Just got a T-40: Some questions...

Hi, all. When I started playing bass 20+ years ago, I played on a school-owned Peavey, and thought it would be fun to have one in my arsenal again. When I was researching to find out the model I used to play, I learned about the T-40. Sounded so good, I bought one off Ebay! $309 including delivery. But I have some questions, and I am hoping for some feedback as I embark on the world of the T-40.

(1) The Serial Number is 211270, which seems to be missing some numbers. The headstock says "Patents Applied For," which I believe means it is an early one. Can anyone tell me the age of my bass?

(2) The bridge pickup is not working! Can it be that the pickup is no good? Or is there (hopefully) a simpler explanation? I fiddled with all the knobs and got nothing. If it is the pickup, are replacements available?

(3) The phase switch appears to be a replacement. It looks different than the pickup selector (like a bat intead of a paddle). Also, it is three-way switch, and I thought the phase switch was only one way. Not original, right? Will it affect playability?

(4) Two of the screw heads that hold the tuners to the headstock are different sizes than the other two screwheads. I assume these are replacements, but thought I would ask...

Sorry for all the quesitons. I am excited, but want to get to the bottom of the pickup and phase switch issues before I get too far into the bass. Thanks for reading!

First off, welcome to the show and congrats on picking up your first T-40.

(1) There were indeed a few six digit serial numbered T-40s and T-60s early on. Chip Todd (designer of the T-40 and T-60) has stated that he doesn't remember if the six digit ones came before or after the 8M serial numbered ones. But he has stated that there cannot be very many of either category because they went to eight digit serial numbers rather quickly. That being said yours would be 1978. Congrats on finding such an early model. I have been collecting T-series serial numbers for several years and have only found 21 (22 counting yours). 12 of these are T-40s and 10 are T-60s. For comparison I have found 55 8M serialized T-40s and T-60s.


(2) I'm afraid I can't offer much help on the electronics side. I've got a load of projects sitting on my workbench that I haven't even started. I've got to learn how to do this stuff myself. There aren't any replacement pickups available per se. You can find toaster and blade pickups on eBay from time to time. Some members here have replaced their T-pickups with Darkstar pickups.


(3) Your phase switch does sound like a replacement. A six-digit T-40 with the PAF headstock decal should have the small flat switches. The phase switch should be a two-way, but a three-way in that position won't affect playability. My number one go to T-60 has a three-way in the phase position. While the phase function doesn't work (which doesn't bother me) it does act as a kill switch.

(4) Correct. All screws on the rear of the headstock should be the same size.

Thanks for your fast reply, Tony. I am pretty disappointed by the failed pickup - wish the seller had disclosed that.... But if the six digit serial number is a rare creature, maybe it's worth putting more dough in it to repair. I hope it's an easy fix!

I will check back in and post what I find out.

Thanks, again!

Double A wrote:

Hi, all. When I started playing bass 20+ years ago, I played on a school-owned Peavey, and thought it would be fun to have one in my arsenal again. When I was researching to find out the model I used to play, I learned about the T-40. Sounded so good, I bought one off Ebay! $309 including delivery. But I have some questions, and I am hoping for some feedback as I embark on the world of the T-40.

(1) The Serial Number is 211270, which seems to be missing some numbers. The headstock says "Patents Applied For," which I believe means it is an early one. Can anyone tell me the age of my bass?

(2) The bridge pickup is not working! Can it be that the pickup is no good? Or is there (hopefully) a simpler explanation? I fiddled with all the knobs and got nothing. If it is the pickup, are replacements available?

(3) The phase switch appears to be a replacement. It looks different than the pickup selector (like a bat intead of a paddle). Also, it is three-way switch, and I thought the phase switch was only one way. Not original, right? Will it affect playability?

(4) Two of the screw heads that hold the tuners to the headstock are different sizes than the other two screwheads. I assume these are replacements, but thought I would ask...

Sorry for all the quesitons. I am excited, but want to get to the bottom of the pickup and phase switch issues before I get too far into the bass. Thanks for reading!

I had problems with a pickup as well, and similarly to your issue, my phase switch was broken, I did put some new caps in it as I didn't have a way to test the old ones, and put a new switch in, but that cured the problem. even if you re-cap it and put a new switch in its going to cost a paltry $2 or so :-)
I am not sure (I'd like to think yes) if there is a wiring diagram on here, if not I have one I could post.
Good luck!

If you can't find the wiring diagram on here, PM your email address to me and I'll send it to you. I'll even toss in the Peavey bass setup sheet.

PM Sent. I bought a two way switch for the Phase. I found on another string which one to get from Radio Shack. Does anyone know what type of switch to get for the Pickup Selector? Might as well get a new one of those, too, if I am going to re-wire.


Then, off to someone who knows what they heck they are doing - Every time I touch a soldering iron, disaster strikes.

Double A wrote:

. Does anyone know what type of switch to get for the Pickup Selector? Might as well get a new one of those, too, if I am going to re-wire.

DP3T or commonly known as a 3 position/center off

Double A wrote:

Then, off to someone who knows what they heck they are doing - Every time I touch a soldering iron, disaster strikes.

It's not a terrible process really...When Frank shoots you a copy of the diagram you'll see its not bad

Double A wrote:

Hi, all. When I started playing bass 20+ years ago, I played on a school-owned Peavey, and thought it would be fun to have one in my arsenal again. When I was researching to find out the model I used to play, I learned about the T-40. Sounded so good, I bought one off Ebay! $309 including delivery. But I have some questions, and I am hoping for some feedback as I embark on the world of the T-40.

(1) The Serial Number is 211270, which seems to be missing some numbers. The headstock says "Patents Applied For," which I believe means it is an early one. Can anyone tell me the age of my bass?

(2) The bridge pickup is not working! Can it be that the pickup is no good? Or is there (hopefully) a simpler explanation? I fiddled with all the knobs and got nothing. If it is the pickup, are replacements available?

(3) The phase switch appears to be a replacement. It looks different than the pickup selector (like a bat intead of a paddle). Also, it is three-way switch, and I thought the phase switch was only one way. Not original, right? Will it affect playability?

(4) Two of the screw heads that hold the tuners to the headstock are different sizes than the other two screwheads. I assume these are replacements, but thought I would ask...

Sorry for all the quesitons. I am excited, but want to get to the bottom of the pickup and phase switch issues before I get too far into the bass. Thanks for reading!

Hi. Welcome to all things T-40.
Your bass and one I have must almost be cousins!!
My serial is 211150 and the pots are dated '77.
If you look at the post Possible parting with an old friend,
you will see that Tony has explained the relevance of
the six digit numbers.
I am in the UK and have a whole pile of "T"'s - if you PM
(private message) me with your e.mail address, I will
help you out as much as I can.

All the best.
Flat Eric.

PM Sent. I just got back from the shop. The pick-up works, it's just that whoever installed the 3 position switch for the phase switch installed it incorrectly. So- easy fix. Sweet!

The guy who runs the shop is familiar with the T-40. He said that he has changed the wiring on T-40s before by making the phase switch able to switch between humbucker and single coil, and changing the tone knobs to adjust the tone when the pick-ups are acting in either capacity.

He explained to me that I would not likely use the phase switch, and that the way the bass is normally wired, the tone knobs don't work in single coil mode.

I guess the only drawback is that I can't run one pickup as single coil and the other pickup as humbucker. But in reality, I can't imagine ever doing that...

Hi. Got your PM, I will be in touch.

I have had basses that have been wired that way but I have put them
back to std, to keep originality and to keep the huge amount of variation
you can get with the controls.
You can use the phase switch to get a whole load of other sounds.
If you put the pups out of phase and then back of one or other of
the volumes, you get get some really interesting stuff.
In truth, all these variations are great for recording and developing
"your sound" but in reallity, live - I set it to the way I like it and then
leave it. There is only me and the guitarist (with drummer and vocals)
and to keep the whole plot going, I don't have time to mess around
in front of an audience.
I'm glad you have the pup sorted.
I will drop you a line.

All the best.
Flat Eric.

Got the bass from the shop yesterday. Plays sweet. I put Rotosound flatwounds on it (77's). I love those strings because they are smooth/mellow enough for the music I play, while still having some bite.

I put a thumb rest between the two pickups. I always anchor my thub somewhere, and choosing between the front and back pickup on most two pickup basses is not entirely comfortable. Purists may object to adding screw holes in the pickguard, but the pickguard was really scratched up and warped anyway. Plus, I bought this thing to play and I need to be comfortable.

I am on a band break right now, but will start playing gigs again next month. Can't wait to play this baby live!

I may have missed any correction, but whatever, the selector swith has to be a 3-position, ON-ON-ON switch to achieve both pickups on and also have them each separately.
Chip