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DIY Stompboxes => Building your own stompbox => Topic started by: ethanw on March 06, 2007, 06:11:37 PM

Title: Bixonic Expandora-mods for more bass?
Post by: ethanw on March 06, 2007, 06:11:37 PM
Just got a 1st model expandora, I kinda like it. Needs some more bass though. Anyone figure out any mods? It looks like a modded rat and the Ruetz mod would probably work on the 47 ohm.  Wondering if a cap change would help, can't quite figure out where.  Schematic here:  http://www.geofex.com/FX_images/expandor.gif (http://www.geofex.com/FX_images/expandor.gif)

Thanks in advance-

Ethan
Title: Re: Bixonic Expandora-mods for more bass?
Post by: Meanderthal on March 06, 2007, 08:53:45 PM
 See that 0.022uf cap between the 2 LM308s? That appears to be the bass bottleneck. Changing it to .1uf should do the trick.

Title: Re: Bixonic Expandora-mods for more bass?
Post by: ethanw on March 07, 2007, 12:05:45 AM
Thanks for your help! I'll try it tomorrow and report back-

Ethan
Title: Re: Bixonic Expandora-mods for more bass?
Post by: WGTP on March 07, 2007, 09:40:28 AM
If that doesn't work, there is all kinds of tweaking that can be done to the 2.2/47 & 4.7/560 section for more bass.  I think one of the latter versions had a switch for more bass, but I don't know what is does.   :icon_cool:
Title: Re: Bixonic Expandora-mods for more bass?
Post by: ethanw on March 12, 2007, 02:56:16 PM
Damn! I can't get the Expandora apart. When I try to take the nut off of the footswitch the switch rotates slightly and started to crack! Then, it looks like you have to desolder the jacks to get the board out. I'll post if I figure out how to get this thing apart without breaking it. Thanks again for the good info-

Ethan
Title: Re: Bixonic Expandora-mods for more bass?
Post by: jonathan perez on March 12, 2007, 02:57:13 PM
desolder braid
Title: Re: Bixonic Expandora-mods for more bass?
Post by: Gus on March 12, 2007, 07:38:07 PM
Yes thats a fun effect to take apart.  Now this effect has a simple side chain MAYBE the rat section is fine but the sidechain is overcontrolling the photo fet.

  What I mean is the bass pickip level is more than a guitar, and you might have to adjust one or both parts of the circuit.