Reverse scan cable

[Sam Chavez]

Jibe not jive he said pedantically.

[Steve Guttag]

Yes, Dave, I think you have mostly hit the nail on the head (spelling of Jive...as in "Jive Turkey" versus jibe as in "agree"...thanks Sam...I didn't think he was insulting me).

The shield is an electrostatic means to drain noise away. It ALWAYS has to go to Earth to be effective. You need to drain into something. As to one-end or both. It depends on frequency and are you shielding in or out. In higher frequencies, you'll end up shielding at both ends. To prevent a ground-loop you can attach use a capacitor at one end so DC is blocked preventing the loop but high frequencies can drain at the closest end.

"Grounding" is really just referencing. The ground conductor (including in high voltage electrical AC circuits) is a zero current conductor (has to be if you believe in Ohm's law) that keeps both ends tied to each other. It need not actually be at ground potential, from an audio stand point (it does in a high voltage AC circuit). With audio, you have a "reference" level that is typically "signal ground." Signal ground HAS to be at the same potential everywhere in the circuit. Current only forms complete circuits so if they are not all at the same potential, you'll have a problem. Look at some old TV audio circuits...those sets typically didn't have a ground reference and where the audio was driven from could be from whatever power supply rail made sense for the rest of the audio circuit (could be over 100V)...it doesn't matter so long as everything in the circuit references the same potential.

Now, once you start using earth ground as the same reference as signal ground, then you need to be diligent an ensuring are are indeed referenced everywhere in the circuit or a potential difference will exist and a "Ground loop" will form...if there is a potential difference exists, current flows. So, in the case of a soundhead, which could very well be floating, it is good practice to tie that to the same ground as the sound processor to ensure that they are at the same potential. You CAN use the shield and get away with it in 99.9 percent of the cases. The shield is typically a small conductor and its job is to drain noise, not establish potential. Using a larger gauge wire will do a better job and keep the tasks of noise and potential separated.

Here is another tip. In the CP500, signal ground and chassis ground are tied via a resistor with something like 470Ω. Yeah...no...that is a recipe for ground loops. If you get a hum on a CP500, make a short jumper between the chassis (there are quick disconnect terminals on the chassis) and the ground terminal on the Phoenix connector and magically your hum will disappear.

[Marco Giustini]

thanks Dave, Sam and Steve! Very useful stuff!

[Sean McKinnon]

Jibe... Duly noted!

I certainly don't think Steve is a Jive Turkey! https://en.wikipedia.org/wiki/Glossary_of_jive_talk

[Steve Guttag]

That's alright...I, apparently, referred to you as Dave! You can also watch "Airplane" to let Mrs. Cleaver give you some Jive Talk. That is much better and more authentic than the Bee Gees "Jive Talkin'"

[Sean McKinnon]

I LOVE that movie! One of the best!

-Dave (aka Sean)

[Randy Stankey]

Jibe not jive he said pedantically.

Jibe: In sailing, to turn your boat across the wind, causing the sails to swing to their opposite sides.

Jive: A form of lively music and dance associated with Swing or Jazz music of the 1940's or 1950's. Also a form of slang or dialect speech associated with this type of music.


The "B" and the "V" keys are right next to each other on the keyboard. Easy mistake to make.

[Sam Chavez]

People mistake jive for jibe all the time. As a kid raised in downtown Oakland I heard jive in all forms but never the word jibe. To my mind in general usage, "does that jibe with your understanding of the situation?"

[Marin Zorica]

Just one quick thing.......many today's audio manufacturers advises you to connect only one side of audio cable (if line is balanced) to ground, that is i think not because it needs to be like that, but because to get off ground loops on easy way. So when you start doing installation and forgot everything about grunding etc...... In new installation today i always request from electrician to pass min 25mm2 ground wire from electrical box to audio rack and projector rack.