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Topic: 1967 Fender Bassman AB165 - Quiet Wow! |
Ray Minich
From:
Bradford, Pa. Frozen Tundra
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Posted 2 Jun 2018 4:21 pm |
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Just finished recapping a 1967 Fender Bassman AB165 my dad gave me just before he passed away.
He bought it used for $200 in 1971.
New electrolytics from the kit from Studio Sound.
I hate those @#$% eyelets Leo, wherever you are...
Rewired the AC input to do away with the "deathcap", converted the cord to 3 wire...
It's so freakin hum free I can't believe it.
Now if I can figure out where the "high cut caps" are that I see referred to in net articles I may remove them to see the effect.
There's also comments about converting the unit to the AB864 schematic. Looks tricky.
If anyone has any recommendations I would really appreciate the suggestions.
Thanks all.
_________________
Lawyers are done: Emmons SD-10, 3 Dekleys including a D10, NV400, and lots of effects units to cover my clams... |
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Jim Sliff
From:
Lawndale California, USA
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Posted 2 Jun 2018 8:42 pm
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| Quote: |
| There's also comments about converting the unit to the AB864 schematic. Looks tricky. |
Just follow the schematic. It's actually very simple - mainly a change to the driver circuit. If you don't understand the electronics I wouldn't do it though - you probably won't notice that much of a difference unless you're seriously "dialing in" the amp with NOS tubes and some component value changes to "massage" the toe.
The high cut caps are part of the preamp's bass channel, meant to voice the amp for bass instruments. There are various mods done for "regular" guitar on that channel to get a stronger, punchier sound and leave the "normal" channel for "vanilla" Fender cleans. Those mods are normally only done with an understanding of how they work as "prepackaged" versions don't always provide the desired results - it usually takes some tweaking, and that can only be done if know what to tweak.
You do know about discharging the filter caps any time you open the chassis, right? And how to rebias?
_________________
No chops, but great tone
1930's/40's Rickenbacher/Rickenbacker 6&8 string lap steels
1921 Weissenborn Style 2; Hilo&Schireson hollownecks
Appalachian, Regal & Dobro squarenecks
1959 Fender 400 9+2 B6;1960's Fender 800 3+3+2; 1948 Fender Dual-8 Professional |
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Ray Minich
From:
Bradford, Pa. Frozen Tundra
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Posted 3 Jun 2018 11:39 am
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I'm gonna just leave them alone...
Cost/benefit in time and effort not there right now.
The deathcap on the two wire power cord was a lot more of an issue than keeping my fingers out of the B+. A new 3 wire power cord with ground to the chassis fixed that.
Watch out for the various rebuild instructions on the net. They have mistakes.
Thanks for the help Jim, I appreciate it.
_________________
Lawyers are done: Emmons SD-10, 3 Dekleys including a D10, NV400, and lots of effects units to cover my clams... |
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Len Amaral
From:
Rehoboth,MA 02769
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Posted 3 Jun 2018 2:35 pm
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| There are some vids on YouTube regarding changing the stock 2 conductor power cord to a grounded 3 conductor cord if you haven’t already changed it. |
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