A 67 blackface Bassman head with AB165 circuit worth $350?

[Fendert]

Here is the catch, its going to need some tech work, new tubes, probably a re-biasing, etc. should I do it, or is it not worth it?

 

I Have a friend who is an amp tech, I would get him to look at it and see what it needs, I can do everything my self, except re-biasing

[duncan]

yeap.

[MattACaster]

Totally! I LOVE my AB165.

 

Next to the blonde Bassmans with the presence controls, they are my fav.

[Ripfence]

Yes, by all means snag it.

[SiCkboy78]

Man you guys and the deals you find. Yea Id say its worth it. I just bought one but mine is AA864 spec. It was upgraded to that, and has new filters, caps, and power cord, and was just biased before I bought it. It looks rough as hell, but is sounds wonderful. Paid 499 plus shipping for it.

[Fendert]

Totally! I LOVE my AB165. Next to the blonde Bassmans with the presence controls, they are my fav.

 

Wow I'm convinced! Thanks guys!

[Dolf]

Hells yeah.

 

Same circuit as the one I had. Cap job + retube will be what, $200?

 

Worth it.

[guitarcapo]

If that is all it needs yea buy it. Make sure it doesn't need a "cap job" though. The "3-prong power cord" is another issue. Basically ask if a cap job has been done recently because the filter caps fail at around 20 years. Basically listen to hear if the amp hums at 60Hz when you turn it on, turn up the volume, and have no guitar plugged in. That will definitely be a tech job.

 

But biasing is overrated in my opinion.

 

Hear me out:

 

Usually after you figure out how to measure the power tubes with a biasing tool and make the calculations, you come up with a figure that the amps should be biased to, but that figure is arbitrary and ultimately BASED ON WHAT SOUNDS GOOD TO YOU. 60% dissipation? 80%?...At the end of everything you are still biasing based on what sounds good to you... and the bias is just a guidline. At that point all the bias adjust does is maybe give you some information so that you don't run the tubes too hot. But if you just adjust the bias while playing your guitar, and find that spot that sounds best (while starting from the "cold" side and just increasing the bias until it sounds good and isn't getting better (or sounding worse because it's distorting too easy) you're going to be fine and maybe better off than people who bias with some goal in mind.

 

A few Fender amps don't even have a bias adjust (Blues Deluxe...Hot Rod series) even though they aren't cathode biased (also the popular the Fender Blues Junior). They are biased by fixed resistors... and are actually biased really hot for what the EL84 power tube is spec for. There's even a tech online (Bill Macrone) that has figured out how to add bias controls or different resistors to fix this design problem. But my point is that even in THAT case, there are thousands of Blues Juniors being played everywhere and no massive recalls or stories of exploding amps etc.

 

Bottom line is that lately when I put in new power tubes, I just adjust my bias control with the guitar plugged in and starting cold. I just increase the bias until things start sounding good and there's no improvement going higher (watching the tubes aren't getting really hot...feeling the power transformer that it isn't getting too hot etc...) I don't use the bias probe much anymore except when I'm testing to make sure the tubes are "matched" close enough.

Other than that I don't use it much.

 

Lots of times in a pinch I just plug in new power tubes and blow off biasing entirely.

Before you wince remember all those Blues Juniors out there where people are doing the same thing every day.

 

I have another amp (the 1982 Rivera designed Fender Concert II) that has a bias control...but what it does is BALANCE the power tubes in a see-saw fashion instead of making them hotter together. This design basically addresses power tubes that aren't "matched" instead of worrying about bias.