Using the simul 2:90 on half drive, good for tubes?

[steveohdearyme]

Hello all,

I've been the owner of an older generation 2:90 for about 3 years now. Bought from the US and then converted, fixed and maintained. All for the love.

Anyhow, I've had a variety of problems with it and on the same note, I seem to blow a fuse more often than I thought I might. Anyhow, I've got two questions that I'd be grateful for any thoughts on;

1. If I use the amp on half drive, will this prolong the life of the tubes and/or fuses? I've recently been using it with the half drive and deep voicings activated, and the tone is still great. I can still get a decent amount of volume, but I just wasn't sure of its benefits. I consulted the manual, but its pretty informal and tends to yabber on about how amazing the unit is (which it is, granted). But I just wanted some honest information on the half drive voicing.

2. When I turn on my rack setup (consisting of a JMP-1, Boss GT-Pro and 2:90) I get this sort of tremolo sounding hum. It's always been there, despite being serviced and repaired, it NEVER goes away. When I activate any of the voicings, it disappears. Is this something that anyone else has encountered?

Until I switched to half drive, I was about to launch the 2:90 off the Forth Road Bridge. Then swim down to retrieve it, only to throw it out of the highest building I could find. I've had numerous problems with it and put a lot of money into it, but my unit seems incredibly tempremental. I see there are loads of 2:90 users however, so I don't want to give up on it.


Thanks for reading my rant folks!

 

[MesaGod666]

It's an old unit. Time to upgrade.

 

[steveohdearyme]

Ok, just as soon as I've re-mortgaged my flat.

If it's old then I'll just have to see what I can do. Lets not kid ourselves, Mesa gear is ridiculously expensive.

 

[ando]

It's an old unit. Time to upgrade.

Sorry, but that's ridiculous advice. An amp can keep going indefinitely as long as it receives the right treatment and service. To original poster: Find somebody who is fully qualified and experienced with your amp and have him go over it thoroughly. There is no reason why it can't be as good as new with the right repair. It will certainly work out cheaper than buying a new one and once it's all checked out, you'll have your confidence in it restored.

 

[desertdweller]

It's an old unit. Time to upgrade.

Ridiculous. I have a 1994 2:90 and a 1995 50/50 and both look and sound absolutely perfect, and will for many years to come.

About your amp, you definitely need to get it serviced from an authorized mesa repair tech, maybe call Mesa and see who they reccomend. If you were in the US I'd say just ship it to them. These are power amplifiers, they're not the most complex equipment. They can fix it, they have the technology

Oh and half-drive will push the tubes a bit harder than the regular use, so yes they may in fact wear a little faster. Still, tubes under heavy use (3 rehearsals a week, 2 gigs a month, plus just playing guitar for fun) seem to last me 18-24 months. I can't see half-drive making the tube life that much shorter.

 

[steveohdearyme]

Thanks very much guys, thats definately a bit more reassuring!

Interesting that the half-drive would actually shorten the life, I thought that if I was using the unit on a lower power setting (and this might be where my misunderstanding it) that I would be preserving the unit.

I'll definately put it in for a service, the rep in Scotland seems like a top dude so I'm sure I can get to the bottom of this.

 

[mr_fender]

The 2:90's half drive setting doesn't affect the power tubes of the amp directly and does not push them any harder. It changes the bias and lowers the gain of the phase inverter tubes. This pushes the power amp tubes LESS, since there is a smaller signal going to the power tubes. It is not a lower power setting, like the Class-A setting on other simul-class amps (which actually "turns off" half of the power tubes). All of the tubes are still working full power. That's probably why they called it "Half Drive" and not "Half Power". In fact, it could potentially prolong power tube life, since they are being driven with a smaller signal.