Rheostat 101

[Brosky]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Paul, if Dale doesn't come thru I still have 90% of my old wiring. [/QUOTE]

Don,

Thanks for the offer. Does the new Masters harness include new sockets? Maybe I can buy a set from him rather than cutting up a good used harness. If you don't care about them, I would certainly take them or pay you for them. Let me know via PM.

 

[70herald]

Unlike the heater rheostat which has to pull more amps.

Um unless there are a different number of lamps (or really total wattage) and the lighting range is the same, the rheostat is going to have to control the same voltage / amperage load, and to reduce the lighting the same amount will have to dissipate the same amount of heat. So the amperage will be the same. Still much cheaper to manufacture.

 

[Brosky]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Um unless there are a different number of lamps (or really total wattage) [/QUOTE]

The conversation that you have going is different than my comment, but you have a good point and this is why I wanted to bench test a full set of gauges with the switch to see if the 8 watt bulbs would be a problem.

 

[TR3driver]

A wire wound rheostat can be wound in either linear or logarithmic fashion,

Do you perhaps have an example of a wire-wound logarithmic rheostat ? I'd like to see one ... in spite of hanging about near the lunatic fringe of audiophile-dom, I've never seen or heard of such a thing. Digikey doesn't even bother specifying taper for wire-wounds, as they are all linear. Honeywell doesn't make them either.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]In the old days when audio components were all linear inside, good quality audio equipment used wire wound rheostats,[/QUOTE]I beg to differ. Wire-wound pots are noisy compared to good carbon composition, so they are(were) used only in places where power dissipation was important (like speaker crossover networks) and noise less so (ditto). In fact, the ultimate volume control was always a multi-position switch with discrete resistors between the contacts, similar in theory to the PC-board dimmer, because the contacts could be made with low-noise alloys and not carbon.

I have a very modest collection of antique high fidelity equipment, including an HH Scott tuner and Marantz amplifier (the Dynaco's power transformer bit the dust while I was in college and I stupidly didn't save the remains); and the only wire-wound pots are in the filament balancing circuit and the speaker cross-overs.

 

[Brosky]

Before and after. All back together and waiting for sockets to test the switch and 8 watt bulbs.

 

[2wrench]

Looks brand new, Paul.

 

[Brosky]

2W,

Just a little elbow grease, contact cleaner and Never Dull. It has to work better after removing the crap off of the etched faces and all of the crud from the contacts.

 

[DNK]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Paul, if Dale doesn't come thru I still have 90% of my old wiring.

Don,

Thanks for the offer. Does the new Masters harness include new sockets? Maybe I can buy a set from him rather than cutting up a good used harness. If you don't care about them, I would certainly take them or pay you for them. Let me know via PM. [/QUOTE]
After reading your post it just hit me what you asked for. Sorry to lead you on but the gauge sockets don't come with the kit and you use the old. I remember Dale got new tail light sockets I think,maybe he got dash ones too.
Sorry Paul /bcforum/images/%%GRAEMLIN_URL%%/wall.gif

 

[Tinster]

Hey Paul,

The Dan Masters Power Block uses the existing light
sockets. I had to replace a few tail light sockets and
bought them at Western Auto. Dan's wires are of much
higher quality than the Triumph OEM.

The dash light sockets and light bulbs for which you are
looking may be purchased at British Wiring in Philadelphia.
Also they have the upgraded wires. Nice folks there, very
helpful. Give them a holler.

https://www.britishwiring.com/CAT00_35.PDF

d

 

[Brosky]

Thanks Dale & Don. I'll call them tomorrow.