Atma-Sphere Class D… Amazing

@kuribo The cost has to do with how the equipment is marketed. We use a dealer network and have worldwide distribution. That requires that we have it priced accordingly. Dealers can be quite valuable because they can provide support!! FWIW if we were to use a Purifi or Hypex module, the amp would actually be more expensive than it is now due to the markup we would have to pay on the module. The cost of the chassis, built extra rugged so it will survive abuse in UPS while being built in limited quantities, is a big reason the amp is more expensive. The funny thing here for me is for decades we were always docked on cosmetics. I was always resisting installing a 1/2" thick front panel on our stuff since it would have raised the cost so much, but that is what our competition has been doing all this time. And we still don't have the 1/2" panels!

So we found a way to limit that cost a bit, but the simple fact is that if you do this stuff in the way that we are (the chassis is formed of 3/16" aluminum for example, to prevent deformation with the weight of the power transformer) its simply more expensive. Now if we were to use a SMPS it would allow the chassis to be cheaper, but our research has shown that if you really want the amp to perform the way it should, the SMPS will be custom built for the job. Otherwise it will current limit or other such nonsense and we certainly experienced that!

So we didn't skimp on the power supply or the chassis. We just built it to proper engineering standards without cutting corners. IMO one of the reasons you see such variable comments about how Hypex and Purifi amps sound is because of how they are executed.

So we didn’t skimp on the power supply or the chassis. We just built it to proper engineering standards without cutting corners. IMO one of the reasons you see such variable comments about how Hypex and Purifi amps sound is because of how they are executed.

Thanks for the insight. Indeed, those marketing Hypex, Purifi, and several other class d amps using the modules of others can "tune" the sound through the input buffer op amp choices. I suppose it is a clever marketing technique to appeal to different tastes, rather than offering any color the customer wants, as long as it’s black. Of course most of them degrade the performance of the amp modules to some extent, but as we can see here, there are those who aren’t concerned with high fidelity to the input signal. Other such differences, like type and style of case, input mains filters, mounting configurations, etc., surely do vary widely, from head scratching to immaculate. No doubt these differences play some role in the final result as well-how much, I do not know.

No doubt with the weight of the transformer you would need a stout case. I suppose that can certainly add to the costs, though it is hard as a consumer driven by performance to justify spending 3-4 times as much as a competing product for things like a dealer network and a stouter case, neither of which in my opinion makes it "go faster". You might consider using a smps, a lighter, cheaper case, and offer your amp for half or 1/3 the price. Surely there is a sizeable market at the lower price point.

Again, appreciate the reply.

This really is rich.  First we have ricevs telling Ralph how to redesign his amps, and now kuribo has a go.

Meanwhile, Ralph is model of restraint and superhuman patience.

@twoleftears

Indeed, those marketing Hypex, Purifi, and several other class d amps using the modules of others can "tune" the sound through the input buffer op amp choices

@kuribo If they can ’tune’ the sound just by changing opamps they are either using really terrible opamps or don’t know what they are doing!

We’ve had the idea of a SMPS meant for the amp for a couple of years. That’s not a trivial design project although its certainly an one than the module itself was! Of course we looked at available SMPSs including those meant for audio, but again we ran into not only performance (which impinges the sound and performance of the module) and protection issues but also cost issues! If we make it ourselves then we solve three problems at the same time. In the meantime the toroidal supply is less expensive, works right and we have the right protection although we need a more expensive chassis to support it. IME though, that chassis helps with the mancave/WAF issue. In my case this means that I don’t have to have a mancave to run my stereo (although I do have to be careful about cargo shorts); it can be in the living room without inciting ire. Ya picks ya poison I suppose.

I should also mention we're concerned about noise. For example Bruno uses a current pump to create lower voltages for opamps and the like. We found that is noisier than using a more expensive supply for the same task. As a result the amp puts less noise on the AC line than most tube amps.