I guess we should cover this same ground again....
The ONLY amp that had the bright switch wired like Francesca WAS Francesca! The others that I have seen and been in, all had the Bright switch wired with the caps on lug 3 (Hot). The switch center lug goes to the wiper of the volume pot. The amps that I have built for real wreck owners are exact copies of their real ones. I post pics of the builds so everyone can see what they look like without violating the promise of not posting pics of the originals.
Ron thanks for all your work! You have provided the members here with workable layouts.
Allynmey wrote:I guess we should cover this same ground again....
The ONLY amp that had the bright switch wired like Francesca WAS Francesca! The others that I have seen and been in, all had the Bright switch wired with the caps on lug 3 (Hot). The switch center lug goes to the wiper of the volume pot. The amps that I have built for real wreck owners are exact copies of their real ones. I post pics of the builds so everyone can see what they look like without violating the promise of not posting pics of the originals.
Ron thanks for all your work! You have provided the members here with workable layouts.
Allyn- No sweat, I figure it's my way of giving back to all that helped me get smart enough to build the amp.... lots of dumb questions on my part that could have been avoided if I had had access to the information in an organized fashion. So now we do...
I too had missed this detail on the brite switch and the build guide needs to be updated to correct the misinformation on my part. I have, however, built 2 Express amps the "wrong" way and they don't suck... but I will be modifying my personal amp to the correct way to hear what this does for noise and tone.....
so what we're saying here is that two parallel caps (500pf and 100pf) which equal 600pf is what is used on the bright switch in most wrecks as opposed to a choice with the spdt switch choosing between either 100pf or 500pf values? If so, the lead on the 500pf cap should be brought to front and shown connected on terminal 3 of the switch in the layout.
However, this doesn't make since to me as 600pf is not a typical value for a bright bypass.
If however what is being said is that the two capacitors' common leads are going to terminal 3 of the volume control and their other leads are separated one to each end terminal of the bright switch with the center terminal wire going to terminal #2 (or the wiper) of the volume control then it makes no difference either way. There is no difference circuit wise if the cap commons go to the wiper (terminal 2) or terminal 3 as long as the bright switch wire goes to the opposite one of those two terminals.
I have only two photos of express amps in this regard. One is Franchesca and the other is unkown to me. They are wired opposite at the volume switch like described. So the real question is why is this even important? And Ron, there won't be any tonal change at all if you swap the wires at the pot on your previous builds.
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That second pic could be a clone, note input jack, switch, and resistor on input jack, perf board, etc., compared to the pic of the 'known' Francesca. It could perhaps be a clone of Kelly, looking at the bright switch anyway... ??? But, hello, whatt does Allyn say? To me it just looks wrong. Frankly, for $2K I think KF would have at least bent the legs of the .02 caps a little better....
Allyn, thanks for that info about the uniqueness of Francesca, BTW. Yeah, if you commented about that on this forum in the past a lot of people missed it, myself included. I will pay more attention.
bnwitt, you are right when you say 500 and 100 separately, not a combined value of 600pf. As to the sonic differences this hookup makes between Francesca and the amps that apparently (?) came later, you should just try it if you haven't. If you have and you can't hear any difference, then your point is valid for you. However the question remains then, why did KF make the change if it didn't matter? Eh, I tend to think that, like most people, he improved his game as he went along.
In my first amp it made a big difference, and right or wrong, I won't be experimenting with this again anytime soon on any other versions I build.
Most people stall out when fixing a mistake that they've made. Why?
I've done it both ways. I haven't put one of these together for a while but if memory serves me it's a little noisier with the caps connected directly to the wiper.
Allynmey wrote: ... The ONLY amp that had the bright switch wired like Francesca WAS Francesca! The others that I have seen and been in, all had the Bright switch wired with the caps on lug 3 (Hot). The switch center lug goes to the wiper of the volume pot...
That being said, you must have built this one (11/07) like Francesca
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rooster wrote:bnwitt, you should just try it if you haven't... In my first amp it made a big difference, and right or wrong, I won't be experimenting with this again anytime soon on any other versions I build.
rooster, how about quantifying this "big difference"? Tell me all about it in detail. Since schematically switching the two wires makes no difference, I am somewhat sceptical that this makes a tonal difference at all. And, since finding out that KF believed in wire polarity and had his own personal transformer aura guru, I don't take anything he did to the bank anymore. I'm beginning to wonder if psyclobin mushrooms were part of his amp building routine
This sounds like magic mojo BS to me. I promise the next TW express I build I will try it both ways on the spectrum analyzer, distortion analyzer and oscilloscope. Somehow I don't expect to get much out of that effort but if I'm wrong I'd like to know why. If you can explain it in detail that will help me set up the experiment.
Ron Worley wrote:Hell, I wasn't trying to start up a controversy
Ron
Don't get me wrong Ron, I'm an analytical thinker and need to investigate anything that flys in the face of common sense.
Everyone is free to believe what they want, but I have a need to qualify and quantify these types of things. I have read so many urban myths in the internet tube world that I am immediately skeptical when a statement seems to violate physics. I wish we had a snopes for tube amps. Very few of these urban myth conclusions are derived from double blind tests or even without minimal time between A and B conditions so they are ususally suspect for those reasons alone. Of course I am now wondering how many of these really fantastic sounding clones out there are wired like Francesca.
rooster wrote:That second pic could be a clone, note input jack, switch, and resistor on input jack, perf board, etc., compared to the pic of the 'known' Francesca. .
The second pick comes from the undocumented 90s file Omar has in the trainwreck files section so I assume it is a real wreck as the pictures that accompany it appear to be from a real wreck.
bnwitt wrote: ... I will try it both ways on the spectrum analyzer, distortion analyzer and oscilloscope...
I would love to see the results of that.
I don't recall, during my Express build, that there was much discussion of Francesca being different from others, but I may have missed that. Certainly, what Ron is trying to do is document what the most common layout that Ken would have used for an Express, and for that we have to go by those, like Allyn, who have seen several. Annotations about variations are easy to add and are also helpful. Perhaps Francesca's bright cap/volume pot wiring was a tweak Ken used to get what he felt was the best tone out of her.
That's why we discuss these things– clarification
drhulsey wrote:Perhaps Francesca's bright cap/volume pot wiring was a tweak Ken used to get what he felt was the best tone out of her.
That's why we discuss these things– clarification
Yep, in analyzing each variance I hope to always determine whether each one was a tweak or a mistake. There is nothing worse than cloning a mistake over and over again. Case in point, the V1 V2 designation of the bias taps on the Komet 60 rear plate.
As far as this change is concerned, I read the thread about how one way you leave the unused cap hanging on the grid and the other you don't. Without current flow I don't see how that even matters though. Unfortunately I don't have an express to play with as I haven't kept one for my studio. Most players out here on the west coast want a Marshall or Fender to play. I ask them if they've heard of a Trainwreck and get blank stares. I guess Jersey is too far away and fullerton is much closer. So I'll have to wait to test this until I find time to build another one.
Doc, I assume your bright switch is wired like Francesca? How's she sound? You gonna switch it? If so, let me know what happens.
Last edited by bnwitt on Thu Dec 04, 2008 7:56 pm, edited 2 times in total.
So this schematic in the file is wrong? It has the 100/500 caps going to the wiper of the volume pot and and one each to the opposite poles of the bright switch. The wiper of the treble pot is shown attaching to the cenral pole of the bright switch.
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