[Tyson]

In 4 ohms it will delivery only 1W or less.Not exctly a bargain as a Sino amp and it need a preamp to drive it.
Photos show some caps are 10% precision.

It's made in America, not China.  By Dennis Had, founder of Cary Audio (now retired from there).

[Goosepond]

How much dB/SPL it have?

Hi,

94 db 4 ohms.

Gene

[FullRangeMan]

It's made in America, not China.  By Dennis Had, founder of Cary Audio (now retired from there).

Oh nice, I needed you to remind me of that.
This pedigree made his amps valued.

[mick wolfe]

Short answer:  no.  The Spatial Audio speakers really need some power to move.

Yes, I'm in total agreement with Roscoe. My older Spatial M2 Turbo's  much prefer solid state amplification. My Classdaudio SDS 470C at 600 watts into 4 ohms sounds way better than any tube amp I've tried. I never felt the older Spatial's particularly tube friendly to be honest. Maybe that's why Clayton demoed with Red Dragon mono's a few years back at RMAF?  In fact, I have a friend (whose ear I trust) who prefers driving his Spatial M4 Triode Masters with a LSA hybrid amp at around 300 watts per channel.....  even though he also has the highly regarded Line Magnetic 219ia in house as well. As always YMMV.

[roscoe65]

Expanding on this thought, we cannot simply look at a driver's efficiency and make assumptions about its ability to be driven by a low power tube amp.

I own several 12" drivers (Altec and Goodmans) of 96-99dB efficiency.  I can driver any of them with my smallest amp (4wpc), but they really prefer more power.  In contrast, my Omega speakers (94.5dB) can be driven by almost anything.

I posit that the 12" speakers, despite being more efficient have much greater cone mass than the Omega, and consequently need a little more power and control to get moving.  The Omega's, especially the RS5 driver, have exceedingly low cone mass, so even with a lower efficiency spec can start and stop much more quickly.

[mick wolfe]

Agree again. My RS5 based Omega Omni's are a great match for my LM 218ia. 22 watts of 845 driven power may be a bit of overkill in fact.

[Docere]

Expanding on this thought, we cannot simply look at a driver's efficiency and make assumptions about its ability to be driven by a low power tube amp.

I own several 12" drivers (Altec and Goodmans) of 96-99dB efficiency.  I can driver any of them with my smallest amp (4wpc), but they really prefer more power.  In contrast, my Omega speakers (94.5dB) can be driven by almost anything.

I posit that the 12" speakers, despite being more efficient have much greater cone mass than the Omega, and consequently need a little more power and control to get moving.  The Omega's, especially the RS5 driver, have exceedingly low cone mass, so even with a lower efficiency spec can start and stop much more quickly.

Hi Roscoe, I really appreciate your posts on various sites. In this case though - and I've seen it stated a few times now - I think there is a bit more to the amp-speaker system providing a sense of energy, vivaciousness, drive, bass or whatever. I think this is relevant to the original poster's questions, so will add my 2 cents here.

I'm with you that there is more to it than power and efficiency. I don't think it's merely cone size is the common cause, but perhaps large cones exacerbate the issues elsewhere. Impedance and phase variation with frequency are common factor. As is the amplifier-speaker system: most speakers (driver and alignment) are designed to need the extra control imposed by a low source impedance amplifier (power-source) like high-feedback solid state. SET amps are high impedance current-sources and ideally should be driving speakers that do not need additional control such as low Qes (powerful motors) drivers in suitable cabinets. These types of speakers are not common and the amplifier output impedance would ideally be calculated into the alignment.

Most open baffle bass speakers - like the Spatial - are unsuitable for SET drive, even if they are highly efficient. As I understand it, they generally have high Qes drivers (weak motors) and the alignment offers little in the way of control... and neither do SET amps. These types of speakers generally need the control of low-impedance drive to come alive.

By contrast, my current speakers are 15" GPA duplexes in MLTL cabinets, designed specifically for high output impedance amps, near wall positioning, in my room. Guess what? Through the bass and lower mids, they sound naturally flowing, resolved, balanced, corporeal, and foot-tapping when running with my ~2W SET amp - they can pressurise the room decently. When driven by my 50W Metaxas beast - a really nice SS that works well with many speakers and can drive a short - the room can easily be pressurised and the bass to lower mid resolution is good, but it's also weirdly constipated, flat, taught and mechanical-sounding. My close friend, a drummer agrees; he prefers my SETs too: with the 2W amp he gets a better sense of how tight the drum skins are and can pick up more timing and touch cues than with the Metaxas.

The quality of the amplifier also matters, but that is a discussion for another day.

Edit: significant rewrite so that it makes more sense and I don't sound like a turd.

Cheers.

[Tomy2Tone]

Hey Gene, just seeing if you ever got a Dennis Had 45 set amp. I’m interested in trying one of these in the near future so just wanted to know what you thought if you indeed got one.

[Goosepond]

Hi Tomy,

No, never pulled the trigger. But you never know! I think you should try it though! 

Gene

[Tomy2Tone]

Hi Tomy,

No, never pulled the trigger. But you never know! I think you should try it though! 

Gene

Awe c’mon, look at this delicious piece of fruit. You know you want it! Ha, I know I do.





Does anybody know of any other 45 set amps besides the DH that are reasonably priced?

[Goosepond]

My problem is I really like stuff that looks good. I figure all this great gear sounds good to these old ears.

And this little DH amp looks great!

Gene

[FullRangeMan]

Dennis is become smarter with age, this 45 amp have two power on switches, one for filament, other for grid/plate.