AP-1615 Pre-amp

[Fred Wittman]

Hi John-

If I'm not mistaken, your two phono inputs were for a magnetic and a ceramic
cartridge.  The magnetic, which is the technology that survives today, was
more dynamic but needed more amplification.  You might check if there is a
buffer stage between only one of your phono inputs and the rest of the
preamp.  Also, there is the RIAA equalization.  If you are too young to
remember what that is (count your blessings if that is so), there was a
trick in recording on vinyl that boosted frequencies above 5KHz or 10KHz or
so during the recording stage and re-attenuated them when played back. It
turns out the ambient surface noise of the record was in that range and the
equalization trick quieted it down.  (Try listening to an old crank-up phono
and you'll know what I mean as soon as the record starts.)  If you play
something through the circuit that doesn't need equalization, it will sound
like hell, like there's no high end.  If you want to modify one of these,
you'll have to bypass this circuit.  I'd also recommend using the ceramic
input since you probably don't need the extra amplification stage.  Hope
this helps.

Fred - KG6NYK
----- Original Message -----
From: "John Szatko" <Jfz69 at AOL.COM>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Saturday, March 19, 2005 5:03 AM
Subject: [HEATH-TEMPE] AP-1615 Pre-amp


> Hi,
>
>    I have this unit along with the matching components and an  AA-1640
amp.My
> problem is with all the components to hook up
> now...Turntable,tuner,cassette,cd player,dvd,and even an old 8-track for
getting  those songs you can't get
> anymore and re-record,I ran out of plug-ins.I recall  something was
different
> inside the pre-amps for the turntables.(cartridge and  needle needed a
special
> ground or something)The AP-1615 has two phono inputs.Is  there something
to
> wire around to allow me to plug another unit into one of  those phono
inputs
> without ruining anything?
>
>
>       Thanx  John
>
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Products bought, sold or traded here is the responsibility of the
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