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Here is a video describing (briefly) how to convert a Hot Rod series Fender into a Classic 59 Bassman 5F6-A with a Plexi channel.
I did a second one with some improvements, you can see here: • Hot Rod Deluxe to Bass...
*If you have interest in doing this conversion to your HR Deluxe or Deville, please contact me directly, as there are many details that I have not included in this video, but will gladly share. jloewenheim@gmail.com
Featured are some upgrades that mostly are a result of the great web pages put together by Rob Robinet. Notably, are modifying the normal channel to be voiced as a Marshall following the Plexi Preamp voicing, adding a pre-phase inverter master volume, making the bias adjustable, and having a 3-way negative feedback switch.
For a write-up, go to my site: sites.google.c...
Missing from this conversion is the reverb (the tank is still in the cab). I wasn't sure if I really wanted it or not, but if I do, I will add it back in the way it was standard on the HRD using an op-amp.
Mistaken Description: at the 9:49 mark I erroneously mentioned that Screen Resistors were where the burned marks were on the board. This is incorrect, those are actually the resistors for the Dual Power rail for the (+/-)16VDC utilized by the opamps and relays. Issues with these often cause channel switching and other problems.
Things not mentioned:
-The adjustable bias setup: 15K Bias Divider (stock 5f6a), 50k pot, 39K pot to ground (connected to the wiper and far lug for a min of 39K). This varies a bit from Rob's recommendations.
-I used 1n4007 diodes on a terminal strip for the rectifier-Bridge since no CT
-I had to re-drill holes for the preamp tube holes (originals are too big)
-All Control panel holes needed to be reamed to 3/8" for new pots
-to mount the boards, I used Masonite (cut-up clipboards)
-I reduced to 2 non-plastic classic Switchcraft input jacks and reduced grid leaks from 68K to 33K
-Screen resistors are mounted directly on chassis
-Pre PI Master Volume follows JCM800
Also if you like my channel and this video on amps, I suggest subscribing to the following awesome channels:
-Uncle Doug: / @uncledoug
Uncle Doug has tons of other videos, probably the best teacher on KZbin regarding amps
-The Guitologist: / @theguitologist
Brad runs an all-around great channel, loves to work on wonky stuff as well as standard guitar-related gear.
-D-lab: / @d-labelectronics
Terry is likely the best electronics technician working to repair tube amps on YT.
Related links:
Rob Robinette
-Safety! Rob's word on capacitor discharge and lethal voltages in tube amps: robrobinette.c...
Rob's site is likely the most comprehensive resource regarding classic Fender amps, and now amps work.
-59 bassman site: robrobinette.c...
-Brad the Guitologist working on a Mesa (this guy has tons of awesome videos):
Part 1: • The Forgotten Mesa-Boo...
Part 2: • This Amp is an ABOMINA...
Part 3: • That's It...This Ampli...
Part 4: • Ahab SLAYS the Mesa-Bo...
-Uncle Doug on Biasing: easiest way to really understand how biasing works
• Biasing Single-Ended A...
• Biasing Double-Ended A...
• Biasing Double-Ended A...