Cable Asylum

Long DC cable

173.161.252.168

Maril555

I need to make a longer DC cable for the linear PSU that feeds TT motor, as it induces hum in SUT/Phono stage being 3 ft away from the SUT/Phono.
Moving it away about 5-6 ft. dramatically reduced the hum.
The problem is that is order for the PSU to be in an acceptable location, the DC cable needs to be at least 10-15 ft long.
So I'm wondering if there any downside to having a long DC cable (15 ft)?
Thank you

Follow Ups:

I would also add a capacitor - 1973shovel 03:03:51 10/12/23 (8)
...say several thousand microfarads worth, with an adequate voltage rating, where the cable terminates at the turntable motor.
- RE: I would also add a capacitor - Maril555 10:42:28 10/12/23 (7)
  Could you explain this, please?
  - Sure, but before I do - 1973shovel 09:31:56 10/13/23 (6)
    You list a TechDas Air Force 3 as your turntable in your system, but according to a 2018 TAS review, the TechDAS has an "AC synchronous motor". So is this DC cable for a different table? If so, maybe you could include a picture or two where the DC cable terminates at the table, and we can go from there. Thanks.
    - RE: Sure, but before I do - Maril555 05:06:37 10/14/23 (5)
      TechDas been gone for a while. Now it's SpJ a Luce with Dereneville DAE-01 motor,
      Which is DC and takes DC 2.1 connector
      
      Edits: 10/14/23
      - Nice! - 1973shovel 12:14:38 10/14/23 (4)
        
        In Reply to: RE: Sure, but before I do posted by Maril555 on October 14, 2023 at 05:06:37
        
        Then I would add a radial lead cap at the 2.1 mm DC barrel connector, being sure to observe correct polarity and voltage requirements. A low ESR,
        1,000 uF Nichicon will work, and cost you less than $1
        
        What are you using for a DC power supply? There's possible room for improvement there, depending on what you're using.
        
        RE: Nice! - Maril555 12:27:25 10/14/23 (3)
        
        In Reply to: RE: Nice! posted by 1973shovel on October 14, 2023 at 12:14:38
        
        Could you provide some details on how to connect that resistor?
        And what purpose does it serve?
        I'm using Hewlett- Packard E3616A Linear Power supply.
        I've tried a few "audiophile-grade" LPS before and all of them hummed more than the HP.
        
        I didn't suggest a resistor - 1973shovel 18:52:03 10/14/23 (2)
        
        In Reply to: RE: Nice! posted by Maril555 on October 14, 2023 at 12:27:25
        
        I suggested a capacitor near the load, at the end of your fifteen foot DC cable. This would be to further reduce supply ripple/noise. The configuration would be standard, positive to positive, negative to negative.
        
        You may not even need it, but as noted, they're only about $1.
        
        RE: I didn't suggest a resistor - Maril555 04:44:12 10/15/23 (1)
        
        In Reply to: RE: I didn't suggest a resistor posted by 1973shovel on October 14, 2023 at 18:52:03
        
        I meant "capacitor"
        
        I was just making sure we were on the same page (nt) - 1973shovel 07:36:34 10/15/23 (0)
        
        In Reply to: RE: I didn't suggest a resistor posted by Maril555 on October 15, 2023 at 04:44:12
An option - Fluter 10:45:22 10/06/23 (2)
To avoid any inadvertent hum induction via the DC supply, you could also try a 4-wire star-quad configuration. This would have the additional benefit of increased current delivery capacity as well, depending on your specific choice.

Edits: 10/06/23
- RE: An option - Maril555 18:24:25 10/06/23 (1)
  Thats what Gotham GAC-1 is, Star Quad
  So, to be clear two red wires connected to center pin and two white ones to the barrel?
  - Yep - Fluter 18:44:15 10/06/23 (0)
    Yes, as simple as that. Check out the following for more info...
    - Via Abe Collins' posting (Open in New Window)
RE: Long DC cable - zacster 15:15:18 10/05/23 (0)
Maybe try some shielding on what you have.
RE: Long DC cable - 6bq5 10:50:02 10/05/23 (0)
just pay attention to wire gauge for voltage drop - though I am sure that even at 20' you should be ok-
Happy Listening

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors:

Schiit Audio