To ground or not to ground?

[rankar]

hi guys, glad i found you. this is my first post here and am about to embark on recapping my PL 700 S2.

I've been toying with this idea in my head, researched the different posts on here in the WOPL Building and the Tips board, and thought I'd post here. I know, who am I to mess around with Bob Carver's design, but was just wondering if any of you had even better results installing a modern power cord in place of the OEM 2-prong, non-polarized plug.

Thanks all for your input. If this has been debated, my apologies - I didn't find it in my research.

 

[WOPL Sniffer]

We use replacements when purchasing the reproduction White Oak chassis' but the ground does not get used on the new cord. The old cord works as good as the new cord. Do NOT connect the ground wire/connection when installing an IEC connector.

 

[GeorgeP]

We use replacements when purchasing the reproduction White Oak chassis' but the ground does not get used on the new cord. The old cord works as good as the new cord. Do NOT connect the ground wire/connection when installing an IEC connector.

I would not ground the chassis to the outlet. You may end up with a hummy ground loop problem.

 

[marcok]

This is the best article I found .
The first part requires a theoretical skill , but the second part is very practical .
My experience Is : no ground .
There is an exception : U,K,
Ciao
Marco

 

[rankar]

thanks guys, that's what I thought: don't f around with Bob's design.

good point marcok on the exception. i appreciate you sharing the article.

 

[20tajk7]

To ground or not to ground ? that is the connection

 

[marcok]

Other curiosities , related to TT , or better tone arms :
-Thorens Tp16 and Rega Planar 1 arm have no ground connection.
-Project Debut Carbon arm ( the same as Rega arm ) has ground connection .

Ciao
Marco

 

[wattsabundant]

Does anybody know what the National Electric Code (NEC) says about a 3 wire receptacle that leaves the ground pin floating? Is it a code violation?

One of the conclusions of the app note reads as folows:
NEVER, NEVER DEFEAT THE SAFETY GROUNDING of any device having a 3-prong power cord. The results of doing so can be deadly to you and/or your customer.

Of course the app note would have you buy a bunch of isolation transformers that Jensen just happens to sell. Given that the Phase Linear amplifiers never had a 3 wire power input connector and the input power cord is not referenced to the chassis, but instead feeds directly to the input transformer, leaving the ground pin floating is no more dangerous than the original design. It's also not very likely that an inspector would be in a home and have reason to look at or test the power cable on an amplifier.

 

[marcok]

Double insulation meets safety specs of most countries , except UK , AUS ...
Ground means hum ( not always ) and double insulation means safety .
Ciao
Marco

 

[marcok]

Vintage american preamps ( PL 4000 , Marantz and so on )
now don't meet the specs , because they were designed in the 70 s .
On the contrary Japanese devices generally were already O.K.
Ciao
Marco

 

[marcok]

Look at these pictures .
For it' s a good starting point .
( From Yamaha CA 2010 service manual )
Ciao
Marco

 

[marcok]

Oops I forgot me .
Ciao
Marco

 

[mlucitt]

The primary purpose of the grounded metal chassis using a 3-prong AC cord is if there is ever something wrong with your amplifier, the grounding prong creates a new, low-resistance grounding path to the main electrical panel. This trips the breaker, stopping the electrical current and preventing damage to your amplifier, a house fire, or an electrical shock.

If adding a 3-prong IEC C-14 Power Inlet Module to your amplifier (and grounding the 3rd prong to the chassis with a toothed washer on a shiny metal area inside the chassis) causes hum, then there is something wrong with your amplifier or your house wiring.

Your Phase Linear amplifier was designed and built when most homes in the USA only had 2-prong power receptacles. Look at any modern amplifier - Marantz, Crown, Rotel, Emotiva, etc. They all have 3-prong AC cords, especially the tube amps.

Just my $0.02.