Dennis Had Inspire Amps

[Bombadil]

Many tube amps have a high output impedance. Some as high as 6 or more ohms. When this is the case and your speakers have a lower impedance, this can have a dramatic affect on the speaker's frequency curve. When a speaker has a high impedance, let's say 16 ohms, this will somewhat mitigate that interaction. Into a 4 ohm load, you can have deviations of several dB.

Solid state amps can have less than 0.1 ohms output impedance, so having little to no impact on the speakers.

I have no idea what Had's Inspire amps measure, but many SE amps measure on the high side.

[FloridaBoy]

Originally Posted by Simonatsea

I had Dennis instal special 16 ohm output transformers in my 6V6 amp to cater to my superflys

That is usually changed by using a different tap on the tranny.

[Rosco65]

Originally Posted by FloridaBoy

That is usually changed by using a different tap on the tranny.

I'm told that Dennis does not use tapped secondaries on his transformers, insisting that using the full secondary sounds better. I haven't run mine on anything other than 8 ohm speakers, but his amps are alleged to run well on 2-12 ohms. However, I'm sure that if the secondary is optimized for the speaker impedance it will be a more ideal load match.

[Musica Amantem]

Originally Posted by Simonatsea

I had Dennis instal special 16 ohm output transformers in my 6V6 amp to cater to my superflys

Then it does matter! What happens if the amp is set with 8 Ohm trannies and I couple it to Soul Superflies?

[o]

Power output* and distortion is lowered; damping increases.

*probably only a slight amount with your set, more so with the higher power sep.

See reply #2427 on page 243 "Music Reference-RM 200 test"

[FloridaBoy]

Originally Posted by Rosco65

I'm told that Dennis does not use tapped secondaries on his transformers, insisting that using the full secondary sounds better. I haven't run mine on anything other than 8 ohm speakers, but his amps are alleged to run well on 2-12 ohms. However, I'm sure that if the secondary is optimized for the speaker impedance it will be a more ideal load match.

I did not know that.

[Musica Amantem]

Originally Posted by opnly bafld

Power output* and distortion is lowered; damping increases.

*probably only a slight amount with your set, more so with the higher power sep.

See reply #2427 on page 243 "Music Reference-RM 200 test"

" ... the lowest distortion, but also reduced maximum power, occur when the load impedance is much higher than the tap value ..."

Well, it will run smoother (less distortion) and the 101 dB's sensitivity advantage over my current 98 dB's should compensate somewhat for that loss of power ... Then, a 16 Ohm trannie would have max power but higher distortion ... Is that the deal?

[FloridaBoy]

Are the ZU really 101db?

[Bombadil]

Originally Posted by FloridaBoy

Are the ZU really 101db?

Stereophile measured two different Zu speakers which were each spec'ed at 97dB. They measured them at 92.5dB and 91.5dB. So that's an average of 5dB under Zu published specifications.

[Comzee]

I know someone here was asking about the Spatial M4.
I had a chance to listen to the "Spatial M3 Turbo S", which is quite similar to M4, but a bit better.

I used my SE HO Fire-bottle, and I wasn't impressed for the price ($3k).
The M4 base model are ($1700) still more expensive than my Omega Alnico Compact.

The Spatial pair only had one thing on the Omegas, which was bass sound pressure. The two huge subs really do knock, if you like that type of thing, great buy.

If you're into a fuller sound, full frequency experience, the Omegas best it by (imo) a far margin. The Spatial M3 mids were pretty scooped out.

I can see why too, it's only two frequency ranges with a 800hz crossover.
I think the spatial would really benefit from a 3 driver double crossover arrangement. They were missing many nuances from not portraying the full frequency band equally.

Although, this is why I bought my Omegas in the first place, I've only heard one crossover designed speaker I've liked (Magnepan). I have generally disliked any dynamic multi driver crossover speakers (which are REALLY common, almost any tower speaker is this design.)

With regards to how well the 12wpc Fire-Bottle drove the M3 pair, it was exceptional. Unless you like listening at hear numbing levels.