Subwoofer Problem

sharkman

I have a Harman-Kardon SUB-TS7 and it works fine with the standard 5M cable supplied , however when I try to move it to another location using a longer run of cable that I have made up myself I get a constant humming and the unit wont power down on auto like it should .

Ive checked the cable for shorts and its fine . Any ideas guys .

PLEASE HELP .

The Ritz

Sharkman,

If you've checked the new cable with a continuity tester and it's fine, then maybe you're picking up some interference with the new cable/new location. How long is the new cable ? Did you make it yourself, and if so, what cable did you use for it ? You could be picking up interference from a motor-based appliance (fridge) or you could have a "ground hum" problem - ideally all your devices should be grounded at the same point - see http://www.audioholics.com/tweaks/connecting-your-system/ground-loops-eliminating-system-hum-and-buzz for further info. Hope this helps.

There must be something in the air, my sub died last night when I was installing a new AV receiver, I spent a complete age checking and re-checking the amp settings and the cable, only discovered the real cause of the problem by trying out a different sub.


Ritz.

sharkman

I use a high quality speaker cable , it dont run past anything electrical . Do you know where I could get a 20m cable made up ?

The Ritz

Sharkman,

I use a high quality speaker cable

I'm a little puzzled - are you connecting your speakers through the sub or are you connecting an AV receiver to the sub using a sub cable with RCA plugs on it ? A little more information on the set up would help

I make my own interconnects, so can't readily point you at a source for a 20m cable (60 ft ? is the sub in a different town ? ) Just don't pay silly money for it.

I'm very conscious of not starting a "cable flame war" here, I might end up banning myself, but if you can solder, a bog standard 75ohm coax cable (RG59) and decent RCA plugs will do fine. I use 75 ohm RCA plugs (e.g Canare) but have used "Maplins best" in the past with no problems.


Ritz.

sharkman

Your Puzzled !!!!

I'm connecting the receiver to the sub using a sub cable with RCA plugs on it . I i've got ATM KA OFC POWER LINE SPEAKER CABLE SPL2,5-2 Which diddnt work , so I got bog standard Maplin Speaker cable and soldered some RCA plugs on Which wont work either .

Now , with the sub pluged in the same place , if I run the cable which came with the kit (5M) across the room it works fine .

big_moe

rca cable needs a ground. speaker cable doesnt have that. thats where your hum is coming from.

get some phono cable made up. a place called all cables just off south circular road will do it for ya.

or as a last resort, use coax cable GROUNDED with rca plugs

http://www.one-source.ie/contact_us.php?osCsid=24ffdc7069068555672b0c246a7fdde8

adam

The Ritz

Adam beat me to it, puzzled no more I am !



Rtz

sharkman

Sorry , what do you mean by coax cable GROUNDED with rca plugs ?

big_moe

coax has an inner cable and an outer ground cable.

for the rca plugs, you would attach the pin of the rca plug to the centre coax cable. then the ground cable on the outside would attach to the ground on the rca cable.

and that will take out the hum

adam

Owenw

If you're not overly 'patriotic' :pac: with your cash, Mark Grant Cables are always highly rated on AV Forums. £25.00 stg for a 5m phono subwoofer cable with excellent Canare connectors: http://markgrantcables.co.uk/shop/index.php?main_page=product_info&cPath=43_4&products_id=4

I have a number of digital coax interconnects from MGC and those canare connectors are built to last.