Mr. EQ Modification

jswingchun · February 19, 2008, 10:35:42 AM

I built the Mr. EQ from runoffgroove.com to use with my bass. It didn't really do what I was looking for on bass, though it worked pretty well on my kid's guitar.

ttp://www.runoffgroove.com/mreq.html

I would like to have it be A LOT LESS subtle of an effect. When I engage the pedal I would like it to sound like a boost combined with turning the tone knob on my bass down all the way down.

I'm still new enough at all of this that I can build from a layout, but I don't really have any idea what to do to modify something.

I would imagine there are some caps I could change out to make the treble cut more pronounced. I don't mind buying different caps to mess with and experimenting, but I don't even know which caps I would change.

I know I would like to have switch 1 on the pedal cut the highs.

Can somebody point me in the right direction?

newfish · February 19, 2008, 11:00:51 AM

Hi!

Simplest way to cut treble is to put bigger input and output caps in there.

Bigger input caps *should* also give you a bit more volume too - I think.

jswingchun · February 19, 2008, 11:37:21 AM

Quote from: newfish on February 19, 2008, 11:00:51 AM
Simplest way to cut treble is to put bigger input and output caps in there.

Thanks for the reply...

Hopefully nobody laughs out loud at this question, but...
Are the input and output caps the first cap after the input and the last cap before the output?

Could I do the same thing (basically) by switching the cap that is on the trace connected to switch one? It is labelled C5 on the layout and is a 680p cap. If that would work then I could make the cut switchable.

Or am I way off base here....

John Lyons · February 19, 2008, 11:46:49 AM

The Mr EQ circuit is for guitar frequencies so yeah, it will be subtle on bass.
Putting in larger input and output caps will let more bass through the circuit witch will help tailor it for bass.
I'd start with something like 1uf or higher,probably 10uf...

EDTI: Yes, the first and last caps are the in/out caps.
By the way...thse will not cut treble...they just allow more bass going in (larger caps) and more bass to go out.

The caps for the filtering sections will also have to be tailored for bass as well.
As far as which caps to change and to what values....I'll leave that for someone more familiar with the circuit.

John

jswingchun · February 19, 2008, 12:35:26 PM

Quote from: John Lyons on February 19, 2008, 11:46:49 AM
The Mr EQ circuit is for guitar frequencies so yeah, it will be subtle on bass.
Putting in larger input and output caps will let more bass through the circuit witch will help tailor it for bass.
I'd start with something like 1uf or higher,probably 10uf...

EDTI: Yes, the first and last caps are the in/out caps.
By the way...thse will not cut treble...they just allow more bass going in (larger caps) and more bass to go out.

The caps for the filtering sections will also have to be tailored for bass as well.
As far as which caps to change and to what values....I'll leave that for someone more familiar with the circuit.

Thanks....
There really isn't a shortage of lows going thru the effect, but I may change out the in/out caps anyway.

According to runoffgroove, the circuit is designed for both bass and guitar:

<The LO peaks works well for adding more bass to a guitar or bass. The MID peak functions as a relative treble peak for a bass guitar, like the rare Yellow Humper. As expected, the HI peak adds a crisp sheen to a guitar (but has no effect on a bass).>

Hopefully someone else chimes in with some ideas of what I can change. I think I will drop runoffgroove and email as well.

thanks again....

DDD · February 19, 2008, 01:45:31 PM

jswingchun,
what about the idea to ask guys from ROG to adopt their Mr. Eq for bass. I do really like Mr. Eq schematic and hope there are a lot of people who like it, too. Let's ask together?

jswingchun · February 19, 2008, 02:27:56 PM

Quote from: DDD on February 19, 2008, 01:45:31 PM
jswingchun,
what about the idea to ask guys from ROG to adopt their Mr. Eq for bass. I do really like Mr. Eq schematic and hope there are a lot of people who like it, too. Let's ask together?

Like I said before, it already is designed for bass. It was just more subtle that what I was looking for. I have an email in to ROG asking about what I could change to make it more of what I am looking for. If I hear anything I will post it.

If anyone has any ideas, let me know.

I probably should have built a tone control circuit and a clean boost circuit into one pedal. That probably would have been a better solution for me.

John Lyons · February 20, 2008, 09:08:54 AM

Youo might find this interesting. Scroll down...

http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=ja_en&url=http%3A%2F%2Fhomepage3.nifty.com%2Fichian%2Fanalog%2Fspectrum%2Fboost_freq3.htm

John

jswingchun · February 20, 2008, 12:34:04 PM

Quote from: John Lyons on February 20, 2008, 09:08:54 AM
Youo might find this interesting. Scroll down...

http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=ja_en&url=http%3A%2F%2Fhomepage3.nifty.com%2Fichian%2Fanalog%2Fspectrum%2Fboost_freq3.htm

I will have to check this out when I get home. Our internet security here at work won't let me view the site for some reason.

News:

Mr. EQ Modification