[skytra7]

I bought a new amp second hand from a friend. I have a problem in that the left channel is doesn't give any sound the majority of the time. This happens especially when I am playing it at low volumes, although even when I play it loud it sounds distinctly a lot lower than the right channel!

It does work if I change the input selector to something else and put it back on CD input selector, but even then it still doesn't sound as strong or equal as the right channel. All I get is a hiss and tinny music. I have checked plenty of times that I have bi-wired it up right as well...

Also, I have swapped the speakers around and it does the same thing with the other speaker, so I know its not a speaker issue.

I have changed inputs and put the phono cables onto different ones but the same effect occurs.

I asked a friend if it could be something to do with the length of the speaker cable, but he doesn't think that that should be a issue and to be honest neither do I.

I wanted to ask this question on the forum before taking it down to a shop to be serviced.

I'd be really grateful for any help you can give me (I wonder if anybody else has had this issue?) because this is my last hope of sorting it out, otherwise I'll have to dip my hands again into my shallow pockets!


Cheers for reading and any help you can give,


thanks

[dwhite]

A model number would help.

Also I suspect you may be talking about a stereo integrated amp and not a AV amp, so your in the wrong forum, I can move it for you if you want.

[skytra7]

Yes the amp is called Pioneer A-400, I'd still appreciate the help and yes if you could move this thread to the relevant one as it is not a AV amp but a stereo one Id be well grateful


Thanks

[ssuellid]

iirc the A400 has a combined volume and balance control. The fact that you have some sound does suggest there is something wrong with the balance.

Have you tried adjusting the balance to see if it makes any difference? If it does not then you might have a knackered pot.

[skytra7]

Thanks for reply sssuellid,

I don't have an instruction manual, so how would I be able to change the balance because I can't seem to be able to see it?

Thanks again...

[BlueWizard]

You need to go through a systematic process of elimination.

First, make sure Balance and Tone controls are set properly. Then make sure all the wiring connections are correctly connected, and are clean and tight.

Word of caution; ALWAYS turn the AMP OFF when connecting and disconnecting any wires from it whether they are input wire or output wire.

If you are disconnecting or reconnecting input wires, BOTH the amp and input device MUST BE TURNED OFF.

Next, disconnect the speaker wires at the speakers and cross them over left to right, right to left. So, does the lack of sound follow the wire, or does it stay with the speaker. If it stays with the speaker, then you have a problem with the speaker. If it follows the wire, then the problem is farther back.

Next, reconnect the speakers normally, right to right, left to left. Does the speaker work now? If so, you have a poor speaker connection. If not, then we move on.

Check the speaker wire connections at the amp. Make sure no stray wires are shorting things out. Remove the speaker wires and cross them over left to right. Does the problem follow the wire? If it does then the wire or the wiring connection if the problem. If not, we move on.

Reconnect the speaker wires normally right speaker to right amp, left to left. How does it sound now; is it fixed? If it is, then you had a problem with the amp/speaker wire connection. If not, we move on.

Next see if you can find a voltmeter. If you don't have one, you can get one at the local hardware store for less than £10. Measure the output levels of the amp on the left and right channels using the Voltmeter set to AC. The voltage will be below 20 volts, so use the right scale. Are you measuring roughly the same voltage on each amp channel? If so, that would imply that the problem is not the amp or before the amp.

Next, using the source that is giving you the problem, cross the input wires. Say if it is a CD player, connect the right channel output of the CD to the left channel input of the amp, and left out to right in. Does the problem stay the same or does it follow the wire? If it follows the wire, the problem is the CD player, if it stays the same, then the problem is after the CD player.

Reconnect the inputs normally right to right, etc... Did that fix the problem? If so, it was probably a bad connection.

Replace wires and cables to see if new cables improve the problem. You can just substitute with any old cables you have laying around, or borrow some from a friend, until you have established what and where the problems is.

If you've narrowed it down to the amp, then make absolutely sure it is not something silly like the Balance control turned to one side. If it appears to be a problem with the amp, then logically, it should be a problem with everything connected to the amp. If other inputs into the amp sound OK, perhaps it is that one input channel. Connect your input device to another input, say instead of connecting the CD to the CD input, connect it to the AUX or Tape input.

It could also be dirty switches and controls, try working the input selector switch back and forth a few times to clean any dirt off of the connections. Try turning the volume control and the tone controls up and down a few times. If you hear a crackling sound, that is dirt on the connection. Work the volume, tone, balance, back and forth over the crackling area until it clears up.

Us a systematic approach to isolate the problem.

Steve/bluewizard

[skytra7]

Thanks for help ssuellid and BlueWizard it seems it was the balance control wheel which is on the same knob as the volume knob. The left is okay now..I must have accidentally moved it when I was carrying it!!

I have novice like knowledge when it comes to hifis... And I am truley grateful cause it saved me a packet as I was going to take it in to be serviced.



Thanks again, I'm very happy!!!!

[ssuellid]

Its a relatively common mistake to make even for non noobs. The combined volume and balance controls have always been prone to 'user error'. The A400 is a nice amp.