how do i get more output from a bad monkey?

[maertz13]

full disclosure, this is regarding a pcbguitarmania PCB, however, in all possible places I have changed the values of components to match the pedalpcb schematic. with the small exception of C3, which is currently a film cap. the PCBGM schematic had a 470n film there. i've already changed the volume pot to linear taper, and still, i've got to turn it almost all the way up to get to max gain. the bias on Q1 is about 4.2. i have already corrected the issue where they had Q2 the wrong way around. it SOUNDS good, it's just too quiet.

any idea how to get more clean gain out of this circuit? volume at max shouldn't be unity gain.

 

[fig]

Wow, did I read the title wrong!

 

[Coda]

You have to take away a few of its coffee breaks. That’ll show him…

 

[Paradox916]

I don’t know… I’m just here to hold the football.

 

[jwin615]

 

[maertz13]

View attachment 56139

started there, had pretty low output, so i went through and made it match this. problem persists

 

[jwin615]

Was just posting for the community, wasn't try to be a smart@ss or anything...

Looking at it now sober, check R18/R18.
So, modify the output stage. Omit, don't jumper GPCBM R17 and change R18.
You can try leaving R18 as is, won't hurt but I think going to 10k will increase your output greatly.

EDIT: waking up more. Looks like R17 is completely inverted between the two.
Robert has it going to Vref.
I'm thinking maybe it's a bad probe/ripoff by GPCBM and they sent R17 to the wrong rail?
Anyone else want to chime in?

Volume issue is definitely in that output buffer though

 

[Bricksnbeatles]

for whatever reason I’m in the GPCBM Facebook group, and I’ve seen quite a few people mentioning that their bad monkey board doesn’t work

 

[Coda]

for whatever reason…

95% of the time you hear this whenever people talk about their Gpcbm experiences…

 

[maertz13]

Was just posting for the community, wasn't try to be a smart@ss or anything...

Looking at it now sober, check R18/R18.
So, modify the output stage. Omit, don't jumper GPCBM R17 and change R18.
You can try leaving R18 as is, won't hurt but I think going to 10k will increase your output greatly.

EDIT: waking up more. Looks like R17 is completely inverted between the two.
Robert has it going to Vref.
I'm thinking maybe it's a bad probe/ripoff by GPCBM and they sent R17 to the wrong rail?
Anyone else want to chime in?

Volume issue is definitely in that output buffer though

no worries bud, i don't think i chose my words all that carefully. wanted to point out where i'd made adjustments in favor of the (in all likelihood) more accurate PPCB schematic.

i'm pretty green here, and admittedly know the least about power related things. one goes to VR, the other to VREF. are those different?

 

[maertz13]

for whatever reason I’m in the GPCBM Facebook group, and I’ve seen quite a few people mentioning that their bad monkey board doesn’t work

one person pointed out that the schematic was a duplicate of one from a forum that was KNOWN to be incorrect and fixed later in the thread. they also mentioned that they were disappointed that someone who sells PCBs wouldn't test their work.

the first issue was with Q2 being the wrong way around. i'd already read that people were having trouble with 4580's, so i went with the 4558's that I already have an abundance of.

granted, the PCB was a free giveaway with a couple other boards (that worked), and i have very little invested in that regard. but i'm hoping to make this work and also learn something from the process. what i also learned is that my order with GPCBM will sit in their queue for a week before they ship it, it will take 2 weeks to ship, and their website goes down regularly. if PPCB made the darkglass tone capsule board, i'd never had to deal with GPCBM again

 

[Bricksnbeatles]

if PPCB made the darkglass tone capsule board, i'd never had to deal with GPCBM again

Add it to the wishlist! Surely others who want to build it too

 

[maertz13]

Omit, don't jumper GPCBM R17

yeah that broke it. bass control is now volume and it sounds like a gated fuzz

 

[maertz13]

any other ideas?

 

[Feral Feline]

SPANK IT!

"Bad Monkey..."


So is the DG Tone Capsule in the Wish List yet?
If so post the Wish List link to it here and I'm sure people will upvote it...

 

[maertz13]

So is the DG Tone Capsule in the Wish List yet?
If so post the Wish List link to it here and I'm sure people will upvote it...

https://forum.pedalpcb.com/threads/bass-preamps-sansamp-bass-driver-b7k-alpha-omega-etc.13116/page-2#post-228115

but seriously, the bad monkey

 

[cdwillis]

Changing that audio taper volume pot to a linear one will give you some more perceived volume, but maxed out will be the same. I thought the Bad Monkey used 100k linear pots for all the functions originally.

Double up the clipping diodes (two sets of 1n418s instead of just one per side) and you'll have about twice the output. You might want to adjust the increase the size of the gain pot to put the maximum gain higher since it'll have more headroom.

 

[jimilee]

Humbuckers. Hot nasty in your face humbuckers. As previously suggested, you might go with a 500k or 1M pot. Is use a 1M and maybe put a 1M resistor across the lugs. Then you can remove the resistor if you need to.

 

[mdc]

If it sounds good and you just want it to be louder, you could just tack one of these onto the end and tuck it in the enclosure. Replace the gain pot w a trimmer.

Have you been able to a/b it with an original?

 

[maertz13]

Have you been able to a/b it with an original?

i have not, but it's reputation seems to be that it's VERY loud