Sell or mod my 64 bassman AA-165?

Rock on,

That is great on the low powered tweed twin clone.

So then obviously you don't want another blaceface
tone. You are on a budget, so I would mod that little
head that you have. You'll get the most bang for the buck
that way too.

Success, indeed. I've done a few of these and the guitarists love'em. In fact it makes most of the Marshall
friends jealous too. : )

Where in Texas are ya located?

email me at NOspikeoneSPAM at NOSPAM airmail dot net.

Remove NO SPAM to send.

or we can try out the new pm feature here.

 

Do NOT mod that amp. It's a very rare model - FWIW, it was made only for a month or so in very early 1965. Notice both it and the AB165 circuit have January 1965 dates codes, that's what the "165" means. Sell it to someone who cares about old Fenders, and buy a real Marshall or a good clone.

If it was a later SF Bassman (or maybe even a later BF AB165), there are thousands of them and it isn't any great loss, although I wouldn't personally mod any BF amp these days. The Bassman isn't the most desirable, but it's still not geting any more common, or any cheaper.

 

Yeah, good point, I didn't think of that.
Trying to figure what that might fetch...
Then get a later model bassman to mod.

Thinking anything descent is probably going to
cost more then the baseman to start with so
it is kinda a no win, unless he buys a crummier
bassman to build from.

He has budgetary constraints..any good Marshall
is going to fetch some $$$$ a good clone too.
And it sure as **** ain't going to be worth it
to dig into a TSL now is it?

 

I disagree about that amp being particularly rare, it does however, bear the infamous distinction of being the first Fender model to be screwed up by the CBS era regime! Yippee

Here is a link to some HC reviews of a Marshallized Fender mod I've developed and performed on scores of amps just like yours.

CLICK HERE TO SEE HC REVIEWS

 

Do you really mean AA165? I've never heard of that. I've heard of the 6G6-B, AA864, and AB165, but not a AA165.

http://acruhl.freeshell.org/mga/main/AA864_vs_AB165.html

 

My Bassman says AA165 on the paper chassis tag. PE stamped on the tag, is that the date code? I had it repaired, it had been repaired before with the wrong resistors and some wrong capacitors, now it is back to stock. I haven't had it that long so am learning new stuff about it all the time. Looking forward to this discussion.

 

The AA165 got the screwy bias balance circuit and the AB165 added the 220k feedback resistors.

 

I wouldn't modify that amp either. You will not get a convincing 18W marshall tone out of it IMHO. You should be able to get a decent amount of cash for that amp (although some of your signal caps have been replaced unfortunately) and with a little more you can pick up a used 18W or something like a Winfield or Pete Cage which are both great bang for the buck. They also sound really good! There are plenty of kits out there if you are so inclined as well.

Here's the link for Winfield:

Winfield

 

I guess modify is the word eh?

The amp has already been worked on already.

It is obvious that rock on isn't too happy with the
amp as it sits, otherwise he wouldn't think about
doing anything with/to it.

It is not original either, so we can dispense
with the collector value argument too.

The pics show a couple of my pet peeves too.

1. The way the power cord was installed.


2. The output socket "fix". If you are going to
do one, do them both.


Still the most bang for the buck is to make it into
some cool amp he'll use and be happy with.

AND

You can do it without drilling holes in it.

So why not?

 

Because, as fullerplast has already correctly noted, he's unlikely to get the results out of it that he's seeking ("a Marshall OD tone with a master volume"/"good classic Marshall tone at volume levels for home use").

Add my vote to the folks advising Rock-On!! to sell the Bassman and buy what he really wants.

 

Yes, quite extensively. There's a still a difference between that and 'modding' though. What's been done (although largely unnecessary and potentially tone-changing, in the case of the coupling caps) is still 'maintenance', and in any case could be put back to stock very easily.

Yes... I'd agree with both of those. I'm also unhappy with the way the screen-grid resistor is touching the wire from the PT.

It's got the wrong knobs too...

Still, I would guess that the most bang-for-buck is to sell it (it's still got some collector, or at least old-Fender-enthusiast potential) and buy something else.

Nah, that's an in-house screw-up. Although CBS did buy Fender at the start of 1965, I doubt they had a team of engineers lined up and waiting to get in there and mess with the products in the first few days!

What's interesting is how many amps they must have been cranking out then - the AA165 was made for only about a month, and yet isn't impossible to find. The AA864 is almost common, and that was made only from August '64 to Jan '65... five months at the most.

 

Lessee, this amp revision was January 1965, when CBS took over Fender, and the revision included the first of many "enhancements" associated with the CBS era that culminated in the '68/'69 silverface abominations that included not only the AA165s bias/balance, but the partial cathode bias and suppressor caps caps through out the circuit.

OK, perhaps if I reworded it without reference to CBS (although it may be difficult to prove or disprove the association).

How's this:

The AA165 bears the dubious distinction of being the first Fender amp to incur circuitry changes more often associated with the silverface amps that came out years later.

 

That's OK, the knobs seriously affect the tone and you should put them back immediately .


The power cord being connected with a 'chocolate block' is not good. It should have been stripped back further, then the core wires taken directly to the AC outlet. The screws in those little terminal blocks can work loose with time.

I can also see that the 'death cap' appears to be still present on the ground switch, even though the cord has been replaced with a 3-wire... get rid of that.

On the output socket, the new screen-grid resistor should be mounted directly above the socket (like the original one on the LH socket in the pic), with its leads as short as possible to stop it flapping around and stressing them. Also, it should (ideally) be a wire-wound type - that's a metal-film by the look of it. Wirewounds are the most robust when it comes to short-term overloads (like when a tube blows) and so more reliable. Also, if a tube does blow, that resistor will get very hot, so having a wire touching it is very bad practice since the wire insulation will melt.

Plus, as TheAmpNerd said, if you're going to change the resistors on one socket, do them both! Long-term heat cracking of the original carbon-comp resistors (both the screen-grids and the smaller grid-stoppers) is a known issue on old Fenders. That amp's been 'fixed', not 'serviced', in other words - most likely one or both of the replaced resistors broke.

Oddly, someone has gone to the trouble of changing almost all the original coupling caps, which was almost certainly not necessary. These are the yellow caps on the tag board. Changing the electrolytic caps (the small black ones) is a good idea - and it's been done, including the bias cap (often overlooked) but they've left the carbon-comp bias feed resistor, which can also be a good idea to replace...

Even more baffling, although they've changed most of the caps in the tone stacks (I've never seen one of those fail, ever) they've left the two phase-inverter-to-power-tube ones (the red ones at the RH end of the board), which are about the most commonly prone to leakage and the ones that cause the most serious trouble if they do!

Maybe done by more than one tech... it's quite random and not very logical, anyway.

 

Given that the circuit must have been finalized at the start of January 1965 - or else there wouldn't have been time to make any significant quantity of AA165s before the AB165 revision later that month - I'd take a bet that it was developed before the CBS buyout. Not only that, I really don't think any serious personnel (or design practice) changes happened immediately. Certainly not within days. I think it's unfair to blame CBS for everything that went wrong at Fender - they didn't help, but there are plenty of things that were definitely the fault of the previous regime too... for one, who do you think designed the infamous 3-bolt Strat neck? Leo Fender .

Most of the first obvious CBS features of the guitars started to come in mid-'65, so I'd think it's more likely that any CBS-inspired amp changes began about then too. I certainly don't think they came in on Jan 5th 1965 with orders to immediately downgrade and mess up everything.

I'd agree with that. I think sometimes these days it's hard to remember just how quick all these changes were though. We talk about the 'classic BF period' as if it went on for ever, but in fact it was less than five years - three of which were under CBS.