Twisted (sort of) heater wires

[loverocker]

Was someone having an bad day at Marshall when they assembled this:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... otohosting

Or am I being too harsh? My heater wires are about 10x more closely twisted then this - do I have the wrong end of the stick, and in fact only one or two twists per segment are needed?

[zaphod_phil]

Says it's totally original too. Looks like someone at Marshall was using multistrand-cored wire which doesn't hold a twist very well. Or else they were just feeling slightly lazy that day. It will probably work OK, but us EEs just don't like the look of it Remember, Soldano amps don't have their heater wiring twisted at all....

[loverocker]

Paul - I can't really make out the brass rod - are they the two horizontal 'wires' running along the top and bottoms of the sockets? If so, I can see that they're obviously not twisted - and Phil says neither is Soldano's.

Help me out fellas - I thought this was one of the 'must-haves' in amp making I can see that DC+filtered heater supply would be OK, but what's the scoop?


PS: Paul, that Wreck layout looks great I'm slowly coming around to the idea of doing everything perpendicular, but I've found it a bit hard to do in the donor chassis I've used so far. Do you plan out full-size on paper first?

[Aaron]

heh. i'm not sure i understand ANYTHING here..i cant quite make out those pictures either. Paul, you mean that your wiring to and from the board to the tube sockets is all prependicular to the filament wires (and that this in itself reduces noise/hum)? also, how are you connecting the filament solder lugs to the brass rod? directly w/solder or by a short jumper wire?

i too thought twisted wire was key for minimum hum.

[Plexi]

"""and Phil says neither is Soldano's"" And probably alot more.. the older Orange amps had all the sockets linked with straight hookups.

And i built most of the combo amps with single side wires..not twisted.
I've also built them with the twisted wire. Both were quiet.

Hows the wreck sound you built Paul? Have you tried building any of the other wrecks yet?

Richie

[zaphod_phil]

Going by what I vaguely remember of my university electronics, provided the heater cables are close together, they enclose a very small area and the field outside that area falls of quite rapidly. Twisting is one very good way to ensure they enclose almost no area, but as long as they're reasonably close to each other compared with their distance from the signal circuitry, we're doing fine.

[Ian]

Well if I’m looking at the right wires;- then as everyone here knows (because it was at one time seriously disputed), in my amp Marshall just used simple twinned speaker wire, i.e. not twisted at all. And that use of twinned wire can also be seen in contemporary factory photo’s from the mid 1960’s. Perhaps that fits with what Phil says about the main consideration being to keep the two wires close together?

But am I alone in thinking that 100W circuit looks amazingly clean? The chasiss shows the staining of age, but all the components are pristine, and all the wiring looks brand new;- not bad for an amp of 33 years? Maybe its all been specially cleaned? But even the cable colours look bright & fresh;- 33 years but no sign of colour fading. Right or wrong, I’d & steer clear of that.

Ian.

Ps:- Loverocker;- I also thought about importing vintage Jap guitars, maybe Tokai LP’s, but especially 1980’s Jap Fenders (if that cryptic remark makes any sense, ).

[zaphod_phil]

Yes, I agree - those guts don't look entirely original to me either. And that lightly twisted heater wire looks pretty new...

[loverocker]

Funny you should mention speaker twin wire, Ian - that's exactly what I was thinking of. I'll try it in my next 18Wer - plus Paul's approach to other the signal wires coming in from above and see if it's quiet.

To be honest the twisting isn't so bad (once I'd realised that it was best to grip one end in a vice).

Re Tokais: I um... appear to have a bit of a habit: 4.5 so far, ranging from 1978 to 2004 (custom-order - waiting for the wood to be seasoned) The one that gets all the double-takes is http://www.firstmail.com/guitars/tad1.jpg

[markh]

I've seen a few Marshalls with that loose "sideways C" style of wiring. Most of the components in there look appropriately vintage to me - check out the molded caps and particularly the tremelo transistor. I've also seen a few old amps in good shape like this - wire colo(u)rs don't fade much in the dark!

Twisting is better from a theoretical point of view, but the high gain Soldanos all use "parallel pipe" heater connections, and those aren't know for being excessively noisy!

--mark

[Ian]

Hi Mark,

Well you’re right, because you’re the Admin, LoL! Only kidding!

I've seen a few Marshalls with that loose "sideways C" style of wiring. Most of the components in there look appropriately vintage to me

Yep, you’ve certainly seen inside many more old Marshall’s than I have! And after the cautious "sceptisim" which greeted the photos my amp, perhaps I should be the very last person to raise any suspicion, ?

Of course, guitar Cab’s are nowhere near “light-tightâ€

[markh]

hi Ian,

I'm near the Big Black, but not in it, fortunately!

While not quite as old, check out my '83 JCM. It's has unfaded wires and "C Clamp" heater wiring, and it's so original I don't think even the fuses have ever been changed!

--mark

[Plexi]

I agree with Mark.. the componets look like ones used in many amps of that period. I don't think the wires are twisted at all in Marks amp.. Which i don't see that as a problem. As for amps on e-bay,i think no matter what they tell you it is, i'd wonder..lol Some are and some aren't..

the one thing is the transformers, and they don't show those very close,the choke looks to have the mounting ring ..and you may not see many of those. or could have been replaced. No way to tell with just a shadow of a pic.. As for the wires and color..could be the flash,and making them brighter looking..the pink wires look white.. ha or maybe they are white. I have an older 67 100 trem, and its cleaner than that one.
Richie