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Projects => Tech Help - Projects Page => Topic started by: CRM-114 on February 21, 2019, 03:06:42 AM

Title: Cherrybomb Same old splat
Post by: CRM-114 on February 21, 2019, 03:06:42 AM
I've recently wired up the 2015 Cherrybomb PCB from the site.  I've also read what I could on the project from this forum.

I seem to be running into the same old problem as others. 

I've swapped in and out several BC109 transistors.

The biggest issue is the crackling that seems to get louder the harder I play the guitar, even starting at very minimal gain settings.  It is very frustrating as it seems like there is this killer dirt sound rocking out underneath the static crackle.  Maybe you can call it splatty, but again, the unpleasant sounds seem to be "on top of" the overdrive sound, which itself seems nice and grainy. 

Is there a definitive answer about this issue?  Is it down to biasing?  If so where should I start?
Title: Re: Cherrybomb Same old splat
Post by: CRM-114 on February 21, 2019, 03:20:47 PM
I tried some other transistors, including 2N5088 and 2N4906 trios.  They all sounded pretty much the same.  Tripple checked the wiring and component orientation.  Couldn't find any problems.

Bummer.

Title: Re: Cherrybomb Same old splat
Post by: zgrav on February 21, 2019, 04:10:57 PM
how hot is your guitar signal going into the box?  is it plugged straight into it, or is it in a chain?  if it is not plugged straight into your effect, try doing that and see if it sounds different.   
Title: Re: Cherrybomb Same old splat
Post by: CRM-114 on February 21, 2019, 06:09:06 PM
Les Paul with humbuckers direct into the overdrive then direct to the amp.
Title: Re: Cherrybomb Same old splat
Post by: zgrav on February 22, 2019, 02:35:03 PM
Try putting another effect in front of it if you have one and see if it changes the tone of the cherrybomb.  I am not suggesting that you would need to always do that if it sounded better in that lineup, but it might help you isolate where the issues are with the sound you are getting (signal level, input impedance are the two that come to mind).

  I am not familiar with that pedal, but if biasing is important for the transistors to hit a sweet spot in this pedal, it would have been nice if some trimmers had been built into the circuit board.   
Title: Re: Cherrybomb Same old splat
Post by: CRM-114 on February 23, 2019, 05:09:54 PM
The Cherrybomb seems to sound the same in a chain of effects or out of it.  If I stack it with a Rat you can't really make out the crackle when both are wide open, but you aren't making much out at all then either.  I'd try a different guitar, but I don't have one right now (this one sounds fine when not using the Cherrybomb).

I've read years old thread on here about this build (unfortunately only after I built mine) and several folks seem to have had similar problems yet there have been no conclusive fixes.  Interest tapers off or folks just accept the crackle/static.  At one point folks seemed to attribute things to a flipped electrolytic capacitor, but in the version of the board I have it seems that cap has been changed to a non-polar film cap (which I used). 

The more I listen to it, it doesn't really sound like a bias issue.  It's not splatty like a off biased of dying battery fuzz.  It also sounds the same across two different power supplies and a handful of 9v batteries.

I've built several dirt boxes and other effects (I had really great experience with a couple of madbean Rustybox projects).  I've not quite heard this sort of sound before.  But I'm just a hobbyist with no theoretical knowledge.
Title: Re: Cherrybomb Same old splat
Post by: marmora on February 23, 2019, 08:18:15 PM
Here's someone else's take on the Colorsound Overdriver circuit. Maybe some ideas here will help you, or maybe just an interesting quick read.
http://atomiumamps.tumblr.com/post/157119810141/lets-talk-about-fuzz-for-a-minute-this-is-the
Title: Re: Cherrybomb Same old splat
Post by: CRM-114 on February 23, 2019, 09:41:58 PM
Super Cool.
Title: Re: Cherrybomb Same old splat
Post by: Bret608 on February 26, 2019, 11:49:20 AM
Someone with a clip of an Overdriver clone they built out there on YouTube (DrewBB maybe?) mentioned in the comments that the circuit isn't wild about humbuckers. I wonder if trying out some lower gain transistors (especially for Q1 and Q2) may help in your case? Looks like you have tried out some swaps already. I think I've seen folks post that it's at mid-gain settings where the crackle is most pronounced (i.e. clean boost or full fuzz work fine).

Honestly though, I've listened to clips of original units and even those seem to have some element of the crackle. I'll be finishing up and testing one of Brian's more recent versions with that electro changed out for film, so I'll be curious to see how it sounds with that mod.
Title: Re: Cherrybomb Same old splat
Post by: CRM-114 on February 27, 2019, 04:40:23 PM
I was just about to update.  I finally got around to spending a few hours just playing the box last night.  I also got to borrow a Vick Audio Overdriver for comparison. 

The full on fuzz does not suffer from the crackling.  The fuzz is just amazing.   Medium gain has some crackle, but there are setting where it is fine.  I can't get much clean boost at all and in that range, the odd heavy picked notes will crackle over the clean tone.  Eventually, I hope to buy or test out some low gain transistors and give them a shot. 

For now, I'm just digging the hell out of the fuzz tones.  It may just be the nature of the beast.

Also, the Vick Overdriver has simiar crackle behavior.  Over all the two boxes sound very, very similar.  It has a bit less crackle at low gain settings, but also has very little clean boost.  The entire unit may roll off highs a bit more, but maybe it's just a trick of the ear.  It is a cool dirt box. 

So I guess I was being picky.  Videos online sometimes show a grainy character, but seemed to have a nice clean boost and light overdrive.  I might still get those sounds out of these boxes, but it isn't as simple as it looks.  That's fine, but the more info you have, the better.  Adjust your expectations appropriately.  Cleaning up by rolling guitar volume down seems to avoid crackle more than using the unit's dial. 
Title: Re: Cherrybomb Same old splat
Post by: Bret608 on February 28, 2019, 08:42:07 AM
Thanks for sharing the detail on your experience with it...I wonder if the 18v Power Boost version has better clean boost capabilities? I was reading that David Gilmour pretty much just left one on all the time as a clean preamp/tone shaper. For me though, I would be more about the fuzz!  :)
Title: Re: Cherrybomb Same old splat
Post by: CRM-114 on March 04, 2019, 07:36:46 PM
I share your speculation.  I don't have an 18v source to try myself.  I'm glad I like the fuzz so much.
Title: Re: Cherrybomb Same old splat
Post by: madbean on March 04, 2019, 08:21:30 PM
I pulled a populated board out a couple days ago and I plan on taking another look at it. I'll let you know what I find. I've built several but it's been quite a while since I listened to any of them. Hopefully I'll have some insight to give soon.
Title: Re: Cherrybomb Same old splat
Post by: CRM-114 on March 08, 2019, 02:40:30 AM
That's very cool of you.  Like I said, I played a commercial pedal that had the same thing going on.  For now, I plan to enjoy it for what it is.