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Post by blademaster2 on Oct 13, 2021 5:21:08 GMT -5
I picked up a Princeton '64 handwired combo recently and I was hoping to find the schematic (for reference, I have no intention of modding it).
Online (Vintage Fender Amp Repair) I saw the AA1164 listed for the Princeton Reverb, which looks to be the same circuit as my amplifier based on the features and tube configuration and the title block, however the literature that came with the amplifier said it was a handwired AA764 circuit.
Looking up the AA764 circuit on the same site it is for a Blackface Champ instead, had fewer features and cannot be the same as my amplifier. I cannot imagine Fender listing the incorrect schematic reference in their literature, so the only explanation I can see is that they changed their circuit reference numbering.
I will keep looking for more information, but if there is anyone out there who can quickly answer my query I would very much appreciate the help.
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Post by thetragichero on Oct 13, 2021 10:36:33 GMT -5
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Post by blademaster2 on Oct 13, 2021 18:52:34 GMT -5
Thanks!
As a handwired circuit I can imagine some differences, but the AA764 printed on the card that sat on the top pf the amp - and the accompanying description - do not match what is on that website. Additionally it does not fully match the AA1164 either since the preamp tube is different.
I will keep digging.
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Post by thetragichero on Oct 13, 2021 19:56:22 GMT -5
what's similar and what's different?
"handwired" is such an interesting marketing term. it evokes such idyllic images of craftsman but could just mean the pots and jacks are chassis-mounted and connected to the pcb by wire instead of traces (which could potentially cause more problems than it solves. a good pcb is a pretty incredible thing and certainly a must for high gain amps). this is not so much directed at you as it is shaking my fist in general in the direction of marketing-speak
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Post by blademaster2 on Oct 13, 2021 23:10:02 GMT -5
Yes, all points that I had considered as well.
The handwired amplifiers are made with turret boards (there might be a better name for these) as opposed to printed circuits. They look totally different compared to the printed circuit versions. That means that the dielectric material insulating the conductors for many connections in it will be different, and *perhaps* the resulting differences in parasitic capacitance is more evident in a high-impedance tube circuit than we might expect for a lower-impedance transistor circuit. I do not myself ever expect to hear any difference, of course, but it is conceivable that the complex wavefronts of audio signals and their transient responses will be subtly different in this type of construction for a tube amplifier.
The circuitry is therefore harder to construct, and might be necessarily simpler/different than a printed circuit implementation (which is why I want to see the circuit myself). One thing for sure is that it will be easier to service, including the pots (I have been frustrated in other items where a pot is easy to find with the same value and taper, but much harder to find where the replacement will install easily onto the printed board). It may well have more reliable solder joints also.
"Marketing-speak"? Quite possibly - and since I cannot A-B compare against a PCB amplifier of the same design, and will not spend the money to do so, I will never know if I could ever vouch for any difference at all. I will never become a salesman for these models but I am also aware that subtleties that are audible are difficult or impossible to measure with instrumentation, observe, or prove in a scientific sense. The craftsmanship of the cabinet is also noticeably superior to, say, my VOX AC15C1. For me, it is an indulgence I can afford and I am willing to pay the difference (also employs Americans to do the assembly, and although I am Canadian I do like the notion of supporting our North American continent however I can as opposed to offshore).
You are correct to remain skeptical, no question. I am also.
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Post by reTrEaD on Oct 16, 2021 18:46:24 GMT -5
I picked up a Princeton '64 handwired combo recently and I was hoping to find the schematic (for reference, I have no intention of modding it). Online (Vintage Fender Amp Repair) I saw the AA1164 listed for the Princeton Reverb, which looks to be the same circuit as my amplifier based on the features and tube configuration and the title block, however the literature that came with the amplifier said it was a handwired AA764 circuit. Looking up the AA764 circuit on the same site it is for a Blackface Champ instead, had fewer features and cannot be the same as my amplifier. I cannot imagine Fender listing the incorrect schematic reference in their literature, so the only explanation I can see is that they changed their circuit reference numbering. I will keep looking for more information, but if there is anyone out there who can quickly answer my query I would very much appreciate the help. , amps of the Blackface era have some strange numbering in their documentation. The numbers indicate the date (month and two-digit year) but aren't specific about the model to which they belong. For instance, the schematics for blackface Deluxe, Deluxe Reverb, Super Reverb, and Twin Reverb all share the AA763 (or the later AB763) designation because they were designed in July of 1963. But they are all quite different from one another. The blackface Princeton had a few different versions. The transitional model AA763 with volume, tone, speed, and intensity contols, the updated version AA964 with volume, treble, bass, speed, and intensity, and the Princeton Reverb with volume, treble, bass, reverb, speed, and intensity. It sounds to me like this Princeton '64 'handwired' is basically a reissue of the AA1164 Princeton Reverb. It's likely to follow the same schematic and layout, although it would be prudent to use your eyes and carefully verify. I can say will near-certainty that they've abandoned the Fender Death Capacitor and are instead using a 3-wire power cable. But there might be other changes, as well.   We can never have too many sources for antique information. Here's another one you can add to your arsenal: The Fender Amp Field Guide |
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