Can an amp be slightly damaged and still seem to work fine?

[radiorog]

Hi there, I've recently purchased a Leema tucana anniversary edition, ex demo with little use, at what I feel is a decent price. On the second day of use it shuts itself off and had to be sent back. The CPU transformer had failed, and Leema replaced and was sent back. After a missed courier meant the unit had to go back to the UK depot and spend a couple of nights in miu s 3 degrees C conditions, it arrived back with me. The volume dial had come off in transit, and there seemed to be a clear issue that the screw fixing the volume knob on, wasn't tight. It had scratched the front face plate doing so. Again it was sent back and Leema replaced the face plate FOC. The amp was sent back to me, and this time the courier had left the unit on its side, which crushed the pins on the mains cable, and the remote is temperamental. These are both being replaced.
The unit seems to play fine, and sounds great. I seem to notice a fraction more bass boom than before (I have big issues with boom from my dynaudio speakers being in a corner, they are moved out as far as I can manage, and will be replaced eventually). It could simply be that when I first tried this amp before it broke, I noticed how much less bass boom there was with this amp, and know I noticed some, it feels more than before. I am completely open to this being psychosomatic.
My question is, can the amp have some broken components, but it can still be working? Is it possible something could be dislodged or damaged, even something tiny, but that the amp would still work, although not at it's 100% full capacity?
I am just worried as it has been on a lot of travels over the past few weeks, and also been out in freezing conditions.
As mentioned, it sounds great still, and putting ears next to speakers, there is no humming or buzzing coming from then.
Thanks

 

[Sue Pertwee-Tyr]

Being out in freezing conditions will have caused absolutely no harm whatsoever. But it is understandable that you need to restore confidence in the amp, and may be looking for flaws where on your initial experience of it you weren’t doing so. Try to relax and just listen to the music, rather than trying to dissect the performance.

 

[gez]

What exactly is a CPU transformer? The Tucana looks like a pretty traditional A/B amp to me, where exactly is there a CPU in use in the amp?

I would expect that Leema would at the very least have listened to the amp (no matter how briefly) before sending it back, so I think it's fairly safe to presume that the amp was "working as expected" at the time it left Leema. That means the only treatement of concern that happened to the amp after that point was it being sat on it's side, which will do no damage at all to the amp (presuming it was placed down gently of course not just dropped).

I do understand your concern though. I've done similar in relation to amplifiers myself, worrying if somehow an amp component could be "below spec" in a way that would only subtley alter the sound quality meaning I'd not get the full performance of the amplifier. I keep telling myself in those situations that if something was broken or working below spec, in the vast majority of cases it'd affect only one channel and thus I should be able to hear the difference it causes.

 

[slawekt]

What exactly is a CPU transformer? The Tucana looks like a pretty traditional A/B amp to me, where exactly is there a CPU in use in the amp?

Microprocessor is used in control circuitry as in many other amplifiers , it has nothing to do with amplifier output stage, even some tube amplifiers out there use microprocessor too.

 

[gez]

Microprocessor is used in control circuitry as in many other amplifiers , it has nothing to do with amplifier output stage, even some tube amplifiers out there use microprocessor too.

You mean for volume (for example)?

I'd be very surprised if such circuits would have a dedicated transformer. The Tacuna has three toroids, one per channel for the audio circuits, and a third small one that is most likely for the standby circuit, not to power any ancilliary circuitry.

 

[slawekt]

You mean for volume (for example)?

I'd be very surprised if such circuits would have a dedicated transformer. The Tacuna has three toroids, one per channel for the audio circuits, and a third small one that is most likely for the standby circuit, not to power any ancilliary circuitry.

Third transformer powers microprocessor which is part of control circuit as I said earlier

 

[radiorog]

Thanks for answers everyone. I had the same question, what's is a CPU transformer, and Leema told me it was a dedicated power supply for things such as input selection.
Well the amp has just failed again. Everything went very quiet, and could only hear n inaudible low level muffle coming from speakers. It will be going back, and I don't think I'll risk it being fixed and sent back again. Shame, as it sounded excellent when working.

 

[colasblue]

Sounds like you've had an absolutely terrible experience and lost confidence in the product/brand.

I certainly don't blame you for that.

Kit arriving damaged in manufacturer's packaging is fairly inexcusible really. The packaging must clearly be inadequate, though bending a mains plug takes some doing and I doubt just leaving a package on its side can do it.

It must have been dropped from a great height at some point.

If that's happened there can be any number of other issues and you're quite correct to reject the unit IMHO.

It's not like we get lots of reports of faulty Leema equipment and it's generally considered a top brand so you've probably just been unlucky, but then again I was "unlucky" with a Chord DAC and have never bought the brand again and just don't get me started on the reliability of the Tag Mclaren kit I bought once. I'll never buy anything made by IAG on the basis of that.