NAD amp distorting heavily after running a bass guitar through it. [Archive] - Audio & Video Forums

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jonlesser
01-16-2005, 01:00 PM
[note I also posted this in the amp section]

My NAD 214 stereo amp is dead or dying. Any signal I run through it is extremely distorted and I have to turn up the volume to even hear that.

Beginning a few months back it would sound fine and then all of a sudden die and the sound would become horrible distorted. The time it takes the amp to go from working fine to distortion box continually shortens from 20 to 10 to 5 to 2 to 1 minutes. Now it doesn’t work for anytime at all.

I haven’t been playing nice with it recently. I have run a microphone and bass guitar through it. However, the amp had experienced the problem I described above before this.

So my question is this: Is there any fundamental reason why running a bass guitar or mic through this amp would hurt it? Also, does anyone have any idea what might be wrong with my amp.

Thank you!
-Jon

Ps here is my setup in case it’s helpful.
NAD 214 Stereo Amp
NAD 512 CD player
Adcom preamp
KEF Q55 speakers
Monster XP cables

RJW1138
01-17-2005, 08:47 AM
Jon, here are some of my thoughts on this:

- Were you using the mic with a preamp or not? If not, a mic has such low output voltage that I'm guessing you really had to crank up the volume on your amp in order to get any SPL out of it. Running at this high of a gain could be dangerous if anything goes wrong I'm guessing, like you gave a static shock to the mic or something...I'd be leary about having the volume set REALLY high on ANY kind of amp, for the sake of the amp and the speakers.

- Guitars have very large dynamic ranges, and it's very easy to set the volume at a place where you like it, then say smash on your strings and produce a sound that's dozens of dB's higher. This could also send a much louder signal than you want through your amp and speakers. The thing to do is smash on your strings and produce the loudest sound you can when setting the volume on your amp, so that you know what the maximum level is going to be...playing softer will result in obviously lower volume than that.

- Other than that, I don't know if there's any "fundamental" reason not to use those instruments through a regular home audio amp. Maybe someone more knowledgeable than I could explain about possible level or impedance mismatches or something else that could be going on but that I don't know enough about.

But, if your amp had this problem before you started using the instruments, I think that's a pretty good indication that it was doomed to begin with, and it wasn't your instruments that did it.

Anyways, good luck figuring things out and getting that amp fixed/replaced.

JoeE SP9
01-23-2005, 05:03 PM
I am a bass player and over the years have used my stereo amps (Adcom, Hafler and Krell) for music making from time to time. I have never experienced what you are describing. Are you sure it is not your speakers that are the problem? I have experienced musical instruments blowing stereo speakers.

Geoffcin
01-23-2005, 05:29 PM
[note I also posted this in the amp section]

My NAD 214 stereo amp is dead or dying. Any signal I run through it is extremely distorted and I have to turn up the volume to even hear that.

Beginning a few months back it would sound fine and then all of a sudden die and the sound would become horrible distorted. The time it takes the amp to go from working fine to distortion box continually shortens from 20 to 10 to 5 to 2 to 1 minutes. Now it doesn’t work for anytime at all.

I haven’t been playing nice with it recently. I have run a microphone and bass guitar through it. However, the amp had experienced the problem I described above before this.

So my question is this: Is there any fundamental reason why running a bass guitar or mic through this amp would hurt it? Also, does anyone have any idea what might be wrong with my amp.

Thank you!
-Jon

Ps here is my setup in case it’s helpful.
NAD 214 Stereo Amp
NAD 512 CD player
Adcom preamp
KEF Q55 speakers
Monster XP cables

With a capacitor. Occasionally one will go bad slowly and leak it's guts out. I've seen this in a receiver before. Your going to need that checked out by a tech.

Most pro gear is made to be used with balanced inputs. Your preamp does not have one. Whether this is the cause of your problem I don't know, but with guitars it's best to stick with pro gear.

JoeE SP9
01-27-2005, 08:47 AM
With a capacitor. Occasionally one will go bad slowly and leak it's guts out. I've seen this in a receiver before. Your going to need that checked out by a tech.

Most pro gear is made to be used with balanced inputs. Your preamp does not have one. Whether this is the cause of your problem I don't know, but with guitars it's best to stick with pro gear.
I do agree with your thoughts on leaking caps. However, most if not all "musical instrument" amplifiers have single ended inputs. The Ampeg B-15, Sunn Collesium, Fender Bassman and Traynor YBA-3 amps I use are all single ended. These are not to be confused with amps used for PA and other purposes. Those amps do usually have balanced inputs. I can't think of any way short of using them as clubs a guitar or bass can harm an amplifier. I still ask, have any other speakers been tried?