Can you improve an old Boss buffer by modifying it?

[Snufkinoob]

I've never been too snobbish about buffers vs true bypass, but the MIJ BF-2 I recently picked up definitely has a bit of 'blanket-over-the-amp' thing going on. Now if its not something else inherent to the circuit design causing it, why do you never see mods to improve the buffer? It's been a common enough complaint over the decades (rightly or wrongly), so could you replace all the old buffer components with 'better' values, or remove them all entirely, and hook up a 'good' mini buffer in its place? (Presuming there would be room. Maybe fit it in the battery compartment!)

[Mark Hammer]

1) There's input buffer vs output buffer.  You'll note that preferences and design changes between the TS-808 and TS-9 are with respect to the output buffer stage.

2) I doubt any single buffer really detracts all that much.  It's the cumulative effect of multiple buffers, in addition to the cabling connecting pedals and perhaps what the various buffers might NOT be doing, rather than what they might be doing.  All buffers are designed in anticipation of something, but what?  For instance, are Boss buffers designed in anticipation of a pedalboard full of other Boss pedals? in anticipation of running a 25ft cable to the amp?  What were they designed for?

3) Is the issue with your BF-2 really a question of what you stuck in front of it, and nothing generic about the buffer itself?

Not trying to smack you on the wrists.  Rather, buffers never function in complete isolation and identically in all contexts.  What can be an ideal design for onecontext can be insufficient for another.  So, think about the entire signal path before leaping to conclusions.  Just a thought.

[amz-fx]

The BF-2 leaves three buffers in the signal path when it is bypassed. One is a transistor buffer and two are opamp buffers that are designed with pre-emphasis/de-emphasis -- not a simple mod that we could tell you to do. If you really want to try a different system, you could convert it to true bypass, or even a buffered bypass where the signal from the first transistor is used for the bypassed signal. There are plenty of instructions on the web on how to true bypass Boss pedals.

regards, Jack

[Rob Strand]

It's possible there is a level drop and/or a modification to the frequency response.

Measure the signal drop through the pedal at about 200Hz and tweak the gain to make it unity.

Measure the frequency response, or, measure the gain at few specific freq frequencies.
If it's not flat you can tweak the pre-emphasis/de-emphasis caps.  Adding parallel caps is usually easier.

Use can use a signal generator and a multimeter.  Many cheap multimeters have poor accuracy above 1kHz.   However, for gain checks near unity it's usually OK provided you measure both the input level and output level and calculate the ratio; ie. don't assume the input is constant because you haven't change signal generator level.  You can also use PC software but you should validate the levels and frequency response so you know it actually works.

[amptramp]

If you have a number of pedals in series with what would be a reasonable frequency response individually for guitar (where the lowest note is at 82 Hz) of what would seem to be a comfortably low turnover, you have to add the db drop of each stage at the lowest guitar frequency for the low frequency turnover and you have to do the same with the high frequency response (which may be less certain).

For the lowpass part, the response is given by:

Vout = Vin (Xc/(R² + Xc²)^0.5

and Xc is given by:

Xc - 1/(2 * pi * f * C)

For the highpass, switch the numerator and denominator in the response.  You will see that even if you have a generous bandwidth, the losses all add and you need a wide response to get an acceptable frequency response.