dp
Joined: Feb 26, 2006
Posts: 3546
mojave desert, california
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Posted on May 14 2006 12:11 PM
Ivan:
I hear you! I'm sure that Bassman hit the stores sometime in late 1968 or so...mainly beacuase of the weird speaker cabinet that came with it. The speaker cab I have is a 4x12 Bassman Silverface monster...but, the speaker arrangement is kind of weird and unique: the speakers are arranged in a "diamond" pattern (top, bottom, right, left) and the the baffles form a inverted pyramid sort of shape. Really odd. But it sounds nice. That style 4x12 cabinet was released in 1968, from what I can tell.
Thanks for bringing up the dating issue. It's always challenging to figure out the dates (and history) of vintage gear. I'm glad I finally learned how to read the transformer codes.
-dp
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dp
Joined: Feb 26, 2006
Posts: 3546
mojave desert, california
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Posted on May 14 2006 12:22 PM
IvanP
... In my January '64 Showman, two of the transformers are from the middle of '63 and one even from '62! So, even though your tranny is from '67, it doesn't necessarily mean that the amp is from '67 ...
Ivan:
You post points to the major production changes that occured at Fender post-1965. When CBS took over, production philosophys, procedures, and techniques underwent considerable change. The sheer volume of units produced increased dramatically. Weird serial number combinations obviously occured as the new production ramped up. Old components and new were combined in order to meeet greater production goals. Your Showman was literally built at a different Fender facility (pre 1965) than the one that built my Bassman (post 1965)!!!
-dp
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unlunf
Joined: Feb 28, 2006
Posts: 106
The Vatican
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Posted on May 14 2006 02:09 PM
Dave,> .....
Old components and new were combined in order to meeet greater production goals. Your Showman was literally built at a different Fender facility (pre 1965) than the one that built my Bassman (post 1965)!!!
-dp
Well, that's true in the strictest sense, but only because CBS consolidated many, if not all, of Leo's small buildings into one giant factory of 175,000 sq. ft. (!) All the parts (and their bins) were carried over to the new building, so the manufacturing process didn't suffer as a result. (Nor did it improve, either.)
My personal take on all this "history" is that it has become a catechism to set things in stone, and pretend that there's no possibility of any variances. In the reality in which I participate, I have found that Fender, both the Leo and the CBS versions, have had many lapses of faulty record keeping, and many more occasions where "an authority who ought to know" was quoted incorrectly - or worse, that person intentionally misspoke himself. This has gone on almost since Leo sold to CBS in late '64, but it has certainly been musrooming since his passing in 1991. Even books by Forrest White and others disagree on what was done, when it was done, and how and where..... it's all a hazy mish-mash to me. And I was there. No, not in Fullerton CA, but I was alive and active in the scene, even if a thousand miles removed.
So I'd like to offer this little tidbit, if you will. Both as an aspiring musician, and as an erstwhile technician for more than 40 years in the pro music field, I have seen a great number of what I'd call "transitional" products come out of all of the major factories of that era, not just Fender. It was well known that Leo liked to save a buck when he could, and he'd buy a pallet of transformers if that's what it took to get the best deal. The fact that it took a year or even two years to use up that stock was of no concern to him, he was of the mind, "I've got the space to store these, why not use it, and save a bundle on the purchase price?" Not hard to see why a '63 xformer shows up in a '64 chassis that gets stuffed into a '65 cabinet by CBS assemblers. Other examples abound, the aforementioned "Fender Amps" book details several of them.
Remember, the catalogs were "cast in concrete" as far ahead as 6 months prior to the actual sale of their products. In those days, there was no such thing as "print on demand"! This gives us the very easy likelyhood of amps like yours, which falls into the 'transition' category.
Which is really all a "who cares", so long as it sounds good, right? 
HTH
unlunf
— MY RIGHT HAND IS FASTER THAN YOURS!
(copyright 2003, Bruce Welch)
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dp
Joined: Feb 26, 2006
Posts: 3546
mojave desert, california
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Posted on May 14 2006 05:15 PM
unlunf
...Which is really all a "who cares", so long as it sounds good, right? ...
unlunf:
I agree with you: it's the sound that matters most when it comes to old amplifiers.
I think it's also kind of fun to do the detective work and see what you can find out. Maybe you'll find some valuable information, maybe not.
-dp
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holikujak
Joined: Apr 03, 2006
Posts: 107
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Posted on May 15 2006 04:55 PM
oooooooo, it just arrived today! its beautiful.
question though i know the 12at7 is at the end farthest towards the tube but where do i put the other tubes? i have a jj ecc83s, ei 12ax7eg. and a mesa 12ax7a i suspect these are all the same as the mesa also has ecc83 on it but i dont want to kill my amp
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holikujak
Joined: Apr 03, 2006
Posts: 107
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Posted on May 15 2006 05:09 PM
also whats the difference between the speaker jack and ext. speaker jack in the back of the amp? which one do i plug into my speaker?
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holikujak
Joined: Apr 03, 2006
Posts: 107
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Posted on May 15 2006 05:50 PM
oooooooo forget those questions, i figured them out. it sounds SO NICE! this amp and 24 means im getting no work done tonight. also this vox big ben overdrive pedal came today and its a great combination! its nice and subtle and really fills in the sound, while not touching that sparkly clean sound. now this is what an amp should sound like!
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dp
Joined: Feb 26, 2006
Posts: 3546
mojave desert, california
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Posted on May 16 2006 10:22 AM
h-jack:
again...congratulations!!!
the tube installation: 2 x 6L6, 1 X 12AT7, 3 x 12AX7 (aka 7025)...all in a row from left to right...
you want to use the "speaker" jack as your main 4 ohm out...the "external speaker" jack is for any extra speakers in-addition to the original load.
sounds like you are now under the spell of the "Bassman Effect"!
you'll never hear guitar music the same again!
-dp
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diceophonic
Joined: May 20, 2006
Posts: 2174
PacNW (Vancouver, Wa U.S.A.)
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Posted on May 22 2006 03:05 AM
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WR
Joined: Feb 27, 2006
Posts: 3832
netherlands
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Posted on May 22 2006 04:12 AM
Kyle, thanks for that, that's good info. When I got my (early SF) bassman, I was told it was 'blackfaced' but I never even bothered to check, it sounded okay. these things are never about good or bad but always about good or better. I might open her up and check what the circuit actually is / has become, maybe there's room for improvement huh?
WR
— Rules to live by #314:
"When in Italy, if the menu says something's grilled, don't assume it is."
https://www.facebook.com/The-Malbehavers-286429584796173/
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diceophonic
Joined: May 20, 2006
Posts: 2174
PacNW (Vancouver, Wa U.S.A.)
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Posted on May 22 2006 10:01 AM
Hi WR no harm done I thought I would share what I know about
AB165 circuit Vs AA864 circuit:) I'll hunt down the Schematic's Yeah thiers no bad or good your right, yeah take a look at the guts and see what you see sometimes thier will be surprises:) hhmmm??? also the cool thing is you can make any bassman and any Fender point to point amp back to old school circuit.
Cheers
— -Kyle
Beyond The Surf YouTube channel
Beyond The Surf Instagram
The Verbtones @ Instagram
The Verbtones @ Facebook
The Verbtones @ bandcamp
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WR
Joined: Feb 27, 2006
Posts: 3832
netherlands
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Posted on May 22 2006 02:03 PM
diceophonic
Hi WR no harm done I thought I would share what I know about
AB165 circuit Vs AA864 circuit:) I'll hunt down the Schematic's
just in case - there was no sarcasm in my post! yeah, I'd love to try out the AA864 schematic - http://www.schematicheaven.www is my second favorite site 
PS, that's one pretty looking amp you've got there - if mine looked as neat on the inside, I wouldn't want to put it back in the cab!
WR
— Rules to live by #314:
"When in Italy, if the menu says something's grilled, don't assume it is."
https://www.facebook.com/The-Malbehavers-286429584796173/
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diceophonic
Joined: May 20, 2006
Posts: 2174
PacNW (Vancouver, Wa U.S.A.)
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Posted on May 22 2006 06:44 PM
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unlunf
Joined: Feb 28, 2006
Posts: 106
The Vatican
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Posted on May 23 2006 01:42 AM
dice,
I agree with Wannes, a clean amp is joy to behold. 
Your earlier post showed the inside of the speaker cab. I see the fiberglass batting that Fender installed is AWOL. Did you do that, possibly on someone's recommendation, or did it come to you in that condition? You should get some pictures and see how the factory installed common R-13 insulation over all the wood surfaces to reduce possible vibrations, and to tighten up the bass. It does make a big difference, but better yet, it's a reversable mod - if you don't like it, just pull it back out (and the few staples needed to hold the upper pieces in place).
I need to make a few comments on your 'knowledge' about the CBS circuitry versus the AA864.> When I got my 65' bassman it was stock AB165 circuit my amp tech told me that the AB165 & AA165 circuits are not the greatest becuase the AB165/AA165 circuits which was quite a departure from traditional Fender circuits pre-CBS, The BASS channel and NORMAL channel are not really voiced well for guitar or bass guitar and is often not used and the normal channel does not have much head-room even with better speakers it would not matter it's all in the circuit layout, AB165 circuit conversion rebuilds the entire circuit board so the NORMAL channel is the more desirable AA864 circuit pre-CBS (about like the NORMAL channel of a Super Reverb) and the BASS channel becomes a really cool lead channel with a tweed/Plexi flavor to it and killer bass tone for bass guitar a true bass circuit. in 1965 Fender was bought by CBS and the first amp CBS messed with was the Bassman and so we have AB165/AA165
from 65' to 70's but in 1964 the layout for the bassman was AA864 this circut is tones better so I had mine back-dated to AA864 and man what a change from AB165 to AA864 anyways but if you dig AB165 right on but check into to it?
Having graduated from Parents School cum laude, I was able to decipher your 90's English, and ended up with the following:
You said that your amp is an AB165, but that your tech maligned both that and the alleged AA165. Question - can you (or he) produce any evidence of any AA165 schematics, please?
You said that your tech recommended that you revert the amp to AA864 specs, and that doing so would yield a tone akin to a Super Reverb. According to all the reference material I can lay my eyes on, the tone stacks for both circuits, channel for channel, are the exact same - no differences at all in the component values or layouts. Moreover, the Super Reverb of the day (AA and AB763) had entirely different tone stack values. While it would be fairly close, I don't think anyone would mistake a Bassman for a Super Reverb, tone-wise.
You said something about somehow getting a tweed/Plexi tone from this reversion. Come again? If the tone stack is the same as has been used for several years, then I have to wonder, how come no one else has made this comparison before?
You said that the Normal channel didn't have much headroom, and that even with better speakers, it wouldn't matter, it's all in the layout. Come on, man, this is getting a little far-fetched, don't you think? Let me lay it out here - When you signed up for this forum, one of Brian's bullet points was that if you spread BS, you will get caught out. Here's where the hook is gonna get set, but I'll try to be gentle. 
Headroom is not a function of any pre-amp stage, it is derived from a combination of the power supply and the power-amp stage(s). A very casual glance at a schematic will tell even a novice that the two pre-amp channels are constructed so similar to each other, that what affects one has to affect the other. IOW, if the Normal channel has no headroom, then neither does the Bass channel. And to cap it off, parts layout will affect some rather esoteric phenomena, but not headroom. Ditto for the speakers, no effect on headroom here, either.
Doubtless you garnered all this at your tech's knee, and that's fine (especially since you paid for it). But while you should listen to him, I strongly suggest that you don't do so in blind faith. Always question everything you hear, especially if it purports to be a fact that can be verified. I've just called into question many points, and you should follow my advice just given - question what I've said here. Go to www.schematicheaven.com and check out the Bassman schematics, particularly the tone stacks. Hunt for an AA165 schematic - if you find it, I'll eat crow, right here, in public. 
Ask questions. I can't repeat that enough. In fact, the only stupid question is the one you don't ask. 'Nuff said.
No hard feelings, right? Just setting some of the record straight, that's all. 
unlunf
— MY RIGHT HAND IS FASTER THAN YOURS!
(copyright 2003, Bruce Welch)
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diceophonic
Joined: May 20, 2006
Posts: 2174
PacNW (Vancouver, Wa U.S.A.)
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Posted on May 23 2006 03:25 AM
Unlunf good points but hey I ain't no Amp tech geniuse, the beauty about forums is that one can spread the love of what one know's or what you think you know and learn as you go with an open mind, pass on helpful info to one another, learn from others, trial and error baby!!
The kat that rebuilt my bassman is one the best amp guys in Portland Oregon named Opie http://logaudit.net/opie-lux/
http://myspace.com/opielux
Short and sweet
AA864 Bassman's and 6G6-A, 6G6-B Bassman's are more desirable circuits and better sound'n then
AB165, AA165, AA568, AA270, AA371 Bassman's circuits
I see the fiberglass batting that Fender installed is AWOL. Did you do that, possibly on someone's recommendation, or did it come to you in that condition?
I got the cab this way without the fiberglass insulation minus the speakers
image
image
image
image
image
Bassman AA165 - Schematic
http://www.prowessamplifiers.com/schematics/fender/download.php?sFileID=267
No hard feelings, right?
Cheers
Kyle
— -Kyle
Beyond The Surf YouTube channel
Beyond The Surf Instagram
The Verbtones @ Instagram
The Verbtones @ Facebook
The Verbtones @ bandcamp
Last edited: May 23, 2006 12:35:36
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WR
Joined: Feb 27, 2006
Posts: 3832
netherlands
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Posted on May 23 2006 03:57 AM
you beat me to it kyle, that schematic is also listed at schematicheaven. bon appetit, unlunf.
one more point, since you mentioned it in anoother thread too: i think for all practical purposes and from a players pov, speakers do have headroom, defined as 'the amount of volume you can get before distortion and/or compression kicks in' - I know some technicians define power rating as 'power handling before distortion', thus begging the question and claiming a lower power rating for that praticular speaker. but form a players pov (and a guitar technicians pov I'd suspect) power handling as defined as what it can take before it blows all to hell. in fact, many speakers are designed to break up and distort early.
I personally like to set the amp exactly so that I get a slight break up form the JBL's - and I like that better than amp's break-up. but that's a matter of taste I guess.
nuff said
WR
— Rules to live by #314:
"When in Italy, if the menu says something's grilled, don't assume it is."
https://www.facebook.com/The-Malbehavers-286429584796173/
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diceophonic
Joined: May 20, 2006
Posts: 2174
PacNW (Vancouver, Wa U.S.A.)
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Posted on May 23 2006 09:57 AM
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unlunf
Joined: Feb 28, 2006
Posts: 106
The Vatican
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Posted on May 23 2006 12:30 PM
Ya know, my father once said, "If I'd known at your age what I know now, I'd have set the world on fire."
Took me a long time to understand what the hell he meant. Somehow I think it's gonna take you guys even longer.
Toodle-oo!
— MY RIGHT HAND IS FASTER THAN YOURS!
(copyright 2003, Bruce Welch)
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diceophonic
Joined: May 20, 2006
Posts: 2174
PacNW (Vancouver, Wa U.S.A.)
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Posted on May 23 2006 12:45 PM
Hey Unlunf give it up man if your wrong or right cool just learn to take the blows, swallow your pride and be humble dude, Hey I am also diggin' my youth man and I will always be Hungry for Knowledge and info till the day I die if it be life or music etc... that's what life is about!! trial and error baby!
— -Kyle
Beyond The Surf YouTube channel
Beyond The Surf Instagram
The Verbtones @ Instagram
The Verbtones @ Facebook
The Verbtones @ bandcamp
Last edited: May 23, 2006 13:13:36
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WR
Joined: Feb 27, 2006
Posts: 3832
netherlands
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Posted on May 23 2006 01:07 PM
unlunf
Ya know, my father once said, "If I'd known at your age what I know now, I'd have set the world on fire."
Took me a long time to understand what the hell he meant. Somehow I think it's gonna take you guys even longer.
Toodle-oo!
Know what Unlunf, I'll just refer you to Schopenhauer's Eristische Dialektik oder die Kunst Recht zu behalten to show how that argument is not valid even if it's right. (and to not make the same mistake and in case your german isn't what it used to be, I'll summarize: relying on any kind of aspect of the messanger to render the message valid is unfair and invalid debating tactic. so is relying on your age, (undocumented) experience or your father.)
crnch - shifting back into friendly gear - crnch
WR
— Rules to live by #314:
"When in Italy, if the menu says something's grilled, don't assume it is."
https://www.facebook.com/The-Malbehavers-286429584796173/
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