Pacific Transformer noise

Express, Liverpool, Rocket, Dirty Little Monster, etc.

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RockinRocket
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Pacific Transformer noise

Post by RockinRocket »

How much noise buzz is acceptable for transformers?

Express attenuated to low tv vol my Pacifics are making a lot of buzz.. more than any other amp that I remember. Buzz is not amplified but you can hear the mechanical noise of them working and it also depends where the vol is set. Is it both transformers making noise?
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xtian
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Re: Pacific Transformer noise

Post by xtian »

"How much" is subjective, obviously. But like you, I like to play my amps quietly, and transformer noise that's loud enough to hear from a few feet away in a quiet room is too much noise in my opinion. It's just the PT vibrating with AC--the OT will not (should not!) be making any noise at idle.
I build and repair tube amps. http://amps.monkeymatic.com
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DaveWell
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Re: Pacific Transformer noise

Post by DaveWell »

Can you post good picture of your built, it will help us helping you
RockinRocket
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Re: Pacific Transformer noise

Post by RockinRocket »

The transformers are buzzing when playing attenuated quietly is when you can hear them. All transformers make noise but I wasn't really sure whats making the noise. I think its output transformer. My last set didn't buzz this much that I could remember.
RJ opened up a set of Pacific reissues and I remember him making mention of a wood shim they used but I forget why.
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xtian
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Re: Pacific Transformer noise

Post by xtian »

Sry, I missed that--does it only buzz when using attenuator? Can you confirm the impedance of the attenuator matches your amp?
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ToneMerc
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Re: Pacific Transformer noise

Post by ToneMerc »

RockinRocket wrote: Fri Jul 07, 2017 4:27 pm The transformers are buzzing when playing attenuated quietly is when you can hear them. All transformers make noise but I wasn't really sure whats making the noise. I think its output transformer. My last set didn't buzz this much that I could remember.
RJ opened up a set of Pacific reissues and I remember him making mention of a wood shim they used but I forget why.
I noticed the exact same buzzing years ago when running several different amps through a Rocktron Juice Extractor.

TM
RockinRocket
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Re: Pacific Transformer noise

Post by RockinRocket »

The buzz is always there. You just wont be able to hear it when the vol of the attenuator is turned up.

I suppose I haven't been playing a NMV amp with this much gain in a while. After about 1 o'clock
(where JMP gain stops) the Express is driving everything much harder. Pretty sure the buzz is the output transformer getting massive signal overload at higher gain vol.
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RJ Guitars
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Re: Pacific Transformer noise

Post by RJ Guitars »

Do you get the buzz immediately when you power up or only after the tubes are hot?
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RockinRocket
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Re: Pacific Transformer noise

Post by RockinRocket »

Its when playing (applying signal). As Vol is increased it gets more noticeable. Of course this is only noticeable when I'm attenuated to quiet TV vol.. trying to keep every one happy. I just thought Pacifics were baked to keep transformer noise this to a minimum. This is a high gain amp and probably normal. Ive been playing Plexis and have forgot what the other Pacifics I used do under attenuation. It no big deal really but a bit annoying!
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Littlewyan
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Re: Pacific Transformer noise

Post by Littlewyan »

My Pacific OT makes a slight rattling noise which is a bit of iron inside I think going mad with the magnetic field. I could open it up to find out but for me it only happens when I'm attenuated real low just below talking level and then I only notice if I'm 2 feet away from it.
RockinRocket
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Re: Pacific Transformer noise

Post by RockinRocket »

You know I turned on my JMP Plexi with Merren Transformer, dimed the vol and the transfomers are very quiet. Same as my vintage Marshalls. The Express dialed in at 10-11 o'clock to match the gain eq voicing of the Plexi still makes a ton of transformer noise.
Just because the Pacifics are USA that doesn't necessarily mean they are of quality, right? 35 watt rated have anything to do with the noise? Pushed to hard?
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