Son of Ben - bass pot range

ttolliver

New member
Hey everyone --

Just finished my Son of Ben and I have an odd response from my bass control. There's almost no noticeable change from bass at any setting when there's low to mid gain dialed in. If you dial in a high gain setting you get a change in bass from the first 20% of the knob range, then nothing from the remaining 80%.

I ordered and Tayda definitely sent me a B1M. I just didn't think to test it's resistance before installing.

Not expecting anyone to troubleshoot the circuit from just that description. But I'm curious if that sounds like a bad pot or something wrong elsewhere in the circuit?

Thanks in advance!
 

ttolliver

New member
I should probably toss in that my J201s came from Small Bear and I was able to dial those in to 4v and 1.67k.

I also put in the optional C10 and a 250p for C3.
 

Chuck D. Bones

Well-known member
I have not built one, but by looking at the schematic it's clear to me that the BASS pot is not going to do much. There's no bass boost, only bass cut. The cut is only about -7dB.
 

Jovi Bon Kenobi

Well-known member
There's almost no noticeable change from bass at any setting when there's low to mid gain dialed in. If you dial in a high gain setting you get a change in bass from the first 20% of the knob range, then nothing from the remaining 80%.
first off, I'll say that the bass control does indeed not do much. It is very subtle. Not that it's a bad thing, it's just different. What it doesn't do is boost bass frequencies. Same goes for treble. I really think it sounds great regardless of this odd choice.
If anything, I'm getting more of a noticeable difference in the bass pot sweep in low to mid gain settings than I am in higher gain settings. It is more subtle in higher gain modes. The effect as a whole does color the sound slightly. It's strange, I think it may be most at unity to your original tone with both bass and treble maxed, then it reduces either when adjusting respective knobs.
 

Jovi Bon Kenobi

Well-known member
And I should add that I did not install the optional electrolytic capacitor.

I wonder, if all the bass and treble pots do is cut their frequencies, could you increase both by altering values on the PCBs? Then you could get an actual boost (as well as cut) to either of you so desired.

I'm satisfied with mine as it is. I would definitely steer people away if they want to boost bass and treble with their drive pedals.
Does it do clean boost? Yes
Does it overdrive and sound good all through the drive sweep? Most definitely.
Is it frustrating because it can't get fat? Maybe, but if you don't need that then it's great.
 
Last edited:

Chuck D. Bones

Well-known member
The BASS & TREBLE controls on the SoB are indeed cut only. This is the case with the majority of pedals. Mods are always possible, but sometimes the better question to ask is this:
What pedal can I build that is already designed to do what I want?
There are pedals on this site that make clean boost and provide boost and cut on the treble and bass controls. Like the Integral Preamp.
There are pedals on this site that make distortion and provide boost and cut on the treble and bass controls. Like the Chela.

The Covert does both. I have one of those and I love it.

My $0.02 ±5%
 
Last edited:

zgrav

Active member
I put together the SOB Preamp without much issue, although these days I'm generally suspicious of my stock of J201s. They worked OK here, with no issues dialing in the right trimmer settings. I've seen some reviews describing the Bass pot as ranging from the British amp sound at minimum to the American amp sound as it gets maxed. That may be easier to keep in mind than thinking about this as a traditional bass control. The treble pot also seems like more of a upper mid-range adjustment than a higher frequency range. But it seems to work well with the tone pot on my guitar.
 

ttolliver

New member
Thanks Chuck and zgrav!

I'm cool if it's subtle, or if it does as you suggest and just alter the nature rather than act like a traditional bass. My first build was the Zendrive and it was like this. I was mostly concerned there is a problem because the change all occurs bunched up at one end of the pot.

The other part of the story is that this is only my second build, and the first from PCB only. So I'm still prone to assume anything odd is my fault.

Since I have spares in inventory for pretty much everything for this build except the PCB I'm planning to toss another one together quick. On the second I would leave out C10 and try a 300p I found for C3 just for giggles. Although I know if I change more than one thing I just confuse the issue, hehehe. I think I'll also measure the values on everything that I can before assembly.

Thanks again!
 

Chuck D. Bones

Well-known member
Some unsolicited advice:
C10 is more of a gain boost than a bass boost. You can leave it out for less gain/distortion or make it smaller for more of a mid-boost effect. Some pedals have a switch to select a big or small cap.
Changing C3 from 250pF to 300pF will be barely noticeable. When I'm fooling around with filter caps, I usually go in 2x steps until I get close to the sound I want.
You might want to try building something different instead of building two of the same pedal. If you like FET-based pedals, check out the Covert, Corduroy, FET City, Tantric, Bohemia, Sabbath, Deofol, M800, Stinger, Pineapple, Monarch, Distortr, etc.
You might find the ones that don't have trimmers easier to get going.
 

ttolliver

New member
Great advice -- thanks. I think you hit the nail on the head. I do really like ODs that lean towards amp sim. You're helping me build my next order list =)
 
Top