My primary amp for many years has been a Fender Bassman, in one form or another. In February 2005, I bought a Bassman 70 head from a music store in Mississippi (which, ironically, is the same state where I obtained my original '68 Bassman 50). It was advertised as an amp that works part of the time but not all of the time...just the type of challenge I could sink my teeth into.
(all pictures are thumbnailed)
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The BEFORE (black Tolex) and AFTER (silver Naugahyde) pictures. Fortunately, re-doing the exterior didn't require an abundance of skill on my part (although it would have been helpful). The parts came, literally, from all over the world. The faceplate was made in Thailand and I could only speculate about the rest of them! |
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The faceplate is curled at the edges (every silverface I've seen is warped in this same manner) and shows the scars of war wounds. I'm convinced there's a secret ingredient in Tolex that attracts cigarette butts, drink stain circles, and male dogs. How 'bout those jacks and corners? Can you say "rust," kids? What a difference new chrome (and knobs) can make. |
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I put the Bassman 70 chassis (aren't those mismatched power tubes nifty?!?!) in the case from my old '68 Bassman (50W). The only original exterior part is the pilot light lens. The covering is hard to photograph but trust me on this: It looks FABULOUS! |
This amp was taken in on trade at a music store in Canton, MS. The most recent owners (perhaps not the original owners of this '79 vintage amp?) played Bluegrass and at a Pentecostal church. Since Bluegrass festivals tend to be outdoor affairs, this explains the rust (especially in the high humidity of the south). I chose the Bassman 70 above the other versions of the Bassman series because I wanted something with more clean power than the other Bassman amps and I needed it to use the standard 22" chassis for the aftermarket cosmetics I had already acquired. I also preferred the split output transformer load of the '70 (as opposed to the standard Fender method of simply running the extension cabinet in parallel) and wanted a LINE OUT jack. It was a match made in heaven.
Here's what I found when I cracked it open:
* Ground terminal on AC plug was burned off; power cord shortened and spliced.
* Loose terminal on ON/OFF switch.
* Bad solder joints causing intermittent contact on both terminals of replacement fuse holder.
* Wire to pin 3 of V6 (plate of outer 6L6GC to primary tap of the output transformer) burned off at tube socket terminal. Secondary burn marks on adjacent 470-ohm resistor, burn mark on the chassis.
* Discoloration of 470-ohm resistor on socket of V2 due to excessive heat.
* Burned-through terminal on HUM BALANCE pot (6.3V filament).
* Broken lead on .01 uf capacitor in signal path of MASTER VOLUME control.
* Broken wire on terminal of BASS-channel VOLUME control.
* Broken wire on SPEAKER OUT jack.
* Ooze coming out of 220 uf power supply capacitor.
* Dead bugs inside chassis.
The last one didn't have any effect on the operation, of course, but just told me that this amp had been ridden hard and put back in the stable wet. It took me 3 days to fully examine and repair it. Fortunately, I had all the replacement parts in stock except a new power cord. I took out the MASTER VOLUME control because it didn't do a whole lot for the bass function -- and it's much easier to get aftermarket faceplates for amps that don't have them. At this point, the only deviation from the original circuit was to change it over to the mid-'60s bias configuration. I did my final open-chassis check on Friday night, then put Charlotte into her new clothes to show her off at a Saturday gig.
I ran my in-case checks the next afternoon, just 4 hours before playing it for real. It sounded good and there was nothing burning so I figured Charlotte was good to go. I was the house bassist for an open stage at The Dolphin; two other bass players plugged in their guitars and I was very pleased with the sound.
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Here's the chassis after a round of new filter capacitors and cleaning up the inside. Note the yellow SoZo cap in the middle of the original blue caps. Several wires were scored from being too close to hot resistors and the like. It's obvious that Fender didn't want to spend a dime more on wire than they absolutely had to -- I've never seen wires stretched so tight!
Now that I've had a little time to fiddle with it, I replaced the original capacitors with SoZos -- and closed it up before I thought about taking a picture. So just pretend those blue things in there are yellow, OK? SoZo recommends some staggering number of hours of burn-in before they claim their capacitors will sound their best. I can't see what will be so different then as opposed to now, but I'm thrilled with what I'm hearing today. I don't know what they put in those things, but the first time I fired it up I had to back off the bass AND treble to tame it -- I didn't want to sound too overpowering (unless I'm trying to drown out somebody I don't like!).
Ah, yes...the drowning-out thing. Seventy watts is plenty of wattage for the average cottage. I've never had to mike this thing in a bar because I can keep up with the rest of the band without augmenting it through the PA. I attribute this to the efficient speakers and the porting of the cabinets, and the power tubes.
Those tubes: JJ Electronic 6L6s from Bob at Eurotubes. Bob's a great guy to deal with and hearing what his tubes have done for my amp has made me a believer in JJs.
This amplifier will silence critics of Fender's ultralinear line because it sounds like a 'bass amp' should. I removed the feedback-suppression loops, eliminated the Master Volume, replaced the original capacitors with a brand that uses modern technology to revive a retro sound (a true oxymoron), installed larger filter caps, and 'blackfaced' the bias circuit (while leaving the 'silverface' phase-inverter intact). Essentially, I have probably taken the basic Bassman 70 as far as you can go from its dubious 1979 roots back to Fender's halcyon days without altering its core tone chain.
I use a solid-state Peavey KB-100 when I need to grab an amp and run, if I'm playing at an open stage where I need something quick and portable, and it does a good job. But when I'm headlining and need to sound my best, for my money there's nothing that can match a Fender Bassman. And I expect that Charlotte will fill the bill for a long time.
Why "Charlotte?" Because one of the dead bugs I found inside the chassis was a spider.
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