From tim6l–(at)–lonline.com Wed Oct 16 23:01:05 CDT 1996
Article: 24910 of alt.guitar.amps
Path: geraldo.cc.utexas.edu!cs.utexas.edu!howland.erols.net!feed1.news.erols.com!super.zippo.com!zdc!zippo!news
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 2×12″ 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 4×10″ 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
