mesa 400 plus

Probably the best tube at this time is the Svetlana 6L6GC. You won't believe it's the same amp. A matched set of 12 would cost $210 from Lord Valve. All you have to do is tell him the Mesa color code (mine is Yellow, for example). Just plug the new tubes in and go. No rebiasing necessary.

The preamp tubes last a long time but if you want to replace them, it's not going to hurt. They're only $10 each. I prefer Sovtek 5751 in the first two positions (the preamp tubes), and 12AX7LPS in the second two positions (the driver tubes). That's for a cleaner, fatter sound. Distortion and overdrive enthusiasts should use other tubes.

Nightbass

 

The Mesa manual says that you HAVE to use their tubes because they are the ONLY tubes that are biased properly. Is this true?

 

No. Lord Valve amd The Tube Store can provide tubes in the proper bias range. Mesa just wants to charge you twice as much.

BTW, I put a set of the Svetlana's in my Buster, and it sounds great. Got them from Lord Valve.

For your 400+, Lord Valve can sell you a set of Sovtek 5881's for around $140. You'll lose about 25% of your rated power, but unless you are in an ungodly loud band, that's usually not a problem.

 

Why would you lose power with the Sovteks? That doesnt make sense to me if they're good tunes.

And, unfortunately my band is extremely loud, so I'm concerned about losing power. How is output effected by the tubes?

 

The amp is designed for use with 6L6 tubes, which are capable of handling more current than 5881's, and will therefore produce lower wattage. They are good tubes, but not necessarily the tubes that were intended to be used in the amp. They will work fine, and will not damage your amp, but will produce less power. But you're talking somewhere along the lines of 400 watts RMS as opposed to 500 watts RMS. You won't necessarily lose power, but headroom, which means the amp will begin to overdrive a little sooner. This may or may not be a good thing, depending on the kind of sound you like.

 

How does this amp get moe than 300 watts? Don't they use 12 x 25 watt bottles?

I am going to start another thread 400+ v. Vintage SVT.also.

 

call mesa , theyll sell you the svets and take 25% off for 400+ owners, 4 preamp tubes included ....came to 210. if i recall.