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Tube amp woes! any help?!


Daryl Chaney

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Hey,

Just wondering if anyone can shed some light on these problems with both my beloved tube amps.

 

I have brought both these amps to my regular amp tech, but he can't find the problems - has anyone had similar experiences as below.

 

Ampeg B-25 '69

After approximatley 2 hours of use at normal volumes, it trips the fuse box. At a recent gig in soundcheck it tripped the fuse on my side of the stage after about an hour, but then didnt trip for the rest of the night.

My amp tech had it on for about 2 days but it didnt trip his fuse box.

 

I recently replaced all the tubes & biased, but i replaced the 5AR4 rec with a GZ34 and replaced the sovtek 7199 with a Jan Phillips NOS 7199 - this wouldnt cause the amp to eat up more power would it ?

 

I use a step-up transformer 110volts-230volts, as im in Europe, but their doesnt seem to be any issues with it as far as i can tell & what my amp tech told me.

 

Anyone have any similar issues like this ? - We rehearse in a separated room from the main house which had its sockets & power installed only about 5 years ago, and have never had any problems with power. AHHHH :facepalm:

 

Musicman 65 (2100 Chassis / 12ax7 preamp tube) '74

I had this as my backup to the ampeg for a while now and only recently started using it because of the ampegs above issue. I noticed that at any volume i get a rather disguisting distortion from the amp, when i start to dig slightly into my bass.

 

My amp tech has narrowed the issue down to the Output section.He scoped everything along the amps sections & once it hits the output stage it distorts. he said the power tubes & caps/etc etc are all fine and the only thing he can think thats causing the issue is the output transformer!

But he can only be sure by replacing the transformer, which he doesnt have a spare of, and the only way is for me to buy one and try it

 

Has anyone had an issue like this with their Musicman ?

 

Any help or advice would be great, im dying here! i've got no backup to these two amps & am now considering getting a SOLID STATE Markbass!

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could be an issue with the step up transformer , it seems odd that the amp's fuse doesn't blow but rather the rooms :idk: as for the MM it could be a tranny , they do some odd things when going out , but also caps will too , even though he said they were ok , they can still be working , yet affect the sound , when they get old and dry out , common on old amps . Soooo :idk: A second opinion couldn't hurt either .

 

edit: Oh make sure you have the proper fuses in the amp so it is protecting it properly just incase there is something going on it will save it as it should .

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could be an issue with the step up transformer , it seems odd that the amp's fuse doesn't blow but rather the rooms
:idk:
as for the MM it could be a tranny , they do some odd things when going out , but also caps will too , even though he said they were ok , they can still be working , yet affect the sound , when they get old and dry out , common on old amps . Soooo
:idk:
A second opinion couldn't hurt either .


edit: Oh make sure you have the proper fuses in the amp so it is protecting it properly just incase there is something going on it will save it as it should .

 

 

+1 and why I asked if he checked draw on the peg.

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cheers for the replies guys, I may indeed get a second opinion alright.

 

gspointer - not sure if he tested that, he said he had a quick look over it & couldnt see anything wrong.

I have a hunch it could be the step up transformer alright, but thats a 70euro hunch :(

 

Pretty sure all the fuses are correct, but im gonna have a quick run over the ampeg myself tomorrow & put the old tubes back in to see if that makes any difference, dont think it will but it'll definatley rule it out.

 

Cheers!

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