Modding a compressor for Bass

[toddvirgil]

So my friend plays bass and asked me to build her a compressor. Do I need to do anything to the circuit to make it Bass-friendly? I was thinking about building a Keeley 4 knob, but maybe there's a better one for Bass? Or maybe it doesn't matter?

Thanks!

T

[toddvirgil]

No bass players out there? Surely someone knows what to do to mod these compressors?

[Yehudi]

I made a 4 knob keeley comp. Even on guitar turned out a bit too bright for me (maybe for all the tantalum in it!!). So I'll be modding it, and since I too play bass I can have a go on some changes and post it back for you, but I recon it will be manly a matter of changing input and output cap values.

[toddvirgil]

Thanks Yehudi!

[Yehudi]

So... On my K4knob I have one more tantalum than the original, don't know if that's adding some brightness to the signal  (from what I know, tantalum's do brighten things up a bit).
On my first try I changed the Input cap from 10n to 47n and the output from 47n to 100n.
This did improve the body loss I've noticed the first time... so I'm considering taking it further and going with 100n at input and 220n on output (theese are actually values I read somewhere as working good in this build when you're a bass player). Post more news whenever possible! cheers    

[Silver Blues]

I recently built an Engineer's Thumb. Installed a wrong component so it didn't compress but it passed signal fine, and I noticed zero low end loss. My only mod was to replace the 10nF input cap with a 47. You could also replace the output cap with something bigger (if it's a simple volume pot preceded by a capacitor my go-to value is 10uF because it ensures you lose NOTHING. It's cutoff is somewhere like 0.5Hz with a 100K resistor. If the circuit uses stage coupling caps it might be worth it to increase those too.

[johnk]

the Keeley four knob makes a great bass compressor if you change the input cap to a 390n and the output cap to a 1u. it will have zero low end loss that way. I built one for my bass and I love it. the diamond bass compressor is also another great comp for bass.

here's a pic of mine:

[Ross]

The stock Keeley compressor is pretty decent on bass, but I find it tends to suck both lows and highs out, especially on higher level settings. Do you notice any high-end loss with your mods?

[johnk]

nope. no top end loss at all.

[toddvirgil]

Thanks Johnk, this is perfect!

[toddvirgil]

Hey John -- Ok, dumbass noob question -- How do I know which is the input cap and output cap? The Input seems obvious since there's one right on the same strip -- but how do I tell which one is the output cap?

Thanks!

[johnk]

the input cap is the first one from the input jack going into the fisrt gain stage. the output coupling cap is the one usually going to lug 3 of the output volume control.

[toddvirgil]

Hey John -- Sorry, I've never really spent anytime trying to analyze the layout itself (now's as good as any time to start though, right?) -- so am I correct here with the two that I've circled?

[johnk]

yep.

[toddvirgil]

Thanks man :)

[johnk]

On 6/30/2013 2:48 PM, toddvirgil [via Guitar FX Layouts] wrote:

Thanks man :)

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