New amp run-in

 

John P
Unregistered guest
Hello people, I've just bought a Nad c372 amp and I'm a little upset with the bass, or lack of it. I've only had the amp for one hour though! Am I likely to see a dramatic improvement after a certain number of hours? Thanks.
 

Silver Member
Username: Gman

Mt. Pleasant, SC

Post Number: 518
Registered: Dec-03
Are you driving a passive subwoofer with this amp? Have you driven your pair of speakers with another receiver or amp before this one with satisfactory results?

And you aren't likely to hear any improvement in the amp performance, as amps don't have moving parts. Speakers can have a break-in period--but not amps (unless they are poorly made)--as at worst, they should be "charged" in less than a minute--and generally within 1 second.

What speakers do you have? I find it hard to believe that this 2 x 150 watt amp will have a hard time driving most speakers--except the most inefficient or odd designs.

It could be possible there is something amiss with the amp.
 

Silver Member
Username: Myrantz

Post Number: 271
Registered: Feb-04
John P

You'll see similar findings here:
https://www.ecoustics.com/electronics/forum/home-audio/17225.html
 

John P
Unregistered guest
Thanks for your replies. So what's all this stuff about needing to "burn an amp in" - is it nonsense? I've been told that the bass is poor on my amp because it isn't run in yet!
 

Silver Member
Username: Gman

Mt. Pleasant, SC

Post Number: 521
Registered: Dec-03
John P--

It is nonsense--particularly on a solid state amp. Could you imagine a computer not working well and the company telling you that it needs to burn-in?
 

John P
Unregistered guest
Yes, fair point. In that case I'm very disappointed. I've got large speakers, rated 39hz and above so they should give adequate bass response but my amp has the bass tone control set to max yet still produces inadequate bass in my opinion. I shelled-out on a decent amp to give me a better than average sound and although I'm not a "bass head" I certainly like to hear good bass, just not the floor shaking type. What integrated ss amp in the same price bracket do you recommend? I want one where I don't have the bass control set to full all the time, I'd like a bit more control than that. I also listen at low to moderate levels, never loud. Thanks for your time.
 

Gold Member
Username: John_a

Post Number: 1126
Registered: Dec-03
John,

I checked the NAD C372 spec. It is very impressive.

It gives 20Hz-20kHz ±0.3dB. That is awesome precision, no one could hear 0.3 dB.

The "what you can hear" spec is 3Hz-70kHz -3dB.

But that extends whole octaves beyond the range of hearing, in both directions!

Either your amp is up to spec, or it isn't. If you think it isn't, take it back. If, however, it meets the published specification, the problem must be with some other component in your system. Most likely, the speakers. Consider also that you may have become accustomed to an artificial bass "Hump" at 80-100 Hz or so. This is sometimes a dirty trick of speaker manufacturers.

Just to confirm burning in is nonsense, in my opinion, too.
 

Gold Member
Username: John_a

Post Number: 1127
Registered: Dec-03
John,

BTW Check your speakers are connected to the amp with the correct polarity, so they are in-phase. Phase cancellation from switched polarity on one speaker is the most common cause of missing bass.
 

Bronze Member
Username: Sun_king

Leeds, West Yorkshire UK

Post Number: 65
Registered: Mar-04
What was the amp you had before the C372 and have you changed any of the other components in your system?
 

Silver Member
Username: Soccer

Post Number: 107
Registered: Apr-04
I beg to disagree on the burn-in question, because the audio path in the amps's circuit board travels a series of connection points (solders, resistors), which will influence and unbalance the audio signal (thus distorting), until all these "connections" are sensibly at the same temperature. Now, due to the existence of various solid state devices (not moving), they all diferent times to achieve optimal temp. I've seen very good amps blowing speakers due to "uncontrolled" peaks. Here one thing you can look for in an amp spec is the damping factor, the higher the better
 

Silver Member
Username: Soccer

Post Number: 108
Registered: Apr-04
One other thing, better have a powerfull amp feeding the speakers than the opposite, weaker amps more often blow speakers due to less control, damping factor, and other issues
Enjoy
 

John P
Unregistered guest
Sun King, I had a Marantz 6010OSE powering the system previously. That had adequate although not deafening bass. I use Kef Q7 speakers and a Nad c541 cd player. All was fine before the C372 arrived on the scene.

John A, I have checked the polarity of my speakers and all are Aok. I agree with you, the specs of my new amp are excellent and that's the reason I bought it. I was presuming it would be an upgrade but I'm most disappointed. It's a nice sounding amp but I just don't like the way I have to have the bass control set to max all the time....and am still found wanting on numerous cds. I've heard Rotel are good for bass - what about Arcam? This time I really want to get the purchase right. I want loads of bass from my amp, so much that I have to turn the control down, at least that way I will have some leverage! I can't see that it's a speaker problem because my Kefs were fine previously. Is there another speaker out there that I should be looking towards? I live in the UK so Maggies etc are hard to source. Thanks people.
 

Gold Member
Username: John_a

Post Number: 1150
Registered: Dec-03
John,

This is very weird.

In your place, I would try changing the polarity on one channel, anyway, just to see what difference it makes. Are we both talking about "+ to +" and "- to -"? - that is what I mean by "polarity". It could even just be the + and - have been mixed up internally, behind the sockets, in the receiver/ speaker. I doubt it, but changing polarity on one channel, deliberately, is the way to find out. If the Kefs were OK before, then the finger of suspicion would point to the amp. But that would be a really stupid thing for them to get wrong. Apart from a very obvious effect on bass, there are stereo test discs with in-phase and out-of-phase source material: it is very easy to hear the difference.

After all that, though - and I do not say this lightly - IF that spec is right AND the amp delivers according to it AND nothing has changed with the speakers THEN the amp that was the problem was the old one. Maybe it got you hooked on bass, and you need audio "detox" treatment. No offence. Hope you understand. It is easy to get hooked.

You should not need tone controls with gear like that. You could check features like "loudness" controls are not the problem. When on, "loudness" cuts everything by xdB, but then turns up treble and bass: if you compensate for that by turning the volume up, you get "disco" type sounds, all top and bottom, no midrange.
 

John P
Unregistered guest
Thanks John A. It is a possibility that I was spoiled with the other amp! Hard to go back though when you've had nice deep bass. How do you recommend I detox, shall I fast from bass for a while? Won't be a problem with this new amp! Ha!
 

Gold Member
Username: John_a

Post Number: 1155
Registered: Dec-03
John,

Thanks.

"How do you recommend I detox".

Listen to real music in the real world, too. It is the reference. It is what we are trying to reproduce.

Isn't it that simple.....?!
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