Has anyone read this?

[jckid649]

I came across this article from Dr. Z and in it he talks about some of Ken's influence in the way he designed amps. Particularly he spoke of the OT's Ken used and how he designed them. It seems that there was more to it than just simply the kind of iron that was used or Ohm's. He even said that the material the laminates were made out of and the way he had them stacked and the unique impedance's that he used were a big secret. He said when he followed Ken's advice in designing the OT's for his Z-Wreck's that it opened up a whole new world in the way an amp can sound.

Has anyone heard any of this before or took into account any of this when looking for trannies?

[brewdude]

How do I get into the article to read it?

[roberto]

Click on "Download" on the right side of the attachment.
Depending on your browser it will pop-up another web page, or adobe.

[funkmeblue]

do a search here on the amp garage and you will find mr. z explains the output transformers

[martin manning]

There are several variables to play with when designing an output transformer, including core size, type of steel, and interleaving pattern. My impression is that the trades for increasing bandwidth and minimizing losses vs. size and cost are well known, but the subtler effects on tone quality for a guitar amp are more of a black art. See: http://www.duncanamps.com/technical/transformers.html

I don't know what to think when I see something like the quote below. Is this a deliberate attempt to confuse or just poor editing?

[M.Z.] I’d do the standard Marshall EQ, the cathode follower, the basic
front end, but on the back end I’d do this 6V6 design that will
be cathode biased, and I’m going to do it split-load cathode
bias, and because of that, I’m going to be able to do this true
half-power switch. And it really is half power without changing
the tonality or feel of the amp at all. I probably should
have patented it, but you know, that’s expensive, and then I’d
have to spend time enforcing it.

TQR: I can think of better ways to spend your time.
Believe me.

TQR: So the amp is running on two or four power
tubes…

[M.Z.] Yes, and I played the game with the output transformer and split
the difference between the 8K and the 4K ohms so it works
very well with 4K and with 2K. That’s the problem when you
go to half power. Like in a Twin, if you pull two tubes you
should actually increase the speaker impedance load by half.
The same thing with a Marshall, but my amp does that internally.

[roberto]

I think simply some distracted words (half instead of double) of a person that knows what to do and it's tired to explain always the same things. It happens to everybody I think. The righ one would be:

Yes, and I played the game with the output transformer and split the difference between the 8K and the 4K ohms so it works very well with 4K and with 2K. That’s the problem when you go to half power. Like in a Twin, if you pull two tubes you should actually increase the speaker impedance load by double.

He problably has a 3dpt switch: cathode resistor and OT taps.
One pair of tubes has EG 220R and 220µF in parallel to ground, the other pair (the one switchable on or off) just a 220R in parallel to the other 220R.

[kwijabo]

not to knock on the good dr. since he has kindly posted here in the past, but i think that's a bit of marketing hype. you want to patent a switch that cuts the signal from two output tubes? who knows though, maybe it could fly.

also, i read the phrase "increase the speaker impedance load by half" five times to make sure i wasn't reading incorrectly. obviously, you cannot increase something by half. you can increase it by 50%, but not by half. i don't know if it was poor editing or just mis-spoken.

anyways, i posted what i think the schematic is before:
https://tubeamparchive.com/viewtopic.ph ... highlight=

i think it is two sets of cathode cap/resistors. the input to the grids get grounded or sent through on two of the output tubes. this way they're always drawing current and keeping the voltages the same, 1/2 or full power. then the OT is set in between what it would need to be for a full tube set or 1/2 tube set.

[jckid649]

What I'm interested in about the article is the way he said Ken designed his tranny's. It may be a question better suited for Rj or Allyn since they are the 2 guys that are most referenced for carrying the Pacific tranny's, but I just wonder if any of them knew about the laminate issue.

[VacuumVoodoo]

Different core laminations stacking patterns - it's old stuff, even mixing different iron qualities in same core has been done long before old geezers like myself were born. Not to mention that every winding sectioning and layering scheme has been tried, tested and documented.
There are old books and even more relevantly, old patents to study if you want to learn.
As for magic mojo in guitar amp OTs, just remember that iconic sounds came through the cheap, simple generic transformers often bought from surplus stocks. There were no dedicated guitar amp OTs.
Since not many people have the necessary in depth knowledge today -unfortunately even among some of current transformer manufacturers - it makes a fertile soil for myths and mystery tales. Don't despair though, there are still a few of us around who can design an OT from ground up on a napkin.

[jckid649]

Different core laminations stacking patterns - it's old stuff, even mixing different iron qualities in same core has been done long before old geezers like myself were born. Not to mention that every winding sectioning and layering scheme has been tried, tested and documented.
There are old books and even more relevantly, old patents to study if you want to learn.
As for magic mojo in guitar amp OTs, just remember that iconic sounds came through the cheap, simple generic transformers often bought from surplus stocks. There were no dedicated guitar amp OTs.
Since not many people have the necessary in depth knowledge today -unfortunately even among some of current transformer manufacturers - it makes a fertile soil for myths and mystery tales. Don't despair though, there are still a few of us around who can design an OT from ground up on a napkin.

It's too bad that someone doesn't compile all of this knowledge together into some kind of course. I'm sorry but to me the Fischer family is being selfish by trying to hide and conceal everything that Ken knew and keep it all from the world. Exactly what good can come of that. They aren't making a profit from it. It seems from everything that people have said about him he seemed like someone who liked to teach people who really wanted to learn and move forward with amp designs. If they actually had the best interests of his legacy at heart they would disseminate his wisdom.

I do have to say I have heard so many people say, "There was no "magic" or "mojo" in what those old designers who started Fender and Marshall did. They just used what was available at the time." First, I understand that they did what any business would do: Build the best product they could at the lowest price possible without overly compromising the quality of the product. This is the philosophy that they started with and the one that continues.

However, I suggest that what was available to them at that time happened to combine itself in such a way as to create a truly outstanding product that, though they follow the same philosophy, does not reproduce the same product. Some of the greatest creations were not on purpose. Marshall was trying to recreate a Fender for crying out loud.

Every area of industry proves that quality has slid over the years as corporations cost cut at every corner and quality degrades, being the least important to a business's bottom line.

Everything in the audio industry seems to be leading toward cleaner and cleaner, more digital, more processed, lower noise....essentially More Sterile. They aren't designing with guitar amps in mind. That's why so many new designs sound like crap.

Instinct and good ears are giving way to science and overly educated minds. Sometimes what works doesn't make sense on paper. That's why people like Ken sometimes sound like they are crazy with some of their ideas because we are outsmarting common sense nowadays.

I'm glad that there are a few guys left that know how to do some of this stuff, but if it doesn't get passed on in a more complete way it will be lost forever and what a tragedy, as we have already seen with the Fischer legacy.