It is very sad if it actually did.We’ve spent 10 years developing and refining our Exception Phono preamp to meet our standards of performance.
Geekly.RZ did just fine, I think: https://www.audiosciencereview.com/...xemplar-exception-phono-amp.7144/#post-163021Words are inadequate to explain the Exception Phono.
Not impressed with that design. Firstly, the output has a high impedance, it would have been better if the output had been taken from the cathode as a cathode follower. It then wouldn't have had any gain, but that's probably not a bad thing.Even the choice of tubes is not the greatest, The 6c45p and the 6bz7 is not the way to do a proper high gain MC amp IMO. 3 stages, something like the Loesch with a modified GenRad power supply is much better IMO, I build several over the years. Working with 417As can be a bit tricky though, you need allot to select them. I liked 437As much better,great amp driver, plus had more than 100 of them, a great tube but they are now pretty much extinct like $300 each.
http://www.tempoelectric.com/phono.htm#circuit
https://www.teresaudio.com/haven/preamp/preamp.html
A variation.
Good points.Not impressed with that design. Firstly, the output has a high impedance, it would have been better if the output had been taken from the cathode as a cathode follower. It then wouldn't have had any gain, but that's probably not a bad thing.
Secondly, what happens to the valves when the bias batteries go flat?
Not impressed with that design. Firstly, the output has a high impedance, it would have been better if the output had been taken from the cathode as a cathode follower. It then wouldn't have had any gain, but that's probably not a bad thing.
Secondly, what happens to the valves when the bias batteries go flat?
Yes the parts branding is not necessary. I liked to shock mount some sockets when needed to help reduce microphonics.All good points. I'll add in that this is likely to be quite microphonic as well. Very poor power supply rejection. AL did a couple of nice tricks in there, but there's too much emphasis on parts brands and not enough on optimizing the circuit.
The maximum theoretical dynamic range of a vinyl record is only ~70dB. So does it matter if a phono preamp has SINAD that's not much better than that? I'm sure there's a fairly simple answer and I'm probably missing something obvious. School away!
At Exemplar, we’ve learned not to depend on the numbers. In the electronics world, they measure the speed of circuits in microseconds and our ears hear harmonic structure in nanoseconds. In the end, it’s not about charts and numbers…..it’s about bodily sensations and emotions.
So you see, according the company, no valid measurements are even possible. Although I don't know what hearing an "harmonic structure" at a billionth of a second could mean, I'm sure it's a very emotional experience. I also wonder what sorts of bodily sensations arise from swapping out your standard wall plug for their 1.5 meter, two thousand dollar power cord? Maybe it's not insulated well, and you get a mild shock.
600 Ohm testing is more or less standard at stereophile. JA runs it on the output of DACs, phono pre-amps, etc. It was requested that I start showing the same data because some gear has far lower input impedance than the 100k I use for testing. Unfortunately the analyzer only has 100k, 600 and 300 ohm. So nothing in between. Like you, I pushed back that 600 ohm testing is not useful for distortion, etc. as it is too harsh.Whilst the performance is clearly lacking in virtually every parameter you chose to test, who on earth loads any domestic active phono stage, pre-amplifier, or D/A converter line stage with a 600ohm load and then calls it out for a rising impedance at LF?
I like to see 600ohm used as a load on equipment designed to drive line levels. I know that these days it's not common to see anything with a 600ohm input, but if a phono stage or whatever will drive 600 ohm satisfactorily, then there's a good chance it'll drive any length of cable, and won't be troubled if the load is 20k, 10k or even lower. With anything I use in my own system, I test at 10k and 600 ohm and expect no significant difference in performance except for a small voltage difference.600 Ohm testing is more or less standard at stereophile. JA runs it on the output of DACs, phono pre-amps, etc. It was requested that I start showing the same data because some gear has far lower input impedance than the 100k I use for testing. Unfortunately the analyzer only has 100k, 600 and 300 ohm. So nothing in between. Like you, I pushed back that 600 ohm testing is not useful for distortion, etc. as it is too harsh.
In this case though, I am not measuring distortion. Instead, it is a simple way to show the effect of high output impedance in a way that is simpler to understand than pure impedance graph. People understand frequency response. Impedance is harder to grasp.
In this regard, I am not seeing an issue with showing that graph with 600 ohm load.
There are many variations, the one I put up was different from Arthur's. There are many variations. The battery charges in circuit. There are many ways to build a good MC front end. I also like using transformer. It is amazing though how much people can charge for junk, like the one Amir just tested.