Primaluna & Klipsch Cornwall frustration HELP


Well this is a little frustrating. I have a Primaluna preamp and Primaluna Dialogue 5 power amp. Found a great deal on some Klipsch Cornwalls. Heard Klipsch and tubes were made for each other. Hooked them up and it had very little bass. I was expecting a BIG sound. Sounded almost anemic. Hooked them up to a class D audio amp through the Primaluna preamp and it was fantastic. Lots of slam. A great rock and roll sound. These are very efficient speakers so I don't get why they don't sound good through the tubes. 42 watts per channel at 8 ohms. Happened to talk to a Primaluna guy and he told me I needed a more powerful Primaluna amp. That has got to be BS. Do I have bad or weak tubes?? These are KT88's! Maybe they are going out. Who knows. Tried to call Kevin Deal at Upscale but he is out of town. I am not buying a bigger Primaluna amp. Kind of offended that I was even told that. Would the KT120's make a difference? Could it be something else wrong with the amp. Thanks for any help. By the way the amp sounds sweet with small monitors where I don't expect much bass. Thanks for any direction.
128x128dylanfan

Did you accidentally connect a speaker out of phase?

Also, hard for me to think you need more power. I have heard Klipsch Chorus that have 15" woofers powered by a 3.5w/ch tube amp, and there was no problem with bass. And the speakers were not in corners or up against the back wall.
I agree. This should be a great combo. Has me racking my brain. No tube people in my area. I will have to order other tubes if I want to switch.
This should be a great combo.
Not necessarily, as I see it.

According to the impedance curve shown here for the Cornwall II, its impedance is in the vicinity of 5 ohms at most bass and mid-bass frequencies, while rising to much higher values at most higher frequencies.

Learsfool (whose sonic perceptions are always above reproach IMO) mentioned that he obtains excellent results using a Dialogue Two with Cornwall IIs. However your Five is described as using zero feedback, with its description pretty clearly implying that the Two, from which a lot of its design is derived, used significant amounts of feedback. Which presumably means that the unspecified damping factor of the Five is significantly lower than that of the Two, and its output impedance (which is inversely proportional to damping factor) is therefore significantly higher than that of the Two. Typically a zero feedback tube amp will have an output impedance that is a significant fraction of the five ohm impedance your speakers have at most lower frequencies, which will result in an under-emphasis of those frequencies relative to frequencies at which the speaker impedance is much higher. Which in this case would mean an over-emphasis of most frequencies in the mid-range and lower to mid-treble regions, relative to the bass and mid-bass regions. All of that being in contrast to the frequency response that would result with the near zero output impedance and very high damping factors of nearly all solid state amps.

So while several good points and questions have been made and asked, including those regarding trying the 4 ohm taps, checking speaker phasing, and the possibility of weak tubes, it seems to me that the damping factor and output impedance characteristics of the particular amp may simply not be a good match for how the impedance of the speaker varies as a function of frequency.

Good luck. Regards,
-- Al
Over my head Al but thanks for the response. So what kind of speaker sounds best with this kind of amplifier?? Or should I ditch the thing. Not enough adequate power for my Dynaudio X12's or my KEF LS50's . That's why I got the Cornwall's. Now this tube amp will not work with Klipsch speakers. What the heck works with the amp?
So what kind of speaker sounds best with this kind of amplifier?
In general, I would expect speakers having much flatter impedance curves (as well as having fairly high efficiency) to be better bets.

Regards,
-- Al