Hi Bass!
Lucky you, a B25 would just fit in my bedroom.
But I have no Laney to swap…
Well, I haven’t heard my V4 with 6550’s yet, but yesterday I tried it with a ’65 Mustang plugged in, and now I have to buy one (trying those things is never a good idea) – well, V4 IS clean (and sounds sooooo good).
I’m thinking about taking texas specials off my tele and putting something cleaner back in… Or I’ll just buy a Mustang. And keep my tele hot like it is now.
Help please…
This was just to say that with the right guitar the amp already is clean, 6550’s could be something not necessary, since overdrive/crunch is developed mainly in the preamp (this is my experience, at least).

THIS
http://remmelt.com/amp/
is where the value for the resistors came out (as far as I can remember – the whole thing is still foggy)

anyway, let’s talk about serious stuff:
I put the new bits in the amp, new tubes, switched the beast on, and after just a couple of crakles and pops (and a heart attack on my side) it LIVED!
yes, it’s working. loud as hell, it is. sounding like nothing else, yes.
great amp, worth every pound (and it’s a lot of ’em!)

question: it’s still crunching a bit early (volume knob set on the first notch on the scale). power tubes look ealthy, lit, with just a little shade of blue, and don’t change their color much when I play hard, so I guess they’re running pretty clean. maybe the pre tube is getting old (it’s a GE, don’t know the age of it)? texas specials on my tele pushing the preamp too hard?
and… how does the whole tone control work?!? still wondering…

ok, I must be too tired really. I knew they had to be 1/2 watt… simply wans’t careful enough in that moment.
and the other two resistors are not 15ohm but 15Kohm… Still no idea about what I had in mind when I placed the order. Weird. 5W seem to be a specific choice too. Who knows!
As for the eyes… I can’t imagine how you can decipher that, my schem is printed A4 and still a nightmare to look at!
mmm… those resistors… I need a check-up.

(by the way… some OT rage: protools is good when it works, a nightmare when it doesn’t – damn. I hate it.)

I’ve actually been up there some months… Well it was Harrogate to be more precise. I’ll save some cash to come back some day…

Talking about the amp… I ordered some parts yesterday: tubes, C9 (small cap), some resistors (including the 4 10ohm/5watters), the two electrolytics in the bias circuit, and that’s it for now. I’ll try to put everything back to specs and see what happens.
I’ll change the filter caps later, since hum was really low and looking at them, they seemed fine (this is my average degree of accuracy 😕 )

I’ll keep you updated!!!

At this point, I imagine the guy started something that he never took to an end.
At the moment everything else looks to be ok, since it’s as well hard to understand what the previous owner changed, and what was simply modified by the factory.
One thing is curious: on the pc board there are R59 and C22 marked, but no component is there and I can’t find them on the schem… Could it be a factory revision?
At this point I thing I’ll change the bias caps too. I still have to test the diodes (do you know which type they are?).
About the two mistery resistors:
Can it be that they are there to take the end of the filament wiring to ground?
The hum balance variable resistor was disconnected.
Not that I know what this is made for… Just guessing.
(by the way, I’ll put 7027s for now, like it was supposed to be… 🙂 )

By the way, a little question:
what’s a safe (well, as safe as it can be) to discharge capacitors? And to test them?
Always got confused on this subject, maybe because of my not-so-perfect english, maybe because writers tend to assume that you at least have SOME experience… and I have less than that. Bought a couple of old tube books and the one wrote by Pittman, but they’re not so exaustive either. 🙁

Hi bass!
Strange things, as always.
I thought about a conversion too when I looked at it, but first, the resistors’s placement doesn’t make much sense and second, it was made on just one socket…
I think I could just take them off and see. They are not good for bias testing either… The resistors that control plate and grid are ok, so nothing bad should happen. Don’t know why on the schematic the value for R39, 40, 45, 46 it says “PR1” instead of 4.7 like mine… Some schems say 10ohm instead, I think ampeg liked to mix things up a lot.
Thinking about it, the two new electrolytics could be a substitution for C19 – but I have to check this afternoon.
I’ll put the bias resistor back to specs, but the real question is (something I always get confused about): more resistace=cleaner, or the opposite? Maybe the amp was running too “cold” and the overdrive I was hearing was some kind of result of that?
I’ll try to contact methodofcontrol immediately (yes I know, I’m at work now… but I’ve got nothing to do!)

PS I just noticed I misspelled the title of this topic… that’s sad.
have anice day!!! 😕

hi,
well I tried to put the 1M ohm resistor across input tp and ground, but it doesn’t seem to be that effective.
I’ll try to re-check the joints and post here what happened.
In case, if you pedal has a LED, then I found some more info on how to cancel the “pop” thing,
I’ll try to find the link (it must be buried between my bookmarks) and post that too.
have a nice day!!!