The Trouble with Preamps.

What’s wrong with the following conversation:

“Hello, Pacific Valve?”
“Yes”
“Which one of your CD players has a volume control?”
“Currently its our modified Sheng Ya”
“That’s it?”
“Yes, Can I ask why?”
“Well, I want to go straight into my amp and I do not want any lousy preamp mucking up my sound”
“But sir, not that I am trying to sell you a preamp, but going straight into your amp without a buffer can seriously affect the sound”
“You heard me, no preamp”
--Click—


What’s wrong with people? They got this idea in their heads of a straight wire with gain, going directly into an amp. Sarah Vaughn’s voice, on some mythical path to the speakers, is going to bypass the evil preamp and make its way to mother amplifier who is waiting for the electronic reception. I can see it now, its Mrs. Field herself - chocolate chip cookies and milk on hand waiting for the signal like a kindergartners first day of school. So happy to see it, mother amp is going to amplify, ever so delicately and yet forcefully that the san preamp guy will have the best sound on the blog. He has out smarted every one else – what a genius. This, for some reason, is their idea of audio nirvana. I can hear him now, “…a straight wire with gain, you see and since there is a volume control on my CD player, why, no other volume control is necessary, you see… “

Like all things in audio, sometimes true, mostly not true.

If it were true, then why have preamps at all, right? Are preamps just over done, glorified switchers? So, it cannot be always true.

You can do the math and look for the impedance mismatches and see how the CD player is going to effect the sound or you can do as I do, perform the ear test. First you will need a preamp of some sort – either your own or borrow a friends.

Here is what an impedance mismatch generally sounds like, and I mean generally:

The midrange congests. It sounds like someone is placing their hand over the midrange. Then all of a sudden, without any warning, the congestion goes away and comes back. I cannot explain this electronically, but it seems to happen every time.

The bass thins out. Listen for the lower registers not being there. This could be deceptive, since it will have juice and punch, but nothing to punch through.
Try to find an Instrument in space. How easily can you isolate it? What does it sound like? On a mismatch, it will be hard to locate the instrument and then once you do, it will smear back and forth and eventually, get on your nerves.

Now, plug your preamp in. Does this go away? Is the image stable? Has the bass returned? Be sure that the volume is set for the same level, and you should easily tell if a preamp purchase is in the offing.