Lonestar Special Help needed again!!!

[pjlcc14]

OK guys....really appreciate you guys zeroing in on my Rectifier tube going bad a couple of months ago....now I got a new problem.....couple of days ago I started getting some random scratch / hiss noises....very short in time....not real loud....but very random......bothe channels, and on all 3 watt selections. Today....No random noises at all........but I don't have anything on my 5Watt selection....on either channel. But the 15 and 30 work fine on both channels. Is this a tube? They look like they are all burning even.......and the eraser thump doesn't produce any odd noises either.
Help.......again!!!!! :?:

 

[MrMarkIII]

It's called OCD.

 

[SBG200]

OK guys....really appreciate you guys zeroing in on my Rectifier tube going bad a couple of months ago....now I got a new problem.....couple of days ago I started getting some random scratch / hiss noises....very short in time....not real loud....but very random......bothe channels, and on all 3 watt selections. Today....No random noises at all........but I don't have anything on my 5Watt selection....on either channel. But the 15 and 30 work fine on both channels. Is this a tube? They look like they are all burning even.......and the eraser thump doesn't produce any odd noises either.
Help.......again!!!!! :?:

Sounds like preamp tubes to me.

 

[pjlcc14]

Anyway to pinpoint......or just replace them all???????

 

[pjlcc14]

Anyone???? :?:

 

[simonich]

I would take a known good pre-amp tube and swap through all of them 1 at a time starting at one end or the other.

if the problem clears up, you're golden. if it doesn't, either (a) it's multiple tubes, or (b) it's not a preamp tube problem.

to solve (a) you could replace all the pre-amp tubes and see if that helps.

 

[pjlcc14]

Do you think one or two pre-amp tubes would totally knock out the 5 Watt setting...but not affect the 15 or 30 Watt settings?????

 

[simonich]

Hummm.... I doubt it. The preamp is just passing a signal to the output stage. if the output stage works at 15 and 30W, then the pre-amp signal is getting through ok.

I suppose maybe it could be something whacky with the phase inverter tube (V5).

As far as I know the only thing that happens going from 15 to 5W is that (a) the amp goes from push-pull to single-ended, and (b) one of the two power tubes operating in 15W mode has the signal cut off. All of this happens in the power amp section.

Another thing you could try switching the two outer power tubes (the ones ON in 15W mode). does the problem still exist? i.e. nothing on 5W mode? if so, i'd take the amp into a tech, because at that point I'm thinking it's some of the internal switching that's gone dead. (e.g. could be the mini-switch itself, or could be a component in the 5W signal chain, etc)

Though i've not had such a problem before, so i'm really kind of guessing/fishing here.

Also, does the problem happen with both reverb on/off and the loop on/off?

 

[pjlcc14]

Reverb on or off....channel 1 or 2......when you switch it to 5 Watts using either channels switch.....it just goes blank.

 

[Murphy Slaw]

?

30 watts works okay?

I'm thinking rectifier tube.

I don't own one, but USED to think I wanted one.

The LSS has pretty much lost my attention lately though. Too many problems.

Murph.

 

[pjlcc14]

It's not the rectifier.....when that goes out.....you lose 15 and 5 watt settings.....plus that what was wrong 2 months ago. I'm thinking since the 5W only burns one tube......maybe its only one powertube..........only problem with that theory is....when I switch to 15W and it push / pulls thru 2 tubes....wouldn't the one bad one screw up the sound on the 15 watt setting.......which right now sounds good....as well as the 30W setting.......I'm confused as hell on this one!!!!!!

 

[ja22y]

Theory is good but in practice, who knows? Just swap the power tube pair, inside to outside and see. Once you've checked out the easy stuff (tube, jacks, connections) and it still has the issue then it's time to cash in on the 5-year warranty, you paid for it so why not use it.

 

[pjlcc14]

Another thing you could try switching the two outer power tubes (the ones ON in 15W mode). does the problem still exist? i.e. nothing on 5W mode? if so, i'd take the amp into a tech, because at that point I'm thinking it's some of the internal switching that's gone dead. (e.g. could be the mini-switch itself, or could be a component in the 5W signal chain, etc)

Though i've not had such a problem before, so i'm really kind of guessing/fishing here.

BINGO! .....Thanks man.......i swapped the tubes from 1234 to 2143.....and it works great.......kind of baffling, cause I would have thought that if a bad tube was on the 5W loop.....when I would switch to 15W and use one good tube and one bad one....that I would hear it....but I didn't.....crazy!
Anyway....looks like this 2 year old just needs a new 4-pack set of EL84's!!!!!

On that subject.....what's you guys opinions of EL84 brands.......not to worried about the cost......just want long term reliabilty and GREAT tone!!!!

 

[ja22y]

I'm glad that was an easy fix. If those are stock Mesa than 2 years on them is about what the average with moderate use. It's also a good practice a to change the rectifier tube when you change the power tube, or atleast has one ready.
Get NOS tube if you can find them. They last on the average 3 to 4 times more than new production, not to mention sound a thousand times better. NOS Tesla (not JJ) is the best band for the buck and you can find them easily (about $30 each). If you do the math, these Tesla are actually cheaper than production tubes. If you like sparkling clean, the GE are good althought they are hard to find now, used to be dirt cheap. Ok now my secret is out, hopefully it doesn't drive-up demand and thus cost.