Impressed with Tubes

Pubul57 - I would have no problem agreeeing with your comments about PP/SET amps interaction with speakers with a flat(ish) impedence curve, and there is no reason that a quality amp can't handle moderate speaker impedence dips, BUT one of the problems is that amps have varible output impedence to deal with that can be as problematic as speaker impedence (one of mine has a rise to 3.5ohms in the mid bass) so its important, at least on paper, to match the amps varying output impedence with the speakers varying impedence. Not a walk in the park if your looking for anything approaching ideal matching of amps and speakers without listening. FWIW.

I agree with you, and when you do hear an good match between pre/amp/speaker it suddenly becomes obvious that something good is happening, a sense of balance from highs to lows. One advantage to well designed integrateds.

OK, you guys are making me feel pretty inferior here. Are you telling me that I should be able to listen to a specific speaker/amp combo and then determine that somewhere around say 180hz there is an impedance mismatch of 2ohms. Please don't tell me you're telling me that,LOL.

Regards,

Not quite. But in speaking with your amp and speaker folks, you should be able to see if there are any red flags that would be obvious to them; if they are honest, then at that point you should not end up with any grave mismatch, and then it is up to you and your taste - there will never be one choice that works best for everyone....

Pubul57 and Phaelon, my comments about 4 ohms has little to do with the tube amp in question. 4 ohm taps on output transformers in general have less performance than the higher impedance taps, regardless of the size of the output transformer. Its *easy* to demonstrate!

IOW a simple way to get a speaker to appear to be more transparent is to keep the impedance high. The speaker won't sound any different, but the tube amp driving it (regardless of the amp) certainly will.

If you could switch a speaker from 4 ohms to 16 ohms and keep all the other variables equal, the result is that the tube amplifier will make less distortion, have more bandwidth and exhibit slightly more power. Right now the only way to demonstrate that is by using a set of ZEROs to accomplish the conversion from a 4 ohm speaker to 16. But if the speaker were 16 to start with, things would be even better.

Over the holiday weekend, I found out that at least one major manufacturer of transistor amplifiers also found out that higher impedances helps transistors sound better too- not because of limited current availability, but due to the aspects of the way the transistors work in the first place.
He used a set of ZEROs to discover this.

The evidence suggests that there is not really a good argument for 4 ohms regardless of tube or transistor, although the reasons are different depending on the amplifier.