GK Fusion 550 question

elwuss · #1 02-24-2013, 04:30 AM

hi there!

I'm new around here.

I have recently bought GK Fusion 550 and I have a question for other Fusion owners.

what tubes do you have in there?

mine came with JJ and the guy who fixes my equipment tells me it's not the perfect choice for the bass preamp section.

says the JJs are way too much "aggressive" tubes.

thanks!

elwuss · #2 02-26-2013, 01:04 AM

please guys, any Fusion 550 owners?

I googled it, but can't find any info on what exact tubes they put in the amp.

thx!

Phlipper · #3 02-26-2013, 03:05 AM

I dunno about the 550 fusion, but I've been using JJ tubes from Bob Pletka (Eurotubes) in most of my guitar amps for 15 years. Bob's preamp tubes are graded for distortion characteristics within each series (12AX7 low, medium, and high gain, 12AT7, short plates, etc.) so you can get just about any preamp 'flavor' from a JJ tube that is possible. The only amps I never like JJs in were Mesa Boogies. All my Peaveys, Matchless, Laneys, and one Ceriatone got JJs of one stripe or another.

If my guitar tech called a JJ tube "way too aggressive" I'm finding another tech, because that shows pretty severe ignorance of how preamp tubes in general are classified, sorted, and sold. Not just JJs. Hopefully your tech just meant the SPECIFIC tube in YOUR GK broke up way too early for a bass pre. It's gotta be easy to get to. Pull it out and check the numbers on it. In some guitar amps preamp tubes can vary the tone wildly, in others ... not so much. Some amps just sorta sound like what they sound like, and pre and power tubes just get you an ealrier breakup. Not sure how much variation one can get from bass pres but I'd imagine it'd be noticeable.

elwuss · #4 02-26-2013, 03:34 AM

thanks for the answer.
english is not my native language - "way too aggressive" was my translation of what he said

I know it can vary a lot on the tone - he meant these JJs have too early breakup for a bass amp.

unfortunately, I don't know which exact JJs are those... I just wanted to find out if the JJs come with every new GK Fusion 550.

Phlipper · #5 02-26-2013, 04:08 AM

Yeah, that's probably what he was saying. Kool.

It should be easily accessible. Easy to pull and check. Then these guys at TB can tell you which way to go for cooler/cleaner bass tone. A JJ 12AT would knock a ton of gain out of a guitar preamp. Might do the same for bass?

elwuss · #6 02-26-2013, 04:24 AM

I know, I will check which tubes I have in it.

The thing is - I don't want an early breakup.

I want the clean sound, but I want to benefit from the 3 tube preamp tone-wise.

with these tubes, I have to lower the gain, so I don't benefit from it as much as I could