[Jerry]

Did I find the perfect amp for passive horizontal bi-amping? Probably NOT
perfect, but pretty good.

Today I replaced the Radio Shack amp that was driving the mid/tweeter with a
Kenwood integrated amp. The Kenwood amp is somewhere in the 30 to 35 wpc
range as opposed to the 22 watt Radio Shack. Reason I’m now using the
Kenwood, is that this amp has an unusual design. The power amp inside the
Kenwood is really a Sanyo thick film hybrid integrated circuit. Now, Sanyo
recommends a supply voltage of plus and minus 27 volts.

Now, in this IC as the power output exceeds 35 watts, distortion rises
exponentially (and I mean it really zooms off the chart). This is why the
rating of 30-35 watts even though the theoretical power output is much
higher.

Well, for whatever reason the Kenwood amp has rail voltages of 40 volts!!

This makes the Kenwood an ideal amp for horizontal bi-amping on the
mid/tweeter. With this amp I have just terrific headroom for transients and
I’ll never have to worry about stressing the amp and getting into the high
distortion range. If I ever tried to put that much power into the
mid/tweeter, amp distortion would be the least of my problems. Both the mid
and tweeter would be well cooked.

It's a little early to predict how well this amp will perform (it's been on
for 6 hours now), but so far it seems very good.

Additional news is I bought a new (for me) scope. I got a 2213. Here is a
pic and you can review the specs:

http://www.testequipmentdepot.com/us...k2213&2215.htm

There are two areas I wish to explore further, transient response in the mid
to high frequencies under both single and bi-amp. Next, harmonic distortion
in the upper frequencies under single and bi-amp. Any suggestions on test
methods would be appreciated. My first inclination is to have a
significant fundamental signal present during these tests as a way to create
the typical "instability" we'd see in music.

Regards,
Jerry