Amplifiers and Horn Loudspeakers

Why do you think it is that amps with zero or very little negative feedback sound so much better than those with lots? And that on amps with adjustable feedback changing it is indeed very AUDIBLE?

Horns for the post part are expecting constant power output out of the amp, regardless of the speaker's impedance curve. When you add feedback, the gain of the amp is used to force the amp to behave more as if it has a 'constant voltage characteristic'. A lot of horns are not expecting this- impedance bumps will result in less power and dips will result in more. This can lead to colorations since many horns simply are not designed for that.

Everyone has different sonic tastes in equipment-
speakers, amps, preamps etc. Here's my 2 cents worth of my subjective opinion. I own 3 pair of Klipsch Heritage speakers. 1981 Cornwalls with Deang upgraded (from Klipsch Forum) type B crossovers using Auricap capacitors. 1983 Cornwalls with Deang upgraded type B crossovers using aluminum Jensen PIO capacitors. And 1989 industrial LaScalas with Deang upgraded type AA crossovers using aluminum Jensen PIO capacitors.
The upgraded crossovers raise the sonic perfomance of Klipsch Heritage speakers to a much higher level over the old stock networks. I highly recommend them.

I totally disagree that you can't run solid state
with horns. I own Mcintosh SS-MC 7150 autoformer amp & C38 preamp. I have run Mac with Klipsch Heritage with good sonics to my ears. There are other people at the Klipsch Forum that also like Mcintosh SS with Klipsch speakers. Currently have the Mcintosh gear hooked up to a pair of stacked old Henry Kloss New Advents-top Advent inverted/upside down so the tweeters are together.

I have also run a Llano Phoenix CAS 300/VA2 mosfet tube hybrid amp with the Mac C38 preamp, a deHavilland Verve 6SN7 tube preamp & now with a George Wright AU1000 12BH7 tube preamp with Klipsch Heritage speakers with good sonics to my ears. The 1989 LaScalas are currently hooked up to the Llano Phoenix CAS 300/VA2 mosfet/tube hybrid amp with George Wright 12BH7 tube preamp with tone controls. The VA2 voltage section of the Llano amp uses either 6SN7,6SL7 or 12SN7 tubes. Currently using a pair of RCA 12SX7 GT tubes in the VA2 voltage box.

I also own two SET systems-Welborne Labs SET 2A3
Moondogs & Welborne Labs Reveille 6SN7 tube preamp-currently hooked up to my 1981 Cornwalls.
deHavilland Aries SET 845 & deHavilland Verve 6SN7 tube preamp hooked up to my 1983 Cornwalls. Good sonics to my ears using SET amps.

Making a blanket statement that you can't run SS with horns is just plain wrong/false in my humble opinion. It all boils down to personal sonic preference. Go over to the Klipsch Forum. They are plenty of guys that use & prefer tubes. And other guys that use & prefer SS. Me, I like both!

In my band I run transistors with horns all the time. That is not what I would do at home though. It seems that horns are far more likely to own up to the bad side of their reputation with transistors (honky, shrill) and that transistors are largely responsible for this.

OTOH I can't think of a good reason to run transistors on anything at home :)

no-sir- I don't like it!

It seems that horns are far more likely to own up to the bad side of their reputation with transistors (honky, shrill)

Good point. The typical resonance problems of a horn design will be fully revealed in all their glory (ugliness) with SS gear. Certainly a tube amp will reduce a horns shrill nature by balancing the harmonic content out across a number of partials rather than a honk at one frequency. A good example of synergy.

A lot has to do with the output impedance of the driving amp too. A lot of horns are highly reactive and this plays havoc with feedback networks in transistor amps...