Mesa Dual Rec 3ch w/KT88/6550?

[kramerxxx]

Has anyone done this?

Did it bring anything to the mix?

I'm looking to get better detail, clarity and fidelity from my amp. I had a Mercury Magnetics OT install a few years back and that helped a bunch. I sent MM an email yesterday and they said the tranny would handle KT88/6550 power tubes. I know from some research that these tubes pull a little more current than JJ EL34Ls and KT77s which I've run in this amp. I have another amp that runs this power tube type and it is massive compared to my Dual Rec.

Thoughts?

 

[dtrax]

A few months back I went ahead and installed KT88's in my Triple.

The main difference I've noticed in tone is a bit more upper mids, compared to 6L6's. The low end is a hair tighter and larger too. I recommend them without reservation with Rectifiers. I like 6L6's, but I wanted a bit more mids out of my Triple, and these tubes get me there while retaining the huge low end. Your amp will still sound like a Recto, however, just a different shade of the same color.

 

[fluff191]

Out of curiosity, what do you bias the KT88 up to?

 

[dtrax]

I have it set to 6L6 mode. Eddie from Eurotubes - great customer service BTW - helped me out when I got my tube kit. I could have swore I read EL34 mode the recommended bias for KT88's, but alas I was mistaken. The amp was making some strange rumbling and popping noises when I installed the 88's. He suggested I clean the sockets with some contact cleaner, which after switching to 6L6 mode, my TR screamed like a mofo.

 

[domct203]

Out of curiosity, what do you bias the KT88 up to?

+1

I'm curious to what the KT88 current draw is in a cool biased amp like the Rectifier. I'll bet they are in the 30% range.

(to the OP) BTW- your OT has nothing to do with suppling power to the KT88's. The only issue there would be impedence matching. I'm surprised MM didn't explain that to you.

Dom

 

[fluff191]

I was just asking cause my Recto has an adjustable bias and wouldn't know what to bias these up to.

But after some digging and knowing a rectifier's plate current is about 475v, the KT88's would still be running pretty cool at almost 40ma a tube.

I actually might try these.

 

[ElectricTurkey4369]

I'm also thinking about trying some KT88's in my roadster.

I tried KT77's and they were pretty good.

 

[Jonberrier]

+1 for KT88s.

I have them in my Rectoverb head and my roadster head. You can get ridiculous bass if you want it, but the upper mid bite is best part about them. I did mod mine to have an adjustable bias and I think I have them running about 50ma per tube. Still not really warm, but no crossover distortion.

As for current draw, they do need slightly more heater current than EL34s. The mesa power transformer is more than capable of producing it.

6550s are another story. If you want your amp to be cleaner then these are for you. to my ears they are very "clinical" sounding tubes. Great for big powerful bass amps, not so good for dirty guitar tone. With that being said, I like these tubes in a fender twin.

 

[ElectricTurkey4369]

+1 for KT88s.

I have them in my Rectoverb head and my roadster head. You can get ridiculous bass if you want it, but the upper mid bite is best part about them. I did mod mine to have an adjustable bias and I think I have them running about 50ma per tube. Still not really warm, but no crossover distortion.

As for current draw, they do need slightly more heater current than EL34s. The mesa power transformer is more than capable of producing it.

6550s are another story. If you want your amp to be cleaner then these are for you. to my ears they are very "clinical" sounding tubes. Great for big powerful bass amps, not so good for dirty guitar tone. With that being said, I like these tubes in a fender twin.

If you dont have a bias pot, would it be better to run KT88's in EL34 or 6L6 mode?