Gonna start getting down to fixing '63 bandmaster

[Quencho092]

Ok, as a disclaimer, I don't care to hear vintage 'conservationists' whining about keeping the amp original and judging my practices. I just want to make the damn thing work and never break again and I don't want to ship it anywhere, I know there are good amp builders here and lots of knowledge so I trust you guys have great input to offer! I will post pics and clips when done.

I'm replacing all the carbon comp with metal film, all the old astron electrolytics in the doghouse were already replaced with F+T.

Ok, so this is what it seems like I need-

-all carbon comp resistors replaced with metal film
-I'm leaving the molded blue mallory's on there, but need to replace the orange astron caps on the board. There's 2 of them, they read 25 + 25 MF, there's another one that just says made in USA TD 25-25 MF.
-Trannies were fine last I ran the amp, so I'm not touching them until the interior is perfectly wired up and i could cancel that out from the equation
-I want to replace the whole bias circuit. in the corner where the pilot light is, there is another orange astron cap, a big carbon comp resistor that reads WAY off spec.
-I need a crash course on getting the power cable converted to 3 prong so I dont get shocked anymore. When this amp was working the tone was great, but I used to get shocked while leaning against metal posts in my friends car port. I would sometimes hold my strings and touch bandmates to shock them, it wasn't lethal but FUN! :friday:
-REPLACEMENT SCREWS FOR EYELET BOARD!


So basically, what caps do I throw on for the ON BOARD caps and the cap in the corner next to the pilot light? Would all 1/2 watt metal film resistors be overkill to ensure the damn thing will never break again? I've heard about sozo, sprague, other brands, but you guys with building experience actually know so I'm looking for that input! IM REDUNDANT AS HELL! AHHH

Remember, I don't give a flying %^&$*^#!*#&%^ about worshipping the vintage gods, I just want the thing to sound great so I could gig the damn thing and I don't want to ship it so a tech can read a schematic and just solder on components because I can solder well and follow directions.

 

[Chickenwings]

Re: Gonna start getting down to fixing '63 bandmaster

.....but what did you think about keeing it original? lol

http://fenderguru.com/amps/bandmaster
http://fenderguru.com/where-to-find-parts
http://torresengineering.stores.yahoo.net/fenshowabovk.html

those 3 links should cover everything you need to know to get your amp running like you want.

 

[the guy who invented fire]

Re: Gonna start getting down to fixing '63 bandmaster

metal film...dear lord...

Oh well...

FWIW, if you need help putting on a 3 prong cord the rest of this work is way beyond your knowledge...please for the good of the amp and for your safety take this amp to a pro and get the work done.

Also, those blue Mallory caps might need to be replaced...

Also, the bias circuit is a GREAT circuit but the bias cap is likely gone and the resister has drifted too far at this point...replace the resister with a small resister + trimmer set up for an adjustable bias and you'll be fine...

 

[crusty philtrum]

Re: Gonna start getting down to fixing '63 bandmaster

Don't use metal film resistors unless you want the clean sound of an ENGL. Use 1 watt carbon film.

Replace the electrolytic cap(s) in the bias circuit, paying attention to the reversed polarity. Don't exceed 100uF here otherwise oscillations will probably occur.

Sprague Orange Drops capacitors are usually the safe bet for replacements in Fender amps without getting too exotic.

Replace any resistors that are soldered across the underside of the power-tube sockets, allowing them to stand clear of the socket a little to reduce the effect of heat (and don't forget to remove the tubes before doing this).

But before doing any of this, you will need to make sure the entire power supply is good.

 

[Quencho092]

Re: Gonna start getting down to fixing '63 bandmaster

hmm, ok. I guess you guys have me convinced about the carbon film, I did research and there's much 'voodoo' about it. I will get all carbon films replaced.

The amp worked, it just started to crap out/make noise/lose headroom. I changed tubes and caps and it kept getting worse. Many of the resistors were out of spec when I checked them with the multi-meter.

Thanks for the references and opinions on carbon, hopefully it works out!

So you know this is all in past tense, the amp only worked for a few months after I bought it on the cheap before I had to change the resistors above the power tubes, then it started sounding dirtier and dirtier, noisier and noisier. It never recovered from there.

 

[the guy who invented fire]

Re: Gonna start getting down to fixing '63 bandmaster

hmm, ok. I guess you guys have me convinced about the carbon film, I did research and there's much 'voodoo' about it. I will get all carbon films replaced.

The amp worked, it just started to crap out/make noise/lose headroom. I changed tubes and caps and it kept getting worse. Many of the resistors were out of spec when I checked them with the multi-meter.

Thanks for the references and opinions on carbon, hopefully it works out!

Just a word of experience...a lot of the tone you are so in love with might be those out of spec resisters...

 

[Quencho092]

Re: Gonna start getting down to fixing '63 bandmaster

metal film...dear lord...

Oh well...

FWIW, if you need help putting on a 3 prong cord the rest of this work is way beyond your knowledge...please for the good of the amp and for your safety take this amp to a pro and get the work done.

Also, those blue Mallory caps might need to be replaced...

Also, the bias circuit is a GREAT circuit but the bias cap is likely gone and the resister has drifted too far at this point...replace the resister with a small resister + trimmer set up for an adjustable bias and you'll be fine...

I know ground is the chassis, so I'm guessing a 3 prong is the same specs as 2 except it bypasses the polarity switch and 3rd prong lead goes to chassis thus grounding it. I was just wondering if there were any other procedures for grounding to get the full safety benefit. Please correct me if I'm wrong, I read much about this stuff and I know some of the safety basics like discharging caps, obviously unplugging the amp, etc but I want to make sure I'm not missing anything.

The caps were discharged in the past by hooking up an alligator clip via pliers and my other hand in pocket, the clip went to a 10 watt 100k resistor I had laying around then to alligator clip on chassis. Is this wrong? I've heard of guys discharging caps by touching the lead with a screwdriver tip while the side of the shaft is touching the chassis to ground it as the risky way. The amp has not seen a power outlet, and I hooked up the clips to the + and - leads of each cap just in case a few hours ago.

I'm not a total stranger to this stuff, but it's been a good 7 years since I take any interest in it or do any work which is why I check in to hear what you guys think, I appreciate the advice a lot!

Would sozo's sound bad here? I don't mind using something exotic or different. I think its nice that the components on these amps are cheap except for the tubes and transformers.

I want to see if I can get all the resistors via mouser. is this the right format from xicon? http://www.mouser.com/ProductDetail...GAEpiMZZMu61qfTUdNhG%2bDQRbLcOBw9kXcJ/T18EjU=

I opened up the amp and took a look, and spent about an hour writing down the resistor value and quantity list. Would LED's sound good in the place of the diodes in the rectifier circuit, if so what would you guys recommend? I'm planning this thoroughly and jotting everything down to make sure I get this done right, I'm going to build a mouser shopping cart up tonight.

thanks a million for the references and pointers I'm open to any suggestions or corrections.

 

[Quencho092]

Re: Gonna start getting down to fixing '63 bandmaster

Just a word of experience...a lot of the tone you are so in love with might be those out of spec resisters...

I'd feel much better having all new 1 watt carbon film across the board. It won't cost an arm and a leg and it would help my peace of mind!

What if they're too out of spec, or bound to get worse? I feel like I'm eliminating a big variable by replacing all of them with good stuff. If '63 spec sounds good, it will sound good.

But I do trust your judgement, I'm sure there are differences in tone from amp to amp because of the varying resistor values, I just want to throw all good dependable components in here to have a low noise good tone final result that I can depend on.

 

[Quencho092]

Re: Gonna start getting down to fixing '63 bandmaster

hmm shopping cart is almost populated with 1w and 2w xicon carbon films, I was thinking of getting an eyelet board for a princeton and populating it with the right stuff as it would be almost the same as the ab763 bandmaster im doing.

Perhaps a compact 'princeton reverb' head would be a neat build. I'll see how things pan out, but look out in the next 6 months!!!

 

[misterwhizzy]

Re: Gonna start getting down to fixing '63 bandmaster

Would LED's sound good in the place of the diodes in the rectifier circuit, if so what would you guys recommend?

The rectifier circuit is not designed to have anything to do with the sound if it's solid state. If there were a tube there for rectification, the answer might be different. But since it's diode-rectified, I doubt they need replacing. Just leave those alone. If you decide to replace them, do it with exactly the same parts.

There is no signal running through the power supply. The diodes only serve to make sure that the AC signal does not pass when it's on the negative side of its voltage swing.

 

[ratherdashing]

Re: Gonna start getting down to fixing '63 bandmaster

Would LED's sound good in the place of the diodes in the rectifier circuit, if so what would you guys recommend?

This question tells me that you should definitely not be doing this yourself. Seriously.

Please, for the good of this beautiful amp, and for yourself, take it to a pro. If you so much as open that chassis I'll cry.

 

[the guy who invented fire]

Re: Gonna start getting down to fixing '63 bandmaster

This question tells me that you should definitely not be doing this yourself. Seriously.

Please, for the good of this beautiful amp, and for yourself, take it to a pro. If you so much as open that chassis I'll cry.

I agree and have said the same thing...this can end really badly for both the amp and it's owner...

 

[Quencho092]

Re: Gonna start getting down to fixing '63 bandmaster

I've modded those creme knob vibrolux customs cleanly and successfully to get NFB circuit running for a few friends, I'm not a dumbass with this kind of stuff it's just been a while since I do it.

The chassis is open. I've followed schematics before and I'm aware of the dangers of charged electrolytics. I have no intention of shipping this amp, and there are no decent pros in the area that wouldn't rob me blind and charge insane prices. The amp is getting all Sozo caps and everything is getting checked obsessively before it ever sees a power outlet. I have the right slo-blo fuse in there as well.

You guys could go ahead and cry, but this amp is of no use or value to anyone unless somebody fixes it, I'm also not dumb enough to play guitar through it while testing to see if it works, I'll be running an cassette in a crappy old walkman cassette player to the input then flipping the mains with a leather sandal. At the very worst the amp will fry the cassette player.

I'm going to populate the board and run through everything with my fluke and if doesn't work proper it will be sitting around until I save up 500 in expendable cash to ship it to a pro. I bet all of you guys had a first complete rebuild project and asked for input/took flak from somewhere.

If it helps you guys sleep better, my cousin who is an experienced electrical engineer, restores old reel to reel and audiophile stuff as well as working for Florida Power and Light and AT&T will probably be working on it with me.

 

[Quencho092]

Re: Gonna start getting down to fixing '63 bandmaster

If it helps you guys sleep, as a safety precaution, Baku, aka 'dummy load' will be used to test voltages

 

[hamerfan]

Re: Gonna start getting down to fixing '63 bandmaster

You can first test the rectifier section without preamp tubes and without power tubes. Test the voltages with the fluke. Then shut off and drain. Then put in the preamptubes and test again and shut off. At least test with all tubes and a speaker added.

 

[Quencho092]

Re: Gonna start getting down to fixing '63 bandmaster

sounds good dudes. As a matter of fact I have no tubes for the amp right now, it will be getting fresh ones. If my gear sales go well I'll be running NOS everything.

I'm going to leave those sweet sounding mallory molded caps in there unless there are any problems. I already ordered sozo caps for the doghouse and the bias/rectifier mini board, I'll wait to see how the original mallories sound.

I found an old accutronics reverb tank in my garage, is it economically smart to build a stand alone fender reverb unit, or to just go with building a small princeton head? I have a trashed SS newer fender champ cab with chassis that might be suitable as a square shaped princeton head.

Might be nice to run my bass amp>12'' JBL cab, bandmaster >15'' weber california, Princeton reverb head>Jensen C12N I have in the garage, with a touch of stereo delay between the bandmaster and princeton AHHH THE GAS

 

[ratherdashing]

Re: Gonna start getting down to fixing '63 bandmaster

Shocking yourself has nothing to do with it. It's just that ... and please don't take offense to this ... you have no idea what you're doing, and an amp that good deserves to be worked on by someone who does. I'm sorry, but that's the truth of the situation.

You're treating this like a paint-by-numbers exercise, and the assumptions you're making show that your electronics knowledge is pretty dire. In the example I quoted, you probably read somewhere about people using LED's for clipping diodes and assumed that they'd also be good as rectifier diodes. This shows that you don't know what a rectifier does, which is one of the most basic components of any amp. The kind of person who doesn't know what a rectifier is for, and why LED's would make no sense whatsoever in that capacity, should NOT be working on a '63 Bandmaster. And that's just one example.

I get that you want to do this project for yourself, and that's really cool, but I'm sorry to say you're just not ready. A BF Bandmaster restoration is not a beginner project. Odds are very good you will either ruin this amp, or go through a huge amount of trial and error only to take it to a tech anyway. I know a LOT more about audio circuits than you do and there's no way I'd take on what you're trying to do! Not without doing a lot of reading and practice first, at least.

If you really want to go through with this, can I suggest that you start with the basics first? Read up on electronics and amplifier circuits so you have at least a basic understanding of what's going on in there. And I'd definitely recommend practicing on a simpler circuit first (building a Champ kit, or a 5E3 Deluxe kit, maybe?). Once you've got that under your belt, you can think about working on your Bandmaster.

 

[Lazarus1140]

Re: Gonna start getting down to fixing '63 bandmaster

It could also be a Blonde in '63, right?

 

[the guy who invented fire]

Re: Gonna start getting down to fixing '63 bandmaster

Shocking yourself has nothing to do with it. It's just that ... and please don't take offense to this ... you have no idea what you're doing, and an amp that good deserves to be worked on by someone who does. I'm sorry, but that's the truth of the situation.

You're treating this like a paint-by-numbers exercise, and the assumptions you're making show that your electronics knowledge is pretty dire. In the example I quoted, you probably read somewhere about people using LED's for clipping diodes and assumed that they'd also be good as rectifier diodes. This shows that you don't know what a rectifier does, which is one of the most basic components of any amp. The kind of person who doesn't know what a rectifier is for, and why LED's would make no sense whatsoever in that capacity, should NOT be working on a '63 Bandmaster. And that's just one example.

I get that you want to do this project for yourself, and that's really cool, but I'm sorry to say you're just not ready. A BF Bandmaster restoration is not a beginner project. Odds are very good you will either ruin this amp, or go through a huge amount of trial and error only to take it to a tech anyway. I know a LOT more about audio circuits than you do and there's no way I'd take on what you're trying to do! Not without doing a lot of reading and practice first, at least.

If you really want to go through with this, can I suggest that you start with the basics first? Read up on electronics and amplifier circuits so you have at least a basic understanding of what's going on in there. And I'd definitely recommend practicing on a simpler circuit first (building a Champ kit, or a 5E3 Deluxe kit, maybe?). Once you've got that under your belt, you can think about working on your Bandmaster.

Not trying to be rude but these are facts...

Doing a fairly simply mod on a PCB amp and tearing a handwired amp to nothing and starting over are 2 very different things.

When you said you weren't sure about the 3 prong cord I had a bad feeling but LED's in the rectifier circuit proves that you have NO BUSINESS doing what you are about to do...

You have no idea whats going on in there and getting hurt is just half of it.

 

[the guy who invented fire]

Re: Gonna start getting down to fixing '63 bandmaster

It could also be a Blonde in '63, right?

Short answer:

Yes

Long answer:

Bandmaster was tweed until 1960 and the first non tweeds were brown tolex 3x10 combos (these amps are VERY rare) then later in 1960 they dropped the Bandmaster as a combo and went to a 2x12 piggyback set up and since all the piggybacks were blonde the switch was made...first with Oxblood grill cloth then wheat and the circuit changed a bit (mostly the vibrato circuit) then in 1963 they started making the change to the Blackface Bandmaster...

The first Blackface Bandmaster were in blonde tolex cabs but have nothing in common with the brownface Bandmasters at all then by late 1963 they switched to the black tolex as well...