How Quiet are Polytone Amps?

[mule71]

How quiet are your Polytones with no instrument plugged in and volume at 0?

I picked up a used Minibrute III (a mid-80’s one) at a decent price, but it has a noticeable underlying hum. The hum does not change with an instrument plugged in, or when increasing volume.

Just wondering if this is normal with Polytones or whether something isn’t properly grounded.

[medblues]

Mine is very quiet unless volume and gain are full up then it has a tolerable hiss not a hum.

[whiskey02]

Same as medblues states above for my MB I.

[Meggy]

My mid-90s MB2 is pretty much silent with the volume at zero - I've certainly never noticed any noise or hum at all. It's pretty quiet even with the volume up, unless I spoil things by playing a guitar through it...

[Pierrot]

I had years ago a minibrute V, a minibrute II, and a megabrute and they all were quite silent.

[mule71]

Thanks for the responses. Looks like I’ll be taking it in to my local tech to examine.

[WilliamScott]

Silent, but my wife keeps telling me I'm going deaf.

[Greentone]

I own a, ah..., stoopid large number of Polytone amps. They are all pretty quiet at idle. Of course, there is one place in my home that is right over the florescent lamps in my shop down one floor. _Any_ amp I place in that spot picks up the florescent hum. I have to remember not to use that spot...or remember to turn off the shop lights.

[mad dog]

My mid 80s MB II is pretty quiet. As in no hum. But since I usually have P-90 and P-13 equipped guitars plugged into it, there's not lack of buzz from the p/us.
MD

[losaltosjoe]

My early 1980s Mini Brute I is nice and quiet on idle or at any volume (i.e., no hum). Good luck!

[Greentone]

Just finished playing my late-70s Mini Brute IV with several archtops and a Telecaster. If the pilot light weren't shining red you wouldn't know the amp was on.

Nice, reliable amp.

[Herbie]

My MB IV is very quiet too. But it had a hum. It went away by connecting the chassis of the preamp to the chassis of the reverb tank. You can do it Yourself if You can turn a screw and solder. Of course it can be caused by something else too.

[mule71]

Thanks for all of the suggestions. My Polytone is a III, so doesn’t have the reverb tank. I’ve tried the amp in numerous parts of the house, but there’s no change in the hum.

Funnily enough, I was playing bass through it last night when there was less noise outside and my ear kept telling me that my bass was out of tune. I kept playing and realized that the hum was causing this perception. I bent my low G up slightly and matched the tone of the hum. I’m in the UK, so looked up the note for 50 Hz. That would be it - slightly higher than a G. Time to research causes for a 50 cycle hum, but I may leave the surgery for the tech.

[vintagelove]

I’ve had a bunch. If working correctly, they should have an acceptable noise floor. One of mine is currently obnoxiously loud, she’s due for a recap and a service. I can say for sure I had one that had a noticeably increased noise floor right before it “died”. It went in for service and she’s as good as new.


I’d make an appointment for the amp doctor. .


some of my favorite amps btw.

[smmllr]

My early-mid 80’s Mini Brute II is pretty quite, except when I plug in a P-90 Gibson and take my fingers off the strings.

[rio]

Mine is from the 80’s and has no sound like that. I had a later Polytone years ago and it also had no hum. Sounds like there’s an issue.


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[Durban]

I have a couple PT's they are quiet.


if noisy its normally easy and CHEAP to fix, so dont listen to some of the normal BS

[Papawooly]

50Hz at your place 60HZ over here...
Whenever there is a 60Hz tone on ANY equipment I have ever used it is nearly always a grounding issue.
Poke around with a flashlight (unplug 1st) and see if you can see any ground connections that may be lose or have poor contact and address them. I would pop the amp out of the cabinet and repeat.

Once fought same issue in our studio control room with a tall 19" rack full of gear.
It was caused by a ground loop, but we had to re-do all of our grounding to a Mecca point.

Polytone s/b much easier to fix. The link below may help... Good Luck!

How to find and fix hum in 3 easy steps | PS Audio

[Boston Joe]

I had an 80s MB3 that was pretty quiet.

Since you've moved it around, you can probably rule out any kind of ground problem (unless your whole house has a ground problem). I've started using a ground-isolated power strip, and I get a lot less hum.

So yeah, it probably needs a tech's attention.

[Greentone]

My guess: amp needs new filter caps.

[edh]

I bought a MBIII Polytone. I was leary at first. but the person assured me that it was a great amp. I went ahead and pulled the trigger. First polytone that I owned. I couldn't be more satisfied. It was a 15" amp.Get's great tone. I bought it for a song and a prayer. The guy I bought it from knew he was selling it below market value. He wanted to get rid of a few amps that he had.

Forgot to answer your question. No...I have no problems with the amp buzzing, scratching. If you have these problems try cleaning the pots, before you decide to sell it.

[Nohhyuk]

How quiet are your Polytones with no instrument plugged in and volume at 0?

I picked up a used Minibrute III (a mid-80’s one) at a decent price, but it has a noticeable underlying hum. The hum does not change with an instrument plugged in, or when increasing volume.

Just wondering if this is normal with Polytones or whether something isn’t properly grounded.

My Baby Brute does the exact same thing. The hum is very low in volume—any playing at all will make you not notice it. But, having the amp on in a quiet room, you’ll definitely notice it when not playing.

[mule71]

My Baby Brute does the exact same thing. The hum is very low in volume—any playing at all will make you not notice it. But, having the amp on in a quiet room, you’ll definitely notice it when not playing.

Here's a post my tech made about my amp's repair:

Polytone Minibrute Repair (Minibrute III repair) - Keld Ampworks Guitar Amplifier Repair Keld Ampworks, Newark, Lincoln

[Nohhyuk]

Here's a post my tech made about my amp's repair:

Polytone Minibrute Repair (Minibrute III repair) - Keld Ampworks Guitar Amplifier Repair Keld Ampworks, Newark, Lincoln

Thank you, Mule71. I’ll take this info to my amp tech!

[pauln]

If all else fails, Henriksen offers $200 trade-in for Polytones, including dead ones. Save the link for that rainy day.