We should reject hard-to-drive speakers more often

in your experience ralph, when an autoformer is used to better couple tube amps with lower impedance speakers, is there a meaningful sonic penalty? seems to me that what is happening is many many more metal windings are being placed between tube amp's built in transformer (leaving aside the otl’s for a moment) -- and so my guess is that there must be more of the classic wooly, expansive, slightly echo-y transformer sound that is introduced into the music, more or less....

of course, this point and my question is moot for speakers that could never be driven by the tube amp in the first place, but have you done an experiment with a more ’normal’ higher impedance speaker... then adding the autoformer ... then trying hearing the sonic change from the additional transformer present in the chain?

just curious

@mrdecibel  there are a few tube amps that can power the apogee scintilla and full range, most of them have 1ohm taps. There is a guy that used to post on the apogee forum that is powering his apogee full range with Tube Research Labs amps, four monoblocks with 1200 watts total, and he has owned quite a few of the usual suspect solid state amps that are supposed to be used with this type of speaker. He says the tube amps do the best job.

@jon_5912 Wrote:

 High power class D amps more than make up for the difference in dynamic contrast between low and high efficiency speakers. 

In my opinion, a high powered amplifier that can drive lower impedances will never be a proxy for a speakers lack of true efficiency. 

Mike

I have been around the block with Apogee speakers back in the day, including the Scintilla ( I actually owned, for a year, the Duettas ). My question was, as stated, " adequately " drive? I am not fond of tube amps ( low / poor damping factor ), which is a shame, as I own horns. The times I used tubes for mids / highs, and ss for bass, I always was aware of the " transition " between the two. Listen, I have always said, " whatever the listener enjoys, that is fine. I like what I like, and I don’t like, what I don’t. My best, and enjoy ! MrD.

@ditusa wrote:

In my opinion, a high powered amplifier that can drive lower impedances will never be a proxy for a speakers lack of true efficiency.

I fully agree, Mike.

@mrdecibel wrote:

The times I used tubes for mids / highs, and ss for bass, I always was aware of the " transition " between the two.

Even via my horn hybrid, actively configured main speakers using different SS amps for the top horn section (~600Hz on up) and bass bin it doesn’t go unnoticed that they "speak" slightly differently when compared to using two identical amps here, not least when the identical amps are bi-amped vertically. The difference is likely somewhat more subtle vs. the scenario of tubes + SS you’re describing, but it goes to show there are points in coherency to gain with extra attention invested here.

The SS amp chosen for the subs below ~85Hz is less critical wrt. ultimate coherency, but to my ears what is critical in this region is choosing an amp that doesn’t go totally bonkers with a damping factor in the thousands as a means in itself, but this is obviously also a matter of proper subs-amp-room matching and what sounds the most musically full and natural here, or whatever one finds appealing. Overly damped (i.e.: "tight") bass isn’t natural bass to my ears, nor is the inverse scenario - it’s certainly about finding the right balance in relation to one’s (p)reference and context.