure.

Pat

[Paul Joppa]

... You guys are going to ban me if I keep flip flopping on a cure.

Nah - all the interesting problems are more complex than they seem (until you find the answer of course!). It takes longer but it feels better when you get there. Welcome to the next level!

Back to square one - well, square two, since yo have checked the voltages in the FP. With the volume turned all the way down, and no source device connected, is the noise there?