Uploaded July 2025 | Updated September 2026, 1 week ago
In this video, we'll troubleshoot and modify a 1966 Fender Blackface Bassman Amp owned by fellow YouTuber Bob Bradley. youtube.com/@BOBBRADLEYCHANNEL
The amp came to me with an intermittent issue. It was cutting out and popping randomly. So first we'll track down that issue and move on to some tasteful mods, one of which I like to call the "ABNormal Channel Mod", which turns the Normal Channel into a more Marshall-like channel with more pronounced midrange. We also will experiment with some different preamp tubes like the 12AU7 and 12DW7. Along the way we'll try to figure out whether this amp is really a AA165 or AB165 circuit by comparing schematics. In the end we'll check out the tone with some incredible guitars - a 1965 Gibson ES-335 with 3-Patent Pickups, a 1958 Fender Stratocaster, and an R9 Gibson Les Paul.
#guitar #electronics #repairing
Extended demo video: youtube.com/watch?v=WGHAu6Cti1w
0:00 Intro w/ Bob Bradley
2:01 First Look
6:03 First Listen
8:58 AA165 vs. AB165 Schematics
16:25 Troubleshooting with a Chopstick!
21:00 Pulling the Board
28:03 Blowing a Fuse
32:20 Difference Between Me and Other Techs
33:06 Diagnosing a Bad Blue Molded Capacitor
36:27 My Philosophy on Capacitors
38:43 Calling the Owner
43:20 Explanation of the ABNormal Mods
57:53 Bill Gates Weather Mods
58:53 S-Logo Svetlana, Sylvania & RCA Tubes
1:02:13 My Personal Goals
1:03:29 1966 Gibson ES-335 thru Bassman
1:10:13 1958 Fender Stratocaster thru Bassman
1:16:19 Gibson R9 Les Paul thru Bassman
*SHOW YOUR SUPPORT*
1: Become a Member on Locals: theguitologist.locals.com
2: Donate via Paypal: paypal.me/guitologist?locale.x=en_US
3: Buy Merch: bit.ly/GuitologistMerch
4: Send in Viewer Mail. (Contact Me for details at electrictoothsyndrome@gmail.com)
5: Purchase an ad! (Rate sheets available upon request at email above.)
6: Buy something from a sponsor and tell them I sent you.
7: Stand in the middle of the street naked screaming "LONG LIVE THE GUITOLOGIST!" Then when the cops arrive, tell them about my channel.
8: SUBSCRIBE TO THE FIXOLOGIST CHANNEL: youtube.com/@fixologist1
♠RECOMMENDED BOOKS
-RCA TUBE MANUAL amzn.to/2GOBVqS
-Designing Tube Preamps for Guitar and Bass: amzn.to/2DK5tmt
-DESIGN AND CONSTRUCTION OF TUBE AMPLIFIERS: amzn.to/2HSNMne
In this video, we'll troubleshoot and modify a 1966 Fender Blackface Bassman Amp owned by fellow YouTuber Bob Bradley. youtube.com/@BOBBRADLEYCHANNEL
The amp came to me with an intermittent issue. It was cutting out and popping randomly. So first we'll track down that issue and move on to some tasteful mods, one of which I like to call the "ABNormal Channel Mod", which turns the Normal Channel into a more Marshall-like channel with more pronounced midrange. We also will experiment with some different preamp tubes like the 12AU7 and 12DW7. Along the way we'll try to figure out whether this amp is really a AA165 or AB165 circuit by comparing schematics. In the end we'll check out the tone with some incredible guitars - a 1965 Gibson ES-335 with 3-Patent Pickups, a 1958 Fender Stratocaster, and an R9 Gibson Les Paul.
#guitar #electronics #repairing
Extended demo video: youtube.com/watch?v=WGHAu6Cti1w
0:00 Intro w/ Bob Bradley
2:01 First Look
6:03 First Listen
8:58 AA165 vs. AB165 Schematics
16:25 Troubleshooting with a Chopstick!
21:00 Pulling the Board
28:03 Blowing a Fuse
32:20 Difference Between Me and Other Techs
33:06 Diagnosing a Bad Blue Molded Capacitor
36:27 My Philosophy on Capacitors
38:43 Calling the Owner
43:20 Explanation of the ABNormal Mods
57:53 Bill Gates Weather Mods
58:53 S-Logo Svetlana, Sylvania & RCA Tubes
1:02:13 My Personal Goals
1:03:29 1966 Gibson ES-335 thru Bassman
1:10:13 1958 Fender Stratocaster thru Bassman
1:16:19 Gibson R9 Les Paul thru Bassman
*SHOW YOUR SUPPORT*
1: Become a Member on Locals: theguitologist.locals.com
2: Donate via Paypal: paypal.me/guitologist?locale.x=en_US
3: Buy Merch: bit.ly/GuitologistMerch
4: Send in Viewer Mail. (Contact Me for details at electrictoothsyndrome@gmail.com)
5: Purchase an ad! (Rate sheets available upon request at email above.)
6: Buy something from a sponsor and tell them I sent you.
7: Stand in the middle of the street naked screaming "LONG LIVE THE GUITOLOGIST!" Then when the cops arrive, tell them about my channel.
8: SUBSCRIBE TO THE FIXOLOGIST CHANNEL: youtube.com/@fixologist1
♠RECOMMENDED BOOKS
-RCA TUBE MANUAL amzn.to/2GOBVqS
-Designing Tube Preamps for Guitar and Bass: amzn.to/2DK5tmt
-DESIGN AND CONSTRUCTION OF TUBE AMPLIFIERS: amzn.to/2HSNMne
