Fender Bassman 50 Heavy Maintenance

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Coolcat
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Fender Bassman 50 Heavy Maintenance

Post by Coolcat »

Since someone asked if I could make some sort of journal or something about the maintenance on a bassman 50,.. here it is.

So the amp is an old fender bassman export (bassman 50).
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This is in fact a picture I made after all of the work was done. I forgot making pictures of the state it was in when it got here. But it was just so realy bad.
This thing had been sitting in the attic for years. It even had mice droppings in it. The owner recently tried it, but he told me there was no sound, and he saw sparks coming out of the tubes.
It was equipped with RCA tubes, but they were just soo bad.
I think pictures say more than words.

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Just look at the amount of dirt on the glass, and yes, most of the time it's not recommended to use power tubes that broke in two.

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The preamp tubes had little cracks in the glass too.

So I began removing all of the tubes, and then checking the internals. The following picture is from after the work had been done.
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With an amp of this age, it's the best thing realy to replace the electrolytic caps. (yes, the things that look like batteries). As for the film caps, they can handle time pretty well. The fat electrolytics just go bad over time. This one had the good old mallory caps, but they were in such a terrible state.. So I changed them for new ones. I marked them in the following picture.

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Marked the 'work zones' in the next one.
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These make up the power filter, so they constantly have to handle the high voltage.

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The caps are hidden under a metal part that goes on top.


So, thats about everything I have pictures of. I had to do some other things like replacing a resistor that was broken in half, change a tube socket that was burned, and replaced the inputs as they were quite rusty.


If you have any questions, i'd like to answer them.
And yes, please keep in mind when you decide to work on your own amp, that these cute little things can store enough current to kill you even when they are turned off.
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Haze
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Post by Haze »

Awesome! thanks for documenting it all. I'll be doing much of the same thing to my Bassman. New tubes, caps, etc.
this one looks a lot cleaner than mine on the insides though:
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Still has all the original bits, including the now chewey caps
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Sloan
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Post by Sloan »

i liek it
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Mike
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Post by Mike »

Great, great work.

Haze get them caps replaced.
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Haze
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Post by Haze »

IMONIT
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cobascis
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Post by cobascis »

What's the deal with bassmans? They seem to be incredible sounding amps for bargain prices? 50 watt FENDER tube amp for <$400?! How can these be so cheap/awesome?
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Haze
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Post by Haze »

Not EVERYONE knows about their awesome potential with guitars? They're great clean amps that take anything you throw at them and they are built like fucking tanks. I have no idea why they go for such a low price either. Even early SF ab165 circuits average out around 500 or so and those are the "good ones"
I picked mine up for 3 bills but other than needing a good service its solid. Hasn't seen any maintenance since in 33 years and its still going strong! If you see one for $400 locally you owe it to yourself to at least go try it.
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cobascis
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Post by cobascis »

Nice.

Do you know how the Bugera V55 circuit compares? I know they use the same tubes.

Another question, you can swap out 6L6s for EL34? Preference?
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Will
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Post by Will »

I had an AB165 for years - they are great. Silverface Fenders in general are the best deals out there right now.
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Haze
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Post by Haze »

i had just told isaac that today, something along the lines of "SF twins are like the holy grail" and how the Vintage ones can be had for about the same price as the RI models.

No idea about the v55, lots of people have been comparing it to the classic 50s though.

Not sure if you can switch over to EL34s either, out of my range of knowledge. Would have to be re-biased [?]
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cobascis
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Post by cobascis »

I guess I'm just wondering how many factors are there in an amp besides the tubes, as the v55 and bassman both have 2 6l6s and 12ax7s.
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robert(original)
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Post by robert(original) »

i recently had my bassman 10 amp fully service, i should have taken before and after pics but i didn't think of it.
i got my bassman ab165 dripedge thru a trade with aen. and my bassman 10 was 250 bucks, plus about 170 to get it completely re-done.
at one time i thought about buying about 3 old bassman heads just to keep around till they got valueable.
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cobascis
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Post by cobascis »

robert(original) wrote:i recently had my bassman 10 amp fully service, i should have taken before and after pics but i didn't think of it.
i got my bassman ab165 dripedge thru a trade with aen. and my bassman 10 was 250 bucks, plus about 170 to get it completely re-done.
at one time i thought about buying about 3 old bassman heads just to keep around till they got valueable.
awesome. $250?!

Silverface Champs go for next to nothing, too. Good recording amp?
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robert(original)
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Post by robert(original) »

get a bassman instead. loud enough for practice/gigs/good recording amp, great cleans.
and easy to repair, and think about it like this.
if my amp has been around for 40 years with minimal problems. then it will be around for another 40 years with moderate problems at worst.
think of a line 6 spider amp. if something goes wrong on the board, have fun fixing it yourself, you will have to send that shit off and wait for a long ass time, and in the end you will probly just get a new board installed and a bill from the company.
thats if the company even lasts for 5 more years.
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cobascis
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Post by cobascis »

robert(original) wrote:get a bassman instead. loud enough for practice/gigs/good recording amp, great cleans.
and easy to repair, and think about it like this.
if my amp has been around for 40 years with minimal problems. then it will be around for another 40 years with moderate problems at worst.
think of a line 6 spider amp. if something goes wrong on the board, have fun fixing it yourself, you will have to send that shit off and wait for a long ass time, and in the end you will probly just get a new board installed and a bill from the company.
thats if the company even lasts for 5 more years.
Yeah. I hope I can get one before (if) the prices rocket, I just got an amp that will keep me going for a few years. My mind is plagued with tube amp horror stories about death and electrocution -- how do you guys go about fixing this? You can touch the caps? I guess what I mean is, will some things always hold a lethal charge, or is the entire thing dis chargeable?
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robert(original)
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Post by robert(original) »

you can make a wand, or buy one from a snotty electronics store.
just gotta discharge the amp.
and really as long as you don't touch point a, and point b, you won't get shocked, you just have to know what point a, and point b, are.
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Will
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Post by Will »

I'm on the fence about my next amp - either the VHT Special 6 or a SF Champ. The Champs seem to go for <$350 all day long.
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robert(original)
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Post by robert(original) »

i have heard 2 bronco amps, and thought they they were prefect bedroom volume tube amps.
one was here locally and one belonged to dodgedartdave, but i think he had another cab plugged in.
both sounded very nice and clean, not really plain, but not as boastful as a more powerful amp.
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Post by cobascis »

rob have you demo'd your bassman 10? most of the youtube bassman demos are a bit ...
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Post by robert(original) »

i did a demo, a fully informational, all the way thru styled demo.
it came out to 11:46
i tried to edit it with a program i PAID 30 dollars for, and it failed, it crashes every time. so i gave up.