Should I continue to put money in this amp?

[karpathion]

So, I bought an old Crate Stealth 50w head, about 2 months ago. I paid $75 for it, because the input jack was fucked.

I ended up replacing the input, effect loop, and speaker jacks. While I had the board lifted, I noticed a few swollen electrolytics, so I went ahead and changed all of those. Since I was doing that, I changed all the old Wima tone caps in the preamp with some new polyester film caps I had.

I've spent about $50 on this thing already, so my total is about $125 in it.

Last night I started noticing a gradual drop in output.
After a few minutes, it made one of those quick big drops in volume, them came back up. I look up and sure as hell, the 2 far left power tubes are burning a dark orange, almost red.

A quad of 6v6's is just as expensive as 6l6's. They range from $70-$120.

I just don't know if I want to keep putting money into a 20 year old, Crate tube amp. Yeah, this little thing is a diamond in the ruff. Best tube amp Crate ever made. Lee Jackson knows how to do that modded Marshall thing as good as anyone. It's the only ever amp I've ever had that felt like my old Pittbull. I like it!

The thing is, as soon as I change the tubes, I'm going to find something else that needs to be fixed. Now, it becomes a money and time pit.

Is it worth it if you really like the amp? Or do you just say fuck it, and sell the damn thing.

[LesStrat]

You already have the answer inside of yourself, grasshopper.

[Securb]

Can you pull tubes from something else just to test it? If not buy a used amp at Guitar Center do a tube swap then return it. 

[karpathion]

It's my first 6v6 amp. I got nothing. If there was guitar center within 100 miles of me, I would have bought another amp.

[Oinkus]

I have a pair of 6v6s I have no use for if you want them. I am having issues with my Prosonic and no idea WTH I am going to do about it.

[GoldenVulture]

From your description it seems more like a bias component problem than a valve one, which would be a lot cheaper to fix than replacing your valves.

[Dr. Vegetable]

If nothing else you can have fun electrocuting yourself.

[GoldenVulture]

If nothing else you can have fun electrocuting yourself.

While you look for a burnt out bias feed resistor.

[karpathion]

From your description it seems more like a bias component problem than a valve one, which would be a lot cheaper to fix than replacing your valves.

I thought that too, but the bias will hold at the 18ma recommend by Lee Jackson. The tubes just started changing color last night. I just want to believe it's tubes. I've seen the same thing before.

If nothing else you can have fun electrocuting yourself.

I'll be fine as long as I stick to my safety procedures. 
Drink a 12 pack of beer, and take a Xanax. Yep, that should do it.

[karpathion]

I have a pair of 6v6s I have no use for if you want them. I am having issues with my Prosonic and no idea WTH I am going to do about it.

I appreciate the thought, but if I'm going to do it I'll just order a new quad. I don't mind spending money on tubes. I just don't want to end up $300-400 in an amp that would only bring $200, to someone who really wanted it. 

I wish Lee Jackson had designed this amp for a better company. It's a beast of a head.

What year is your Prosonic? That amp might be worth sending to a tech. I've heard some tasty clean and dirty tones from those amps.