Bluesbreaker Clone Mod Ideas

[skelts]

Built my first kit pedal recently, a Bluesbreaker clone/transparent overdrive. Not without some issues with the LED clipping stage but managed to sort it thanks to the help of this forum.



Now it's working I'm keen to start making tweeks to it make it my own. Here is a few things I would like to alter if possible.

1. The overall tone of the pedal is a bit bright and the tone never goes past noon. Is there any way to remove some high end from the overall sound, or changing the usable range of the tone pot?

2. When SW1 is engaged and LED's D6 and D7 start clipping there is a very slight signal drop. This is something that I understand is normal with extra clipping stages but was wondering if there is anyway to negate this?

3. When SW1 is engaged, the additional LED clipping is quite subtle. Nice, but subtle. Is there anyway to have this switch introduce more "oomph" (maybe introduce some kind of additional gain stage)? Would love to control something like this on another footswitch and have it adjustable with another gain pot - probably getting carried away now!

Any other ideas welcome. Just excited to experiment and get to grips with pedal building now instead of following the kit instructions

[11-90-an]

1. The overall tone of the pedal is a bit bright and the tone never goes past noon. Is there any way to remove some high end from the overall sound, or changing the usable range of the tone pot?

maybe increasing R11...

2. When SW1 is engaged and LED's D6 and D7 start clipping there is a very slight signal drop. This is something that I understand is normal with extra clipping stages but was wondering if there is anyway to negate this?

the LEDs clamp the maximum voltage... boosting it after would make sense.

3. When SW1 is engaged, the additional LED clipping is quite subtle. Nice, but subtle. Is there anyway to have this switch introduce more "oomph" (maybe introduce some kind of additional gain stage)? Would love to control something like this on another footswitch and have it adjustable with another gain pot - probably getting carried away now!

Probably increasing R5 value... that would change the overall sound of the pedal though, as you are increasing gain...

if you want, add a 50k pot in series with R5 (don't change value) and pin 7 of the IC...

[GGBB]

1. The overall tone of the pedal is a bit bright and the tone never goes past noon. Is there any way to remove some high end from the overall sound, or changing the usable range of the tone pot?

Add 100pF or more (experiment) between op amp pins 6 & 7 to reduce high end. You can "limit" the upper setting of the tone pot by adding a resistor between tone pin 3 and R7. Try 10k to start.

2. When SW1 is engaged and LED's D6 and D7 start clipping there is a very slight signal drop. This is something that I understand is normal with extra clipping stages but was wondering if there is anyway to negate this?

Not really - that's what hard clipping does. You can kick in a volume boost at the same time by switching in a resistor between volume pot pins 2 and 3 (try 100k to start) or between pin 1 and ground - but it will be pretty much impossible to make this work exactly right at any gain or volume setting.

3. When SW1 is engaged, the additional LED clipping is quite subtle. Nice, but subtle. Is there anyway to have this switch introduce more "oomph" (maybe introduce some kind of additional gain stage)? Would love to control something like this on another footswitch and have it adjustable with another gain pot - probably getting carried away now!

You can simultaneously boost the gain similarly to the volume above - switch in a resistor between gain pot pins 2 and 3 to raise gain of the second stage - between pin 1 and op-amp pin 2 to raise the gain of the 1st stage. You can also raise gain by reducing R16 and R17 (switch in parallel resistors) - but this will roll off more bottom end making things sound brighter - kind of like a treble boost.

Any other ideas welcome. Just excited to experiment and get to grips with pedal building now instead of following the kit instructions

Add a little more bottom end by changing C13 and C14 to 22n and 33n (or experiment).

[MikeA]

1.  You can roll off the highs without affecting lows by increasing C12.  Going from 10nF  to 15nF will leave <200 Hz unchanged, but will roll off 1kHz point by 2 dB and 2.5 kHz by 3 dB.  22 nF will roll these points down by 4 and 6 dB respectively.   MikeA

[antonis]

https://www.diystompboxes.com/smfforum/index.php?topic=125484.msg1196082#msg1196082

https://www.diystompboxes.com/smfforum/index.php?topic=125484.msg1196109#msg1196109

As I told you in the other tread, particular tonestack cut-off calculation is akward a bit..
By just increasing C12 value, you might result into more highs cut for full pot rotation but you'll also result into less usable range for pot lower settings - i.e. you'll "off-set" pot's range and not expand it.. 

[skelts]

the LEDs clamp the maximum voltage... boosting it after would make sense.

This sounds like it could be fun 10-90-an, how would you suggest doing this?

Add 100pF or more (experiment) between op amp pins 6 & 7 to reduce high end

I have seen this popping up on a few other schematics with a switch and now it has just dawned on me that this is probably a "hi-cut" that you see on a few of these pedals. Might be the perfect solution GGBB, thanks!

You can also raise gain by reducing R16 and R17

I saw someone else on here put a schematic up that put these on a seperate switch. I quite like this idea, may give it a go.

I think I will try playing with resistor values before altering the caps around the tone pot, sound like it could get messy. Thanks to everyone for your suggestions

[antonis]

If you use a booster for LED voltage clampping, place it AFTER tonestack to "recover" both configurations signal attenuation.. 

Although a single BJT or J/Mos FET booster should do the job, you better utilize another 1458 (or any other dual op-amp) for boosting and VB stabiling..

[PMowdes]

 T