Tubes vs. solid state.

Pinkus, the only issue with transistors is that without feedback, they will make more distortion than tubes will. However, if the design is competent, the higher orders will not manifest nearly so much as they will if feedback is applied. Its my opinion that in time we (as designers) will sort out what must be done to make them work properly.

One of the best amplifiers I have heard is transistor, made by Ridley Audio. It was zero feedback and class A and fully differential. It employed a heater to heat the output devices to a fairly high temperature (and then regulated the heat) and made as much heat as any tube amp of the same power. The amp made 100 watts and cost about $100,000 for a pair (they could drive a 1 ohm load); a bit pricey for my blood but proof that the extra distortions of transistors can be tamed if handled right.

For the time being as I mentioned earlier, it is a lot easier to use tubes to keep the distortion down. It might be cheaper too. If one looks at the whole amp/speaker thing from the point of view of obeying human perceptual rules, the issue of higher output impedance of zero feedback amps becomes moot- that is 'what is' so you deal with it in the design.

Pinkus, Our tin ears must be forged from different pewter alloys. . . I have never liked KX-R, but as you know have used lovingly a Capri for a year and a half.

BTW, I was not aware that feedback or lack there-of even applied to pre designs.

G.

Is hard to decide between them because each person has different sound tastes, the tube lover will rather tubes and the same will happens to solid state amp lovers.

Guidocorona, feedback is very definately a factor in preamp design. A very famous Ampex recorder (model 351-2), used by RCA and Mercury as well as many others, featured a zero feedback record circuit.

EQ of phono preamps is often handled in the feedback loop of the preamp. The Dyna PAS-3 is a good example as is the ARC SP-3. If not, you will often see the term 'passive equalization' used by the manufacturer. Harmon Kardon used passive phono EQ in their famous Citation 1 preamp decades ago. IMO/IME passive EQ is harder to execute, but allows the phono preamp to sound better- smoother, with less ticks and pops. Refer to my prior posts as to why that is.

Chatta, there is of course an intellectual preference that each audiophile carries. Despite this conscious preference, the human brain apparently knows when it is being fooled, whether we consciously acknowledge it or not. Dr Herbert Melcher, a famed neuro-chemical scientist, has proved this recently in tests using audio playback- its fascinating stuff: as the brain detects violations of how reality actually sounds (false noise floor, slow waveform delivery, etc.), the processing of music moves from the limbic centers to the frontal lobes of the human brain. When we are comparing cables or listening to MP-3s, the processing is entirely in the frontal lobes.

It is becoming conventional wisdom that the sound of tube and solid state are converging. Perhaps in some respects that is the case, but, there are aspects of certain tube gear I haven't heard matched in solid state stuff. In general, better tube gear presents a larger scaled soundstage and a more natural, relaxed sound (I am not talking about warmer and sluggish). The initial attack of notes seem more realistic (less brittle and artificially edgy) and the notes seem to bloom into space and then decay more naturally. Better tube gear also tends to sound less "dry" (I am describing a sensation more than a particular sound).

I am a bit leery of making statements about tube being superior in sound to solid state because, frankly, I think a lot of tube gear sounds worse than the equivalently priced solid state alternative. I really don't particularly like most high-powered tube gear. If a speaker is efficient enough, I like the sound of well-built single-ended triode amps; if more power is required, I like output transformerless tube amps.

That said, I've heard a lot of solid state gear that have certain aspects of performance that better my tube gear and I could easily with such. For example, the Lyra Connoisseur linestage and phonostage sounded pretty good to me--very dynamic and beautifully dense and realistic harmonic structure. A friend has a First Watt J2 amp that sounds reasonably good on his horn system (he says it does less well driving his Spendor SP100s). I've also heard nice sounding systems driven by Ayre amps and Belles amps too.