#1
Well I've been modding my Valve Jr. a lot lately and I added a master volume but I didn't want to drill a hole through it's original chassis. As I was trying to think of a way to get around drilling it I saw Cathbard's cookie tin amp thread and though hmmm that would be perfect. So here I am.



And its going in this tin, which I'm going to repaint.


My wiring and everything isn't going to be anywhere near as pretty as Cathbard's this is going to be more of a function over form thing. Also a question for Cath or anyone that can anwer it should I be worried about the tubes sticking up and being so exposed? I've seen some amps that have the metal bars, are those important or just an extra safety measure?
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
Last edited by grungebaby at Jul 17, 2011,
#2
The tube guards are just a bit of extra protection for the tubes when they're exposed. It's really up to you if you think you'll need them. If the amp is going to get moved around a lot it might be worth getting them.
#3
OK, here's some tips.
1. Reinforce the tin anywhere that it gets jerked around - tube sockets, phono sockets, switches, etc.
2. Mount as much as you can to the lid. Find room on the lid for the circuit board, even if you have to mount it vertically. Trying to run wires between the lid and the body is a pita. The more you can have mounted to the lid the better.
3. I used shielded twisted pair for runs between the sockets and knobs to the lid.
4. You only need to worry about the tubes if you are moving it around a lot and really, with this type of amp it's not really that wise. It's a "have on display" sort of thing.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#4
Alright thanks, I'm not worried about moving it around too much because this is about to become my stay at home practice amp. I didn't reinforce because I'm already undersupplied as is, I don't have a dremel or tin snips or anything good to really cut it with. but I've mounted everything but the input and 2 volumes on the lid, my tin is a lot bigger than what you've used. Also what do you use to cut through the tin?
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#5
Well I clamped the aluminium to the tin first then drilled it with a holesaw. Unfortunately 2mm aluminium was too thick for my nibbler. For the big hole for the transformer I used a jigsaw with a hacksaw blade then finished it off with files. The hole for the IEC power socket was the hardest part because it is an odd shape. I used a holesaw and a file. All the other holes are round so I just used holesaws.
On the Tim Tam amp I didn't reinforce it (which is a mistake) and made the cuts using a Dremmel with a diamond cutting wheel and my nibbler for the square holes. The round holes were again, a holesaw. Don't forget to put a piece of wood behind it when drilling.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
Last edited by Cathbard at Jul 18, 2011,
#7
Well I got most of the wiring done, before I finish it and try it to see if I messed anything up I'm getting something to eat. and then I'll finish everything and post the finished pics.
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
Last edited by grungebaby at Jul 18, 2011,
#9
I'm not sure, but I don't have anything in contact with it if you think it will be shorting something out, as messy as it looks I made sure nothing stupid like that happened because I REALLY don't want to have to redo that again
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#11
Well I've got that so its not going to short, I had it in the old chassis too. Thanks for the heads up though.

And as for the pics:


As I said before function over form. But I just tried it out and nothing, no sound but what fun would it be if it worked on the first shot? So I'm going to sleep then figure out whats wrong with it tomorrow err later today I guess.
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#12
Well I've got that so its not going to short, I had it in the old chassis too. Thanks for the heads up though.

And as for the pics:


As I said before function over form. But I just tried it out and nothing, no sound but what fun would it be if it worked on the first shot? So I'm going to sleep then figure out whats wrong with it tomorrow err later today I guess.
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#13
Get yourself a chassis mount capacitor like the ones sticking out the top of my JD amp - much easier.

Goodluck, man. Hope it works.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#14
Thanks, I could probably use some help now though. It seems that I took a huge step back from where I was last night, the light would come on and the tubes would glow but no sound and now the lights not even coming on. I did sort of break the power switch when I was pulling connectors off, one of the tabs came out of the switch, so I'll check that first, but what else could be a likely culprit?
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#15
UPDATE: I tried taking the switch out and that it was on as soon as I plugged it in and still no dice, tubes did not light up at all. My master volume came disconnected but that shouldn't keep both pre and power tubes from lighting up should it?

I'm really hoping I didn't damage one of my transformers, is there any way of checking them?
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#16
check all your voltages at the rectifier.

if the tubes aren't lighting up there's an issue with your heater circuit.

if the switch lights up then your ac fuse is fine.
Prs se Holcomb is the answer
#17
Alight my switch doesn't light up, I'm trying to get to the fuse now, what would be a common reason for it blowing?

Edit: The fuse is still intact. I'll test the switch and make sure its actually working.
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
Last edited by grungebaby at Jul 19, 2011,
#18
Most common reason is that you've shorted something out. Maybe the positive lead of that capacitor is touching the tin?
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#19
Well the fuse is intact. The switch is fine too.
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
Last edited by grungebaby at Jul 19, 2011,
#20
Double and triple check all your wiring. Once you're satisfied everything is going where it should, start measuring your voltages.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#21
Well I had been getting away without a multimeter until now, was that a bad idea? and I'll try to get one asap. Where should I start measuring once I get one? and also I just remembered I think a wire might have came loose off the board that comes from the PT, could that have caused any damage?
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#22
If you are building amps you NEED a multimeter.
Yes it could have done damage but usually when you burn out a transformer you can smell it.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#23
Well I haven't done any biasing and up until now I haven't had any real problems, and that puts my biggest worries to rest, all I can smell is the very faint smell of spray paint. I'll go and get me a multimeter and come back, should I get digital or analog.
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#24
Digital ones are normally better, they usually have a far greater input impedance. Analog is only better for specialised applications and decent ones cost good money. For you, a digital one is the go. They are pretty cheap, digital technology has seriously reduced the price of multimeters. You can get things like Digitechs for what amounts to spare change. They aint no Fluke but they will satisfy you.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#25
Alright thanks, I'll update once I get one and then after I get it working I'll try to get clips
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#26
Alright, I got a multimeter, so what do I need to start measuring first?
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#27
Start with the voltage at the positive terminal of the first filter cap. It should be somewhere in the area of 350V dc to ground. Then check the next filter cap and the third. They will read a few volts (like about 50 less) than what's on the first cap. If that's all ok, follow the wire to the tubes and make sure it's getting there. That's pin 7 on the EL84 and pins 1 and 6 on the 12AX7.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
Last edited by Cathbard at Jul 24, 2011,
#28
Alright, I'm not getting anything on the cap.
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
#29
now paint it like R2D2.
I wondered why the frisbee was getting bigger, then it hit me.
#30
^ Not a terrible idea, I might be making a matching cab for it too so that would be kinda cool.

Also update: I don't know why I didn't think of this before but I tested the cord and it was fine, tested the connector thing and it measured like .1v so I sat there puzzled for a minute then measured on the strip of metal towards the bottom of the connector and like magic 120v so my connector is broken which really explains A LOT so I'll try and get that fixed then move on to see if the amp actually works or not.



Well it works, I jumped a wire from the metal strip to the terminal that it was supposed to go to and everything works as it should . So now to just rewire everything and get everything set up and then start refining it.

Thanks to Cathbard and AcousticMirror for all the help.
Guitars:
LTD F-50
Yamaha EG-112
'77 Harmony
Roadworn Starcaster
Gretsch G5120

Amps:
Vypyr 15
Epiphone Valve Junior combo
Last edited by grungebaby at Jul 24, 2011,
#31
Glad you got it working. Have fun.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band