I think i'm back !

[Chuck H]

FWIW I had to repair a Fender Custom Shop amp head, I guess it was a design by "Mr Zinky" or whatever pothead (in a bad way) "guru" they had hired at that point, and it was 3X as bad (not kidding) , it looked like a joke, most parts which were meant to be joined together were placed at far ends of the chassis so you had dozens of wires going end to end many times and others crisscrossing from pots, jacks and switches to tube sockets.
And it was *all* white wire , no colour coding at all, except for transformwr wires which were factory coloured.
Not kidding , the amp must have weighed an extra pound just because of all that wire.

Bruce Zinky is actually a revered circuit designer, BUT... He hasn't worked directly for Fender for many years, HOWEVER... Pretty much all of the channel switching Fender Pro Shop designs are "based" on only two Zinky designs from when he worked there. Most end up being little more some idea kludged into or out of one of Bruce's designs and what you have is the result of many years of other designers retrofitting and nudging one or two Zinky amp circuits that they don't even make anymore as they were originally. Bruce is no more responsible for what comes out of the Fender Pro Shop than Ken Bran is responsible for the layout and lead dress in any number of Marshall clones.

I'm actually a Zinky fan. Does it show?

[J M Fahey]

Yes it does
Iīm not talking sound or design but execution, amp was definitely one of his, I guess those were dropped when he left.

As of Ken Bran, you canīt blame (or praise) him for JCM800 or 900 but he was definitely there in the early Plexi era.

This Fender amp was definitely from Mr Zinkyīs era and if it ever was shipped to a customer that way, then he approved it.

A plant manager can be forgiven (not really) if one crazy amp assembler came one wild day on a very bad mood and fully messed , say, wiring one of the 2000 HRDLX being built that week by wiring *everything* with a 12" piece of white wire, even 2 points half an inch away (result would have been similar to what I had to wade through) and somehow manage to bolt that chassis to an awaiting cabinet without anybody else noticing it (VERY unlikely by the way, because work is split between sections and chassis are open topped) bit itīs impossible in the very small Custom Shop environment with its very low , boutique type production.
IF somebody wired and delivered it that way, itīs because it was accepted practice,or the sloppy/mad wirer would not have been able to do it.

Again, I donīt say a word about Mr Zinkyīs designs, sound or personality ........ , but what I saw, I saw with my own eyes.

In fact, a normal, boring Engineer or Tech doing standard QC there would have not allowed that, unless over ridden by somebody above him with more golden braid on his shoulder.

Pity I didnīt take pictures .

In fact, I *have* wired amps on a couple occassions, out of necessity , with single colour wiring, once with split away 2 conductor lamp cord, but I have identified wires with some colour dots at each end, either black sharpie on light coloured ones or white typewriter correction fluid dots on the darker ones or black.

[J M Fahey]

50 years ago, I was in college as a physics major. I took some computer classes. We studied a language called FORTRAN. We had to "type" our programs line by line onto IBM punch cards. We sat at a console with a keyboard, and card after card fed into it from a hopper, and we hit the keys which punched out holes in the cards. The famous hanging chads of the 2000 election.

The punch card machine was programmed by this large panel inside a hatch. It was full of jumper wires that connected various functions. In fact all teh equipment used them, the card readers, the line printers, and the card sorters.

What does this have to do with anything? Well those programming punch boards looked like this:

Wow !!! Long time no see!!!!

Well, I am much younger than you ....

ok , tick "much" off, or replace with "slightly"

and also programmed in FORTRAN, used perforated cards or, because they were somewhat expensive and always in limited supply, very often used its poor cousin: perforated tape

I still keep a couple, would love to get somebody who could read and decode/print them.

We had limited access to the mighty IBM 620 computer (or was it 1620?) in its air conditioned, dust free room, so in practice used it mostly for complicaded statistical or error correction analysis, while regular design calculations were done pencil and paper (not even 4 operation calculators available) or themighty slide rules, of which I still keep a couple , and still use (on purpose ) at elecronics shop desks when ordering stuff.

50% donīt care, 50% shout "wtf is that?" and canīt believe something with no keys or display, let alone batteries, can perform complex calculations with less than 1% error (perfectly acceptable in Engineering) and WAY faster than the time it takes them to *type* the problem.





FWIW even Isaac Asimov, who imagined human like robots with their positronic brains , did not extend the analogy to computers or calculators and astronavigators in his SF novels calculate hyperspace trajectories with slide rules

[DRH1958]

Bruce Zinky is actually a revered circuit designer, BUT... He hasn't worked directly for Fender for many years, HOWEVER... Pretty much all of the channel switching Fender Pro Shop designs are "based" on only two Zinky designs from when he worked there. Most end up being little more some idea kludged into or out of one of Bruce's designs and what you have is the result of many years of other designers retrofitting and nudging one or two Zinky amp circuits that they don't even make anymore as they were originally. Bruce is no more responsible for what comes out of the Fender Pro Shop than Ken Bran is responsible for the layout and lead dress in any number of Marshall clones.

I'm actually a Zinky fan. Does it show?

Zinky designed the Prosonic which IMHO was a very good amp. Very un-Fender like amp.

[g1]

I'm not joking to say this wiring nightmare may be part of marketing a custom shop "hand wired" non-pc board amp. To the layman some gut shots might appear 'exotic'.

[J M Fahey]

This is whatīs to be expected inside a handmade amplifier, where the builder is definitely not OCD afflicted about wiring neatness but itīs still functional and repaireable (as in you can follow wiring and it makes sense).




This is a partial view of a Fender Tonemaster and quite similar to what I repaired:


Think **all** wires being white, not some red/blue/black as here and add some 50% more and youīll be much closer

[Chuck H]

I'm glad you made the effort to find an image. What a turd. No excuses. My Prosonic certainly didn't look like that inside. I'm still calling shenanigans about Zinky's involvement in that mess. I mean, he WAS part of a team and therefor not the only one making decisions. Even it he did design the circuits. The other possibility is that his proto looked that bad and they straight up duplicated it rather than refining it. Still... Thanks for the mess.

[Enzo]

I don't recall what it was. I don;t recall a lot now days. But I do recall getting a Fender something or other once that was a sea of white wires inside. I remember thinking WTF myself, and that was before "WTF" became a thing. The industry was using wire colors purposely 80 years ago. That is where the idea that transformer wires might be consistent colors came from, at least in the USA. And Fender had been using colors for decades already. I had to wonder what gave them the idea to do this. It is one thing to grab a roll of wire and go hide out to build a prototype, but a production amp???

[KevinOConnor]

Hi Guys

Daz, your two tube amps might have had much different supply voltages and that can make a difference to how they respond to changes and how they sound loud or quiet. If you reduce the supply voltage to the preamp alone, the tone will become rounder and warmer - I'm referring to significant changes not just 10s of volts.

High-voltage tube circuits tend to be very clean and for distortion can have very good sustain. However, because the signal windows are much larger, it takes a lot more drive to get to distortion and the touch response of the amp is spread out over a larger attack of playing. In some ways this can give a more consistent sound over a wider loudness range, but once you get to the compression point it can seem more dramatic.

The low-voltage preamp and amp has a narrower attack response range due to its smaller signal windows. In some ways, its tone might seem more consistent with level since it is already warmer playing quietly and the compression point seems less dramatic.

The output tube difference certainly plays a role in all of this. EL-34s have a much more open tone than a 6V6, and a much brighter one if you like the "brittleness" (some consider it harsh). The V has a creamy tone, just a lot more inherent distortion with this tube and it can easily sound muddy. A quad of Vs sounds much cleaner than a single pair, but not as clean as a pair of 6L6s. This power tube difference makes for a significant difference between how the two amps play. If the bias range is adjustable and there is sufficient heater current capacity, you could try TL-34s in the small amp, and you could have tried 6V6s in the big amp if you still had it.

The 100k from the MV wiper is my mod, shown in TUT back in '94. It makes the tone versus MV sweep more consistent.

PS - I have to say I'm impressed with the 'save' feature of this forum. I just typed all of the above and went to post it and the system said I wasn't logged in - which I had been. Thought it was all lost, but logged in and here it is!

Have fun

[Justin Thomas]

loudthud, is that a real schematic, or a joke somebody drew up?

I know this thread is ancient but I of course cane here looking for info about these now that I own one. It's a real layout. Trying again to post this pic.