RE: Vintage Power Cords

Posted by Palustris (A) on January 31, 2017 at 11:17:14

In Reply to: Vintage Power Cords posted by mark.korda@myfairpoint.net on January 31, 2017 at 05:38:07:

"He does this measurement by measuring the chassis voltage, with interconnects disconnected then measuring again with the power outlet plug flipped upside down or prongs reversed in the AC outlet. The lower voltage measured on the chassis providing the least distortion."

I did this 25 years ago before three wire grounded plugs were common. I was more concerned that there could be dangerous ACV on the chassis. Further, any AC voltage on the chassis causes current to travel through the interconnect cables since the two chassis of the connected components are at different voltage potentials. This is not only dangerous, but it also causes noise and hum. All this was solved by the introduction of three wire power cables and by not using the chassis as ground, with the exception of one location where the green ground wire from the power cord is connected.

Some consumer gear in the 1950s and 1960s used the chassis as ground throughout the unit. This creates many ground loops and the only way to fix the situation is to make a ground bus. Everywhere the chassis is used as ground, that connection should then go to the bus which is only connected to the chassis where the green wire from the power cable is connected. Any older gear that reaches my workbench receives a three wire cable before any other task is started. If the chassis was used as ground that is rectified too by installing a ground bus.

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Follow Ups Full Thread

Topic - Vintage Power Cords - mark.korda@myfairpoint.net 05:38:07 01/31/17 (23)

Check out this old article in the Bound For Sound journal . . . nt - alaskahiatt 09:12:35 02/02/17 (0)

OMG!!! Answer the question please!!! - samstone 17:08:37 02/01/17 (2)

Some components need 3 tests - M3 lover 09:23:59 02/02/17 (1)

RE: Some components need 3 tests - samstone 18:14:57 02/03/17 (0)

RE: Vintage Power Cords - Palustris 11:17:14 01/31/17 (2)

RE: Vintage Power Cords - samstone 17:13:36 02/01/17 (1)

RE: Vintage Power Cords - mark.korda@myfairpoint.net 17:33:36 02/01/17 (0)

Alrighty then - E-Stat 06:18:02 01/31/17 (15)

RE: Easily measurable stuff here - BigguyinATL 13:38:53 02/01/17 (0)

RE: Alrighty then - airtime 07:49:19 01/31/17 (13)

RE: Alrighty then - E-Stat 08:58:39 01/31/17 (6)

RE: Alrighty then - sony6060 10:29:03 01/31/17 (5)

That's a start - E-Stat 10:36:04 01/31/17 (4)

RE: That's a start - mark.korda@myfairpoint.net 11:00:48 01/31/17 (3)

RE: That's a start - Steve O 12:47:39 01/31/17 (0)

RE: That's a start - fredtr 11:56:03 01/31/17 (0)

RE: That's a start - airtime 11:15:29 01/31/17 (0)

RE: Alrighty then - Coner 08:33:02 01/31/17 (1)

Such exists - E-Stat 08:51:36 01/31/17 (0)

RE: Alrighty then - Uncle Mike 08:32:13 01/31/17 (3)

RE: Alrighty then - airtime 08:42:55 01/31/17 (2)

It is... - Uncle Mike 13:44:36 01/31/17 (1)

RE: It is... - mark.korda@myfairpoint.net 05:49:00 02/01/17 (0)

Follow Ups

RE: Vintage Power Cords - Palustris 11:17:14 01/31/17 (2)

RE: Vintage Power Cords - samstone 17:13:36 02/01/17 (1)

RE: Vintage Power Cords - mark.korda@myfairpoint.net 17:33:36 02/01/17 (0)

RE: Vintage Power Cords

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