[Slapshot]

Hello. I am intending to put together a SET system for my office/den. The room is 12 x 9.5. I'm considering amplifiers from 2.3wpc (the Decware 25th Anniversary), to 8wpc (the Coincident Frankenstein monos) and a few others. The critical question is, I want to match whichever one of these amplifiers that I choose with a pair of CAM's, that I will be ordering from Louis.

How much power is needed to effectively drive them?

I've read several discussions lately, in other forums that go on and on about SET amps not truly being able to drive speakers well unless the speakers are of at least 98db sensitivity. I hope that's not the case, and I came to you, here in the forum, as you would certainly ahve the real life experience to answer this question. I will obviously also follow up with Louis. Thanks.

JC

[NoDisco]

Go solid state with a tube pre. I’ve done push pull monos and sep, but nothing beats this combo. I’m almost convinced the type of SS amp doesn’t even matter since I’m using a 20 year old NAD, and it sounds wonderful. YMMV

[SET Man]

Hey!

   Every time I see this kind of question it always make me think of Tootsie Pop owl commercial... "The world may never know"

   Well, is all depend on your room size, how loud you listen and somewhat also what kind of music you listen to most. For example my room is 10'x17' with 8' ceiling and I sit about 12' away from speaker. My Fostex 6" is 94dB raw and my main SET amps are 18wpc. I usually listen to music around 85-90dB peak. So, I don't think I ever used more than 2 or 3 watts.

   Anyway, sure 2.3w will work for you but I think that's pushing it. To me you want to have some reserve power to handle the music dynamic swing. So, if you ask me I would say 8 watts would be a good start. But also another thing, a well designed lower power SET amp can out perform a crappy designed higher power SET amp.

   Good luck and keep us posted.

Buddy 

   

[effluviography]

I use a Decware Mini-Torii in a 10x12' room. It puts out about 4 watts and plays WAY louder than I can take in my listening room. I use custom sized CAMs - a little narrower and deeper than the regular CAMs. I also have a 2 watt Decware Zen amp, but don't typically use it in that room. I will point out that I use the 2 watt Zen amp with Blumenstein Orca speakers, which are much less efficient than the CAMS. I use it in my living room which is about 20x30' and it plays pretty darned loud without distortion - loud enough to upset the neighbors (I live in a townhouse). Hope this helps.

Decware and Omega - they work exceptionally well together in my experience.

[RDavidson]

The claim that you need 98db sensitive speakers when pairing to a flea watt amp is a simplistic generalization. There are some high sensitivity speakers that aren't necessarily easy nor simple loads. CAM's on the other hand are VERY easy to drive. Aside from their high sensitivity, they have low mass, very strong motors, and are a non-reactive load to the amp. The Decware Zen will get you a very long way. I've had a Zen UFO with my CAM's. While a little more headroom is always nice to have, I would be VERY surprised if you ran out of steam with a Decware Zen. It's a stout little amp. Most of the time you'll be using a fraction of a watt. You might also consider First Watt. The SIT-3 is beautiful sounding with Omegas. Not to mention, it is dead quiet, which is a great consideration with high sensitivity speakers. Another great match is the F3 if you can find one. The J2 is also really wonderful.

[JLM]

I ran a 7 wpc Tripath against 90 dB/w/m 30-20,000 Hz, 8 ohm single driver in a 8ft x 13ft x 21ft room, sitting 7ft away listening to mostly small jazz/classical ensembles at realistic levels.  It worked remarkably fine, but jumping up to 40 watt mono-blocks turned the loudspeakers from polite dinner guests into NFL linebackers in tuxedos (significantly improved resolution and dynamics).  The lesson here:  make sure your amp has a commanding grip on the loudspeakers.

[roscoe65]

I have experience with the SAM and a number of RS5-based models.  In my experience, the sensitivity of the Alnico driver and the RS5 driver are similar above 500hz.  In the bass through lower midrange the Alnico driver is a bit more sensitive.

The RS5 driver has exceedingly low moving mass.  It will get up and moving with very little power (<1 watt in near field).  While equally sensitive, the Alnico driver has greater mass and has a lower threshold for acceptable power.  I used a 2wpc 45 amp on my SAMs, and while they did work they wanted a bit more power.  With a 5 wpc amp, the speakers really took off.

One characteristic of the Decware amps is that they work well into wide speaker impedances.  I’ve found this to be important in single drive speakers that have rising impedance in the bass.  I own a couple of Dennis Had SEP amps and they output pretty much the same power into 2-20 ohms and provide excellent bass with the single driver speakers.

[Doody]

I drive my CAMs (and a sub) with 1 watt from a Chord Hugo 2.

Doody

[RDavidson]

I ran a 7 wpc Tripath against 90 dB/w/m 30-20,000 Hz, 8 ohm single driver in a 8ft x 13ft x 21ft room, sitting 7ft away listening to mostly small jazz/classical ensembles at realistic levels.  It worked remarkably fine, but jumping up to 40 watt mono-blocks turned the loudspeakers from polite dinner guests into NFL linebackers in tuxedos (significantly improved resolution and dynamics).  The lesson here:  make sure your amp has a commanding grip on the loudspeakers.

This is a good point, but also needs careful consideration. Different amp types/designs are a big variable. It is easy to over-damp Omega drivers (and likely most drivers of this kind). Too much grip can suck the life out of the lower midrange and bass. It's a balance that can be tricky and this is where the general recommendations for class A tube and SS are safe bets. Class D can also work quite well. Like class A, their sonic signature is very uniform whether using a fraction of a watt or many many watts. Tripath amps always sounded a bit thin and brittle to my ears. Mating tubes and buffers was a popular pairing with Tripath. I think this was likely a factor in the changes you heard when you went to 40 watt monos as well. I'm assuming those weren't Tripath based.

[seikosha]

No one is really going to be able to answer this for you until you can specifically state how many db’s you consider is a “realistic” level.  What’s good for one person could be grossly insufficient for another.

[RDavidson]

He didn't state what levels he typically listens at, so yes, that's a very important consideration as well. I pretty much never listen at "realistic" levels myself (i.e. true to life or event levels). I prefer to listen at comfortable / relaxing levels (conversation levels or a little louder. I never crank the volume knob). His office is about the same size as mine. A few watts can go a VERY long way with the CAMs especially in this small space, I've found. Note the other user using the headphone output from his DAC. I'm willing to bet I could run my CAMs off a headphone out to the levels I prefer (in my space and at my listening distance ~7ft from the drivers).

[seikosha]

I’m with you Rdavidson, my SE84 Decware is sufficient for my Alnico Omegas, but I know folks who play their rigs at levels that you’d have to shout at each other in order to have a conversation and they would tell you that it’s not loud.

[NoDisco]

Depends on how much distortion you like...at any listening level. Some people really like it. Depends on what type of tone you like. Frankly the grip SS puts on my SAMs makes for some great tunes. I put a tubed pre in there, and I got what I am looking for. Will switch back to tubes when I get bored, or not.

[Docere]

Hello. I am intending to put together a SET system for my office/den. The room is 12 x 9.5. I'm considering amplifiers from 2.3wpc (the Decware 25th Anniversary), to 8wpc (the Coincident Frankenstein monos) and a few others. The critical question is, I want to match whichever one of these amplifiers that I choose with a pair of CAM's, that I will be ordering from Louis.

How much power is needed to effectively drive them?

Rdavidson has answered this well... and I'm glad he touched on the over-damping.

I've read several discussions lately, in other forums that go on and on about SET amps not truly being able to drive speakers well unless the speakers are of at least 98db sensitivity. I hope that's not the case, and I came to you, here in the forum, as you would certainly ahve the real life experience to answer this question. I will obviously also follow up with Louis. Thanks.

JC

That is a simple heuristic: easily understood and broadly applicable; safe. But not accurate in specific situations. CAMs have been enjoyed with 1.5-ish Watts of 45 SET power. There is more to SET-speaker matching than power and efficiency (which is mostly about volume): room size, speaker impedance (reactivity), speaker phase angles, amplifier output transformer quality, amplifier output impedance versus speaker alignment (are the speakers in need of additional control from the amp?), preferred listening volume/habits and speaker suitability for low-level listening (e.g. high Qms drivers)... and so on. Again, Rdavison summarised this well.