Posted by Wayne Parham [ 65.69.120.165 ] on May 09, 2004 at 13:30:53:
In Reply to: Re: Hi posted by Frank Stuppel on May 08, 2004 at 20:10:51:
Hi Frank,
You wrote:
>> If you are using high efficiency speakers, a problem you will
>> encounter, is that many of the preamps, will only allow you to
>> turn the volume up “one or two clicks” and you have maximum
>> volume. This has the effect that you may not be able to really
>> adjust the volume. This is very annoying. So too much gain in
>> the preamp is not necessarily good.
That always annoyed me too. I like it when maximum rotation of the volume knob corresponds to the point where the amp reaches clipping at full source level input. That also tends to make the adjustment range most useable. But this level matching is asking a lot from separates, and it isn't really something I expect from them.
Still, the task is actually quite simple, technically. The only thing that is really required to stop a preamp from overdriving the stage after it is a voltage divider. It could be done with a transformer too, but I think that's an unnecessary overcomplication. A pair of resistors will do nicely, or a stepped attenuator if a person wants to fine-tune the level, to be able to make adjustments.
I guess what I am suggesting is the use of what some might call a passive "preamp," or rather, just a simple stepped attenuator as a solution to situations like you've described. If an active preamp tends to overdrive the amps, or to provide so much gain that only the first quarter to half turn of the volume knob sets the system to full output, then a stepped attenuator used after the preamp can be used to change the point where full volume is reached.
You can set the stepped attenuator once and leave it alone, making it a hidden component that's tucked away, out of sight. Use it like a fine-tune trim adjustment that's set once when you setup the system. There are some really good stepped attuators available, and that allows the owner to set the "baseline" levels for the system so that the preamp volume control is more useable.
I don't know if you're into that as a solution, but your mention of the preamp levels made me want to throw that suggestion out there. The volume knob position thing is probably a small issue technically, but I think it makes a big difference in the "feel" of quality of a system.
Wayne
[ FSAudio Forum ] [ Help ]