Wire

[2tone]

I wonder if anyone is measuring voltages (mv) on the surface of the pvc or teflon wires? I remember Ken saying that the Climax amp that was manufactured by kendrick had used some vintage look alike wire, not cloth covered but a synthetic material. It wasn't a good insulator, and caused measurable voltage to appear on the surface of the synthetic coated wore. I measured my climax at the time and had readings of up to 12 mv on the wire's surface!. certainly could introduce some artifacts/noisy peak and die off artifacts from the notes. This introduced another variable in the consistency of these amps...

[RJ Guitars]

Does it make sense that the results of using of solid core wire is more critical in some positions above others?

My intuition is that the contribution of Harshness or Smoothness would be more significant in the anode leads vs. the cathode leads as well as a few other key wire runs in the layout.

rj

[Cliff Schecht]

Maybe, it makes sense. I doubt the short wires in the cathode really have an audible effect on the sound, these are usually kept very short (see below). But aren't there a few lengthy ground runs on the Express? These would have an effect on the sound, as does the entire chassis grounding scheme. Aluminum is low in resistance but there will still be some resistance built up between the different ground connections which could be a source of parasitics that haven't been considered before. Voltage in the ground affects current flow throughout the circuit. Just a thought..

I would expect the cathode to be much like the emitter on a BJT, that is the emitter is the most sensitive node on a transistor. Does this hold true for cathodes as well?

[ckpop]

On the subject of short cathode grounds most forget about one important aspect. It is the feel and response of the amp to the player. While you can't always hear the difference of shorter cathodes experienced player can feel the difference.
I found also out it can change the gain slighty of a stage just by the lenght of the wire to ground and where you put the ground connection.

[2tone]

I think the above points are certainly valid. When you can carefully A?B different components and layout you can hear differences. It's ear training. A lot of players may not hear changes otherwise. Electron flow is affected by resistances, spatial layout, inductances etc. Lengths of wire run, especially at smaller diameter are important. Often a half inch movement of a wire will get rid of a parasitic oscillation in a high gain amp. There are infinite possibilities and configurations concerning wire, and then components' internal characteristics are another area. Some people say it's not a factor when changing caps of the same value. Some respected amp builders poo poo the idea of NOS tubes over modern day tubes. I can't agree with them, and won't argue.

[geetarpicker]

My two clones of Orphan Annie are so so close to the original but with just that extra zing on top that I'd love to curb. It' like I'm 95% there, the feel, the touch, the clean to mean range is 100% but the EQ is just a tad slanted up... Sure I could tweak the circuit (for a while I ran a 100 or 250pf fizz cap) but it damped the feel too much and I really think it's down to parts choice. Makes me think if most everything else is correct match to my original it's perhaps simply a wire change away from being "dead on" for that last 5% of perfection to match my original. I may try and source some true "non-irradiated" pvc wire as I believe that interview with Ken is correct that he truly used the stuff in his amps. However so far my searches are not turning up anything, I guess it's typically not thought of as an upgraded in the wire and more of a downgrade perhaps. I built my two clones with NTE wire, but NTE's data sheets don't mention the radiated treatment details at all. Perhaps it already is. An email replay from NTE got no further info, and it's probably that they get the wire from someplace else and simply repackage it in smaller portions and don't even know what the full specs are. Pardon my grammer, typing quick tonight...

[Structo]

Yes, I think NTE is just a reseller. In other words they buy in bulk and put their name on it.

How close are the two clones to each other?

Do you think it could merely be the difference in the tolerances of the components?
Such as when Ken built your amp, all the parts came together perfectly or by his choice. Maybe a lot of trial and error testing different things.

I often wonder about amps that come off the same assembly line back in the day at Fender.
There was always that one amp that just plain sounded better than it's siblings.

I remember years ago when me and my buddies were into hot rod Chevys.
Back in the day before computer controlled machining and modeling, once in a while an engine would come together where all the tolerances and balancing of the various parts worked out to give you an exceptional motor.
It would just purr and give the power smoothly that it was designed to deliver.

I think an amp is a lot like that. The trick is knowing which part to massage into perfection. But it is not as concrete as a purely mechanical device, because of the interaction of electromagnet components and reactions between them.

I think if you ever happen to stumble onto what sets the two clones apart from the original, you will have really achieved something.

I envy guys like Ken or Alexander that seem to know just what part to tweak to get the results they want.

Good luck on your search Glen!

[geetarpicker]

My two clones sound just a little different, but it was more apparent at first when they were very new. Once they got broken in they seem more similar now. One of them used the parts that were just a tad closer to labeled spec, top pics when into amp A and then the parts that were next in line went into amp B. On my original most of the parts that I could get a decent reading off of (in the circuit has it's limitations) things really were close to spec with no real sign of drifting with age. For most of the parts selection I went though at least 10 of each part and measured them out. If anything though on average the new resistors read a hair on the low side, and the resistors in the original are just about right on the nose. In the end the amp with the parts ever so slightly farther off spec parts (probably like 1-2% on the lower side probably best as I can recall) actually seems to sound a little better though technically it may be further away from my original if you measured it's pieces electrically. Perhaps it's more aggressive. Maybe it's because it has a wolf on the front panel and the other a rising sun! Ha... My original wreck all measures out amazingly close to the labeled specs on the resistors and caps, though some parts just can't be measured so well in the circuit. The place I got my pots from went through a bunch and hand picked some that nicely matched my originals, Most were close to spec in my original though I think 1 was like 20% off or so. I built my two clones at the same time, so they are about as identical as I could make them. The only issue with that was any mistakes that I made along the way were usually made twice, then fixed twice!

[71model]

That's a good observation. I used to test transformers for a living using Doble equip. Any change in physical placement or area will change the capacitance of the xfmr. The changes can be Pri to Grd, Pri-Sec, Sec-Grd. Grounded test and ungrounded test GST, UST. It makes since that it can change with age because the laminated core changes property from oxidation or rust being iron and jarring.
I'm still learning about amps, and now really curious how a harmonics analysis would look at the transformer with different wires(which will have different capacitance). I haven't had many test come out with the same cap value. From bushings, wire, cables, motors, generators, transformer windings, each has a signature cap that will change during it's life.

Glen,

Old transformers behave differently than new transformers. One of the interesting things about metals used in OTs is that distortion characteristics increase with "jarring" of the transformer. Literally, if you hit your OT with a hammer, it will distort more. Strange but true. I have built lots of amps with old and new transformers, and I almost always prefer the amps built with a vintage OT. Mind you, the new transformers from Pacific and Heyboer used in Wrecks are GREAT! However, they do change in characteristics over time. On top of this, component values drift. Blueprinting of great sounding amps is very worthwhile.

Anyway, offer still stands if you want to experiment.

Now, say what you want about solid core wire, but after trying many recommended wire types, I'm sticking with my 20ga 600V PVC. Insulation is thick, but works great and has a positive affect on the tone to my ears.

[Richie]

http://www.one-electron.com/Trans_Tests.html

this might interest you.. check the second pdf, it has a Stancor 3801. used in the Express;
since your there, check the rest of the transformers, pdfs and scope info etc..

[Littlewyan]

Did anyone ever get to run any tests using different wire? I'm hoping to get hold of some 18AWG Solid Core PVC to replace the horrible thin 22AWG solid core that's in my amp. My amp has a bit too much high end and strangely enough the JTM1 that I built using the same wire also has too much high end. They are different circuits but is an interesting thought that the wire could make so much difference.

Unfortunately the only place I have found 18AWG Solid Core PVC wire is Tube Town http://www.tube-town.net/ttstore/Cables ... :3873.html

Haven't looked at Mouser or CPC yet.

[RJ Guitars]

I've got miles of "the" wire in all the right colors, send me a PM and i'll set you up....

[rp]

RJ what is the 'the' wire? You have the non-irradiated PVC? So you must know what that means, can you explain, I always assumed it had something to do with the coloring of the PVC?

BTW Littlewyan, these guys have it but you're in the UK. I used to get my wire from them in the States. For PTFE you can get 25ft loose, I checked their order form and it would be ~$20 to EU as it could go into a fixed rate envelope, but 100ft spools for the PVC would likely go in a box and be more. I know the PO has an int. fixed rate box for ~$50.

http://www.bulkwire.com/

IMO 18 gauge solid core (or stranded) is overkill, so hard to work with, 20 is more than adequate.

[RJ Guitars]

First - i must admit i wasn't on the ball and what i have is 20 gauge solid core, not 18... but as mentioned it is way beyond adequate.

Irradiating the PVC changes the melting point of the PVC... seems like it makes it good for over 100C as a wire insulation. FWIW, the color of the wire insulator makes absolutely no difference in how your amp will sound.

Somebody gave me the wire part number and said it was a protected secret and ask me not to post that brand and part number... not sure why it matters now? There is plenty of it if you look for higher voltage (important hint) 20 gauge solid core with a pvc insulator that melts at 80C (important hint) and was specifically made for the US government (important hint)...

[Littlewyan]

Isn't 18AWG Wire used in the original Express?