unclej

some of you may recall that i needed a canned cap for the ampeg geminii that i've been overhauling. i spent a bunch of time on line and never could find exactly what i needed. when i finally got around to checking out zack engineering www.vibroworld.com i found that they will custom make you what you need. it was a bit pricey and it took a while but it came in today and looked and worked great. so add that to what i've now discovered is a continually growing list of suppliers.

nope. for regular wiring of a dimarzio humbucker you tie the black and white together and insulate. red goes to hot and green to ground.

it sounds to me like when you were installing the toggle the ground wire from your tailpiece broke loose. look for the wire comming out of the left side of the control cavity from the tailpiece and make sure it's soldered to ground.

mahogany, poplar and alder are all pretty good guitar woods that are fairly easy to work with. they make a "normal" weight guitar as opposed to some of the mesquite and walnut ones that i make that are pretty heavy. i can't tell which way you're considering gluing up your three layer pattern. if you're stacking three pieces from back to front that's a fairly easy glue up. if you're gluing three pices left to right you need to have or have access to an edge joiner and a good flat gluing table. since this is your first guitar you might consider making it out of one solid piece of wood. especially if it's going to have "weak spots". anyway, there's my two cents. good luck.

thanks, this gives me a direction to work. it's solid state so with the shorting problem it could very well be bad diodes. i appreciate it.

a buddy brought me an old leslie amp/speaker combo to change out the input connector so that he could play guitar through it. when i first plugged it in the fuse was blown. the next one blew also. so i pulled the chassis and started checking for shorts. what i found was that the center tap and the two red high voltage wires from the power transformer were going to ground. i checked a tube amp that i know is working and those wires don't go to ground. would this indicate a bad transformer or bad components?

that sneaky rascal probably got the idea from you..you'd think he'd be descent enough to give you credit.

ditto on the allparts pots. i've never gotten a bad one from them.

thanks steve. actually i was using a chop stick per gerald weber's suggestion in one of his videos. i watched it again last night and had missed one statement that some harmonic in that area is normal and nothing to worry about. and lk, as usual you're right on. one of the 12ax7's was very microphonic and when i replaced it there was a reduction though not total elimination from the components on the tag board.

before i put the alamo back into it's cabinet the other day i discovered something that's got me curious. the amp was powered up and connected to a speaker. i was gently tapping around on all of the components, wire connections, tube pins, etc. looking for any loose connections. when i got to the bass channel i was tapping on the lugs of the pots and when i tapped one of the wires leading into/out of the pot it made a noise. it wasn't an electrical popping like a loose connection. it was a harmonic noise heard through the speaker each time i did it. the wire led to a small tag board. each of the pots had a wire going to it and connecting to a couple of resistors and a capacitor each and then going on to a tube. most, but not all of the components on the tag board did the same thing when i tapped them. a hollow, harmonic noise heard through the speaker. the bass channel sounds fine when a guitar is played through it. there's no excessinve humming. so what could cause such a thing and is it something i need to correct?

or should i just say that this is the last that you'll hear of it. i put in all new filter caps today, installed a grounded cord, bypassed the polarity switch which was cracked anyway, cleaned the pots, installed the new output tubes and a new rectifier tube, hooked it up to that honkin' big 15" speaker in the ampeg cabinet and after a suitable warm up period i plugged in my '72 silvertone 335 copy and cranked out some of my best chops and grinned like a possum eatin' grits. it sounds absolutely great!! and once again i want to thank all of you who have helped with info and links and guidance and all that. i hope the questions will dwindle a bit or at least be more intelligent from here on. happy new year to you all. unclej

thanks, i'll do just that. this is as close a match as i've been able to find anywhere and i'd like to get this thing finished so i can quit boring you guys with it.

i need to replace this can capacitor on the ampeg i've been working on. the one in it is a 40/40/40mfd 500vdc. vibroworld makes one to fit ampegs that is a 40/40/40 x 475vdc. will it work or burn out quickly? in lieu of that can i wire in three single 40mfd x 500v electrolytics by taking all of the neg. leads to ground and attaching the hot wires in the same configuration that came off of the can?

thanks...and thanks for the link. by the way, i'm replacing the electrolytics in the ampeg that i've been working on and that should get it out the door. i really appreciate all of the help you guys have been.

the last couple of days i've been learning all i can about speakers. i've got my brain pretty well wrapped around impedence. i understand peak, peak to peak and rms. but when you're working on an amp without the factory specs (my alamo) how do you calculate real output so that you can choose a proper speaker. the chassis says 110 watts. would that be the actual effective output or not?

oh boy...FOOD FIGHT!!!

ooops..ok, nevermind

i'm replacing all of the caps in the alamo bass amp that i've been working on. one of the power tubes has a big ole honkin' wire wound that has no markings on it at all. without the schematic (which i still haven't found) how would you know what to replace it with?

great! thanks drak..the tubes actually came in today so i'm anxious to see if it works.

within the next couple of days i should be receiving the power tubes for the alamo bass amp head that i'm restoring. i'm going to have to build a speaker cabinet for it and need a question answered before i start. when all you have is the amp's output rating, in this case 110watts, how do you determine the speaker needs. calculating the total impedence of two to four speakers and the parallel or series or combination wiring is pretty straightforward math but how do determine the total impedence that your shooting for. i re-read all of the speaker sections in all of the books that i purchased and none of them address this question. i've found precious little info on the amp itself and none on the speakers used. thanks

i buy and sell old band instruments occasionally and the ones that have been in granny's attic for a hundred years or so always smell musty..the product fabreeze has always worked. just open your case, spray all over and let it do it's work. assuming that you're in the u.s. you should be able to find it at any grocery store.

thanks guys..actually they're inside the can so i don't know if they're axial or not but i just ordered three individual axials from mouser and will just mount them to the chasis..so you can now let this thread die with dignity and grace.

i've determined that one of the three caps in my mallory type fp can cap is bad..i have spent literally two hours on the net trying to find a replacement and can't. i remember when i brought this up a couple of weeks ago some of you said that you just substituted chasis mount caps. so here's the deal.. this is a 40,40,40mfd 500v can. i've found several 50,50mfd 500v but none with three. i'm assuming that it's better to replace all three as opposed to just adding one to replace the bad one. so what's the most practical way of replacing these rascals?

thank you sir..

thanks..in general i'm just learning how to troubleshoot and repair tube amps..specifically i'm working on an ampeg geminii II. the slightly frustrating thing about all of the books that i've read so far is that they assume that i have knowledge that i don't. so when i book tells me to check that B+voltage it would be great if they had a picture of the specific place that i'm supposed to check..but they don't. i've ordered some videos and i'm hoping that they'll unravel some of the mystery. by the way, the same books gives a step by step process of checking voltage on plates and screen grids but don't say whether the tubes should be in place or removed. which would it be? thanks