Servicing an Ampeg SVT 3 Pro...

[moonbass]

Hi All. Would love a bit if advice:
I've recently purchased an SVT3 and love the sound. But, it sounds a bit farty even with low gain. I wonder if the valves might be shot so I've ordered a replacement set from Watford valves (not cheap, so hope they're ok). Having never set to an amp with a screwdriver, I don't really know what I'm doing. I presume the valves are easy to replace, but wonder what else I should be looking out for? For instance, I hear things about dry solder joints: can these be spotted visually? And I hear that although the preamp valves don't need biassing, the transformer does need something similar to optimise it?
Any thoughts gratefully received. (Even if it's just 'take it to a pro you numpty'!)
Cheers,
Andy

[chris_b]

I'm not going to call you a numpty, but you really shouldn't be doing this.

It could be that the transistors need rebiasing and be nothing to do with the valves at all.

It'll cost more to fix when you're done with it than if you took it in for a service in the first place.

[goingdownslow]

I set the bias on my SVT-3Pro, it was well out, made a big difference. Only needed a multimeter and screwdiver, but not for the faint hearted.

Read up on it here...  Bias Thread

Edited November 29, 2019 by goingdownslow

[ahpook]

i'd change the valves, then see if it sounds any better before trying anything else.

as long as you can work methodically changing valves is fairly straightforward, but as you're a neophyte with amps, i'd leave any other investigation to a techie.

Edited January 29, 2014 by ahpook