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'77 P-Bass pots/resistors?

boroman

boroman

Apr 27, 2009
374
149
boro
www.dustblow.com
#1
I have '77 P Bass. A-neck, a little flame maple neck, grey back pickups. Sound of this bass is very bright, edgy. I've tried to use heavier string to get more deep, standard, p-bass tone, but no effect.

I wonder what pots are inside (or resistors) of late 70s basses. If they are 500k should I change it to 250k for "standard p-bass tone"? I've had 2 japanese p-basses ('62RI and '70RI) and both had that P-punch. My '77 is like "punk rock machine" ;) comparing to these. I dont have problems with sustain or anything in this bass. Just too much HF and presence. Many of you will say, turn the treble down on the amp - but it does not do the trick.

Any ideas?
 
#2
Yeah, the original pups in my '76 are/were like that, too - there *should* be 250k pots in there, but changing them to 500k won't get you where you want to be... I ended up putting in a set of Seymour-Duncan SPB-1 pups - another good choice is Fender's Original '62 pups, although I preferred the SPB-1s because they sounded a tiny bit deeper and less bright than the '62s did...

Another option would be different strings...


- georgestrings
 
#3
All P's have 250k pots and a .50 cap, or should. I have three 70s P's and they're all a bit middy-to gnarly. I'm pretty sure that's a hallmark of that era of pickup. I'm sure some sound mellow though. My '73 is closest to old school. If I dial back the tone, it IS an improvement though. Flats would help, as would a pickup change.
 
#5
Thanks. As for the strings - are there any heavy gauge (lets say 50-110 or 55-110) with the high frequency rolled off a bit? I'm using Ernie Ball for years. D'Addario always were too bright. I dont like feeling of flats in my hands. So maybe there are half-rounds with the feeling of the rounds and sound a little like flats?
 
#7
Just curious, but what's the weight of your bass? I had a 1980 Precision that was very light and sounded pretty much like you describe - a very resonate 'airy' tone, but without the usual P bass thump.
 
#8
My P (unlike most of 70s heavy "anchor weight" basses I've played) is standard weight. Not very light like some custom shop, but rather standard. My luthier says that it might be also A-neck (like jazz bass) so it has more harmonics in the high frequency. Who knows

I've played a VERY light 73 P and it was full of bass and low definition.
 
#9
boroman said:
My P (unlike most of 70s heavy "anchor weight" basses I've played) is standard weight. Not very light like some custom shop, but rather standard. My luthier says that it might be also A-neck (like jazz bass) so it has more harmonics in the high frequency. Who knows

I've played a VERY light 73 P and it was full of bass and low definition.
Click to expand...

That's my pet theory about lightweight Fenders lacking low end right out the window then. :)
 
#11
FranF said:
All P's have 250k pots and a .50 cap, or should. I have three 70s P's and they're all a bit middy-to gnarly. I'm pretty sure that's a hallmark of that era of pickup. I'm sure some sound mellow though. My '73 is closest to old school. If I dial back the tone, it IS an improvement though. Flats would help, as would a pickup change.
Click to expand...

I am not happy with my 76 p-bass pichup either.. No warmth, very middy, so I am swapping it out..
 
#12
I can speak from experience that changing 500k pots to 250k pots will darken up your tone a little but, that isn't an option for you as you already have 250k pots. If you wanted to change the tone cap though, a higher value capacitor should allow you to roll off more high frequencies.

If I were in your position though I have qualms about modding a vintage bass. Maybe a new set of strings is in order.
If you like rounds but want them to be more mellow, maybe try pure nickel strings (nickel core + nickel wraps). I haven't tried them but people on here say they're good for a little bit of roundwound growl but aren't clanky and overly bright. I know fender makes a set and I think DR sunbeams might be pure nickel but don't quote me on it.
 
#13
boroman said:
The resistor is .05M 100V whatever it means.
Click to expand...

You mean capacitor ... (a small "brown disk"?)
.05µ means .05 MicroFarat = 50nF = 50 NanoFarath ...
It can deal with a voltage up to 100 Volts - which has no meaning in a bass electric.

Already Leo Fender used all capacitors he could get for a little money. The voltage or the preciseness didn't matter - and very different caps can be found ever since the Precision 51 ...

Some Precisions until 1965 hat .1µF caps instead ot .05µF. But the .05µF capacitor is THE cap for a P-Bass.
Jazz Basses changed the value from .05µF to .022µF in the 1970s - but Precisions didn't do.
 
#14
boroman said:
OK I've checked the pots, they are 250k CTS with 77 date so they're original. The resistor is .05M 100V whatever it means. So it might be the A-neck and the grey bobbins being so edgy here I think.
Click to expand...

They vary a bit bass to bass. I have two 78s - an A neck fretted and a B width fretless. The fretless has flats, but is overall less aggressive than the fretted. The fretted is by no means lacking in low end though. Tone all the way up and played aggressively yeah it's going to be pretty sharp, but normal finger style it's nice and deep. The numbers mean it's a 0.05 microfarad/100 volt capacitor - pretty standard, should be a little ceramic disc. I'd say maybe try some different pickups if you really don't like it, but I've found rolling the tone knob back slightly to really give my P a thunderous thump.
 
#16
I have '77 pups in my latest parts bass and the sound is anything but bright. (think warm and gooey) My '72 (with '72 pups) is the same. Both of these are fairly light (around 8 lbs) and have rosewood necks. I use TI flats so maybe that makes a difference.
Maybe it is the strings. Nickel will be warmer. At least that's been my limited experience. Since moving to the TI's I only have one bass left ('57 AVRI) with Fender nickels and they are definitely warmer that the "normal" Fender NPS strings and especially the stainless.
 

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