Input Levels

[Mike Lewis]

Hello,

I've asked this question elsewhere but have not received an answer. Is
there a standard (defacto or codified) for the signal voltage
(peak-to-peak AC) output of devices such as tuners, cd players, tape
decks, etc.? It seems to me that there must be, else how would the
myriad of manufacturers ever get there equipment compatible.

If there is a standard, what is it? And if there is not a standard,
what is the rule of thumb you all use.

Thank you.

Mike L.

[Mikkel C. Simonsen]

Mike Lewis wrote:
>
> Hello,
>
> I've asked this question elsewhere but have not received an answer.
> Is there a standard (defacto or codified) for the signal voltage
> (peak-to-peak AC) output of devices such as tuners, cd players, tape
> decks, etc.?

No. There are standards for pro equipment (+4 and +6dB), but not for
consumer gear.

> It seems to me that there must be, else how would the
> myriad of manufacturers ever get there equipment compatible.

They don't really care. They just make sure their own equipment is
compatible with itself...

> If there is a standard, what is it? And if there is not a standard,
> what is the rule of thumb you all use.

The "standards" are -10dB (250mV RMS) and 0dB (750mV RMS). But in the
real world you should ecspect anything in the 100mV to 3V range. CD
players are normally in the high end (1.5 to 2.5V), the other equipment
is normally in the 300-500mV range - but don't count on it...

Best regards,

Mikkel C. Simonsen

[Mike Lewis]

Thanks very much to everybody who replied.

Mike L.

Mike Lewis wrote:

> Hello,
>
> I've asked this question elsewhere but have not received an answer. Is
> there a standard (defacto or codified) for the signal voltage
> (peak-to-peak AC) output of devices such as tuners, cd players, tape
> decks, etc.? It seems to me that there must be, else how would the
> myriad of manufacturers ever get there equipment compatible.
>
> If there is a standard, what is it? And if there is not a standard,
> what is the rule of thumb you all use.
>
> Thank you.
>
> Mike L.

[Kirk Patton]

In consumer audio, there is at least one . . .

Red Book CD standard states that digital full-scale should equal 2 vrms
output.

However, this seems to be passing by the wayside . . . while many of the
current DAC chips are boasting dynamic range approx. equivalent to a 20 or
22-bit word legnth, the associated analog electronics they're quoting for
evaluation purposes aren't quiet enough to resolve this referenced to 2
vrms. Hense, many of these test circuits reference digital full-scale to a
higher voltage (like 4 to 9 vrms) in order to allow the noise floor of the
DAC to be evaluated . . . and of course, many audio manufacturer's products
are based closely on the semiconductor manufacturer's application notes . .
..

Kirk Patton