Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[tigers_gonads]

My active sub takes is signal from the av amp via a 75 ohm coax cable.

What role does the coax screen have ?
Is it just a case of a screen down to earth for filtering out any interference or has it any other use ?

2 years back, I run a cable behind the coveing and down under the plaster so I could relocate the sub to a better position.
Needless to say, i've just got round to trying it out and the bugger does not work 
It may be the av amp settings. It was sat in a wardrobe for 9 months with no power so it would have lost all its settings 
Just to round it off, I can't find the instruction book 
The amp is a Yamaha dsp 

Not looked into the fault yet, thought it was best to sit down with a beer and chill before I get the multimeter out   

[I_want_an_Omega]

Dead easy to check the cable Steve - but you know that 

Yam amps can be set to "none" as far as the sub output is concerned - should be that IMHO.

Good luck - Rob

[Martian]

My active sub takes is signal from the av amp via a 75 ohm coax cable.

What role does the coax screen have ?
Is it just a case of a screen down to earth for filtering out any interference or has it any other use ?

It's the ground return.

[tigers_gonads]

Oh bugger

Amp set up for 6.1 with sub active
No output from the amp.
Cable bells out ok
Tried it with another lead with no luck

Has the sub output on the amp got its own internal fuse ?

[I_want_an_Omega]

Oh bugger

Amp set up for 6.1 with sub active
No output from the amp.
Cable bells out ok
Tried it with another lead with no luck

Has the sub output on the amp got its own internal fuse ?

No.

But if you increase the volume level on the sub to max then try just touching the input cable centre conductor with your finger & you should hear "hum" from the sub. Do that locally and you should hear it if the sub is ok, if so then do so again with the long cable to prove that. No hum probably means a dead sub. Does the sub have speaker level inputs? If so then there is a plan B. Also a plan C but lets take it one step at a time.

TTFN - Rob

[tigers_gonads]

Oh bugger

Amp set up for 6.1 with sub active
No output from the amp.
Cable bells out ok
Tried it with another lead with no luck

Has the sub output on the amp got its own internal fuse ?

No.

But if you increase the volume level on the sub to max then try just touching the input cable centre conductor with your finger & you should hear "hum" from the sub. Do that locally and you should hear it if the sub is ok, if so then do so again with the long cable to prove that. No hum probably means a dead sub. Does the sub have speaker level inputs? If so then there is a plan B. Also a plan C but lets take it one step at a time.

TTFN - Rob

Ok, just turned the volume up to max on the sub and had a play with the cable.
With just the centre part of the plug touching the socket, it hums like a good un.
As soon as the plug is pushed all the way home then the sound disapears.
The sub is a cheapo Eltax with the direct speaker inputs.

[I_want_an_Omega]

Oh bugger

Amp set up for 6.1 with sub active
No output from the amp.
Cable bells out ok
Tried it with another lead with no luck

Has the sub output on the amp got its own internal fuse ?

No.

But if you increase the volume level on the sub to max then try just touching the input cable centre conductor with your finger & you should hear "hum" from the sub. Do that locally and you should hear it if the sub is ok, if so then do so again with the long cable to prove that. No hum probably means a dead sub. Does the sub have speaker level inputs? If so then there is a plan B. Also a plan C but lets take it one step at a time.

TTFN - Rob

Ok, just turned the volume up to max on the sub and had a play with the cable.
With just the centre part of the plug touching the socket, it hums like a good un.
As soon as the plug is pushed all the way home then the sound disapears.
The sub is a cheapo Eltax with the direct speaker inputs.

That proves the sub is ok then Steve. So, it has speaker level inputs x 2 AND a single phono socket? Do you have to switch between them somehow?

If not then you have (IMHO) proved that there is no output from the amp - which is odd as Yams are pretty solid IME. Try switching the sub O/P off & on a few times to see if that helps.

If it fails than you could connect ONE of the speaker level outputs via the cable to one of the  speaker input on the sub. That will only give you L or R bass - but will be better than nothing and at zero cost. The speaker inputs on the sub are high impedance so there wont be any mismatch issues either.

[tigers_gonads]

No Switching between inputs, just a on / off switch and a volume knob.

I'll give the rest a try later
Just been told by the missus since she has got christmas eve off for the first time in years,  I have to go into town for a beer with her 

It would be rude to say no 

Thanks for your help mate.
Merry christmas 

[I_want_an_Omega]

You are very welcome mate 

My plan C was a spare sub that I have - but seems that isn't the problem ..........

Have a great xmas and lets hope for a decent 2013 .............

ATB - Rob

[Martian]

To prove the sub output on the amp is working (which I suspect it is as the sub needs a speaker level input as opposed to line level), connect a pair of walkman type headphones to the sub output and you should hear the bassline frequencies to whatever is being played.

[I_want_an_Omega]

To prove the sub output on the amp is working (which I suspect it is as the sub needs a speaker level input as opposed to line level), connect a pair of walkman type headphones to the sub output and you should hear the bassline frequencies to whatever is being played.

Got me thinking there - he hasn't actually confirmed whether he has a line level input yet has he? Lets wait and see ............ 

[Marks DTM Calib]

In some ways he has as he states that its a coaxial input. Key question is, what sort of cable has been used and are the 0V`s connected correctly?

Also, did you use a good quality screened cable for your install?

[Martian]

In some ways he has as he states that its a coaxial input.

My money says it's an RCA connector that is expecting to see speaker level voltages, although I would expect to see the ability to change that to line level input even on the cheapies.

[tigers_gonads]

Ok, my cockup for not storeing the amp better 
The socket on the amp was loose causeing it to sort out behind the socket.
Just popped the cover off and attacked it with the soldering iron this morning with great results.

Thanks for your help lads 

Oh yeh, the extention cable was run in RG59 screened cctv cable in a seperate conduit away from any mains cables.
Tbh, it sounds a hell of alot better then before.
Or maybe i've just washed my ears out 

[STMO123]

Your neighbours will be thrilled, I'm sure.