kt77's in a 900 sl-x

[vscrl1]

my friend is looking at having his 900 5881 modded for el34 and then wants to put jj kt77's in it. anyone run these tubes in this amp? also, hes having trouble get a decent amount of gain out of his amp. anyone have any advice for him?

 

[RynoAZ]

I've run the 77's in mine - I like 'em. The sound to me is a little punchier and a little deeper, like having a bigger voice. As soon as all my EL34's die (that'll be a while, I have a small stockpile), everybody gets KT77's across the board. I'm that much of a fan.

If you can't get gain from that amp, something is wrong. Some of the better techs here will come along and help you with that.

 

[chuckmehh]

dead preamp tubes are my first guess for the gain. That's a very high gain amp. If he wants like death metal tones, boost it with an OD. A boosted Marshall is a thing of beauty!

 

[vscrl1]

he put some brand new tung sols in it. he said it has good rock gain, but anything past that just sounds mushy and bad. im guessing its the 6l6's in it? he doesnt want to have the 34 mod done if it wont help.

 

[chuckmehh]

he put some brand new tung sols in it. he said it has good rock gain, but anything past that just sounds mushy and bad. im guessing its the 6l6's in it? he doesnt want to have the 34 mod done if it wont help.

I would try boosting it with an OD. I use a cheap-o Danelectro Cool Cat OD with my DSL and it really beefs up and tightens up the gain.

 

[Jonathan Wilder]

he put some brand new tung sols in it. he said it has good rock gain, but anything past that just sounds mushy and bad. im guessing its the 6l6's in it? he doesnt want to have the 34 mod done if it wont help.

No...all the gain comes from the preamp.

Now if you had an amp that at a loud volume setting the low end started falling apart that COULD be either power valves or it could be an amp with low power supply filtering which causes the amp to "sag", which in that case putting bigger filter caps usually solves that. But if you're saying that the low end falls apart when you crank the preamp gain past a certain setting that is usually either a badly voiced preamp or you're reaching the point of blocking distortion at that gain setting.

 

[bennieusmaximus]

are kt77s a direct fit with a bias?looking to put el34s in my sl-x also.is there a kit for this or are the instructions on schematic heaven good enough.

 

[RynoAZ]

KT-77's directly replace EL34's.

 

[Jonathan Wilder]

are kt77s a direct fit with a bias?looking to put el34s in my sl-x also.is there a kit for this or are the instructions on schematic heaven good enough.

Assuming your SL-X is set up for EL34s, KT77s will interchange and bias the same. However, if it's a 5881 version you'll need to perform the 5881 - EL34 conversion before you go installing EL34s or KT77s.

 

[vscrl1]

anyone know what the going rate is on the 5881-el34 conversion is? theres no real techs in the area that i know of. thanks