Blackstone Appliances OD a far more technical question I'm normally comfortable with.

**grygrx** · #1 11-23-2008, 11:44 AM

So, the Blackstone Appliances has two socketed capacitors that you can change:

Socket-mounted capacitor that limits output presence
Socket-mounted capacitor that tunes Red Channel bass at counter-clockwise setting

The first is a 331K (330 pico farads)
The second is 103J (10 nano farads)

I've emailed the builder to see what he would recommend as a 'starting point' for bass guitar. I'm curious what you tech-geeks think.

seanm · #2 11-23-2008, 12:01 PM

Can't really answer without knowing at least the circuit around the caps.

**grygrx** · #3 11-23-2008, 02:03 PM

I put together a video of what's going on inside this pedal and me finding a couple of caps I liked.

http://gallery.me.com/grygrx#100318

**grygrx** · #4 11-24-2008, 07:13 AM

bizity-bump

BassJunkie730 · #5 11-24-2008, 08:12 AM

I wathced the whole video.

Need a schematic or you have to flip that board over.

Until then all I can tell you is to get a pile of low voltage panasonic caps and have a ball - but you'd have to do it blindly and by ear.

any chance you can get us a still shot of the other side of the board?

**grygrx** · #6 11-24-2008, 08:15 AM

I can, but there is a section of the circuit that is fully enclosed and then mounted as a unit to the top of the board.

ZombiCrow · #7 11-24-2008, 08:29 AM

I was thinking about getting one of these, but now I know I need to. The audio from your vid leads me to believe it loses zero lows, and has a great range of sounds. What's it sound like going through an amp and cab? Also, your capacitor changes make ti sound better, to my ears.

bongomania · #8 11-24-2008, 09:07 AM

Quote:

Originally Posted by grygrx

Socket-mounted capacitor that limits output presence
Socket-mounted capacitor that tunes Red Channel bass at counter-clockwise setting

The first is a 331K (330 pico farads)
The second is 103J (10 nano farads)

Unfortunately it's like the other guys said- not enough info to go on. Further, "output presence" and "tunes bass" are not meaningful phrases in this context, without some sort of explanation of what he means.

All I can tell you is that those are both pretty small values- the first is extremely tiny, and the second is about average for the value of the input and output caps on a typical guitar overdrive/distortion pedal.

**grygrx** · #9 11-24-2008, 09:26 AM

Quote:

Originally Posted by bongomania

Unfortunately it's like the other guys said- not enough info to go on. Further, "output presence" and "tunes bass" are not meaningful phrases in this context, without some sort of explanation of what he means.

All I can tell you is that those are both pretty small values- the first is extremely tiny, and the second is about average for the value of the input and output caps on a typical guitar overdrive/distortion pedal.

I swapped the small one for a 102J and liked the change, anything larger started to cut the volume.

I swapped the 103J for a 104J and liked the overall bloom and warmth of the bass response a little better.

Talk about a tweaker's delight!

**grygrx** · #10 11-24-2008, 09:27 AM

Quote:

Originally Posted by ZombiCrow

I was thinking about getting one of these, but now I know I need to. The audio from your vid leads me to believe it loses zero lows, and has a great range of sounds. What's it sound like going through an amp and cab? Also, your capacitor changes make ti sound better, to my ears.

I think it sounds really good, though best into a clean amp.

BassJunkie730 · #11 11-24-2008, 03:27 PM

Quote:

Originally Posted by grygrx

I swapped the small one for a 102J and liked the change, anything larger started to cut the volume.

I swapped the 103J for a 104J and liked the overall bloom and warmth of the bass response a little better.

Talk about a tweaker's delight!

When you say cut the volume - I'm going to assume you mean overall volume?

changing the value of a cap the "limits output presence" sounds like a low pass filter placed on the whole circuit to me. AND if that is the case increasing the capacitance is not going to lessen the volume per se - but lessen the harmonic content like a passive tone control.

NEXT - the bass side cap sounds like it's just that - you are changing the size of the capacitor that is connected to the bass side wiper of the tone control. The bigger the better here - but beware - if you can't change the pot value you may end up with a pretty quick sweep - not bad if you favor a fully counter clock wise setting - but much harder to find a sweet spot in between.

There no free lunch in pedal design - more bass response generally means you have to lessen or change something else like more voltage in the pedal, lessen the gain, change the way components clip, change the frequency response of the unit, etc etc.

Sounds like you'll have to take me latter advice and get a pile of caps and have a ball.
Which can be loads of fun - especially since those components are socketted.