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-   Inspire by Dennis Had (https://www.audioaficionado.org/forumdisplay.php?f=184)
-   -   Dennis Had Inspire Amps (https://www.audioaficionado.org/showthread.php?t=24170)

pstrisik 09-28-2014 10:51 AM

Do you know what sensitivity?

richamor 09-28-2014 12:48 PM

Sorry Peter. Either I don't remember or he didn't say. I can say that they were playing plenty loud at half volume with the 6V6 tubes.

pstrisik 09-28-2014 02:25 PM

No problem. I'm just curious as I'm looking at a change in speakers - internet direct so I can't bring my amp to the store or take them home on a trial. I think they would be fine though. I'm currently at 8 ohms, 93db sensitivity (Omega Super 7XRS Alnico). The designer is working on a 1.5 way version with two of the same drivers: one full range and one with low pass at 500Hz. It changes it to 4 ohms / 96db. The sensitivity is obviously better, but 4 ohms makes them harder to drive - pulls for more current. By all indications, Dennis' amps are up to it, particularly if you are seeing good results with your 4 ohm open baffle. They are not likely greater than 96db sensitive.

He has never talked about different taps for the transformers for different impedances. Don't know if that would be an appropriate mod, or how they are set now.

My AR2ax' are 8 ohm and ~87db. I can tell they need more power and do produce more dynamics with my 70wpc conrad-johnson than with the Inspire.

richamor 09-28-2014 03:16 PM

My LSA Statement monitors are 89db at 6 ohms and are plenty loud. No stress on the amp at all.

As I understand it, the sensitivity is an indication of how loud a speaker will play at given power. It's the low impedance that will kill a lot of amps and drive them into clipping. I watched Dennis short out his speaker leads with no damage. I did that on my ST70 and produced a nice big spark.

pstrisik 09-28-2014 06:12 PM

Quote:

Originally Posted by richamor (Post 640888)
My LSA Statement monitors are 89db at 6 ohms and are plenty loud. No stress on the amp at all.

As I understand it, the sensitivity is an indication of how loud a speaker will play at given power. It's the low impedance that will kill a lot of amps and drive them into clipping. I watched Dennis short out his speaker leads with no damage. I did that on my ST70 and produced a nice big spark.

There is a great thread on AVSForum in the speaker section called "Need help on speaker efficiency". Sorry, not allowed to post a link here. Lot's on this very topic.

Aercool 09-28-2014 11:14 PM

I really like my Zu Omens. They're very high efficiency at 97 dB, the 6V6GT's play *plenty* loud with them. No worries there. The other odd thing about the Zu speakers is they pose a different problem than low impedance - they're rather high at 12 ohms. It actually requires a different tap off the output transformer. It was a piece of cake to do, I changed mine in about 5 minutes. A little solder, and great guidance by Dennis - and voila: the KT-6550's are perfect mates with the high impedance Zu's.

The Zu's are quite affordable too. I love mine. They have some really deep bass and great lively sound. Just throwing another option out there for <10 wpc amplifiers that we love!

richamor 09-29-2014 08:59 PM

Great article Peter! Thanks for the heads up.

The Zu's were/are on my short list for floor standers. The only drawback is the high impedance and lack of dealers around here. Great rep for killer sounds though.

Aercool 09-30-2014 12:30 AM

I don't think Zu has any dealers (I could be wrong on that...). They've got a great return policy though, if you need it. I bought a pair sight-unseen, or I guess unheard... Felt weird to do so, but at $999 for a pair of the Dirty Weekend (which I've since upgraded to the Mk.1-B version) it was a low cost risk.

Coltrane1 10-01-2014 01:49 PM

Quote:

Originally Posted by pstrisik (Post 628768)
Here's a photo of my LP-2 and KT-150. Sophia 274B rectifiers in both. The power tubes are the Valve Art 350B's.

Would you live with the different alignment of the 274B's or ask for an exchange of one?




http://i862.photobucket.com/albums/a...psebb9cc8a.jpg

Nice photos! I first encountered those VA 350B's in a Melody 300B amp....loved 'em.

Will those work in the Inspire KT88 HO amp? I've got it mated to an LP2.

Thx!

Coltrane1 10-01-2014 01:59 PM

Quote:

Originally Posted by pstrisik (Post 640646)
I recall those now. Thanks.

I'd love to hear them. I'm a recent "no crossover" convert though, and have become biased. That may change again over time though.

Me too...there's nothing like an OB no x-over design. These have developed a reputation for being nearly as 'fast as stats'

http://i1192.photobucket.com/albums/...ps2e2fe849.jpg

http://i1192.photobucket.com/albums/...ps75c290b5.jpg

http://i1192.photobucket.com/albums/...psfdeebba6.jpg

http://i1192.photobucket.com/albums/...psa852b676.jpg

http://i1192.photobucket.com/albums/...ps0ee9562f.jpg

and here the same builder as above with his reference speakers using a modern up to date version of the famed Heil AMT driver.....these are local to me...it's tough listening to a traditional box design after hearing these.

http://i1192.photobucket.com/albums/...d94a95b3-1.jpg

http://i1192.photobucket.com/albums/...ps44eff356.jpg

http://i1192.photobucket.com/albums/...ps4ebe494b.jpg


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