CMATMODS Brownie question...

[Pavel]

Got the Brownie recently; awesome pedal! I do wish it had a bit more hair/presence to it. I read that some folks have achieved this by clipping out certain component(s) to make it brighter.

Below is a shot of the circuit board. What did you remove to make the pedal brighter?

Also, what is the function of the trim pot?

[Cary Chilton]

Ditto

[Ohzoso]

Just roll back your axe`s volumeknob somewhere halfway and there comes the brightness. Then set the gain a tad higher if you need more. Great pedal.

[Cary Chilton]

Originally Posted by Ohzoso

Just roll back your axe`s volumeknob somewhere halfway and there comes the brightness. Then set the gain a tad higher if you need more. Great pedal.

wow! Great news for me.... I don't think we could have tried that first???

[steelplayer]

To make the pedal overall brighter, one could try replacing the input and output capacitors with lower values.

If I remember correctly, the trimpot in this circuit adjusts transistor drain voltage.

Hey, drop Chad Mathews at Cmatmods an email. He's a super nice guy and I'm sure he'd help you with all the information you need to tune your pedal to your liking.

best,
LarryW

[recto-robbie]

Originally Posted by steelplayer

Hey, drop Chad Mathews at Cmatmods an email. He's a super nice guy and I'm sure he'd help you with all the information you need to tune your pedal to your liking.

best,
LarryW

+1000 on that one,, highly suggest doing what Larry said,, Chad Mathews is an excellent person to deal with. All good.

[rpjones]

the two .0022uf caps to ground right before the volume pot connection. They simulate the speaker rolloff of a 4x12 cab. If you clip them the sound will be more open. You might want to try clipping one of them first (either one) and see how that sounds to you, if you need more highs just clip the other one.

[Unabender]

Originally Posted by Pavel

Also, what is the function of the trim pot?

Is this the one based on BSIAB2? If it is, the trim pot probably is a set-and-forget kind of voltage divider for the last transistor to operate, if I remember correctly. It's not on the signal path.

[nibus]

Originally Posted by rpjones

the two .0022uf caps to ground right before the volume pot connection. They simulate the speaker rolloff of a 4x12 cab. If you clip them the sound will be more open. You might want to try clipping one of them first (either one) and see how that sounds to you, if you need more highs just clip the other one.

Could you possible post a picture pointing out these caps? i'm an electronics dummy and don't want to render my Brownie unusable.

[Pavel]

Here's the same photo with the caps (or what I think are caps, haha) labeled. Which are the two that roll off the highs? My guess would be 11 and 12.

[Bucksears]

My guess would be 10 and 12; just look for the two that read .0022 on the board, nearest to the volume/out connection.
I suggested clipping these two caps some time ago at diystompboxes.com. It increases the brightness greatly, but still allows you to darken it up as you roll back the tone control.

One config I'm loving right now is using just one .001uF cap in the low pass filter (the two caps we're talking about). I'm gonna have to make some clips of that one day; classic rock/Marshall sound, but not 100% early VH. Leave the two .0022uF caps out for that.

[Pavel]

Originally Posted by Bucksears

My guess would be 10 and 12; just look for the two that read .0022 on the board, nearest to the volume/out connection.
I suggested clipping these two caps some time ago at diystompboxes.com. It increases the brightness greatly, but still allows you to darken it up as you roll back the tone control.

One config I'm loving right now is using just one .001uF cap in the low pass filter (the two caps we're talking about). I'm gonna have to make some clips of that one day; classic rock/Marshall sound, but not 100% early VH. Leave the two .0022uF caps out for that.

You're correct!

I emailed Chad as few people suggested (he got back to me in 1/2 hour... awesome!), and 10 and 12 are the low-pass filter caps.

[nibus]

Originally Posted by Pavel

You're correct!

I emailed Chad as few people suggested (he got back to me in 1/2 hour... awesome!), and 10 and 12 are the low-pass filter caps.

So do you just cut each of those connections with a wire clipper or what?

[Pavel]

Originally Posted by nibus

So do you just cut each of those connections with a wire clipper or what?

To remove them permanently, yes. Just clip them out... if you go this route, I'd remove one of them first, see how you like the sound, and if you want it even brighter then clip the 2nd.

To make the mod easily reversible (requires soldering), here's what Chad suggested: "If you are good with a soldering iron you may try lifting one side of each and see how that works for you. To remove the circuit board just take the knobs off and take the pot nuts loose, pop the LED out and it will come right out. If you don't like the mod then you can solder them back".

[nibus]

Cool, I'll try the soldering trick so I can reverse it if necessary.

IMO if the Brownie had more pleasing / soft highs it would be the ultimate Marshall in a box.