Getting The Right Input?

[Sune T. B. Nielsen]

Hi
I am doing a sound installation where we use old hi-fi equipment. To be
precise part of the concept is to perform sound art on thrown-away
loudspeakers. We use old hi-fi (mostly thrown-away) amplifiers too, and
direct the sound into the amplifiers from portable CD-players trough a
mixer.

We take only one of the stereo-channels from the LINE (if they exist) or
Heaphhone-output from the CD-players and plug them to the mixer.
We use mono outputs from the mixer and split eqach of them so that the same
signal goes to both left and right of one ampilifier. For practical reasons
as well as to minimize the input.

We use input
CD (if that exists)
AUX (if that exists and not CD)
Tape (if that exists and neither CD or AUX)
Phono/mic if nothing else exists

I do not know how many microvolts different kinds of inpust are made for,
but I am suspecting that the signal from the cd/mixer it too powerful, since
some of aplifiers die each time we do our installation.
Is that true?

If it is, should i put some kind of resistor between the output from the
mixer and the input of each amplifier?
If not, what else could be the problem?

Any tips would be appreciated vey much.


Thanks in advance
On behalf of The Infernal Machine, Denmark
Sune T. B. Nielsen

[Kalman Rubinson]

Can you not simply turn down the output on the mixer? Most have a
master volume control. Alternatively, it is possible that the mixer
is defective and putting out DC which is killing the amps. Another
possibility is that the mixer is direct-coupled and passing on a DC
signal from one of the sources.

Kal

On Fri, 21 Nov 2003 23:48:44 +0100, "Sune T. B. Nielsen"
> wrote:

>Hi
>I am doing a sound installation where we use old hi-fi equipment. To be
>precise part of the concept is to perform sound art on thrown-away
>loudspeakers. We use old hi-fi (mostly thrown-away) amplifiers too, and
>direct the sound into the amplifiers from portable CD-players trough a
>mixer.
>
>We take only one of the stereo-channels from the LINE (if they exist) or
>Heaphhone-output from the CD-players and plug them to the mixer.
>We use mono outputs from the mixer and split eqach of them so that the same
>signal goes to both left and right of one ampilifier. For practical reasons
>as well as to minimize the input.
>
>We use input
>CD (if that exists)
>AUX (if that exists and not CD)
>Tape (if that exists and neither CD or AUX)
>Phono/mic if nothing else exists
>
>I do not know how many microvolts different kinds of inpust are made for,
>but I am suspecting that the signal from the cd/mixer it too powerful, since
>some of aplifiers die each time we do our installation.
>Is that true?
>
>If it is, should i put some kind of resistor between the output from the
>mixer and the input of each amplifier?
>If not, what else could be the problem?
>
>Any tips would be appreciated vey much.
>
>
>Thanks in advance
>On behalf of The Infernal Machine, Denmark
>Sune T. B. Nielsen
>

[Peter Larsen]

"Sune T. B. Nielsen" wrote:

> We use input
> CD (if that exists)
> AUX (if that exists and not CD)
> Tape (if that exists and neither CD or AUX)
> Phono/mic if nothing else exists
>
> I do not know how many microvolts different kinds of inpust are made for,

About a volt.

> but I am suspecting that the signal from the cd/mixer it too powerful, since
> some of aplifiers die each time we do our installation.
> Is that true?

About two volts peak.

> If it is, should i put some kind of resistor between the output from the
> mixer and the input of each amplifier?

Depends. Generally speaking something on the order of magnitude from 6
to 16 dB comes to mind as possibly relevant.

> If not, what else could be the problem?

First explain what you mean when you say the amps die, I don't think you
mean that literally.

> Any tips would be appreciated vey much.

I'd first consider how the amplifiers are loaded. Too strong input
should not cause them to go silent, generally their volume control
should be able to attenuate it.

> Thanks in advance
> On behalf of The Infernal Machine, Denmark

Perhaps you should email me in danish, are you in the Greater Copenhagen
Area?

> Sune T. B. Nielsen


Kind regards

Peter Larsen

--
************************************************** ***********
* My site is at: http://www.muyiovatki.dk *
************************************************** ***********

[Peter Larsen]

Kalman Rubinson wrote:

> Can you not simply turn down the output on the mixer? Most have a
> master volume control. Alternatively, it is possible that the mixer
> is defective and putting out DC which is killing the amps.

It is unlikely that the amps are DC coupled. This is about consumer
grade sonic implements.


Kind regards

Peter Larsen

--
************************************************** ***********
* My site is at: http://www.muyiovatki.dk *
************************************************** ***********