Did I break my Amp, again?

[admin_exported]

Hi

I have a 20 year old system with Onkyo parts and Qln speakers - that have been working great.

Last week one of the speakers had no sound - or almost no sound. It was very low volume, and something was obviously wrong. I swapped the speakers around, etc, and also noticed the same problem when using headphones in that output. Had the same problem weather I was feeding CD, iPod, tuner, etc.

I took for granted that the 20 year old amp had failed. Went out and found a good deal on a Rotel RA-04.

Once home I connected CD, tuner and speakers on the floor, and had it running for an hour or so. It all sounded great.

So, I took it apart and put it all into the hifi furniture, adding Squeezebox and the Apple iPod dock. Powered on, and again one channel was lost - now with the new amp. Only a very low sound on one channel. If I swap the speaker cables on the back of the amp the problem moves to the other speaker. Same problem in head-phone.

Is it possible there is something wrong in a speaker that burns the amp? Could it be a problem with an RCA cable?

My new amp was working fine for an hour...

 

[Anonymous]

Just noticed that with the bad channel there is nothing wrong - but the volume.

If I use the Balance control to play only the "bad" channel, and turn the volume up (a lot) the speaker sound fine... There is just an enormous volume difference between the two channels.

 

[scene]

Do you get the lack of one channel on all sources, or just one source? If just one source, then the issue could be with the source or the cable from the source. That is, do you get the error with both the Squeezebox and the docked iPod?

 

[cheyworth]

When you tested 'on the floor' did you use the same cables (speaker) or do you use a spare lenght?

Sounds like a loose cable. if it is the same channel even when swapping speakers the the cable is to blame.

 

[Anonymous]

scene:Do you get the lack of one channel on all sources, or just one source? If just one source, then the issue could be with the source or the cable from the source. That is, do you get the error with both the Squeezebox and the docked iPod?

Same problem with all sources.

I also tried removing all but the CD, and the problem still persist.

Have to put the balance control 95% on right channel to get about equal volume...

 

[Anonymous]

cheyworth:
When you tested 'on the floor' did you use the same cables (speaker) or do you use a spare lenght?

Sounds like a loose cable. if it is the same channel even when swapping speakers the the cable is to blame.

I used the same speaker cables.

Still, when I put the stuff into the furniture I also cut the speaker cables to about half the original length - they where just too long.

When I swap, I swap the speaker cable on the back of the amp. I put the cable from the right speaker to the "other" output (the left) on the amp. The problem then moves to the left speaker (which is now connected to the right output).

 

[Anonymous]

I am not an electrical engineer...

Did I blow the right channel power amp?

If so, how?

Also, something caused the same problem on the old Onkyo amp... Would that be the speaker..., the cable, ...?

Can my new Rotel be fixed?

I do not really want to borrow my neighbors amp and try my speakers on..., and burn his amp too. Do I have to through out the speakers, or can they be tested somehow...

 

[Anonymous]

pergr:
Did I blow the right channel power amp?

In case that is unclear - I mean the integrated power amp in the Rotel RA-04.

 

[The_Lhc]

You've clearly blown something in the amp, so it'll have to be fixed (you could try sending it back saying it's faulty and hope they exchange/repair it for nothing), in the meantime you need to find out what's causing it and it's either the speakers or the cable (maybe, one presumes it's not a source doing it, although a short anywhere could cause this). Something must be shorting out somewhere, or overloading something (it sounds like it must be in the pre-amp section if you can get volume by whacking the balance over, that would indicate that the actual amp stage itself is still ok), and that's usually stray wires from the speaker cables, either at the amp terminals or the speakers.

It does seem a little odd though, if you were shorting an amp channel with the speaker cable you'd expect the amp to blow or go into protection mode, this doesn't sound much like that.

Consult an expert, get them to examine everything, otherwise you could just be destroying amps for ages, which will get kind of expensive after a while...

 

[Anonymous]

For the record, my speakers are Qln, Qubic 111, 4 ohm, rec amp 20W - 150W.

 

[Anonymous]

Can I be sure there is something on the speaker side that is burning amps, or is it possible a source is burning them?

 

[Anonymous]

pergr:Can I be sure there is something on the speaker side that is burning amps, or is it possible a source is burning them?

from what you have described it might be the speaker. However, if it was the speaker, it would have blown the left channel as well when you switched the cables over...
It could be the RCA interconnect (the cable running between your source's output and the amp's input)... to test this just swap the right an left cables over at the amp end and see if the problem follows the cable...
As for the Rotel, if you purchased it new you can always take it back under warranty. If you ask them they might be able to tell you what the fault with the amp is and what is likely to have caused it...
goodluck!

ps. if possible you could look inside your speakers to check for any loose wires- especially near the binding posts where you connect the speaker cables.

 

[Anonymous]

Well, what ever it is, it first broke my old amp and then worked fine for an hour on the new amp, before burning also the new one. Perhaps the shorter tests I have done with the speakers swapped was not long enough to burn the other channel. I can always test longer...

On the RCA: I now have problem with all sources. When the new amp worked fine it was sitting with just tuner and CD. When I moved it into the furniture and connected also Squeezebox and Apple iPod Dock it failed. Even if I remove the Squeezebox and Apple iPod Dock there is still a problem now.

Apart from getting the new Rotel fixed, one way or another, I am not sure what to do with the rest of the kit... do I dare to keep it?

 

[007L2Thrill]

I just checked the insides of your rotel AMP and it does have overload protection, so if your speaker overloaded the AMP or you had any stray speaker strands the AMP would be clicking the sound on and off (did that happen?) plus the only time I have ever come across one channel low was when I by mistake put one of my phono RCA's in to the record tape output (that was a long time ago).

When you say you swap the speaker cables, do you swap them at the amplifier end? If so try swapping the speaker cable at the speaker end to see if you have any stray speaker strands on one of your cables.

 

[Anonymous]

007L2Thrill:

I just checked the insides of your rotel AMP and it does have overload protection, so if your speaker overloaded the AMP or you had any stray speaker strands the AMP would be clicking the sound on and off (did that happen?) plus the only time I have ever come across one channel low was when I by mistake put one of my phono RCA's in to the record tape output (that was a long time ago).

When you say you swap the speaker cables, do you swap them at the amplifier end? If so try swapping the speaker cable at the speaker end to see if you have any stray speaker strands on one of your cables.

No clicking sound what so ever. It worked perfectly when "on the floor" until I turned it off, and then when I connected it all together in the shelf one channel was extremely weak as soon as I powered it up.

I have tried both swapping the speaker cables at the amp, and also to swap the speaker position (left/right). All points to that there is a problem with the right channel output on the amp.

Also the old amp "burned" on the right channel.

I am wondering about the fact that if I turn the Balance to 95% right-channel, it all sounds almost OK. Of course, I need to crank the volume up quite a lot. What could that mean.

Should I bring out the screw driver and open the box...

 

[007L2Thrill]

pergr:

007L2Thrill:

I just checked the insides of your rotel AMP and it does have overload protection, so if your speaker overloaded the AMP or you had any stray speaker strands the AMP would be clicking the sound on and off (did that happen?) plus the only time I have ever come across one channel low was when I by mistake put one of my phono RCA's in to the record tape output (that was a long time ago).

When you say you swap the speaker cables, do you swap them at the amplifier end? If so try swapping the speaker cable at the speaker end to see if you have any stray speaker strands on one of your cables.

No clicking sound what so ever. It worked perfectly when "on the floor" until I turned it off, and then when I connected it all together in the shelf one channel was extremely weak as soon as I powered it up.

I have tried both swapping the speaker cables at the amp, and also to swap the speaker position (left/right). All points to that there is a problem with the right channel output on the amp.

Also the old amp "burned" on the right channel.

I am wondering about the fact that if I turn the Balance to 95% right-channel, it all sounds almost OK. Of course, I need to crank the volume up quite a lot. What could that mean.

Should I bring out the screw driver and open the box...

No, I would not open it up as there really nothing you can do unless you know what you doing! But have to say! It's a strange one that, it does it on headphones - speakers - on any source component, plus your old amp went the same way.

It sounds as the gain is down on one channel that only happens if one of your input cables are damaged or you have something plugged in to the tape REC outputs, but you say if you have the balance at 95% it sounds ok, does it have any type of distortion on the channel that is lower and if you do not play any music is there a humming coming from your speaker or anything on that same channel.

Sorry I can't be much help! As I would like to know what's causing it too.

If you live close to west midlands, bring it around my house and I will try to solve it for you!

 

[007L2Thrill]

If you want to see inside your amp! Here is a picture I found:

 

[Anonymous]

Well, it started working again...

I removed everything except the CD and all was fine.

Put the Tuner back..., and all is still fine... weird.

 

[scene]

pergr:
Well, it started working again...

I removed everything except the CD and all was fine.

Put the Tuner back..., and all is still fine... weird.

That is interesting. One thought... You say everything worked (old amp and new) "before you put the amp back in the cabinet". I'm wondering if when you put the amp back you're either:

a) Shorting out to interconnects (maybe the connectors are getting pushed together)
b) you've got a damaged interconnect that self shorts when you push the amp back.

Worth checking...

 

[Anonymous]

Well, the old amp "died by itself" in the old furniture a couple of weeks ago - most likely without much interference, as far as that is possible with a 3-year-old in the household...

Since I was changing furniture it was also time to replace the amp.

With a different furniture I needed to get new RCA cables for CD and tuner. When I tested the new amp on the floor it was with the old RCA cables. When I put it all in the new furniture with the new cables the problem appeared.

Now, out of this thread I have been discussing the case with a friend who understand the electronics. His thought was that I may be having a problem with the source. His idea was that the fact that with Balance 95% to right channel it sounded almost fine, could point towards that I did not have any proper input at all on the right channel. The sound I got on the right channel by turning Balance and Volume up was just cross talk from the left channel. He suggest I test this by removing all sources but one, and then swap left/right channel on the input - to see if there was a problem with amp or input.

So, I removed everything but the CD. Before removing that too I wanted to power up to check it again. Sounds was back in both channels. All sounded fine. Weird. I out the tuner back too - since last week I had tested many times with just CD and tuner connected; testing by swapping speaker cables back and forth, etc. Anyway, it was working fine with tuner too. After a while I put all four sources back. Everything fine - from every source.

On my friends advice I have left it on and pushed and pulled all source cables a bit to see if there is a short and the problem would appear again. It did not.

Last week I tried lots of combination to have the problem go away. Today I tried loads of combinations to try to have the problem appear again...

My friend's thought now is that a short on any input should be isolated by the source selector on the amp, while some short on the Tape Out connector at the back could have caused the issue.

The RCA connectors look quite good, so it is difficult to imaging pushing them will cause any issue. The Apple iPod dock cable though has both RCA connectors and a 3.5mm cable (head phone size) - possibly that could have touched somewhere and caused a short...

Still need to check if the old amp is fine or not...

 

[jamonbread]

I tried using my headphones with the amp and I get the same audio levels from both channels using my cans? So hopefully my amp is OK

My amp has a pretty crackley volume pot so is it possible that dust is the course of my issue maybe?