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Yamaha TRB Trim Pots?

Jason Hollar

Jason Hollar

Apr 17, 2005
3,565
3,849
Pennsylvania
#1
:help:

Just bought a new Yamaha TRB 1005 at GC. Nice bass, had it professionally set up, now it plays great!

In the control cavity, there are two small pots on the board.

Anybody know what these do? Nothing in the manual about these at all.

The bass is active, so I assumed they'd be a midrange sweep/adjust or possibly an output control. I tried turning them and playing, but wasn't sure I was getting any results???
 
#3
I am not familiar with the newer Yamaha electronics, but on my TRB6, there are four trim knobs, one for overall output, one is the mid boost/cut for one of the mid preset, and the other two are mid freq and moost/cut for the other mid preset (the MID knob on the front of the bass actually selects between flat and two presets instead of being a normal sweep knob).
 
#4
Thanks...

I figured mine was some kind of mid range sweep...but for some reason, I didn't hear much variation in the frequency when I swept it around (with mid control boosted/cut of course).

At this point, everything sounds fine to me -- just curious about these controls since they're not in the manual.

Man, I like this inexpensive bass so much -- I'm going to seriously consider a nicer Yamaha when I'm looking to step up. I'd love to try a TRB6 -- although I'd probably still end up with a 5 for practical purposes.

Thanks again, I'll play around with them some more and see what I can find...
 
#6
Jason Hollar said:
Man, I like this inexpensive bass so much -- I'm going to seriously consider a nicer Yamaha when I'm looking to step up. I'd love to try a TRB6 -- although I'd probably still end up with a 5 for practical purposes.
Click to expand...

There is no nicer Yamaha 5 than the one you've got, at least not new. When they revamped the TRB line from TRB4/5/6 to the 1000 series, they backed off a little bit on materials and pricing, although I've played a couple TRB1005s at GC myself and can't hear much difference between them and my TRB5. I do notice my neck has walnut stringers in it, where the 1005s are just three piece maple. However, the body finishes look nicer on the new 1005s.

Anyway - nice choice. Yamaha TRBs are great, versatile instruments. It will serve you well.
 
#7
I haven't tried the TRB100x series yet, but by all accounts they are very credible instruments. If I'm not mistaken though, they use a 35" scale and have a slightly narrower string spacing. I prefer the 34" scale and wider string spacing on the original TRB series, and I really like the "slap cut" near the treble horn, makes it so much nicer in my opinion... but I would have no qualms doing a gig on any decent Yamaha really.
 
#8
therealting said:
If I'm not mistaken though, they use a 35" scale and have a slightly narrower string spacing. I prefer the 34" scale and wider string spacing on the original TRB series
Click to expand...

No, my TRB5II is 35" scale, and average to a little wide on the string spacing. Here's a quote from the service manual:

STANDARD SPECIFICATIONS
Scale Length.............................889.0mm
Body-Neck Construction···············Bolt On

...889 mm equals 35".
 
#9
I tested a Yamaha preamp in a factory built custom bass for an endorsee - not sure if it would be the same preamp. The preamp has 2 pots (not exactly small) on the boards (2 board stack). The unit had a notch filter built into it, like a SansAmp. The notch filter was only engaged when a toggle switch was in one of it's 2 positions - the other position was flat. One pot set the frequency of the notch, the 2nd pot set the depth of the notch.

Jason Hollar said:
In the control cavity, there are two small pots on the board.

Anybody know what these do? Nothing in the manual about these at all.
Click to expand...
 
#10
WJGreer said:
No, my TRB5II is 35" scale, and average to a little wide on the string spacing. Here's a quote from the service manual:

STANDARD SPECIFICATIONS
Scale Length.............................889.0mm
Body-Neck Construction···············Bolt On

...889 mm equals 35".
Click to expand...

Yes, but yours is the revised TRB series II. :)

The original TRBs, like mine, have a 34" scale.
 
#12
Audere -- Thanks for the insight. I'll have to check if mine has an internal switch...but I wonder if the toggle you're talking about is on the front of the instrument. I have to say, the way it's set up in terms of overall output is great -- perfect for my rig. I'd just like to be able to sweep the mid frequency a touch for boosting purposes...don't like the current frequency so I leave it flat (center).

Will -- too bad we never hooked up...I lived in Fort Collins for ten years until I recently moved to Pittsburgh. Looks like we're the same age & all...

Are you playing many gigs in the mile high city?:bassist:
 
#13
The toggle switch was on the front of the instrument. I believe it was a typical sized mini toggle. The owner of the bass had no instructions for the function of the unit. He has sold the bass now so I can not get you any more info.

Jason Hollar said:
Audere -- Thanks for the insight. I'll have to check if mine has an internal switch...but I wonder if the toggle you're talking about is on the front of the instrument. I have to say, the way it's set up in terms of overall output is great -- perfect for my rig. I'd just like to be able to sweep the mid frequency a touch for boosting purposes...don't like the current frequency so I leave it flat (center).
Click to expand...
 
#14
Jason Hollar said:
Will -- too bad we never hooked up...I lived in Fort Collins for ten years until I recently moved to Pittsburgh. Looks like we're the same age & all...

Are you playing many gigs in the mile high city?:bassist:
Click to expand...
Jason,

Agreed, and yes I am. Check out my website at [Invalid or Expired Link Removed], or the band's site, Link Removed. And look me up when you are back. Looks like we have a big football game next weekend!
 
#15
Jason,

Did you ever figure out those trim pots? I'm in the same situation right now. I've had a TRB1006 for a little over 2 years. I haven't played it very much. I've been playing gigs with my P-bass.

Anyhow, last week I opened up the control cavity and messed around with those trim pots a little and didn't hear too much of a tonal difference. I wonder if they're more for the output of each pickup.

What did you find out?

Joe
 
#16
The trim pots on the TRB100x series are adjustments for the hum-cancelling coils. Yamaha's TRB soapbars have a hum-cancelling coil whose output actually slightly outstrips the "speaking" coil. By adjusting the two trimpots, you adjust the level of that second coil for each pickup so that the humbucking coil matches the speaking coil in output, thus completely cancelling noise on that pickup. That's the theory; in my experience if you play in a high-EMI environment there will always be a small amount of static hiss somewhere on the panpot, and your best bet is to adjust the trimpots so your most common panpot setting (usually right at the center detent, but you can favor the neck or bridge) is completely noiseless at the expense of more hiss elsewhere. You can also try to make each coil noiseless when soloed, but at least on my bass that actually gives the center some noise.

This seems to be far more of a problem with the 1005 than the 1006; I haven't heard a single complaint from a TRB1006 owner about hiss at the extremes of the panpot. I've also heard that replacing the board with a Bartolini 3-band solves the problem, but other than the noise I like the stock board and am not currently in a position to experiment with my most expensive bass.

The trimpots also allow you to turn your soapbars into SCs by completely cutting out the humbucker coils; if your practice area uses flourescents you'll get quite a bit of noise if the panpot's anywhere off-center, but if you want more bite when you slap, this is an option (personally I get plenty of bite and punch by cutting the bass knob slightly and bumping treble and mids).
 
#17
Thanks! That's a really great post. I didn't understand everything you explained, but I could probably figure it out by messing around with things a little bit.

If I understand correctly; I should adjust my pickup balance and tone settings first, and then adjust the pots inside the bass to eliminate hum. Right?

The TRB1006 is a very bright sounding bass. I cut the treble all the way, leave the mid control in the center, and boost the bass just a touch. I favor the bridge pickup, but I get a bit of hum when it's soloed. Even after all of that, the bass still has a decent amount of treble response.

Joe
 
#18
Bassist4Life said:
Thanks! That's a really great post. I didn't understand everything you explained, but I could probably figure it out by messing around with things a little bit.

If I understand correctly; I should adjust my pickup balance and tone settings first, and then adjust the pots inside the bass to eliminate hum. Right?

The TRB1006 is a very bright sounding bass. I cut the treble all the way, leave the mid control in the center, and boost the bass just a touch. I favor the bridge pickup, but I get a bit of hum when it's soloed. Even after all of that, the bass still has a decent amount of treble response.

Joe
Click to expand...

I found the same brightness on my TRB-1005 when I first got it. It's all in the strings; the D'Addario XLs it comes strung with are very bright as nickels go, and last quite a while. They'll mellow a bit as they age and you'll find yourself boosting the treble for better slap tone (ah, the joys of an active bass).

You understand almost correctly. Find the pan and EQ settings that work best for you, remember them, then set the EQ to flat (or turn the treble all the way up so you can hear any and all hiss) and adjust the trimpots until the hiss is as low as you can get it. Reset the EQ and you should have a very quiet bass. If you fiddle with the panpot a lot, either try to get the two extremes to be noiseless by soloing each pickup in turn and adjusting the trimpot for that pickup to quiet it, or just set the panpot to center and adjust there.
 
#19
Thanks for your reply. I completely understand what you're saying now.

I said in my previous post that I favor the bridge pickup... That's completely wrong. I favor the neck pickup. That doesn't have any impact on the process, I just wanted to be on the record as saying I endorse the neck pickup. ;)

Peace and good vibes from Buffalo!

Joe
 
#20
Yeah Liko & Joe!

Thanks for bringing this back up.

I never really fooled with mine ('cause I couldn't figure 'em out) -- but now it seems to make more sense. Will attempt to adjust next time I have all my stuff set up and can hear the subtle differences.

I never use either pickup all the way panned L or R. I almost always go a quarter turn to the neck for R&B and solid walking tones or a little to the bridge for punchy rocco/jaco funk -- or when I'm in awfully boomy rooms. Only ever in the center pan for certain slap tones.

Which pickup seems to exhibit the most hiss/noise? The bridge?
 

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