Modification: RCA Jack Mount Plate

[avantbored]

Many threads about this, but thought I'd make a new one rather than resurrect a dead one.

Looking to modify my YP-D8 with a new RCA jack plate.

My tech has offered to fashion me one from parts.

The question:

Having decided on which jacks to use (These from Parts Express: Chassis Mount Gold Plated Hex Nut RCA Jacks 2-Pair), I now need to find an aesthetically-consonant jack plate. He recommends brushed aluminum or stainless steel; I don't think that would quite match the veneer. Thinking brass- or gold-colored.

What can I get away with here? A gold-colored anodized aluminum? Any sources for this?

 

[rothwellaudio]

Am I the only one who doesn't know what a YP-D8 is?

 

[avantbored]

Hi @rothwellaudio!

Thanks for the reply.

It is my vintage Yamaha YP-D8 turntable!

Yamaha YP-D8, Auto-Lift TT w/Grace, F9 MM Cart - SOLD

"Yamaha takes special pride in their direct drive system which insures quiet, precise drive of the Yamaha YP-D8 heavyweight turntable by means of a powerful DC Hall motor". - Yamaha Electronics Archive This product is the results of Yamaha's tremendous resources in turntable technology...

holthill.com

(Not the actual unit, but can't send photos from my phone to my computer right now).

 

[TConnelly]

Well, I don’t know. But it seems to me that all of the other bits and bobs on the turntable are some form of brushed or polished aluminum. They all seem to go pretty well to me! That and the jack plate will likely be on the back, correct?
Cheers…………….Todd

 

[avantbored]

Time got away from me on this thread! We went ahead with a black plate, some RCA jacks from PartsExpress, and a Vampire Wire connector.

But! I'm getting hum when the motor is operated.

1) We tried grounding the TT internally -- slight hum when motor is not operated; hum when motor is operated.

2) We added the Vampire Wire connector. No hum when motor is off. Hum when motor is operated.

Is this ground loop? The table is in the same Furman as the rest of the system...

Any thoughts? Thanks!!

 

[lini]

(...) Any thoughts? (...)

Did you already measure the resistance beween the outer contacts of the RCA jacks and the separate ground jack?

And a few pics of the modifications could be helpful - so one could see, what exactly you been doing.

Greetings from Munich!

Manfred / lini

 

[gadget73]

^^
Normally the RCA jacks don't want any connection to each other or the chassis. Thats the job of the ground lead. If the insulating shoulder washers weren't used, thats probably your issue.

 

[mdc701]

^^
Normally the RCA jacks don't want any connection to each other or the chassis. Thats the job of the ground lead. If the insulating shoulder washers weren't used, thats probably your issue.

I figured this was the cause of the slight hum in my TT. I switched from a metal chassis to a black acrylic one. So far so good.

 

[avantbored]

Did you already measure the resistance beween the outer contacts of the RCA jacks and the separate ground jack?

And a few pics of the modifications could be helpful - so one could see, what exactly you been doing.

Greetings from Munich!

Manfred / lini

Hi again, lini! Thanks for your input.

My tech was out of town, hence the tardy reply. He has reported that the resistance between signal and ground on each channel is 480 ohms. "Both channels measured the same resistance ... figured it was a small ground loop between the signal grounds and the plate they were attached to."

Here are some pictures, and they are perhaps pertinent to @gadget73's reply.

Normally the RCA jacks don't want any connection to each other or the chassis. Thats the job of the ground lead. If the insulating shoulder washers weren't used, thats probably your issue.

We selected an anodized aluminum plate because it matched the original part the best. But now maybe I'm rethinking that!

I figured this was the cause of the slight hum in my TT. I switched from a metal chassis to a black acrylic one. So far so good.

Thanks @mdc701. Do you also have a jack plate like mine?

 

[avantbored]

Update: Tech has written back and reports:

"The insulating ground washers were used and there is no ground connection from the signal leads to the chassis. Though the chassis ground does connect to the RCA jack panel." He thinks that if that was the issue, we'd be hearing hum regardless of whether the 33 or 45 switches are operated.

 

[gadget73]

Yeah washers look fine, I was only curious in case it had been missed. Not all jacks come with those.

 

[mdc701]

Hi again, lini! Thanks for your input.

My tech was out of town, hence the tardy reply. He has reported that the resistance between signal and ground on each channel is 480 ohms. "Both channels measured the same resistance ... figured it was a small ground loop between the signal grounds and the plate they were attached to."

Here are some pictures, and they are perhaps pertinent to @gadget73's reply.




View attachment 3735159

View attachment 3735160

We selected an anodized aluminum plate because it matched the original part the best. But now maybe I'm rethinking that!




Thanks @mdc701. Do you also have a jack plate like mine?

Yes, i also had one installed in my turntable so i could play around with cables. Speaking of cables, have you tried using a different set from what you are currently using? Sometimes its the cables that cause the hum - maybe there’s a cold solder on the jacks, maybe the cables aren’t shielded, etc.

 

[avantbored]

Yes, i also had one installed in my turntable so i could play around with cables. Speaking of cables, have you tried using a different set from what you are currently using? Sometimes its the cables that cause the hum - maybe there’s a cold solder on the jacks, maybe the cables aren’t shielded, etc.

Thanks for for your reply, @mdc701. The cables are new Blue Jeans cables LC1 that I ordered in expectation of this new modification; I hope the chances for their being faulty / unshielded are low. I have not tried any other RCAs, but I do have a separate ground wire that I could try with a separate pair of Worlds Best Cables RCAs.

One hypothesis we have is that something maybe went loose in the drive from tech to me, though he lives only a few minutes away! So maybe it's cold solder? TBD