GK MB200 vs TC Electronic BQ500

[bass player 53]

For scratchy pots, I've had some success by repeatedly moving back and forth each knob.
Don't know if it's the same problem you are having but maybe it's worth a try.

Yes, thanks. I’ve tried that and judicious use of DeOx; not effective long term. The pots, unfortunately are poor quality. I’ve read reports of others having this problem too. I’ve replaced pots on my vintage Fender guitar amps with no problem. They are not surface mounted and the soldering is much easier.

 

[eniac]

Welcome to my family. I’ve posted this so many times now. I bought the MB200 used, and it was fine. Played it a lot, then stuck it in a case, and not so much. This year, the volume pot started crackling. I sound like a broken record now, but most of the volume pots on all these amps and combos crackle. It’s not as easy as ‘just spray DeOx on it’, and because they are surface mounted, they’re not simple to replace.
My MB200 is 9 years old now.

On every amp I own, every 30 days, I rotate every knob stop to stop ten times, then leave each one at a setting I know I'll never use, but never at full CW or full CCW. None of my amps have noisy pots: Backline 600, China-assembled MB200, USA-assembled MB800, 2012 Aguilar TH500, 2012 ART SLA-2, and some horror-show personal builds that would fail cert the moment I brought them into the lobby. When I store a BG, again, I leave the knobs at settings I know I'll never use. In all my life I've never had to replace or clean a pot on any of my personal gear, except for the volume pot on a MIM PB from the early 2010s, but that one saw hard use so that was an EOL failure.

OT: My favorite active solid state DI is my MB200 set to pre-EQ. So, you might be able to re-purpose yours if the crackling gets intolerable.

 

[bass player 53]

On every amp I own, every 30 days, I rotate every knob stop to stop ten times, then leave each one at a setting I know I'll never use, but never at full CW or full CCW. None of my amps have noisy pots: Backline 600, China-assembled MB200, USA-assembled MB800, 2012 Aguilar TH500, 2012 ART SLA-2, and some horror-show personal builds that would fail cert the moment I brought them into the lobby. When I store a BG, again, I leave the knobs at settings I know I'll never use. In all my life I've never had to replace or clean a pot on any of my personal gear, except for the volume pot on a MIM PB from the early 2010s, but that one saw hard use so that was an EOL failure.

OT: My favorite active solid state DI is my MB200 set to pre-EQ. So, you might be able to re-purpose yours if the crackling gets intolerable.

Thank-you very much for the tips. At the moment, they are all usable, but it’s annoying and embarrassing when you hear that crackling at any volume on a gig. I oversprayed DeOx inside all the pots on my MB150 E, which is my main double bass amp, and of course, they don’t crackle. But, they move around too easily and I just have to set them up properly. One of my MB500’s is ok; I use that with two 15” cabs for Salsa music, and it’s loud as hell. It usually goes FOH, but not always. Salsa dancers like ‘loud as hell’. I bring another MB500 for backup. I have two older Carr guitar amps that don’t crackle, and most of my Fender guitar amps are ok. I had one bad pot on a 1964 Vibro Champ, and it was easy to change out.
I will try your pot rotation method.

 

[Bob_Ross]

Owned a BQ500 briefly. While loud as hell, it was extremely sterile sounding. Not a good amp for R&B, Funk and Soul music, IMHO.

Coincidentally, that is *exactly* the sort of music I’ve been using my BQ500 for! Works great, especially through a couple of RevSound cabinets.

 

[CamJazzBass]

The TC is hard to beat at the price. Is it the best sounding amp in the world? No way. At less than $200, does it make a fabulous backup amp? Hell yes!

 

[shoot-r]

O.P.,

At the price points of the GK MB200 and the TC BQ500, I'd say, if it's financially feasible and your ears really like the MB200, get the TC but keep the GK also.

Play one head till your ears becomes fatigued of it's sound/tone, park it and use the other head till you get tired of it, park it and use the other head till, ect., ect.

You honestly won't get that much for the MB200 on trade or from the hassle of selling it privately.

GK no longer makes available factory service for any of their amps except for their current series of Legacy and Fusion S amps, but...almost every amp repair shop can make repairs if needed on the MB series of amps.

The scratchy pot syndrome is a common problem with just about every amp manufacturer, not just GK.
Years back, my Sunn 200S did it, my Ampeg SVT did it, moving up in time, both of my Mesa M-6's did it, today, my main gigging heads a GK MB Fusion 800 and my Genz-Benz 9.0 does it.

Rotating the pot shaft back and forth solves the problem for awhile.
Since the MB series uses sealed pots, spraying detox/cleaner/lube does nothing other than contaminate the rest of the board and usually causes additional damage.