To Pre or not to Pre

[v3spitfire]

Some have mentioned that certain amps (ie, MC 240) can be run without a pre-amp. It seems this would be the cleanest sound possible, as the way I understand it, a preamp is not supposed to add anything.

I have several preamps. An HK sig 2.0, which was a $2500 dolby/dts preamp new in 1999. I also have an adcom 710 2 ch preamp. I also have an adcom straight line controller (not a preamp), which has no electical power and can be hooked up directly to an amp, receive inputs, and essentially just control the volume. It does nothing more than act as a brake for volume.

I recently hooked each up and just listened to nothing. I then stuck my ear into the RF7 horn (I was bored), and could here a very faint hiss with both preamps (ie, not audible at even a foot away, though the HK was the quiter of the 2).

I then put in a hard rock cd, turned up full blast and stuck my ear back into the horn. Wait, I didn't do that last sentence...back to reality

I think this hiss is natural, and it is very minimal and inaudible at more a foot or less. I went upstairs and could here a similar hiss with my scott/heresy combo. When I hooked up the passive straight line controler (SLC), it was gone completely (or if not completely, beyond my ability to here). I have not listened to music comparing the SLC and the HK (the HK outdoes the 710), but it does make sense that the SLC should be quieter, given there is no electicity involved and therefore should have no extra distortion (not even the .000004% kind). Is anyone else using these types of devices and, given their relatively low cost, they must be giving up something??. But if they're not adding anything, and a preamp is not supposed to add anything, why wouldn't they be ideal. Like I said, I haven't had a chance to listen critically to music to do a true comparison, but does what I say make sense or is there really another reason for preamps. If I kept by ear out of the horns, I'de probably have more time for listening.

Do people who have amps that don't need preamps use preamps only for convenience of adding components, or is there more to a preamp then what I know (probably the latter, but what?)

[jt1stcav]

Until just yesterday, I haven't used a preamp with my SS McIntosh MC250 in almost 2 years. Before the tube preamp I just aquired, I saw no reason to use a pre since only having one source, and to my ears my system sounded excellent (better than my old Carver preamps, but not as airy as my previous AMC tube preamp). My new BEZ 6SN7 linestage adds more dynamics and presence to my music than without a pre, so I would suggest using a high quality pre (tube or SS).

But for your own ear's sake, you should try both approaches and see which sounds more pleasing to you. Your MC240 may prove me wrong!

[garymd]

My MC240 sounds very good without a pre but sounds better with the marantz 7C. You are limited to CDs though. A good pre can add dynamics to the sound of an amp but a bad pre can make it sound worse. Some combos are better than others. I've found that the 240 combined with a good mac pre will improve the sound. The 240 with the marantz 7C makes for a great combo also but is pricey.

There are lots of choices but I've only tried 3 with my 240. The Mac MX110, Marantz 7C and Kenwood KR9600 (SS) which sounds suprisingly good.

[v3spitfire]

I should have been more clear. I don't have a 240, though I wish I did. I mentioned this one since it was one that I know doesn't need a preamp. My uncle has one hooked up to EV Patricians which sound incredible. He does use a mc tube preamp though. You both have answered my question, that a preamp is supposed to add something (dynamics, presence). I had been under the impression that the preamp shouldn't add anything, just move the signal along. I will be able to judge this when I can listen to music without the kids around. Thanks again.