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From: jku@kolvi.hut.fi (Juha Kuusama)
Newsgroups: sci.electronics,rec.music.synth
Subject: Re: guitar audio signals
Message-ID: <112@kolvi.hut.fi>
Date: 12 Feb 88 13:53:49 GMT
References: <502@m10ux.UUCP>
Reply-To: jku@kolvi.UUCP (Juha Kuusama)
Organization: Helsinki University of Technology, Finland
Lines: 34

In article <502@m10ux.UUCP> rgr@m10ux.UUCP (Duke Robillard) writes:
>
>Do turntables put out the same  audio signal as electric guitars?
>what about really old turntables (I think they're called ceramic,
>as opposed to electronic), the kind that need a preamp?  Can I
>hurt anything by pluggin a guitar into a home stereo amp?
...

The principle of turntable pickup and a guitar pickup have slight resemblance;
i.e. varying magnetic field generates voltage to a coil, but no, plugging a
guitar into pickup input of a hi-fi won't work and yes, if you do that,
something is likely to get broken.

Explanation:
The signal from a turntable pickup is about 2-5 mv amplitude. The records
are created with what is called an RIAA equalisation. The amp input is designed
to handle that kind of signal; it amplifies it heavile and adds a heavy bass
boost. If you plug there an electric guitar, you are likely to break at least
your speakers.

The signal from guitars are from 40mv to 6-7 v amplitude (depending from 
the particular guitar).  On a pickup input it will get overamplified and bass-
boosted so, that it is very likely that your amp puts out more than it's rated
output to your speaker. Smell smoke? Ok, when you have bought new speakers,
try experimenting further. The signal from a guitar is typically 100-200 mv,
high impendance, very like a tape deck puts out.

So, from my experience, when you plug a guitar to a tape or aux input, it will
work, but sound really bad. Plunk, plunk, twang... The guitar amps do their
own heavy equalisation (here is why different brands do sound different!),
usually you need some effects et.c. but if you are desperate, you may try
aux input of your deck.
--
Juha Kuusama, jku@kolvi.UUCP ( ...!mcvax!tut!kolvi!jku )