LSS 1 x 12 help

[pjrhd28]

I just re-tubed my LSS with new MB EL-84's about a week ago. Tonight, I was playing at home and for one second, I had channel one just about dimed (although the gain was only about 1/2 way). Ever since, at fairly loud volumes, when I hit a low pitch string hard, I get the note and then the most awful repetitive loud farting electrical noise you can imagine.

I tried different guitars and it looks like the tubes are all OK, but the noise continues.

Anyone got any ideas?

Thanks

 

[LSCMan]

Mesa tubes suck. :idea:

 

[Kyle]

You may have tried this, but stick your old tubes back in and see if it goes away. If it does, order you some JJ's from Eurotubes.

 

[musicbox]

mesa/boogies el84's are MISERABLE compared to the JJ equivalent. they have a cardboard sort of midrange, no bottom, and no chime/bell on the top end.

 

[Bloozman]

I had the same problem with my LSS..I changed to JJ tubes, and still had that farting sound...I came to this conclusion...The LSS is a piece of junk...I sold it and got 2 amps for what I had in it...

 

[picnic]

Bloozman, I know about your problems with your LSS. I had a new one go bad last fall after only 10 days. I took it back to GC in East Brunswick NJ. They gave me a new one in a box. I wonder if you bought my old, bad LSS. Better luck next time.
picnic

 

[brianf]

Something is wrong. I have played my son's detuned guitars through my LSS with no such problem. Now don't get me wrong, a detuned LP is not the LSS best friend but it did not have that low frequency blahhh you describe. What watt setting were you at?

brianf

 

[brianf]

Something is wrong. I have played my son's detuned guitars through my LSS with no such problem. Now don't get me wrong, a detuned LP is not the LSS best friend but it did not have that low frequency blahhh you describe. What watt setting were you at?

brianf

 

[jerseydrew]

stupid question, but here goes.
When switching from MB EL84 tubes to JJ EL 84 tubes, do you have to re-bias? I know nothing about technical stuff. Do you ever have to re-bias if your going from an EL 84 to another brand EL 84?

 

[Kyle]

stupid question, but here goes.
When switching from MB EL84 tubes to JJ EL 84 tubes, do you have to re-bias? I know nothing about technical stuff. Do you ever have to re-bias if your going from an EL 84 to another brand EL 84?

No, and you couldn't if you wanted to.There is no bias adjustment on LSS or any modern Mesa to my knowledge. Check your manual for Mesa's explanation of this. Also, if you order your JJ's from Eurotubes, be sure to email/talk with them and they will set you up with tubes for your style and amp.

 

[speedy mcfeely]

I have posted how good that the JJs make the LSS sound, so I'll spare you guys. If you have a LSS and you have not swapped out the stock tubes for new JJs, the do it now. You will not be disappointed. The amp is so much more rich sounding with a quality set of tubes.

Also you should try some NOS 5751 preamp tubes in V1 and V2. They are amazing.

 

[musicbox]

el84's are cathode biased. you couldn't put a bias pot in if you wanted too. this is also known as 'self biasing', but is not the same as the fixed bias found in the higher wattage amps. you can plug in new el84's without a problem.