Mic Kaczmarczik's Brown Bassman Transformers Information

Brown Bassman Transformers


Fender

Brown Bassman Transformers

This directory contains USENET articles Mic has saved about guitars, equipment, pickup, techniques, players, and so on. Mic has graciously granted permission to post the stuff on the JT30 page on the off chance that it might be useful in the context of Blues Harmonica. Mic is not responsible for the content, just the collection.

Fender

Brown Bassman Transformers
From tim6l--(at)--lonline.com Wed Oct 16 23:01:05 CDT 1996
Article: 24910 of alt.guitar.amps
From: tim6l--(at)--lonline.com (Timothy J. Richter)
Newsgroups: alt.guitar.amps
Subject: Re: Fender Bassman Heads
Date: Wed, 16 Oct 1996 05:38:51 GMT
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>On the subject of speakers: Prior to sometime in '62, the cabinet used a
>single speaker mounted on a "tone ring", an interesting way of porting the
>speaker. After '62, Fender went to a 2-speaker configuration. It's very
>important to make sure the head matches the cabinet, since >the heads
>designed for the single speaker have an 8-ohm output transformer and the
>heads designed for the two-speaker configuration have a 4-ohm output
>transformer. There is an EASY way to tell which head you have: If it has a
>tube rectifier, it's an early 8-ohm, single-speaker head; If the amp uses a
>solid state rectifier circuit (no tube rectifier, but a round plug where the
>tube would go), it was designed to go with a 4-ohm, 2-speaker output. This
>is, of course assuming that someone hasn't replaced the output transformers.


While this is right in 90% of the cases, it is not always
the case that a Bassman with a tube rectifier has an 8 ohm
output transformer. I have a 100% stock Blonde tolex
Bassman. The date code is "LA" (Jan. 1962), and I have a
silicon diode (SS) rectifier. BUT, my amp has an 8 ohm
transformer. Here is a 100% test that cannot fail. (I
think) Each output transformer (if original) has a part
number stamped (or sometimes inked) onto the metal end bell
encasing the wiring. It will have 6 digits and begin with
125... If it is a 125A5A it is definitely an 8 ohm tranny.
If the number is 125A13A it is a 4 ohm tranny.


Also, I would disagree that it is "very important" to make
sure that the cabinet matches the speakers. In 90% of the
cases, you will have a non 1961 Bassman and it wants to see
a 4 ohm load. Most common are 8 ohm 12"s. (fender rarely
used 16 or 4 ohm speakers), so it is likely that a 2x12" box
will match with 90% of Bassman heads. BUT...Wait!!
an 8 ohm load will not be optimal for a later Bassman, but
it will not be disasterous. Fender amps are tolerant
(moreso than Marshalls) and many times throughout Fender
History a speaker load mismatched the amp. (Think of the
EXT SPKR jack--c'mon, did anyone realty change out their
Deluxe Reverb 8 ohm speaker to a 16 ohm and use a 16 ohm ext
cab??!!)...
Anyway. I too have a 1962 Bassman (2 in fact, one with the
8 ohm OT and one with the four). Just tonight I used the
4 ohm 62 Bassman with a Marshall 8 ohm 4x10" and got the
most KILLER tone I have gotten from that amp. Anyway, many
will tell you that mismatching ohms will kill a tube amp,
but in my experience, a 100% mismatch is OK (8 ohm load on a
4 ohm OT, or a 16 ohm load on a 8 ohm OT, or even a 4 ohm
load on a 8 ohm tranny)


>Personally, I have a '62, double-speaker, blond bassman rig that sounds
>great with a guitar. It has that one sound, but it's a nice one.


I'll agree. A limited amp, but what a sound it makes!!!
Also, if you doen't mind modding an amp (gosh!! eeek!)
If you like the NORMAL channel and want to rewire the
BASS channel, you've got three knobs and 2 tubes (4 gain
stages) to work with. (I built a Marshall pre-amp into the
BASS side of a BF Bassman --now it's a versitile amp!)


Just my 0.02
Tim





 

Index:

1974 prices
3 Spring Reverb Tanks
3 Wire Cord installation
5R4 not enough current
5V4 in BF Deluxe
6550s in Super
68 Princeton Rectifier
68 Super Reverb
6L6 in Champ Again
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6L6 in Deluxe Reverb
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6V6 In 6L6 Amp Test
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AA vs AB 763
AA763 vs AB763
Alternative Switches
Bad Fender Mods
Bandmaster Cathode Bias
Bassman 10 info
Bassman Head Running 2ohms
Beef Up Tweed Champ
Birth of Fender Reverb
Blackface Cabinet Dates
Blackface Pro
Blame UL
Blues Deluxe review
Brown Bassman Transformers
Brownface Trem Pulse
Brownface Tremolux Cabinets
CBS Deluxe Reverb Changes
Champ 8ohms
Champ problems
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diy
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Early Blackfacing
Ed Jahns Xformers
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Fender 6V6 Overvoltage
Fender AA568 circuit
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Fender Reverb Transformer
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Fender SF vs BF
Fender Silverface facts
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Red Knob Twin problems
Reduce Champ Screen Voltage
Replacing Glued Baffles
Restoring Grille Cloth
Reverb Amp Effects Loop
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Reverb Unit Mods Page
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Rivera Designed Fenders
Scrape Vibrato Pot
Screen Resistors
SF Deluxe mods
SF Deluxe Reverb Questions
SF Reverb Cathode Resistor
SF Vibrolux Changes
Shielding Plate Problems
Showman vs Twin
Silverface Changes
Silverface Pro Reverbs
Small Trannys Sometimes Better
Super Champ 6C10
Super Molestation
Super Too Much Bass
Tolex Repairs
Tremolo Tick Tips
Tweed Champ Filter Caps
Tweed Deluxe Bypass Cap
Tweed Deluxe Transformers
Tweed Twins
Twin Reverb History
Twin Reverb overdrive
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Vibrato Click Fixes
Vibrato Tick Svc Bltn 9
Vibro King fat switch
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What is Hi Pot
What Makes Fender Sound
What Was Ice Cube
Why 68K Input Resistors
Why No More Cloth Wire
Why Silverface Changes

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