BossAreaForum

█ → you can tweak these trimpots by ear to adjust the pedal's performance to your taste
█ → don't think about touching these without technical skills and/or an oscilloscope

AW-2 Auto Wah
- RT-1 (LED brightness of optocoupler? I read that somewhere ...)

BF-1 Flanger
- VR-1 clock frequency
- VR-2 bias
- VR-3 mixing balance
- VR-4 resonance

BF-2 Flanger
- VR-5 resonance
- VR-6 bias
- VR-7 clock frequency
→ calibration process explained by cctsim (screenshot from the first BossArea Forum)

CE-2 Chorus
- VR-3 bias

CE-2B Bass Chorus
- VR-3 bias

CE-3 Chorus
- VR-3 bias

CEB-3 Bass Chorus (analog version)
- RT-1 bias

DC-2 Dimension C
- RT-1 bias B
- RT-2 bias A

DD-2/3 Digital Delay and DSD-2/3 Digital Sampler/Delay
- RT-1 (main board) clock "high end"
- RT-2 (volume board) clock "low end"

DD-3 Digital Delay (modern)
- RT1 clock adjustment
- RT2 clock adjustment

DM-2 Delay
- VR-1 set-point (minimising distortion)
- VR-2 clock leakage
- VR-3 delay time set-point

DM-2W Delay
- VR-13 max. delay time

DM-3 Delay
- RT-1 BBD bias
- RT-2 leakage
- RT-3 clock frequency (delay time set-point)

HF-2 Hi Band Flanger
- VR-5 resonance
- VR-6 BBD bias
- VR-7 clock set-point

LM-2 Limiter
- VR-5 (?)
- VR-6 (?)

MZ-2 Digital Metalizer
- RT-1 clock frequency

NF-1 Noise Gate
- VR-3 sustain level
- VR-4 decay time

OC-3 Super Octave
- L2 sealed trimpot
- L3 sealed trimpot

OD-2 Turbo OverDrive
- RT-1 (master level?)

PH-1R Phaser
- VR-1 bias

PS-2 Digital Pitch Shifter/Delay
- VR-5 clock frequency

PS-3 Digital Pitch Shifter/Delay
- RT-1 bias

RV-3 Digital Reverb/Delay
- RT-1 bias

SG-1 Slow Gear
- VR-3 bias

SP-1 Spectrum
- VR-3 gain adjustment

TW-1 T Wah
- VR-3 frequency adjustment

VB-2 Vibrato
- VR-4 BBD clock set-point
- VR-5 BBD bias

I received a TW-1 this week and when I opened it to clean it I saw that it has a trimpot like so many other BOSS pedals. I thought that we could list all the BOSS pedals with internal trimpots and sum up what they affect. And we can highlight those that can be tweaked by any user (like the BF-2's feedback trimpot to make the flanger self-oscillate) and also those that require higher technical skills and/or an oscilloscope, etc.

I will put all the information in the first posting. Thanks in advance for all your help!

Deleted - full list below.

Thanks a lot, laurie!

Can you check your info about the PS-2 again? And is my information about the trimpots of the analog chorus pedals correct (bias)?

Which ones are those in your opinion that can be tweaked if the average player is not fully satisfied with the pedal's performance? I'd recommend the resonance trimpots of the BF-2 and HF-2. What about the trimpots of the AW-2 and TW-1? I have another envelope filter by KORG and adjusting the trimpots had a huge impact on the performance (in the positive way).

PS-2 typo... VR4 and VR5

More to follow

Pepe wrote: ↑

Fri May 29, 2020 10:44 pm

PS-3 Digital Pitch Shifter/Delay
- RT-1 bias

RV-3 Digital Reverb/Delay
- RT-1 bias

I'm going to guess there is no reason to adjust these right?

....fwiw, I was actually able to do the PH-1R by ear. I had one in for repair and likely because someone moved the trim pot. there is an extremely small range of pleasing results sitting on split hairs of adjustment. Basically if your PH-1R sounds correct at max depth and slowest rate, don't touch the trim pot!

Pepe wrote: ↑

Fri May 29, 2020 10:44 pm

BF-2 Flanger (cctsim had a great site where he explained the calibration process. It seems to be offline. )
- VR-5 resonance
- VR-6 bias
- VR-7 clock frequency

I have a complete screen capture of that post:

https://1drv.ms/u/s!At7zhavfCGMhu5Vkqq6 ... A?e=At5jpZ

I'll leave that link active indefinitely in case anyone needs it.

-Scott

Wow! A screenshot from the original BossArea Forum. That brings back some memories.

Thanks a lot for the link, sclitheroe! I included it in the first posting.

chromandre wrote: ↑

Sat May 30, 2020 11:16 pm

....fwiw, I was actually able to do the PH-1R by ear. I had one in for repair and likely because someone moved the trim pot. there is an extremely small range of pleasing results sitting on split hairs of adjustment. Basically if your PH-1R sounds correct at max depth and slowest rate, don't touch the trim pot!

You are absolutely right. I did that as well with my PH-1R after replacing the electrolytic capacitors. The sweet spot is clearly noticeable. I used a synthesizer for the process. I played a chord in hold mode so I had the chance to fiddle around with the trimpot until I was satisfied with the result.

These notes are OPINIONS. Use your judgement before attempting any adjustments.

Everywhere that says "should be OK to be adjusted by ear"... you will likely need a scope to get it back to factory setting. So please be sure this is really what you want to do.

Take care messing with vintage pedals. Incorrect settings can affect the resale value of the pedal.

“Scope” means something like a Tektronix 1002B (this is the one I use).

===========

AW-2 Auto Wah
- RT-1 LED brightness of optocoupler. Do not adjust without a scope.

BF-1 Flanger – unable to verify, no schematic available.
- VR-1 clock frequency. If clock frequency should be OK to be adjusted by ear.
- VR-2 bias. If BBD bias, do not adjust without a scope.
- VR-3 mixing balance. If BBD balance, do not adjust without a scope.
- VR-4 resonance. If resonance, should be OK to be adjusted by ear.

BF-2 Flanger
- VR-5 resonance. Set by ear is OK.
- VR-6 bias. Do not adjust without a scope.
- VR-7 clock frequency. Do not adjust without a scope.

CE-2 Chorus
- VR-3 BBD bias. Do not adjust without a scope.

CE-2B Bass Chorus
- VR-3 BBD bias. Do not adjust without a scope.

CE-3 Chorus
- VR-3 BBD bias. Do not adjust without a scope.

CEB-3 Bass Chorus (analog version) – unable to verify, no schematic available.
- RT-1 bias. If actually bias, do not adjust without a scope.

DC-2 Dimension C
- RT-1 BBD bias B. Do not adjust without a scope.
- RT-2 BBD bias A. Do not adjust without a scope.

DD-2/3 Digital Delay (all versions of DD-3) and DSD-2/3 Digital Sampler/Delay
- RT-1 (main board) clock "high end". Can be adjusted by ear. Better with a scope.
- RT-2 (volume board) clock "low end". Can be adjusted by ear. Better with a scope.

DM-2 Delay
- VR-1 BBD bias. Do not adjust without a scope.
- VR-2 clock leakage. Do not adjust without a scope.
- VR-3 delay time set-point. Can be adjusted by ear.

DM-3 Delay
- RT-1 BBD bias. Do not adjust without a scope.
- RT-2 clock leakage. Do not adjust without a scope.
- RT-3 clock frequency (delay time set-point). Can be adjusted by ear.

HF-2 Hi Band Flanger
- VR-5 resonance. Can be adjusted by ear.
- VR-6 BBD bias. Do not adjust without a scope.
- VR-7 clock set-point. Can be adjusted by ear. Better with a scope.

LM-2 Limiter
- VR-5 Feedback. Might be OK to adjust without a scope. No service notes available, so set-point and effect of adjusting unknown.
- VR-6 Threshold trim. Should be OK to adjust without a scope.

MZ-2 Digital Metalizer
- RT-1 clock frequency. Should be OK to be adjusted by ear. Better with a scope.

NF-1 Noise Gate
- VR-3 sustain level. OK to be adjusted by ear. Better with a scope.
- VR-4 decay time. OK to be adjusted by ear. Better with a scope.

OC-3 Super Octave – unable to verify, no schematic available.
- sealed trimpots

OD-2 Turbo OverDrive
- RT-1 2.5V rail set. Do not adjust without a volt-meter.

PH-1 Phaser
- VR-1 FET bias. Do not adjust without a scope.

PH-1R Phaser
- VR-4 FET bias. Do not adjust without a scope.

PS-2 Digital Pitch Shifter/Delay
- VR-4 clock bias. Do not adjust.
- VR-5 clock frequency. No set-point information available. Do not adjust.

PS-3 Digital Pitch Shifter/Delay
- RT-1 bias. Do not adjust without a scope.

RV-3 Digital Reverb/Delay
- RT-1 bias. Do not adjust without a scope.

SG-1 Slow Gear
- VR-3 bias. Can be adjusted by ear… but should use a volt-meter.

SP-1 Spectrum
- VR-3 gain adjustment. Can be adjusted by ear… but should use a scope.

TW-1 T Wah
- VR-3 frequency adjustment. Do not adjust without a scope.

VB-2 Vibrato
- VR-4 BBD clock set-point. Can be adjusted by ear… but should use a scope.
- VR-5 BBD bias. Do not adjust without a scope.