Who makes

I've been around the industry and an avid audiophile since 71 or so. It's really as simple as listening. I've heard a lot of speakers with tubes that were voiced' with SS. If you speak with a lot of the speaker designers, they'll tell you that they don't even 'voice' their speakers. I know one who told me a couple of weeks ago that the first time he hears his designs can be after they are in production. I know how that sounds, but his speakers are considered some of the best ever made and are one of the biggest names ever in high end audio.

I've heard this guys amps with SS as well as tubes. They sound great with both. Personally I'm a tube guy, but I just got an Ayre and it's the best SS I've heard to date.

I think too many of us get caught up in tech specs etc.. Heck, I have MIT MH 770 CVT speaker cables I"m about to sell off. They were made for tube gear and it's with their highest speaker cables. I used them with Quicksilver pre/silver mono's (selling them off ;) ). They sounded awesome compared to every cable I tried with the amps. Now I'm running an Ayre integrated as I am moving over to a remote control system. The cables sound awesome. I'm changing them to AQ since the Vandy's I"m going to eventually purchase were made with the AQ cables in mind. That said, I have listened to the various cables I'm looking at. Trust in the person who's shop you buy at as they are with these products daily and listen to systems not just components.

Not taking anything away from the question I hope as I find it interesting to say the least. I had this same conversation when I got my Proacs with Quicksilvers as I hated the Krell stuff with them (other than the Krell DAC I got), but I listened to them with both SS as well as AR and Quicksilvers it was tubes all day for me. That said, I know someone who got the same speakers with Levinson gear and the bass was unreal and made me want more. The amps offered different sounds and both would appeal to different listeners.

Double tap. ;-)

Excellent responses by Bruce and Bombaywalla.

Bob R. adds a good point also. During the 1980s and 1990s Bob Carver designed some Carver Corporation and later Sunfire Corporation solid state amplifiers that were intended to emulate tube amplifier characteristics to some approximation. That was accomplished in part by putting a resistor in series with the output, as Bob mentioned.

One of Carver's earlier such attempts, during the 1980s, involved configuring an amplifier such that its "transfer function" (the relation between its output and its input) approximately matched that of a well regarded high end tube amp, at least when driving a specific speaker load. As demonstrated by electronically "subtracting" the output of one amp from the output of the other, with both amps receiving identical inputs, and measuring and listening to the residue. That ended up provoking a good deal of controversy, of course.

I can't recall any other solid state amps that can be said to approximate power paradigm characteristics. I recall reading that Nelson Pass, and perhaps some others, have created some designs that essentially act as current sources, having VERY high output impedances (e.g., 25 ohms). But those would not maintain an approximation of constant power delivery as a function of load impedance either, because their output voltage would vary dramatically as load impedance varies. (Power = voltage times current, oversimplifying slightly).

Regarding the McIntosh solid state amps that use autoformers at their outputs, those have very solid state-like output impedances (e.g., 0.2 ohms or less). The autoformers appear to be used to make life easier on the output devices when faced with low impedance loads, by making those loads appear to the output devices as higher impedances. Thereby reducing distortion, and probably also increasing power capability into low impedances relative to what it would otherwise be.

Best regards,
-- Al

Bifwynne, thanks. I was just going by what I was reading atmasphere.
I think Al hit on one company, Pass Labs, that made the solid state amp act like a current driven amp. And The Carver amp that Bob mentioned looks interesting too.