Killing amp buzz

adrian

Hey guys, I have a Peche A La Mouche amp, which is awesome, but the one non-awesome thing about it is that it buzzes at high volumes. (I.e., when I'm not playing, you can hear a pretty loud buzz coming out of the amp.)

I don't know anything about amps, but I have a theory that this is because the cable is not grounded. It's a European-made amp and only has two prongs on the plug, not the third/ground plug. Does that sound like the culprit? And, if so, what's the best way to ground it to fix the buzz?

Adrian

Steveareno

All tube amps buzz to a degree, some worse than others...especially high gain amps, like the Fender Blues Jr. I would change the plug to a 3 prong grounded (strange it didn't come stock). If the pre-amp tube is 12AX7, you should be able to swap to 12AY7. This lowers the gain, warms up the tone and should reduce the noise. Alot of guys do this to the Fender Bassman Reissue.
Swang on,

HotTinRoof

Hey Adrian - the amp sounds like the culprit and something an amp tech can easily make right but be sure the pickup isn't adding to the hum too. A go on another amp will clear that question up - which you have probably already done though its worth mentioning.

I like Steveareno's suggestion for the 12AY7 tube swap as it will warm it up nicely. You'll hear a greater difference if coming from a 12AX7 than you will a 12AT7 - I see the Peche A La Mouche Amp can come with different 12X_7 configs.
Here is a page I had bookmarked from ages ago when I was swapping tubes on a few vintage amps.

http://cydathria.com/fdm/12AX7_sub.html

I used to have a great tube swapping page bookmarked but it's vanished - had everything! Even suggestions on the dreaded 50L6 tube (straight wall current). But I digress...

Just be careful and give the amp to a professional for work - we want you around.

Steveareno

Adrian, the clip of you playing that amp on YouTube is awesome. That is a nice thick, ballsy tone (makes me want to throw my tele away). I don't hear much buzzing and on a gig would probably not be noticed, however even a small amount of buzzing can be annoying at home or in a studio.
Swang on,

wim

Did you ever ground that plug, adrian?

adrian

I'd emailed the Peche people, and they said the noise should disappear if I changed the plug to add a third (ground) pin. I haven't gotten around to doing this, though.

wim

I'm ordering one and asked him to build it with the type B plug. Will report back in a couple of months ..

richter4208

Adrian, what kind of pickup are you using with it? Most small tube amps buzz at high volumes, especially with a single coil style pickup like Peche makes. If grounding/tube swap doesn't help I guess you could use a noise gate like the isp decimator.

Stevereano's idea of the preamp tube swap will probably help a lot.

adrian

richter4208 wrote: »

Adrian, what kind of pickup are you using with it?

Thanks for the info! I was using the Peche pickup with it -- but it's now being borrowed by a friend while I live overseas. Looking forward to trying your technique in a year and a half, when I have the amp again.

nomadgtr

+1 on the ISP Decimator, I have one in my mini rack for my electric guitars. It works great once you dial it in. You should be able to eliminate a lot once you get that ground plug though. The single coil noise is just another fact of life but typically isn't a problem at low gain. It's more of an issue when you crank up say a Strat through a Marshall. :O

Al Watsky

Ground hum from single coils is to be expected.
Nothing wrong with a 3 prong plug.
An alligator clip from the amp chassis to a radiator will also ground the unit. But thats to old school for you I think.
Alternatively you can take the same alligator clip and attach one end to the chassis and the other to the center screw of the wall outlet which will also ground the unit.
The low out put of these "vintage" style pickups and the relatively low volumes that they are used at is the reason we accept them. The low range coil rating , which is very low, I've measured them in the 3.5k range gets us to a pretty flat audio response which is good and the low range also lessens the output signal , so noise seems at a low volume to be acceptable.
If you turn up that amp you might not like what you hear though.
Turn up the amp the ground hum gets louder.
If you orient the pickup coil to the transformer coil of the amp it will lessen but not go away.
Also get hip to the fact that the Peche lead has a conductive film as a shield so that if you roll over the cord with a desk chair , say in a recording studio that may interrupt the shield and make the pickup more noisy. It will still work but it will have a louder ground hum.
So check if your pickup cord isn't the problem.
I replaced the lead on my Peche with a braided shield cable after wearing the first one out and now have much less noise from mine.