From: moskowit@panix.com (Len Moskowitz)
Subject: Re: Connecting NAD 5000 to Aragon 4004 directly
Originator: tjk@csd4.csd.uwm.edu
Keywords: NAD ARAGON VARIABLE OP-AMP
Organization: PANIX Public Access Unix & Internet, NYC
Date: Thu, 30 Jul 1992 13:04:34 GMT
	(queueing-rmail) id 151314.16289; Wed, 29 Jul 1992 15: 13:14 EDT

In article <1992Jul28.173510.14785@galileo.cc.rochester.edu>
eric@prodigal.psych.rochester.edu (Eric Hansen) writes:

>I'd like to connect a CD player directly to an amp, thereby eliminating (or 
>rather, postponing until funds permit) the need for a preamplifier.  The
>CD player is a NAD 5000, which has variable output, and the amp is
>an Aragon 4004.  So, I have several specific questions -- any help from
>people who use/have heard this type of (or similar) arrangment would be much
>appreciated!
>
>1)  I've been told that connecting a CD player directly to the amp will
>  theoretically provide the 'purest' sound possible since there's
>  basically nothing in the signal path.  I've also heard that while this
>  is true (and only possible with a variable output unless you like your
>  music very loud), the op-amps inside the CD player which make this possible
>  are usually not so great -- suitable for headphones, but not great as
>  compared to the gain stages which are built into legitimate preamplifiers.
>  Anyone know about the volume/op-amp stage of the NAD 5000?

I use a direct CD-to-amp setup.  It can be quite clean.  I've also
listened to the NAD 5000 thorugh the fixed level outputs and through
headphones.  Both are good.

The variable level outputs are another story.  Not good.  See the
Stereophile review and Recommended Components list for details.

I'd recommend a buffered volume control, something akin to Corey
Morgenstern's buffered pre-amp (again see Stereophile).

>2)  There has also been question as to the dynamic response which is
>  heard without a preamp - namely, if there is a lack of it.  Since I've never
>  used this arrangement, I don't know.  Most salesman have told me that
>  to get the best dynamics, you *need* a preamp - of course, to make the
>  most profit, you *need* to sell the preamp, so I don't know how
>  accurate this claim is...  It certainly seems reasonable to invest in
>  the preamp if your dynamics will otherwise be lacking, but is this
>  the case?

You don't need a pre-amp if the CD player can properly drive the amp.
That means the amp must have a sufficiently high impedance or the CD
player must have rather stout drivers.  Again, an active buffer stage
can ease any problems you might encounter.

If you don't need them for impedance matching, switching, or EQ,
pre-amps just add noise and cost.

>3)  Last but not least, there's the impedance matching issue.  The
>  Aragon has in input impedance of 22 kilohms.  The NAD has output of 120
>  ohms.  Assuming that one of the principal jobs for the preamp is to match
>  impedances between sources and the amp, is this difference of impedance
>  a big problem?  Will it cause things like hum and/or low volume ceilings?

The Aragon's input impedance may cause some loading and consequent
high frequency roll-off.  Listen and see.

-- 
Len Moskowitz
moskowit@panix.com


Newsgroups: rec.audio.high-end