[cronsell]

Here are some pics of my Ottavos at RMAF...by all reports Rick has designed one hell of a speaker!  And they're beautiful...

[gme109]

Without a doubt, an excellent sounding speaker, especially considering the price. The Ottavo was very open, transparent, and detailed, but more importantly, very musical and non fatiguing. And yes they are gorgeous as well. Credit should also be given to Core Audio Technology, for providing the front end, and all digital amps.

[Tyson]

The Ottavo sounded incredible.  Kudos to Rick for another great room at RMAF this year.

[cronsell]

Thanks for the pictures and report on the Ottavos Tyson...as an anxious recipient of this beautiful pair, I'm grateful to learn they're sounding so fantastic! 

[AvFan]

I could use a little help understanding the recommended power for the Ottavo which is 75 to 300 watts. 

• Is the power at 4 ohms?
• What are the consequences of running these speakers at the lower end of this range?
• Given the range it seems most (reasonably priced) tube amps would not be recommended.  Is that correct?
• The sensitivity of the Ottavo is 87db.  How does that translate to amplifier power, the size of the room and speaker performance?

Thanks!

[Rick Craig]

I could use a little help understanding the recommended power for the Ottavo which is 75 to 300 watts. 

• Is the power at 4 ohms?
• What are the consequences of running these speakers at the lower end of this range?
• Given the range it seems most (reasonably priced) tube amps would not be recommended.  Is that correct?
• The sensitivity of the Ottavo is 87db.  How does that translate to amplifier power, the size of the room and speaker performance?

Thanks!

Yes, power at four ohms. The Core Audio Technology amp we used at the RMAF is 100 watts into eight ohms and we achieved very high output levels with the Ottavo. This is also taking into consideration the lower gain of the all digital path we used. I think there are 70-80 watt push-pull tube amps reasonably priced that would work well.

It's not so much the size of the room but listening distance to be considered. It also depends on how loud of a level you want. There is a myth that tube watts are greater than solid-state; however, that's simply not the truth. You can easily test for this by measuring one watt across the output of both a tube and solid state amp and measuring the level of the speaker's output. Some tube amps lack enough current capability as well. A good indicator of current capability is how close the amp comes to doubling its' output into four ohms versus eight ohms.

Tube amps do clip differently than solid-state but the distortion is still there - just in a different harmonic structure. Some solid state amps clip with grace (little audible effect) and others not so tolerable - depends on the design. Hope this helps.

[AvFan]

Thanks, Rick.  Just for reference I currently have a Pioneer A-27 integrated amp (180 watts @ 4ohms w/first 3 watts Class A) driving a pair of MTMs (RAAL and SB Acoustics) you designed for me a few years back.  I also use a couple of subs in stereo.  The setup is very nice but I'm looking to move to a full range floorstander and I keep finding myself looking at tube amps.  My listening position is about 12 feet from the speakers in a living/dining room space and I typically listen at 80 to 85 db (C weighted).  So, just for example, would a Mac MC-275 at 75 watts/channel drive the Ottavos well in my environment?

[Rick Craig]

Thanks, Rick.  Just for reference I currently have a Pioneer A-27 integrated amp (180 watts @ 4ohms w/first 3 watts Class A) driving a pair of MTMs (RAAL and SB Acoustics) you designed for me a few years back.  I also use a couple of subs in stereo.  The setup is very nice but I'm looking to move to a full range floorstander and I keep finding myself looking at tube amps.  My listening position is about 12 feet from the speakers in a living/dining room space and I typically listen at 80 to 85 db (C weighted).  So, just for example, would a Mac MC-275 at 75 watts/channel drive the Ottavos well in my environment?

At 12 ft. and your typical listening level the MC-275 can perform well. It will only take about 8 watts.

[navin]

There is a myth that tube watts are greater than solid-state; however, that's simply not the truth. You can easily test for this by measuring one watt across the output of both a tube and solid state amp and measuring the level of the speaker's output. Some tube amps lack enough current capability as well. A good indicator of current capability is how close the amp comes to doubling its' output into four ohms versus eight ohms.

Tube amps do clip differently than solid-state but the distortion is still there - just in a different harmonic structure. Some solid state amps clip with grace (little audible effect) and others not so tolerable - depends on the design. Hope this helps.

Rick,

I agree it is a myth that Solid state is lesser than tube but why cant they build solid state amps with the same clipping characteristics as tube if that is what sounds better to a human ear (I believe during the famed Bob Carver Amplifier challenge, Bob tuned one of his Solid State amps - the M1.0t - to sound and clip like a tube amp)?

Most solid state and some tube amplifiers manage to double their 8 ohm power when the load falls to 4 ohms but since most loudspeaker loads are reactive with impedances dropping as low as 2 ohms (sometimes even lower as with the original WATT) it might be better to look at the 2 ohm power delivery (RMS @ 20-20kHz) specifications as well. This is where tube amps struggle. So it best to look at the amps power delivery at your loudspeaker's nominal and minimum impedance.

Some tube 'purists' claim Single Ended is the only way to go, and while there is a audible difference between Single Ended, Triode and UL configurations of tube amps I have never found any one configuration to sound so bad that it detracts from the enjoyment of music.

[ricardojoa]

Thanks, Rick.  Just for reference I currently have a Pioneer A-27 integrated amp (180 watts @ 4ohms w/first 3 watts Class A) driving a pair of MTMs (RAAL and SB Acoustics) you designed for me a few years back.  I also use a couple of subs in stereo.  The setup is very nice but I'm looking to move to a full range floorstander and I keep finding myself looking at tube amps.  My listening position is about 12 feet from the speakers in a living/dining room space and I typically listen at 80 to 85 db (C weighted).  So, just for example, would a Mac MC-275 at 75 watts/channel drive the Ottavos well in my environment?

I have been in touch with Albert at spacetech lab, he is a great guy to talk too and have various designs that might fit you set up and budget.

[ss397]

Just saw this thread. Those are some outstanding looking speakers. I love the dual 8's and the tapered cabinet.

[Rick Craig]

Rick,

I agree it is a myth that Solid state is lesser than tube but why cant they build solid state amps with the same clipping characteristics as tube if that is what sounds better to a human ear (I believe during the famed Bob Carver Amplifier challenge, Bob tuned one of his Solid State amps - the M1.0t - to sound and clip like a tube amp)?

Most solid state and some tube amplifiers manage to double their 8 ohm power when the load falls to 4 ohms but since most loudspeaker loads are reactive with impedances dropping as low as 2 ohms (sometimes even lower as with the original WATT) it might be better to look at the 2 ohm power delivery (RMS @ 20-20kHz) specifications as well. This is where tube amps struggle. So it best to look at the amps power delivery at your loudspeaker's nominal and minimum impedance.

Some tube 'purists' claim Single Ended is the only way to go, and while there is a audible difference between Single Ended, Triode and UL configurations of tube amps I have never found any one configuration to sound so bad that it detracts from the enjoyment of music.

Bob reasoned that most of what was heard was due not so much to the clipping harmonics but the higher output impedance. So he simply added resistance between the output stage and speakers to mimic that. The output impedance is really the Achilles heel of most tube amps because it will change the frequency response of what you hear (depending on the load impedance from the speaker). As you noted current capability into lower impedances is also an issue. I agree that tubes can sound nice and actually used a 35-watt triode integrated at a show once with good results.

[AvFan]

I have been in touch with Albert at spacetech lab, he is a great guy to talk too and have various designs that might fit you set up and budget.

Thanks for the link.  I'd never heard of SpaceTech and there are some really nice looking designs and they can be customized.

[Rick Craig]

Just saw this thread. Those are some outstanding looking speakers. I love the dual 8's and the tapered cabinet.

Thanks for your comments. Soon we'll be building a pair in ambrosia maple!

[jimbones]

Veneer is beatiful Rick, what species is that?

[Rick Craig]

Veneer is beatiful Rick, what species is that?

Tineo veneer with Wenge trim.