[vortrex]

Has anyone used a SET amp with SongTowers, maybe specifically the Atma-Sphere S-30 Mk. 3.1?

[DMurphy]

Aside from the issue of the amp costing more than the speakers, I couldn't find any spec for a 4 ohm load.  It's rated for 30 watts in 8 ohms, and 45 watts into 16 ohms--I'm a little concerned about 4 ohms. 

[jtwrace]

You can always use the Ralph karsten recommended http://www.zeroimpedance.com/

[DMurphy]

You can always use the Ralph karsten recommended http://www.zeroimpedance.com/

Oh Goody.  Another $450.   Haven't you guys ever heard of wine, women, and dark chocolate?
Get your financial priorities in order.   

[Nels Ferre]

Aside from the issue of the amp costing more than the speakers, I couldn't find any spec for a 4 ohm load.  It's rated for 30 watts in 8 ohms, and 45 watts into 16 ohms--I'm a little concerned about 4 ohms.

It is an OTL amp. I would think 15 watts into 4 ohms- assuming it is stable into 4 ohms, which I wouldn't. Ask them.

The Songtowers never cease to amaze. I have run them with low powered amps (one 15W x 2 Ultralinear the other 18W x2 Triode) with great success, but both had output transformers. I've also tried them with a hybrid amp rated 80 WPC into 6 ohms (no 4 ohm rating) and the amp totally bombed.

I would call the manufacturer, they have been asked this before.
 

[johzel]

Oh Goody.  Another $450.   Haven't you guys ever heard of wine, women, and dark chocolate?
Get your financial priorities in order.

This is very funny.  Just sat down with a glass of Pinot Noir and a Godiva Truffle . . . this is the first thread I read.  Oh . . . 2 out of 3 . . . . I have a wife around here somewhere!!   

[jtwrace]

No need to even call....Ralph is very responsive via email ralph@atmasphere.com

[vortrex]

missed the fact that it was 8/16 ohm.  I was only curious, it seems to get great reviews.  that would definitely be a "buy it used" item for me.  on that note, what is the general rule for if your speakers are $2k you should buy an amp in the $X range?

[coke]

missed the fact that it was 8/16 ohm.  I was only curious, it seems to get great reviews.  that would definitely be a "buy it used" item for me.  on that note, what is the general rule for if your speakers are $2k you should buy an amp in the $X range?

This thread might help answer your question http://www.audiocircle.com/index.php?topic=82544.0

[zybar]

Oh Goody.  Another $450.   Haven't you guys ever heard of wine, women, and dark chocolate?
Get your financial priorities in order.

Don't be so negative Dennis.   

The Zeros work very well and allow more speaker options for folks who use Atma-Sphere amps.  Do some reading...this is science, not voodoo!

As for the OP's question...

With a pair of Zero's, I think the S-30 would be fine with the Song Towers.

George

[DMurphy]

Don't be so negative Dennis.   

The Zeros work very well and allow more speaker options for folks who use Atma-Sphere amps.  Do some reading...this is science, not voodoo!

As for the OP's question...

With a pair of Zero's, I think the S-30 would be fine with the Song Towers.
George

Hey--if he wants to spend that much per watt, it's OK by me.  And I'm not saying the Zero thing is voodoo.  I'm sure it does what it says it does.   For a lot of money.   But SET amps?  I think I hear some drums.     

[Wayner]

Perhaps I would consider a low wattage amp for speakers that had an efficiency rating of about 103db/m/w. Otherwise, clipping will occur, even at moderate listening levels.

I am currently restoring a vintage pair of JBL L200's and can drive them to powerful levels with a Marantz 2238 receiver (38 watts per channel).

SET amps are best matched to horn type speakers.

Wayner

[Duke]

Having designed speakers on the S-30, let me just toss out some observations...

The S-30 has an unusually high output impedance, or low damping factor.  It will put out more power into an impedance peak than into an impedance dip, which is just the opposite of a solid state amp.  So if the Songtower was "voiced" on a solid state amp, its voicing probably would not benefit from being paired with the S-30.  The Zero will lessen the magnitude of these effects, but not the general trend.  One would have to eyeball the impedance curve and frequency response curve (presumably generated using a solid state amp) of the Songtower simultaneously to judge whether an amp like the S-30 would be a good match.   

As a general rule of thumb that SET guys came up with, you want the theoretical 1 watt SPL maximum to be at least 102 dB.  So if your speakers are 92 dB efficient, you want at least 10 watts.  This assumes SET or OTL amps which are benign when driven into mild clipping; with solid state amps, you'd proabably want twice as much power.   Also if you have a big room, or an overdamped/open floorplan room, or listen pretty loud, your target calculated SPL needs to be higher.

[Wayner]

OK, I just think it's a poor mis-match "offhandedly". Not to knock the amp in anyway, but it needs to be matched to the proper speakers, just like any other amp.

You wouldn't match a 85db/m/w speaker with a SET amp, right? And the inverse is also true, I wouldn't pair a AVA 550 with a speaker that had 105db/m/w efficient rating.

It's like putting $50 dollar tires on a Corvette.

W 

[JLM]

Years back a friend loaned me his 12 wpc tube amp to trial with my big MLTL's.  Not a good match.  Output was OK (90 dB/w/m in a 2,000 cu. ft. room), but bass was bloated (like a big bottomed woman).

But you might want to look into the $2495 Decware Torii Mk III (beautiful pure class A1 25 wpc integrated/power amp - but hits MUCH harder, SET sound without being one, hand made in USA, lifetime warrantee, dual mono design, all sorts of adjustments possible yet a very simple circuit, point to point wiring, choke regulated power supplies, custom transformers, tube voltage regulation grids, no bias adjustments, switchable output impedance, cheap tube replacements, etc.).

http://www.decware.com/newsite/TORII.htm

[Saturn94]

Aside from the issue of the amp costing more than the speakers, I couldn't find any spec for a 4 ohm load.  It's rated for 30 watts in 8 ohms, and 45 watts into 16 ohms--I'm a little concerned about 4 ohms.

Saw this in a review:

The S-30 Mk III is rated at 30Wpc into 8 ohms and 45Wpc into 16 ohms. Driving a 4-ohm load with the S-30 Mk III is not recommended. If you must drive 4-ohm speakers, an external autoformer is suggested. Karsten emphasizes that this transformer is not just an external output transformer, but matches the amp’s 16-ohm output impedance to a 4-ohm speaker.

[Duke]

Quoted by Saturn94:  "... the amp’s 16-ohm output impedance..."

I believe that the output impedance of the S-30 is about 7 ohms, which is still high pretty high.  To give you an example, that could conceivably triple the effective Qes of a 4-ohm woofer section.   Even with the Zero autoformer in place, the effective Qes could still go up by 50%. 

[vortrex]

keep in mind I don't know what I'm talking about!     I just happen to have read some really good things about atma-sphere so I was curious about them.  although they sound good now, I think I could get some better performance out of my ST's so I am looking into an amp upgrade (Jolida 202 now).

[roscoeiii]

Oh and there are many things about Atma-sphere amps. If they pair well with your speakers...

Also wanted to point out that an Atma-sphere is more accurately described as an OTL amp rather than a SET amp.

[Sarchi]

Years back a friend loaned me his 12 wpc tube amp to trial with my big MLTL's.  Not a good match.  Output was OK (90 dB/w/m in a 2,000 cu. ft. room), but bass was bloated (like a big bottomed woman).

This could be for several different reasons.  I find this to be a useful article on this topic;
http://homepage.mac.com/tlinespeakers/vaughn/downloads/Damping-Factor.pdf