USA Epi hollowbody

[ramone57]

thanks very much for the explanation.  I may have to give this a shot on my ripper.  I rewired it like an LP but I'd like to coax a little more low end out of it.

[Granny Gremlin]

I have found that the lower resistance of the 250k pots enhances the lower frequencies and gives a fuller sound to the bass, IMHO of course.  The higher the resistance, the more you bleed of the low end output of the pickup.  I used four 500k pots on my recent NR repro TB and it sounds thin to me, so the 500k tone pots are coming out soon for 250s.

I first noticed it with a 72 Telecaster bass I rehabbed.  It has 1 meg pots and no low end at all!  It took all of the mud right out of that old humbucker pup.  So, that one will be redone with a 500k tone pot to bring back some of the missing lows.

This is backwards; lower Z bleeds more treble thru the tone cap (higher Z prevents these freqs from being bled off, giving the brighter sound - the illusion of less bass).  You are noting this effect in reverse - it's like how some people call the baritone switch a bass boost.  You are not adding bass buy doing this so much as taking away treble.  Leave the stock 500K pots and turn down the tone control for the same effect with less work/money spent on new pots.

Because of the value of the tone caps on basses, 'treble' that is bled off may include some mids as well.

A much cheaper and IMO worthwile way to mod your tone is to play with the value and quality of the tone cap.  Or no-load pots.

[drbassman]

Did I say it incorrectly but have the right idea? Here's a direct quote from the Stew-Mac site regarding this same idea:

Your tone is affected by the control pots you use. Not just the tone control — the volume pot influences tone, too.

250K vs. 500K pots
250K pots give a slightly warmer tone than 500K because the 250K bleeds off some of the high frequencies.

250K = warmer
500K = brighter
1 Meg = brightest

Usually, 250K pots are used with single-coil pickups and and 500Ks are used with humbuckers. If you want to hear your guitar "wide open" with all the highs, try 1 Meg pots.

Maybe they're incorrect?  I doubt it.

[drbassman]

On another note, I used Gibson pots on my 60's NR rehab, a 500k for the vol and 300k for the tone and it sounds spectacular.  It's become one of my favorites just on tone alone.

[Granny Gremlin]

They're right (though their use of the term 'warmer' is misleading though not untrue).  The point I'm making is that the amount of bass is constant.  All that changes is the amount of treble (and possibly some mids, depending on cap value).  Notice that that quote mentions bleeding off treble but not bleeding off bass - 250Ks are warmer, because they lack treble, not because 500Ks lack bass.

The exact same effect that you desire can be achieved by rolling off the tone knob vs changing the pots and keeping the tone at 10.  Just trying to save you some time and money and prevent people from thinking that pot values can reduce the amount of bass.

Then again, maybe you want a tone even bassier than that, and have not only switched the pot but also rolled the tone off all the way, in which case I'd recomend playing with cap values to change the rolloff point of the tone knob and make it more usefull for your purposes.  That's still cheaper than buying new pots, and will allow more versatility (you can have varrying degrees of that treble back should the need arise).

[Basvarken]

Well I think it also depends on what impedance your pickups are.

I had to change the pots on my modified JCS because they didn't match the Gibson Lo-Z pickup I put in.
I believe the JCS had 250 K Ohm pots installed. That didn't work with the Gibson Lo-Z pickup.
But now I have 2.5 K Ohms  (Yes that's correct: 2.5 K) like it says in the wiring diagrams from the Les Paul Bass / Triumph.
It wasn't easy to find them by the way...

So maybe the higher the impedance of your pickup, the higher the impedance of the pots should be?

[drbassman]

Doh, I reread my first post and I did type it incorrectly.  I did mean to say the highs were bled off with the lower resistance pots.  My thought was the lows are enhanced by the bleeding off of the highs as the resistance is reduced.  Same idea, just poorly expressed by me!!  To my ear, the bass end sounds better with the reduction of the highs, that's the end game. 

The problem I've had with tone control adjustments is the high end reduction seems more muddy and muffled when you just turn the tone knob down vs. using a lower z pot.  Maybe my ear, or brain is deceiving me, but I think the overall sound is better with the 250k tone pots.  I always use a .047 cap, so that is a constant in my wiring schemes.  I've also been trying the orange drops with some success rather than ceramics.

Thanks for the clarification!  I'll choose my words more carefully in the future!

[godofthunder]

 And Uwe compares me to Dr. Frankenstien LMFAO . Seriously great ideas on bass design.

[Lightyear]

.....  I always use a .047 cap, so that is a constant in my wiring schemes.  I've also been trying the orange drops with some success rather than ceramics. ....

+1 - I love the Orange drops - an excellent $2.00 investment!

[exiledarchangel]

Interesting topic. I've recently put togeather from a kit a pbass (please god save my soul) and decided to wire its pup straight to jack.
At first I thought that it had no bottom at all and too much treble (it sounded like a baritone guitard or something) but I think that putting some 250k pots just cuts treble and make you think that it has bass.
Is it possible or I am deaf?

That's her, I call 'er "Hope?":




Great project dude! 

[drbassman]

Very cool p bass.  They all need a little something to jazz them up!

My big dilemma with the Epi is what bridge should I use?  I could do a traditional 3-point, 2-point repro like I used on my 2 NR TBs, or a wooden affair with a chrome tailpiece.  Since I'm installing the neck, I can use anything I want since I'll control the height and neck angle.  What do you all think?

[Dave W]

No need to apologize for the P. Interesting paint job!

Truth is, many bass pickups are capable of lots of treble. Sometimes so much treble that it buries the bottom end by comparison. Finding the right combination of tone control and capacitor can make a huge difference. There's a good reason 250K and .047/.050uf or .1uf are commonly used with a P: it works, at least for many people.

[eb2]

That has a feedback block, no?  If so, you could stud anchor a Schaller 401, and do it up long scale.  Or a Kahler non-whammy.  Maybe even go Epi-traditional and mount 4 individual pieces on an elegant slant.  Or the new hipshot.  So many choices....

About the only thing I wouldn't do is an arch top bridge and tailpiece, like on that fancy pants ES-175 bass they did. 

[drbassman]

That has a feedback block, no?  If so, you could stud anchor a Schaller 401, and do it up long scale.  Or a Kahler non-whammy.  Maybe even go Epi-traditional and mount 4 individual pieces on an elegant slant.  Or the new hipshot.  So many choices....

About the only thing I wouldn't do is an arch top bridge and tailpiece, like on that fancy pants ES-175 bass they did. 

This has been driving me crazy because of the number of choices.  Does Schaller still make the 401?  I wasn't sure.  I have the tailpiece and wooden bridge on my EB-650 and it's kinds nice to have something so different than the 3-pointers I have on 6 or 7 of my other Gibson.

[chromium]

An Alembic-style bridge (or that 2pc Warwick) might look nice on there too.



Marko (MPU from the DP) built that one.