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Author Topic: I got my Mojo Working  (Read 2699 times)

Offline 908ssp

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I got my Mojo Working
« on: July 06, 2007, 11:47:28 PM »
Some of you will remember my comments on occasion about not being totally satisfied with the tone from my Mojo. I knew there was something I really liked about the guitar but I was running into this muddiness and it bothered me now and then. It didn't happen with my MKIIC+ or my SLO but it was bad with my Marshalls. I especially wanted that fat full Marshall tone but wasn't getting that. Any way I think I have the problem solved.

I replaced the volume pot with a 1meg or 1000k pot. I guess this is common knowledge that a higher ohm pot loads the pickups and the result is a brighter tone. I tried a 550k pot which was about a 100k higher then the one that came in the cherry Mojo. I had read recently that the JB pickup was designed for use in Fender guitars with 250k pot. The comments seemed counter to what I was experiencing most complaints were that the JB had a harsh top end and that using a 250 would help that. So against my better judgment I tried a 250k when I was doing the switch swap I wrote about in the equipment/setup section of the forum. And it didn't help me at all if anything it made things worse. So earlier today I swapped in a 1000k pot and it makes a noticeable and very pleasant difference. It isn't earth shaking the Mojo is still very warm and full sounding but now it sounds like there is some nice clarity to the top end. Like someone pulled the blanket off. What is really noticeable is the parallel setting on the bridge humbucker is really bright now where before it was very usable in place of the muddy series position. Now I prefer the series settings on the bridge. The neck pickup sounds way better too much more like a PAF or a hollow Jazz guitar where the tone is mellow warm but clear.

This is another easy swap easily reversible and cheap. You certainly can change pickups but that cost about 20 times as much as changing a single pot.

Alex

Alex

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I got my Mojo Working

Offline Paul Marossy

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I got my Mojo Working
« Reply #1 on: July 07, 2007, 06:55:11 AM »
Who says that the expensive, complicated route always has to the best one? [;)]

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I got my Mojo Working

Offline Bill

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I got my Mojo Working
« Reply #2 on: July 07, 2007, 08:34:00 AM »
Very cool discovery Alex. Thanks for sharring. [8D]

I wonder if Parker would be interested to hear that ?

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I got my Mojo Working

Offline Paul Marossy

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I got my Mojo Working
« Reply #3 on: July 07, 2007, 10:01:08 AM »
You know, you don't even have to replace the pot, if you have a large value pot to start with. You could simply wire a resistor of the appropriate size in parallel with the pot to reduce its value. I use that trick sometimes when a schematic calls for an odd value pot size.

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« Last Edit: July 07, 2007, 11:04:31 AM by Paul Marossy »

I got my Mojo Working

Offline Pavel

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I got my Mojo Working
« Reply #4 on: July 07, 2007, 10:42:20 AM »
to reduce. but not to raise.
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I got my Mojo Working

Offline Paul Marossy

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I got my Mojo Working
« Reply #5 on: July 07, 2007, 10:58:58 AM »
quote:
to reduce. but not to raise.


Correct. I was thinking the other way around, say a 1 megohm pot to a 500K or a 250K pot. Or even something in between. [8D]

EDIT: Could be one way to tone down a guitar that's just too bright for one's taste.

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« Last Edit: July 07, 2007, 11:38:07 AM by Paul Marossy »

I got my Mojo Working

Offline Lwinn171

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I got my Mojo Working
« Reply #6 on: July 07, 2007, 12:03:34 PM »
That's cool, Alex. I never realized the ohm of the pot made a noticeable difference in tone...


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I got my Mojo Working

Offline thedaver8

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I got my Mojo Working
« Reply #7 on: July 08, 2007, 04:40:02 PM »
this is a cool post.  so what comes in the Mojo normally?  500k pot?  i have a mojo and seem to have similar issues.  i think i'm going to change mine out as well
 

I got my Mojo Working

Offline 908ssp

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I got my Mojo Working
« Reply #8 on: July 08, 2007, 07:58:35 PM »
My stock measured 460k but was labeled 500k this is typical. There are lots tuned or super pots that measure 520k to 550k not really enough to hear a difference but enough to make sale.

Another thing I noticed that I like is the tone cleans up significantly with a 1/8 turn of the volume pot, it gets brighter as well as cleaner. Mind you this isn't a huge difference but enough if that's all you need. If it isn't I think different pickups is the only other option or maybe an on board pre-amp and active tone control.

[^]

Alex

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I got my Mojo Working

Offline Bill

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I got my Mojo Working
« Reply #9 on: July 08, 2007, 09:10:34 PM »
This begs the question,

Can you have a variable ohm pot? That is, why not rig it with an inner and outer wheel knob so as to produce a continuously variable ohm/volume knob? I am sure I am missing a key concept here or it would have been done or discussed, so forgive my ignorance in advance. [:I]

Custom '03 Hardtail Artist ; Fly Deluxe 2000; Gibson ES137(4sale); 1974 K.Yari DY85; SchecterDisposable; Martin Backpacker/paddle combo;VoxAD30VT;SWR California Blonde
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I got my Mojo Working

Offline Paul Marossy

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I got my Mojo Working
« Reply #10 on: July 08, 2007, 09:16:50 PM »
quote:
My stock measured 460k but was labeled 500k this is typical.


Yeah, pots usually have a 20% tolerance unless they are precision type pots.

 
quote:
Can you have a variable ohm pot? That is, why not rig it with an inner and outer wheel knob so as to produce a continuously variable ohm/volume knob?


Interesting idea. I would do it with a push-pull pot. That way you could switch a resistor in parallel with the pot. You could say have a 500K pot and pull the switch to get a 250K pot. That might come in handy when in single coil mode. I never liked the coil tapped single coil sound much. That's probably because a single coil pickup would normally be paired with a 250K volume pot...

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« Last Edit: July 08, 2007, 09:58:02 PM by Paul Marossy »

I got my Mojo Working

Offline Uroboric Forms

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I got my Mojo Working
« Reply #11 on: July 10, 2007, 02:17:24 PM »
Thanks! I may try this with mine. Great to know this