tube works mosvalve 962 transformer....

[Gainmonger]

Hey all!
I've got a functioning mosvalve 962 power amp with a super noisy transformer.
I'd like to change it as the noise and vibration are too loud and bleed into the signal.
However, it's the original one. I have the specs but its shape is particular and I can't find a "modern" one that fits.
Has anyone of you replaced it or know a suitable equivalent (size and specs?)
thanks

[Rob Strand]

I can't help with your direct request.    You might consider a toroid.  The dimensions aren't always suitable to replace
a conventional transformer.  You will need to drill holes.  Also, if the enclosure metal isn't thick enough you won't
be able to tighten up the mounting screw as the metal will distort and you might need a mounting plate.
Only you can really evaluate that option.

It's not 100% clear if you are talking about buzz from the laminations? What's
bleeding into the audio hum or buzz?

You might be able to fix the existing transformer.

- Tighten up the screws on the transformer covers/laminations.
   Do that with the mounting screws removed, then remount.

- You might have a fault.  If the rectifiers are damaged or the rectifier or tx connections
  are bad you can sometimes get a situation where the rectifiers are operating as half-wave.
  All the voltages come up as normal but in operation it buzzes and the transformer
  can overheat.   You need to check thoroughly as it's difficult to detect and correct.

- In some cases adding a cap across the transformer secondary windings can prevent acoustic
  buzz from the laminations and buzz in the audio.   Look at C2 in figure 1.  Play with the cap value.

  https://sound-au.com/project04.htm

  "C2 (100nF X2 rated) is intended to minimise EMI (electromagnetic interference), and in particular conducted emissions.  It can be a higher value if you prefer, but more than 470nF isn't necessary.  Some people like to add low value caps in parallel with the diodes in the bridge, but this should not be needed.  They do no harm, but make sure the caps you use will handle the AC waveform without failure."

[pinkjimiphoton]

Hey all!
I've got a functioning mosvalve 962 power amp with a super noisy transformer.
I'd like to change it as the noise and vibration are too loud and bleed into the signal.
However, it's the original one. I have the specs but its shape is particular and I can't find a "modern" one that fits.
Has anyone of you replaced it or know a suitable equivalent (size and specs?)
thanks

please define : noise

most likely not the transformer. unless its loose, like rob suggested.
if its noisy, first thing i'd think is mechanical. make sure all the stuff is tight, especially transformer mounts.
the potting could have been damaged by vibration and make a mechanical noise, but you can fix that with a dab of silicone and tightening it.

first thing i'd suspect is always capacitors when i have noise.
but first, we need to know what kind of noise you're dealing with. that will help us figure out the fix.

next, we need details on the unit. i haven't seen one in years,

https://www.manualslib.com/manual/270896/Tube-Works-Mosvalve-962.html

there's not really a lot of extra functions to have to hassle with it looks like, so first thing i'd do would be replace every freeking electro in the power supply, check the diodes for shorts, and try using a snubber cap to ground in parallel with the main power filters.
when these were designed, they didn't have all the rfi garbage that's out there to pollute analog guitar amps.

if that makes the noise go away, solder 'em in permanently.

i mean, if the amp is functioning, the transformer is working.

if it is VIBRATING when in use to the point it is RATTLING
it will need to be repotted most likely. sometimes if the mounting comes loose, over time, the laminations can get weird and lose some of the laquer or whatever they used to pot it with.

i do NOT know what they used, but in my old auto electric days, we just used spray on varnish to seal stuff. the key is non flammable... but i am very likely wrong, soooo...

anyways...let us know. cuz it could be mechanical noise... or electrical noise....or electronic noise... or leaky noise

or even just noisy ass jfets hissing and crackling.

once we know what, waaaaaaaaaaaaaaaaaaaaaaaaaaay smarter peeps than me can def help you

[Rob Strand]

first thing i'd suspect is always capacitors when i have noise.

The caps are definitely on the list.  With something this age it's quite possible there are multiple problems: mechanical and electronic.

[Gainmonger]

hey all! sorry to post again a year after! my computer was damaged and I completely forgot about the topic
Thanks to all for the replies, it's really awesome.
regarding the noise, it's definitely the transformer buzzing/laminating.it's varnished and definitely could do with a repotting. I don't have the necessary tools though.
I've tightened everything I could but there's no improvement.
The caps look fine and the rectif diodes too.
Does anyone have a schematic with the proper values?
I thought I had the right one but it wasn't.
I think I'd go for a new toroidal transformer, even if it requires a bit of mod but I need the right values for the transformer first
thanks again guys!