Amplifiers and Horn Loudspeakers

Some solid state amps operate in Class A up to a certain point, which is said to be close in some respects to the sound of tubes. I have a solid state amplifier that puts out 250wpc (Class A/B), however it operates in Class A mode up to 25wpc. I'm curious if this amplifier, operating in Class A mode, would be a good match for a high efficiency horn system.

My active speakers operate in Class A up to two thirds power (i.e. 99% of the time I listen to music) I would not characterize the sound to be like tubes at all. There is no characteristic tube warmth in the bass and lower mid (from harmonic distortion), even at high ouput levels.

I can still hear tube warmth when playing music that has had some of the recorded tracks deliberately run through "tubes" in the mix or mastering studio. Tubes are a great tool on dynamic instruments like drums as a form of compressor; the kick drum heavy thud sound is a charateristic of tube effects often applied to modern rock recordings.

Myself, I prefer hearing closer to what the sound engineer or artist intended rather than adding my own seasonings. Although, I completely understand people who add seasonings to taste, just as those who add salt and pepper to a meal. (after all you eat the food - so why not add some spice!)

I suspect the tube and horn match is a marriage born from the necessity to have a more efficient speaker for tube systems to achieve high SPL levels (rather than horn aficionados all wanting tubes). So tubes lead to horns rather than the other way round.

So I see no reason that you should not continue to be perfectly happy with your SS amp when connected to horns...

I own Avanatgarde Horn loudspeakers and have used primarily tube amplifers to drive them. However, I recently purchased Avantgarde's Model 5+ solid-state integrated amplifer that sounds very good. It runs in Class A for the first 1.1 watts. Other solid-state amplifers that I thought sounded good with my horns were the Pass Labs Aleph 3 and First Watt F-3. The problem with most solid-state amps driving horns is when you turn up the volume. The sound becomes very harsh. Using a good sounding solid-state amp with horns will give your system an adrenaline boost.

class a ss and tubes are quite different. that said, horns are going to sound like horns no matter what kind of power you feed them.

My Klipsch speakers, both KLF-20's and Chorus II's, sound very good with my Plinius 8100 (int. SS). I will tell you that they sound even better with my restored Eico HF-81 (int. tube).

Hope this helps,
Mike

I think you will find that most amps with specs like you state for your own will, in most cases, employ undesirably large amounts of negative feedback, a sonic no-no IMHO.

When I first got my A/G Duos, all I had in house was my Bryston 4B NRB so that's what I used 'til my Atmaspere M60s came in. 250 watts/ch, claimed to operate in class A up to about 15 watts and definitely swathed in global NFB. Great for specs but not so great for purity of sound.

undesirably large amounts of negative feedback, a sonic no-no IMHO.

The operational amplifier is used in almost every piece of analog circuitry under the sun. Operational amplifiers are employed in circuits using negative feedback to increase their linearity (accurately represent the input signal). The audio that you listen to has been recorded and mixed in studios and often mastered in another studio....the audio signal has literally passed through 100's of feet of wire and 100's of amplifiers, all with negative feedback, by the time it reaches you on an LP or CD. If negative feedback were even slightly audible then you have already lost the battle for good sound when you leave the record store with your purchases tucked under your arm!

SS with horns is OK....if you want to rip your ears off!!
I am very carefull with horns and tubes!

Shadorne,

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?

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...