6L6's in 200s

[ZcygnusX-1]

I bought a 68 200s that has been retubed, recapped has two new transformers and a new power cable. It has been modified with a rear mounted master volume. an ohm selector switch for your speaker outs 4 8 16. and a "sophisticated bias system" as I was told. that lets you use whatever power tubes you want. It has mesa boogie coke bottle 6L6GC's in it. I think they break up a little early 5 on the volume. My bass is a Zon Sonus RT with a pretty hot active system. Is this break up normalat this volume? I want it a little cleaner. I ordered some JJ KT88's after hearing some good reviews about them. will this help solve my distortion problem? also the 6L6's dont have strong bass. it's a little muddy at higher volumes (4) it sounds awesome at (2) It seems like someone modified it to be a guitar amp. it does sound great for that purpose.  another Q. will a stock 200s accept and bias 6L6's?
thanks

[Soundmasterg]

The KT88 is the stock tube for the 200S and will sound the best in it for bass. The JJ's are a great tube. I have a pair in my 200S right now.

For 6L6GC's, the 200S puts out a rather high voltage...usually around 560v or so. Thats really pushing the 6L6's and with a UL circuit on the amp too, its a bit much. I would say that if you put the KT88's in and rebias, it should work just fine for bass as long as they didn't mod the amp in other ways for guitar. You may want to check it and compare it to a schematic to make sure it is otherwise stock.

[Hop]

I have JJ KT88's in my 200s and it it THE best bass tone period (through 2x15 sunn cab - jbl).  Use it live as well as for all recording sessions (1x15).  Smooth, articulate and thunderous bass tone!  Well worth the extra bucks.