#1
My new (used) BP 30 was working great for a few days. I moved it to another room. After that it basically died on me. If you crank all of the gain/vol dials, a tiny bit of fuzz comes out but that's it. On my last jam, I played around with the tube power modes (which pop a little when you switch 'em, but the manual says it's OK to change modes while it's on. pop continues in no-output state) to get a little gain at minimal volume.

I tested everything I could:
-power cables
-power source/outlet
-speaker cables
-instrument cables
-instrument
-cabs
-preamp tubes
-rectifier tube REPLACED
-fuse looked intact
-circuit board... nothing looks cooked

I was hoping the rectifier tube was the issue, no luck!

Any thoughts?

note on the fuse (from manual):

IEC RECEPTACLE AND FUSE HOLDER –
Within the bottom portion of this receptacle is a small drawer that holds the mains power fuse. An extra fuse is included in this plastic housing. It may be necessary to use a small tool to pry the small drawer open. Be sure to use the appropriately rated fuse for your AC mains voltage conditions.

I find this to be a little confusing... I only saw one fuse in the "drawer." However, if the fuse is blown the amp should be completely down. This guy still lights up, etc, just no juice.
#2
The prior owner may have used the fuse.
'Most' tube amps have more than one fuse and some up to 4 or 5.
Commonly there is a Mains fuse and an HT fuse.
The mains fuse is for overall main power obviously - sounds like that one is OK.
The HT (high tension) fuse is there to protect the rest of the amp from the power section.
If the HT fuse blows, then the amp will still turn on and light up just no sound.
The fact that you have some sound is concerning I guess but that may just be the sound of an electrical device being amplified through the speaker.

I'd replace the power tubes, fuses and grab some preamp tubes and then report back.
#3
Thanks for the info. I ordered some power tubes. I was pleased that 4x only cost me about $40! I am used to forking over for 6550's.

I will look around for the HT fuse/other fuses. When I was examining the board, I didnt see anything which looked obvious (I had to refer to the manual to find the main one, but it was hidden).
#4
Issue was never precisely found by the tech. The problem was isolated in the preamp. He heated/resoldered some of the connections in the pre circuit and this fixed the amp. There was nothing which could be found by visual inspection (and lacking a schematic), so maybe it was a hairline or something.

Cause of problem: Cheap manufacturing.

I am slightly frustrated! This is such an awesome sounding amp with a great design and seemingly good components. Maybe I am just spoiled by my ~30 yr old Mesa/Boogie amps which never have problems. I prefer an amp where... maybe the only thing you never need to fix on them is a screen grid resistor.
Last edited by cGoEcYk at Jan 15, 2014,
#5
^ Yeah i've heard some complaints about QC. My first one was DOA Haven't had any problems with my second, fingers crossed. At the price I paid I'll take the risk, but I'd have been pissed had I paid anywhere close to full list price.

There's a thread on TGP where someone claims to have the schematic if you want it for future reference. The black pearl posse or something like that (it was posted in the last day or so, so it will be right at the end).
I'm an idiot and I accidentally clicked the "Remove all subscriptions" button. If it seems like I'm ignoring you, I'm not, I'm just no longer subscribed to the thread. If you quote me or do the @user thing at me, hopefully it'll notify me through my notifications and I'll get back to you.
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