loos

Although my ground wiring looked OK when I added an additional wire grounded to the common grounds on the back of the tone pot the hum went away. I'm still not getting the sound I wanted but now this project is going to have to wait for other projects to finish. Thanks all for your replies, they have been both helpful and encouraging. Loos

I disconnected where the coil end was grounded, put shrink tubing over the bare bit of wire, added a dedicated ground wire and this did not seem to do what I want, the other PU worked, the P-90 didn't. So I reversed the position of the leads on the switch end and although now the setup worked there was so very much hum it was unusable. Strangely when I touched the bridge the hum was worse. So when I get a bit of time again I'll try replacing the wires and try again. The joys of debugging, alive and well. Loos

I'd imagined that would be the solution but really don't like to cut wires on a gut feeling. Thanks for the feedback, (ho ho) it is good to have your response. I'll do the backplate ground and see how it works. I ought to have results soon and will post then.

I’m hoping someone can help me out with an electrical problem. I have an aftermarket Tele style guitar with a stock Telecaster PU in the bridge and a P-90 in the neck. I’ve been playing it with a standard three way switch but was intrigued by the idea of using a four way switch for the additional tonal possibilities. So I set it up following a diagram but it didn’t work out as I remember so I went back to the three way switch and all was well. I see now, looking at the wiring diagram that there is mention of having to remove the cover ground when using a stock Telecaster neck PU and grounding the cover separately. Of course the P-90 does not have a metal cover so I had just wired it using the two wires, white and black which emerged in the control cavity. This time I decided to remove the P-90 from the body and look more closely at it and I’ve found that there appear to be three wires, one of which is soldered to the bronze plate at the bottom of the P-90 which also has soldered to it the black wire from the coil end. The white wire from the coil travels separately to the control cavity. So I’m wondering if I ought, to make things work, to replace the ground wire attached to the brass plate with another ground wire to the cavity and run the black wire from the coil directly to the cavity. Hopefully this isn’t too awfully poorly worded to make out. I’ll appreciate any advice concerning Tele four way switch wiring using a P-90 in the neck. Loos

Very likely I could have chosen that stacked potentiometer. I didn't think I had enough depth in the Melody Maker cavity and so I chose to use a six position Free-way switch which will give me in addition to the standard three choices: bridge, bridge and neck, neck I'll have the pickups in series, parallel out of phase and pickups in parallel. The Free-way switch is only ~9.5mm deep. I'm putting this on a new pickguard with 4 wire mini humbuckers, one volume pot and one tone so I will be able to change back easily if I don't like the result.

I’m writing again about my Melody Maker. It is a 1965 two pickup model and has three knobs, two volume and one tone. The original pickups have been replaced with mini humbuckers. I find that one of the two volume knobs is really in my way, especially when fingerpicking and I'd like to convert it to a two knob setup. I’ve been playing a Telecaster and don’t have a problem with it’s two knob three position switch setup so I’m thinking that this would make for a more playable guitar for me. Slightly less versatile I know but I would rather not try to learn to keep my hand off that third knob. The Melody Maker body is so dogonne thin I can’t put a push pull pot on it and there just isn’t a whole lot of room on the pickguard. So I’m wondering if anyone here can give me a reason to keep things as they are. Is there anything aside from having to adjust volume and tone when switching between bridge and neck pickups? I can see that I’ll loose the ability to adjust the tonal balance in the middle switch position and wish there was another solution but i can’t see that there is one. Again, advice much appreciated, Loos

Thanks for the replies. I certainly would like to have a drill press but anything with sufficient clearance is too big for my tiny work area. So I guess the C clamp will have to do for the time being.

I’ve a question concerning press in bridge posts. Recently I bought a 1965 Gibson Melody Maker. It was the model with two pickups and the not missed but missing Vibrola tremolo that Gibson put on those student guitars. The holes where the Vibrola were empty, there was a groove across the body where the tremolo rested. The pickups had been replaced with mini humbuckers, the tuners had been replaced. The wraparound bridge had been replaced by a Tune-o-matic clone and a stop tailpiece had been added. The original wraparound stud bushing holes had been plugged and doweled. These changes had been done by the shop where I bought the guitar and goodness, what sloppy work. The dowels were a poor match for color and grain and worse, one of the dowels was chipped on the top so it couldn’t be flush with the body. The pick guard screws were falling out, the tuner screws also were installed in oversized holes and had zero grip. I totally loved the tone and feel of the guitar so I bought it despite the problems, brought it home and set about doing the minimum, plugging all of the oversize holes, re-drilling and reinstalling the pick guard and tuners. I replaced the just good enough Tune-o-matic and stop tailpiece. The tuners are Gotoh 3-on-a-plate and good enough and I guess a match for what came off. At least the dents appear to be in the original places. So that’s the background but I found that the tailpiece and bridge bushings were finger press fits and since I believe that a lot of tone comes from the transfer from string energy to the guitar body I firmed up the holes with a few coats of glue. When it came to replacing the studs they no longer were finger pressable so after a lot of wondering how the heck I would get them back in place I ended up using a deep throated C clamp which worked but left me wondering what others use for press fittings if they don’t have either a press or a drill press. The C clamp worked OK but it wasn’t easy to keep everything square. If I decide I really really like the guitar at some point I will want to do a better job of doweling and install the tune-o-matic studs directly in the wood, again for better vibration transfer, better tone. I’d love some constructive comment on any aspect of this. Thanks, Loos

I don't understand "death cap" except when it's a mushroom. Then I just know not to eat it. I'll look into replacing the power supply capacitors, I've a friend who can help me identify them and I can solder reasonably well. I do have hum. There is a grounded cord on the amp. When I got it the tremolo didn't work so a local tube amp specialist Skip Simmons, went over it, restored the tremolo and added the grounded cord.

I'm still trying to figure out the photograph posting routine. I've been asked for pictures of my Massy "The Vibe" amp. I've gotten the pictures down to the 640X480 limit although I doubt if they will be useful for more than a general impression. Do I just cut and paste? I presume that jpg is format of choice. I've been going over and over this looking for a photo tool but haven't found it and, as you can tell from my portrait I'm slow.

Gasp! It would appear that I've been completely mistaken, somehow I got my drawing with one end duplicated, I guess it was not really taking the amp apart but having taken another set of pictures I see that it's not so unusual and strange in reality. Two 12AX7 tubes, a 6V6 and a EZ81. The second 12AX7 is different looking from the first. I gather one does the tremolo and the other is preamp. Funny how reality is less strange than delusion. Still happy to post once I figure that part out. I guess the first step will be to donate.

I'll have the pictures tomorrow. I just don't see how to post. I guess it's time to donate!

Well of course the pictures are on my computer at home and I'm out of town till the weekend. Also I don't see how to post pictures on the site. If I can figure it out I'll send them Friday afternoon.

I guess I'll find out by buying a 12AX7 and trying it. I know sooner or later I'll need tubes and it seems like I may as well be prepared. The amp has quite a nice vibrato so I was surprised not to find two 12AX7 tubes but two 6CA4/EZ81 tubes instead. From what I can tell the 6CA4 rectifies current but what I know about amplifier design is about what an echo knows about language.

Thanks for the help. It would appear that the pictures at your link aren't of the same amp although many features are in common. Mine however has only one 6V6GT and two 6CA4/EZ81 tubes. I can read the text on those. There is only one other tube and that is the one which has lost its text. I don't see how to attach photos here but I have four small ones which show different tube layout, a similar face plate with some different labels. I can only guess that some of these were either made differently or were modified by their owners over the years. The St George marque is missing from my amp, perhaps it was built by Teisco...