Hi efficient speaker, bass problems

Certainly it is! The slew rate (or risetime) is a measure of how fast the amplifier can respond to a signal. The quicker it responds, the more likely the signal will be processed by the emotional centers of the brain (limbic system) rather than the cerebral cortex. This is where toe-tapping comes from.

Mapman, a damping factor of 1000... well let's put it this way- you won't hear the difference between that and an amplifier with a DF of 50, all other things being equal (which, it seems, they never are...). Its my guess that there are other things that are making that work for you.

It was certainly the case for me that an Atma-sphere S-30 gave me much improved bass over the solid state amp (Pass Aleph 30) I had previously, which had a much higher damping factor. With my 96 dB efficient drivers in a ported box, the Aleph overdamped my bass. -Roscoeiii

Roscoeiii, Are you saying the S30 had more bass or improved Bass?

Atmasphere:
The vented box will need an amp with good bass control to sound proper, especially after roll off.

I cannot see the bass from tubes having more control, well actually never heard that before, i know yours are OTL's and most tubes are not , but your amplifiers do have a high output impedance, based on such i would prefer to run your amplifier with 16 ohm bass speakers, which will half your output power, but allow better control and less distortion due to impedance mis-match.

A question , any reason why 6LQ6 tubes are no longer being used today..

regards,

Both more and improved bass from the Atma-sphere. My speakers's bass has sounded best from the Atma-sphere S-30 and the FirstWatt F1 and F2. Didn't have the chance to directly compare the S-30 and the FirstWatts, but what they all have in common is a low damping factor.

Hello Roscoeiii

Could you tell us the speaker ?

regards,

Weseixas, actually with many tube amps when you increase the load impedance the output power goes *up* not down.

In the case of transformer coupled amps, this is because the OPT is more efficient. In the case of OTLs (and especially if its a *smaller* OTL), this is because the entire output section is running more efficiently- more power is dissipated in the load and less in the output section.

Bass extension has nothing to do with output impedance. Bass 'control' might, but since damping plays such a minor role here, what really is important is distortion. That's what gets you muddy bass! So if the amp is undistorted its more likely to be perceived as 'control'. Just FWIW.

Anyway, if the speaker was designed on tube amps, its unlikely that a transistor amp will exhibit more 'control'. My impression is that transistor amps in this situation exhibit 'punch' but not a lot of definition or subtlety. I often find myself trying to turn them up to get the same impact I expect out of the tube (in this case, OTL) amp. I guess my point is that so much depends on the interface between the amp and speaker that its very hard to make generalities.