Vintage amps full of insulated leads?

[Tom Phillips]

... the available insulation at the time was terrible and would catch on fire or melt and explode.

Where did you get that information?

[diagrammatiks]

I'll have to it up. It's in a mil-spec standards revision somewhere, a whole bunch of guidelines for flammable insulating materials.

Like cloth wire is strictly prohibited in almost all situations. PVC gets rated by grade.

[jrfrond]

Leads should only be wrapped around a terminal a gazzillion times for solderless wirewrap connections.
turrets are supposed to be wrapped just enough so that the entire lead can be soldered without placing undue stress on the turret.

Not a big issue with lead and wire size found in most guitar amps these days but a few twists with 16gauge will torque the turret right out under stress.

If you want to get REALLY technical with this, USA mil-spec assembly procedures require that the illustrated turret receives a 3/4-wrap of bare, tinned wire, so that the end of the lead wraps around to almost touch itself.

I did a 1.5 years in mil-spec gov't work assembly and repair, and though the job sucked and the pay was crap, I learned a lot on how equipment SHOULD be assembled. Things need to be neat, orderly and properly-dressed. Yes, any guitar amp SHOULD be able to withstand a lot of force, at least that of being dropped and still able to function.

[diagrammatiks]

If you want to get REALLY technical with this, USA mil-spec assembly procedures require that the illustrated turret receives a 3/4-wrap of bare, tinned wire, so that the end of the lead wraps around to almost touch itself.

I did a 1.5 years in mil-spec gov't work assembly and repair, and though the job sucked and the pay was crap, I learned a lot on how equipment SHOULD be assembled. Things need to be neat, orderly and properly-dressed. Yes, any guitar amp SHOULD be able to withstand a lot of force, at least that of being dropped and still able to function.

blanket statements like that will get you into trouble.

the bend radius should be a percentage of the wire gauge.

[Enzo]

Now now, he didn;t mention radius, just how far around the turret. That assumes the turret has the appropriate diameter.

[Kazooman]

I can tell you what was granted the special recognition of the extra shielding in the vintage units. The primary inputs to the PT were not shielded. There is a great rotary switch to select five or six input voltages (none of them being standard today) and they are all just single wires strapped together. The output side of the PT (filaments, 48 V for the tape drive motor, and the high voltage supply) that is all unshielded. There is a bridge rectifier and all of the DC outputs are unshielded. All of the wiring through the filter cap section is unshielded. The filament heaters are not shielded and are not twisted.

I would have to check this to be absolutely certain, but I think that the only leads that have the extra spaghetti tubing shielding are those that are shielded cables. They must have been trying to ensure that none of the grounded shields could short out to another lead. Still, these vintage units are a morass of ground bus lines. They run everywhere! Nices lines of heavy gauge bare wire with components solderd to them whereever it seemed a good thing to do. I'll try to find or take a few pictures to show what I am referring to. The dichotemy is amazing. They have ground busses running all over the place and then they go to great lengths to insulate and ground shielded cable.

[Kazooman]

I can tell you what was granted the special recognition of the extra shielding in the vintage units. The primary inputs to the PT were not shielded. There is a great rotary switch to select five or six input voltages (none of them being standard today) and they are all just single wires strapped together. The output side of the PT (filaments, 48 V for the tape drive motor, and the high voltage supply) that is all unshielded and strapped together. There is a bridge rectifier and all of the DC outputs are unshielded. All of the wiring through the filter cap section is unshielded. The filament heaters are not shielded and are not twisted.

I would have to check this to be absolutely certain, but I think that the only leads that have the extra spaghetti tubing shielding are those that are braided shielded cables. They must have been trying to ensure that none of the grounded shields could short out to another lead. Still, these vintage units are a morass of ground bus lines. They run everywhere! Nice lines of heavy gauge bare wire with components soldered to them whereever it seemed a good thing to do. I'll try to find or take a few pictures to show what I am referring to. The dichotomy is amazing. They have ground busses running all over the place and then they go to great lengths to insulate and ground shielded cable.

[Gtr_tech]

Just for the record, the cloth "spaghetti" tubing was called cambric.

[J M Fahey]

they also stopped doing it because the available insulation at the time was terrible and would catch on fire or melt and explode.

Talk about blanket statements.
And somebody should start the Time Machine and go tell that to Leo Fender.
Not forgetting that in my youth (sadly so long ago) I used to reform WW2 vintage Military Surplus Radio equipment (such as Sherman tank radios with a metal 6L6 output, etc.) and *all* I saw there was rubber and cloth covered wire, tied in tight bundles with what looked like waxed cotton thread.
Of course, in a 100% pure Oxygen atmosphere, such as in a Gemini or Apollo Mission, such materials might be very dangerous.

EDIT: just to avoid double posting, agree and let me add that *today* spaghetti, is still much used.
I buy transformer wire in bulk (16/25 Lb rolls) and my supplier has shelves full of all sizes of spaghetti. He carries impregnated (cotton?) cloth type, plus high temperature fiberglass and general purpose cheap plastic (PVC?) plus heatshrink.
Just as a curiosity:cloth (they call it "silk", which it is not) insulated wire is still available, in the thicker gauges, what´s used in arc soldering machines, big battery chargers and such.

[diagrammatiks]

Talk about blanket statements.
And somebody should start the Time Machine and go tell that to Leo Fender.
Not forgetting that in my youth (sadly so long ago) I used to reform WW2 vintage Military Surplus Radio equipment (such as Sherman tank radios with a metal 6L6 output, etc.) and *all* I saw there was rubber and cloth covered wire, tied in tight bundles with what looked like waxed cotton thread.
Of course, in a 100% pure Oxygen atmosphere, such as in a Gemini or Apollo Mission, such materials might be very dangerous.

Ya. I'll be sure to drop the memo about cfc's, pcb's, selenium, and might as well tell him about ddt and asbestos as well.

What kind of other insulation would you ever possibility see in something built in the 1940s.

The type used by Fender in the early amps is definitely flammable.

Later braided insulations were made of woven polymers and aren't the same material class at all.