I get that you want to do everything you can to defend this preamp. But, your thinly-veiled insult is not appreciated. However, it is revealing. I have tried to discuss my experience with the Pyxi in an honest and nonconfrontational manner. I never claimed I performed an "apples to apples comparison". As a matter of fact, I believe I made that quite clear. I conducted a relative comparison with rudimentary level matching of three very different systems. Further, the intent of the testing I performed was about troubleshooting and a diagnosis - not a comparison. The point of my troubleshooting was to isolate noise. I found the noise source. Diagnosis complete. I could go into greater detail testing, measuring, comparing. But what would be the point? It won't change the facts.
Running simulations, calculating gains and loading? I suppose the implication is that all those numbers prove something? Not really. Simulations have their uses and can be a good data point for some things, but simulations can differ quite substantially from real-world performance. And there are very good reasons for this (ask me how I know). However, measurements of the actual product using industry standard instrumentation and procedures are meaningful. That is why I sent the Pyxi to be measured.
For the record, I did not set out to find fault with the Pyxi phono preamp. It has been suggested that the Pyxi may not perform at its best with the Ortofon MC2000 and matching SUT. If that is the case, then this issue will probably not come up very often. But I have not had similar issues running that same cartridge/SUT combination with other preamps. I think that is worth bringing to light. For general information, I own and have owned many different phono preamps (11 are in the house at latest count).
No insult intended. It's simply a mystery, as your conclusion that there is a very obvious hiss difference between the Pyxi and The Aragon seemed, well, improbable to me, and mysteries are just begging to be investigated, don't you know.
The conclusion- that under comparable circumstances with a specific SUT employed that indeed the Aragon noise can be better than the Pyxi, and for exactly the reason that was originally surmised, was not entirely surprising. What was surprising is that the difference is, theoretically, fairly small and that suggests that the major issue is in the methodology as hearing a 1.6dB difference in S/N ratio is not that easy, even in carefully level matched listening situations.
Again, I have no issue with you sending the device to Amir. Quite the contrary. Although the claim that he uses " industry standard procedures" is, well, open to some debate, his APX555 is indeed somewhat superior to the gear that I have, which in essence lies between the prior generation of the APX units and the present one, and I would be very interested in the results.
I probably would have preferred to have it done a little differently- i.e. to have the opportunity to measure the unit prior to sending it to him, but this is not for "defensive" purposes but simply to "calibrate" the system I use versus his for future use on my end.
Oh, and the numbers do prove quite a bit, whatever your sensibilities might be, and to claim otherwise would obviate the value of sending the unit to Amir, would it not. Indeed, the correlation between simulated and measured noise in the units has, in my estimation, previously been quite good.
Even for the Aragon 47k it seems to be the case - the fact that I can extract their published specs from simulation - including S/N ratio is interesting is it not?
Again, I apologize for any offense that I may have given, but perhaps you should also consider being more, how shall I say it, careful in how to present conclusions that can be interpreted in a negative way on an open forum like this.
I have been - inadvertently - guilty of something similar in the past, where I reached a, as it turns out, wrong, conclusion based on a back of an envelope estimation, and posted it. I almost immediately did a real simulation and discovered that I was wrong and posted that result, but the designer read the original post and took (justified) offense. Had he read just a few posts later he would have realized that I corrected my error, and when he did so the "storm in a teacup" blew over.
