(http://img.photobucket.com/albums/v375/sarlakk/pro_zps22c6ea89.jpg)
Please excuse the terrible picture. Now, I know what some of you are thinking - silverface? Go home, dude. But check this out: according to the tube chart, this is the AA165 model, which uses the blackface circuit. It's a blackface in silver clothing.
This is my first real amp, and the first that I've bought for myself. We have a 1966 blackface Pro at my studio, and it's essentially everyone's favorite amp there, so I've been on the lookout for my own for a while. This one popped up on Craigslist for an entirely reasonable price, and I had to go check it out.
I was shocked at how clean it was when I got to the guy's house - I'll have to try to take better pictures at some point, because this amp is almost in mint condition. It's insane how clean it is, I think I must be the third person to own this amp. It has the original leather slipcover (with the original owner's name written on the inside of the handle flap). The dude who sold it to me isn't a guitarist, he plays accordion, and he said he got the amp in a trade at an accordion shop in New Jersey. Apparently the owner had it just sitting in the store for years. I can't be certain, but it really seems like it was owned by one person who must've sold it to the accordion shop decades ago. They traded it to the guy I got it from, and now it's mine.
It's even been recently serviced by a great local shop, so it's sounding as good as it looks. Original RCA and Telefunken tubes (barring one replacement), original transformers, original speakers (reconed). Classic Fender tone for days.
Score!
I would rock that in a heart beat.. looks great. Enjoy it!
8)
68 was the year of the fixed/cathode bias super reverb.
I'd take a look inside just for checking that and the bias control arrangement.
Anyway its a gem!
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Awesome!
I'd pull the chassis to see what you have. Fender was notorious for putting tube charts that have a previous circuit listed. I think they changed from the AA165 to the AC568 in May or June of '68 I have a drip edge '68 bassman that has an incorrect circuit listed on the tube chart. Don't remove the drip edge around the grill cloth if at all possible. They are very difficult to piece back together. :o
very cool amp, more amp porn pic please
Alright guys, how would I go about getting a look at the circuit board? I've never disassembled an amp like this before. What do I need to know to open it up without electrocuting myself?
Quote from: lincolnic on September 26, 2013, 05:24:52 AM
Alright guys, how would I go about getting a look at the circuit board? I've never disassembled an amp like this before. What do I need to know to open it up without electrocuting myself?
Just unscrew the 2 chrome bars on the top of the amp where the handle is. That will lower the chassis. I would remove the tubes first just so you don't break a tube or a socket.
Also, be VERY, VERY careful to NOT touch any electrolytic cap terminals. They hold a very nasty charge, and I don't know if SF amps have drain resistors. (I suspect not.)
Do these old American amps have a three pin plug with a proper earth wire like God intended? Or do they all come with two pin plugs and deathcaps?
Unless it was changed it has the two prong and death cap. The amp should be unplugged and the filter caps should be drained before poking around! The big filter caps should be on the underside of the chassis under a metal cover with 4 screws.
You can follow the eyelet board to see what you have.
Don't forget, if you do take out the chassis. There is a screw securing the power cord to the cabinet that will stop the chassis from removing or rip out if you forget it.
You can look at the board without draining the caps, just don't touch anything ;)
with the cord unplugged,turn on the power and standby switch with tubes on,in a few minutes that will discharge caps.
Quote from: gtr2 on September 26, 2013, 10:35:55 AM
Unless it was changed it has the two prong and death cap. The amp should be unplugged and the filter caps should be drained before poking around! The big filter caps should be on the underside of the chassis under a metal cover with 4 screws.
You can follow the eyelet board to see what you have.
Don't forget, if you do take out the chassis. There is a screw securing the power cord to the cabinet that will stop the chassis from removing or rip out if you forget it.
Actually, it was changed to a three-prong. Can someone explain to me about this "death cap"? They left the original two-prong cord and there's also a fairly large cap in that bag, but I'm not sure if that's something that was changed or just something that was removed. Would this be the death cap? Any other precautions I should take?
check out any 60s fender schematic,you'll see that cap on a switch right on the 2 wire cable.
now you should be safe with current standards.
When you open the chassis check the dc voltage on the pin 1 of preamp tubes and pin 3 of the power tubes.
If you dont know what i'm talking about,well,don't do it for Gods sake!
I've gotten hit with a cap on a fender deluxe and it's no fun. Just look, and take pictures. Don't touch anything inside unless you are familiar with how to drain the caps safely. There's lots of good articles regarding that on the web.
I finally had a chance to get under the hood today, and unfortunately it looks like it's not the AA165 circuit after all. It's the AB668 - the first silverface circuit. I think I'd like to try blackfacing it sometime, but I've never done any amp work before. Have any of you blackfaced a Fender before? Any thoughts?
I did take a lot of pictures for those of you who want more amp porn, but I haven't transferred them to the computer yet.
The most difficult thing to do is the bias arrangement,circuit wise.
Search for any site that gives info on how to do the whole thing and realize if you could accomplish all of it.
I guess Paul Marossy had a section about it on his diyguitarist site.
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I tend to always refer back to the MetroAmp build guild for 50W plexi's for biasing any amp -- it has a really good page on it that explains the voltages, watts, and maths involved.
Googling the AB668, the first schematic I came across shows a cathode bias arrangement of some kind, no adjustment needed as long as you have 6L6's in it? Should be a couple of chunky 7 watt resistors going to ground from the power valve sockets.
The mixed cathode/fixed bias is the reason why this amp doesn't sound so good as it should.
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