transformer mechanical buzz

[Lindz]

I just got a used Ceriatone express.

sounds great, but I have noticed that when I have it wound up but attenuated a fair amount (I live in a condo and use a Weber Mass) I can hear what I assume is one of the transformers sort of vibrating internally as I play. Its loud enough that I can hear the buzz/rattle if the volume is not that loud overall (attenuated volume - its pretty cranked into the attenuator). Some of my other amps do this very slightly but this is much more pronounced

Tried tightening the housings on the trannies and that did not seem to help. It does not seem to be the chassis rattling either..

I've read that loose windings in the transformers can cause this among other things..

1. Is it typically the OT or PT that would do this? I cannot really tell exactly where it is coming from except that it sounds like one of the trannies. Tried putting my ear up to the transformers but still cannot tell for sure

2. Any other suggestions?

3. Is there anything I can do about it besides replace it?

4. Assuming it does not bug me that much would you think its OK to simply run it as is? I assume if it is loose windings or something like that it is probably prone to failure

thanks!

[Mark]

The condition you refer to is a loose lamination on a transformer. A power transformer would hum continually if it had a loose lamination.

I've never heard an output transformer with a loose laminate so I can say what the effect would be.

Have you tried the obvious and replaced all the tubes. The filaments can put noise into circuits?

[Lindz]

OK I recorded a clip - put a mic a foot away from the OT while amp was sitting on my bench - putting my ear right up to the amp it does seem to be the OT buzzing.

attenuator maximum attenuation - almost off but you can hear sound from the speakers faintly - cab is 4 feet away, pointing away from mic.

Sorry the recording is in one ear as I used Windows sound recorder and it pans it

As I said this is quite noticeable when I knock it back a lot with the attenuator

at first I thought I had a rattle or a speaker problem but it is definitely the amp.

thoughts?

[diagrammatiks]

remember when you are attenuating that much that the transformer is putting out 100 percent of its output.

Say if you cranked the amp and then attenuated it down to conversation level the transformer would still be working hard as hell.

that's going to increase any normal electrical shenanigans such as loose windings/laminations etc.

if there is any mismatch between the attenuator and the transformer that will increase the noises.

you are hearing back emf/transformation saturation.

if you operate it too long in that state the transformer will melt.

[geetarpicker]

Most OTs will do this to some extent. I had a '68 Marshall plexi 100 that was almost a practice amp when fully attenuated, simply right off the OT can. That said, on my original wrecks I can just barely hear this effect.
Was this a Ceriatone? Personally I'd pick up a Pacific OT which will sound better anyway.

[Lindz]

I assume that this OT is so noisy is an indication that it is not as healthy as my other amps that are subjected to the same cranked output into heavy attenuation but do not make any (or much) noise

diagrammatiks - living in a Condo with neighbors on both sides makes an attenuator a necessity, and I prefer the sound attenuated, vs master volume. Power scaling is still too loud at night. I do have to play pretty quietly a lot of the time though this was an extreme so the mic could clearly pick up the buzz. I do notice that most of the buzz is there even when I turn down the amp volume quite a bit

I think the Weber Mass attenuators err a bit on the high side impedance wise if I am not mistaken (rheostat, resistors and speaker motor that ballpark 4/8/16 ohms) which I think is the lesser of 2 evils vs too low.

Geetarpicker - yes I think it is Ceriatone tranny looking at it but I bought amp used and its not labelled that I can see. I'll likely pick up a new one soon just for kicks - I'm curious to see how other types sound anyway.

thanks for the input guys

[diagrammatiks]

I assume that this OT is so noisy is an indication that it is not as healthy as my other amps that are subjected to the same cranked output into heavy attenuation but do not make any (or much) noise

diagrammatiks - living in a Condo with neighbors on both sides makes an attenuator a necessity, and I prefer the sound attenuated, vs master volume. Power scaling is still too loud at night. I do have to play pretty quietly a lot of the time though this was an extreme so the mic could clearly pick up the buzz. I do notice that most of the buzz is there even when I turn down the amp volume quite a bit

I think the Weber Mass attenuators err a bit on the high side impedance wise if I am not mistaken (rheostat, resistors and speaker motor that ballpark 4/8/16 ohms) which I think is the lesser of 2 evils vs too low.

Geetarpicker - yes I think it is Ceriatone tranny looking at it but I bought amp used and its not labelled that I can see. I'll likely pick up a new one soon just for kicks - I'm curious to see how other types sound anyway.

thanks for the input guys

like geetarpicker said, it's something that happens to all output transformers to a certain extent.

I'm not saying that you shouldn't use the attenuator, I'm just saying that it puts the same stress on the transformer whether or not you attenuate.

Usually the sound of the speakers would be so loud that you'd never hear the buzzing, but since you are keeping the speaker output low, the buzzing would be more apparent.

[Lindz]

After hearing the Wreck I tried a bunch of my amps, and my Weber Java build and one of my Marshalls buzz enough to notice slightly but much less than the Wreck. The others (couple 18 watt variations, a few other Marshalls) seem pretty quiet ..

I probably would have never noticed any of the other amps but the Wreck was loud enough that I could hear it faintly when I was playing very late the other night with the attenuator pretty quiet and thought I had a buzzy speaker or cabinet rattle at first

[diagrammatiks]

After hearing the Wreck I tried a bunch of my amps, and my Weber Java build and one of my Marshalls buzz enough to notice slightly but much less than the Wreck. The others (couple 18 watt variations, a few other Marshalls) seem pretty quiet ..

I probably would have never noticed any of the other amps but the Wreck was loud enough that I could hear it faintly when I was playing very late the other night with the attenuator pretty quiet and thought I had a buzzy speaker or cabinet rattle at first

don't ask me how I know this but if you crank an amp with no loud attached the output transformer will act like a little speaker.