Question about biasing a JSX?

[Drow Swordsman]

So I see the JSX has a "self-bias" test, but normally I only hear this in reference to it being easy to put 6l6's in the amp compared to the stock EL84's.

But say if you just wanted to keep EL84's in there when you switched tubes, would you use the same self-bias test to bias the amp yourself so you don't have to take it anywhere?

Is it easy to use?

Has anyone here used it, and if so, how DO you use it?

I don't have a JSX yet (I've been borrowing one from a friend and it's going back tonight) but this is one feature I can't find that much information on...

thanks!

[shogun]

i rented the jsx, thought it was for me.. but decided to wait and try out some other amps b4 deciding..

[jb4674]

Generally, you don't want to bias the amp if you've never done it before. Personally, I woujld take it to the service center and pay the tech to show you how to do it.

If you replace the tubes with the same tubes the amp came originally equipped with, there is a good chance you won't have to rebias the amp (notice I said a good chance).

Jimmy

[Tank]

Actually my local store does the replacement for free, if you bought the amp there (which I did). So I don't do it myself, just by chance that I might damage it.

[kmanick]

get a bias probe (eurotubes sells them)
it makes biasing the JSX (or any amp really) very simple
I've gone from EL34's to 6L6's and now to KT-77's with my JSX head and it
literally took about 10 minutes to bias it, each time.
Make sure you gt a bias probe with at least 2 probes though, because the
inner and outer pairs of tubes could be running differently from each other.
If you have a matched set of tubes then you are good to go!

[heffergm]

http://www.eurotubes.com/euro-Generic-Bias.htm

[7 Dying Trees]

If you're trying out the JSX, try patching the FX loop (run a simple patch lead from send to return) and engage the loop and use it to boost the signal hitting the power amp. Makes it sound a lot better. I didn't really gel with it untill I did that, and the amp was always a lot quieter than it's supposed 120w.

So I'd give that a go before switching to 6l6's as apparently the crunch channel loses some of it's nice sound when you do that.

Maybe try kt77's as they should be the best of both worlds

If you haven't biased before, get a tech to do it

[Drow Swordsman]

I'm sorry, I've never done that before without a pedal, do you just mean running a patch cable from send to return on the back of the amp?

[7 Dying Trees]

Originally Posted by Drow Swordsman

I'm sorry, I've never done that before without a pedal, do you just mean running a patch cable from send to return on the back of the amp?

yep, just run a simple patch lead. It doesn't boost the preamp gain, but it sure gives the amp a lot more balls from the power amp being hit harder, and makes it actually sound like a ballsy 120w amp instead of a 40/60w one. The JSX really does not send a hot enough signal to the power amp without the FX loop patch. Makes the power valves work. Also, in a loud band, the JSX doesn't cut through without doing this. and yes. i do use mids, i'm not a flatulant wasp in a jam jar sound lover

[heffergm]

... obviously, if you've already got effects in the loop, leave them there and just bump the levels controls up.

[Drow Swordsman]

Forgot to give an update, but WOW patching the FX loop sure does make a big difference in tone!!!

I also got an MXR M-108 EQ pedal, but I need another guitar cable to be able to put it through my effects loop, I'll give some feedback in one of the other JSX threads once I get that up and running!

Thanks!

[kmanick]

I run an MXR 10 band EQ in the loop of mine and I just leave it on all the time. It makes the amp sound fuller.
I also switched to KT-77's and I like it much better.
Smoother mids and it's a lot crunchier sounding (more recto sounding).
I like it with the EL34's in there too, but to me it sounds more "Marshally"
with them in there. when I'm playing more "80's" metal stuff I put the El34's
back in, when I'm primarily using my 7's I like the KT-77's better, and
Lately I've been all 7's so they have been in there for a while now.