Is the real Trainwreck amp sound much better than clones?

[Alan0354]

Capacitance coupling is only one mechanism and my suspicion is it's not as important here. In this case, magnetic coupling( more exactly, EM coupling) can be more important here. When a signal and ground return forms a loop, it generate magnetic field, any other loop in the same plane formed in the surroundingt can pick up the magnetic field and cause an induced EMF. This is a lot more unpredictable than capacitor coupling.

[vibratoking]

Capacitance coupling is only one mechanism and my suspicion is it's not as important here. In this case, magnetic coupling( more exactly, EM coupling) can be more important here. When a signal and ground return forms a loop, it generate magnetic field, any other loop in the same plane formed in the surroundingt can pick up the magnetic field and cause an induced EMF. This is a lot more unpredictable than capacitor coupling.

What is the basis for your suspicion?

Why is em coupling more important? It's hard to accept your opinion because your explanation is incorrect.

[M Fowler]

Boring, we have discussed all this shit so many times it's a waste of good bandwidth to continue.

[Alan0354]

Capacitance coupling is only one mechanism and my suspicion is it's not as important here. In this case, magnetic coupling( more exactly, EM coupling) can be more important here. When a signal and ground return forms a loop, it generate magnetic field, any other loop in the same plane formed in the surroundingt can pick up the magnetic field and cause an induced EMF. This is a lot more unpredictable than capacitor coupling.

What is the basis for your suspicion?

Why is em coupling more important? It's hard to accept your opinion because your explanation is incorrect.

Because capacitance coupling is not plausible. capacitor coupling to ground chassis is only a few pF, it is common for people to put a few hundred pF to ground and only minor difference. Two wires an inch apart almost will not couple by capacitance only.

Then small magnetic dipole coupling can be from farther away. As long as you have current through the loop, you have EM field circling out perpendicular to the loop. If you have wires forming a loop in the preamp stage, it will detect the EM field. This is well explained in EM books on small magnetic loops and in small dipole loop antennas.

This is just one article on the basics of current loop and field pattern.
http://hyperphysics.phy-astr.gsu.edu/Hb ... urloo.html. Since it is a reciprocal network, the same loop can produce EMF in the presence of varying magnetic field.

The magnetic loops might not be obvious when you look at the wiring. But if you trace through from the signal origin of each stage, through the wiring, back to the ground return, you might find a loop. The bigger the loop, the more total flux produces.

AND please don't roll eyes, I have not offended you, just here to talk. This is a technical forum and please stay technical.

[Zippy]

Ah, so it is all a troll after all.

Trolls don't last long 'round here.

If you want help with a build, this is a great community. If you came just to piss off the locals, you'll find a welcome is soon worn out.

[Alan0354]

Ah, so it is all a troll after all.

Trolls don't last long 'round here.

If you want help with a build, this is a great community. If you came just to piss off the locals, you'll find a welcome is soon worn out.

May I ask how am I being a troll?

[Mark]

Alan draw up a picture of the Express/Liverpool/Rocket layout and illustrate what you think is happening?

I think I'd need to see how the right hand rule is taking effect. My initial thoughts are the wiring is too far apart and the current too small. I could be wrong though.

[Alan0354]

Alan draw up a picture of the Express/Liverpool/Rocket layout and illustrate what you think is happening?

I think I'd need to see how the right hand rule is taking effect. My initial thoughts are the wiring is too far apart and the current too small. I could be wrong though.

I am just putting in my thinking that capacitance coupling should not be that serious. That the wires can form a current carrying loop and radiate signal out. This is particular true from the plate to plate of the power tubes where there is wire going from one plate through the OT to the other plate to the ground through cathode back to the cathode of the original tube. The current at this point can be over 100mA....... I am not saying this is what is happening in this particular amp layout. I am just more bringing an idea out.

Also, there might be possibility of leakage of the OT. At audio frequency, the chassis is not necessary that good in blocking the EM wave as the skin dept is very deep at this frequency. The metal chassis only attenuate the signal, not blocking the signal. So just because the OT is on the other side of the chassis, EM field still penetrates through.

I am not familiar with this amp, I don't dare to make any suggestion as people here already spend so much time. I just join in to talk. I am definitely not trolling, just read what people said and comment on some of the post.

[BLT]

Boring, we have discussed all this shit so many times it's a waste of good bandwidth to continue.

Agreed!

[Reeltarded]

[Zippy]

I am not saying this is what is happening in this particular amp layout.

I am not familiar with this amp...

I just join in to talk. I am definitely not trolling...

If you have so little experience with these designs, then why are you making it a point to play here?

Surely there are other forums you could join. EL34 World, perhaps? The Gear Pages?

FWIW, there is a feature in Dumble amplifiers where there are a couple leads that are purposely PARALLEL - there's your EM territory. Most other amps make a point of keeping leads distant from one another, and then crossing at right angles.

[geetarpicker]

Thanks for the link HBGB.

A few quote from the article.

The one idea I've seen speculated is pretty tough to refute (or prove I guess), that is using lead dress as "invisible" capacitors.

The capacitance value would only be a few picofarads and certainly wouldn't effect tone. I've tried on several occasions with Trainwreck amps to run the cable along the chassis to get some sort of advantage. I've found good co-ax sounds the same and is a lot quieter.

I don't think it's the transformer per se, though the relatively high primary impedance probably has something to do with it. Glen Kuykendall has a Pacific OT wreck. Because of his unique status as the patron saint of recorded TW samples he's been able to audition many other TW amps. Some with the Stancor OT. apparently they all do the right things. The Pacific loaded amps are more "aggressive".?

I think this statement contradicts itself, I do think it is the transformers and this was apparent to me in my earliest stages of noodling with the circuit in 2004. The power transformer has to hold the supply pretty stable so sag doesn't create mush.

These are variables that may be found on any KF TW Liverpool or Express.

I'd like to see these variables as of all the pictures I've seen, I thought the amps were quite consistent.

I'm inclined to agree that lead dress had to be the secret "voicing" since all the amps use the same parts. I also think that the particulars of the power supply, especially the use of a 1k resistor instead of a choke, is part of the overall formula. But exact clones have been made from reverse engineered examples with only limited success!?! Reports of amps serviced by Ken are that they were returned to all their former glory. While I've heard KF amps that were serviced elsewhere after long periods of MIA that never again sounded any better than the many clones. So what the hell was Ken doing to these amps that made the pick attack go crunch and the sustain go bwaaah. Rather than a spikey thwack and fwizzz like the copies. Glen Kuykendall built himself a couple of clones with every part NOS and TW OEM except the Mallory filter caps. And his findings were that the filter caps made a huge difference in getting closer to the sound of his original. This also corresponds with the idea that unwired circuits are partly responsible because the filters he ended up with were some boutique product that was supposed to be like the older caps!?! I might interpret that as higher impedance (or ESR, if that's actually different). So now we have unseen circuits hiding in the lead dress AND NFB and possibly PFB loops hiding on the power rail. But I've never seen a TW that left his care with anything but the original filters inside. So that only leaves lead dress.

The filter caps made a huge difference, I've tried huge paper in oil filters amongst other caps, and I didn't hear any difference from filter caps let alone a huge difference, in fact I don't remember Glen saying this either.

I don't see any science in this thread, it's all Ken touched the amp and behold it was a thing of great beauty.

I put it all down to the design, the transformers and the tubes.

Just to clarify I built two clones of my original '89, and I actually used Mallory TC electrolytics in both, along with Mallory PVC signal caps. I did experiment with strapping in a Zoso Blue electrolytic in the power supply of one of the two clones, and it had s nice darkening effect which I liked. That said once the Zoso was broken in the darkening effect eased off so I pulled the Zoso and put it back to how I originally built it.

That later I found a small quantity of the exact NOS wire that Ken used in his builds and rewired one of my clones. It did smooth out the tone a tad compared to it's twin. I also located some NOS pots and installed them in the same clone. Now my two clones are not identical anymore, and the difference between them is getting more noticeable but not drastic by any means. Both my clones come fairly close to matching my '89 Express but still, that last bit of harshness is hard to dial out. Then with my more recently acquired '85 Stancor Express that original beats the clone by even a bit more. There is a fatness and clarity that the earlier Express has that puts it even more away from what one would expect from a typical nicely built clone.

GK

[Alan0354]

FWIW, there is a feature in Dumble amplifiers where there are a couple leads that are purposely PARALLEL .

Can you tell me what signal Dumble purposely parallel?

[Colossal]

FWIW, there is a feature in Dumble amplifiers where there are a couple leads that are purposely PARALLEL .

Can you tell me what signal Dumble purposely parallel?

Alan,

Do a search of the Dumble Files and Discussion sections (see the Search button above ^^^) and find some gut shots. There are many, many examples posted by members here. You will see that preamp plates leads are intentionally run tightly parallel with cathode leads.