Yes, and what's more, it also finds its way into politics, where wrong (in the sense of not based on reality and facts) opinions can be quite costly to society.
jan
Subjective reality is the reason Bayesian Statistics were developed -- putting a spin on rho!
Back to the VinylTrak article - in his book "Power Amplifiers" he discussed alternative front end arrangements to help with the drought of P-Channel JFETs -- and in this article he shows a nice discrete implementation.
Yes, that is frustrating! I had that exact argument with someone over delay vs. phase shift not too long ago. I have to pick up that book recommendation on our post-fact soceity. I have to deal with this at work sometimes.
Well, my birthday is next month, but a very good friend knew just what to get me. He ordered volume 4 for me. The perfect gift!
Jan:
Just got issue 4. Each gets better and better; how long can you keep that up?
Bob Cordell:
I especially enjoyed your RIAA preamp article and look forward to the supplemental info.
(poke, poke).
My next one will definitely use this architecture. Are you planning to start a topic for VinylTrak? (Dick Marsh has one going for his clever headphone amp from issue 3).
Good job guys!
mlloyd1
Just got issue 4. Each gets better and better; how long can you keep that up?
Bob Cordell:
I especially enjoyed your RIAA preamp article and look forward to the supplemental info.
(poke, poke
).My next one will definitely use this architecture. Are you planning to start a topic for VinylTrak? (Dick Marsh has one going for his clever headphone amp from issue 3).
Good job guys!
mlloyd1
If you're within reach of the northern part of Illinois, you can ask Jan that in person next month.
Hi Joachim,
Yes, in this application you are exactly right. The complementary arrangement gets the devices in parallel and the differential aspect comes inherently, each aspect accounting for 6 dB. In the unipolar arrangement, the pair of devices do not act in parallel, and the differential LTP arrangement costs another 3 dB.
That is why I had to use 4 LTP pairs in parallel to get back that relative 6 dB difference. That is a significant cost in additional parts and in dual JFETs. That additional cost is somewhat the price paid for using obtainium vs unobtainium, the latter of which has its own cost premium due to scarce availability. The LSK389s are about $7 each in the metal can for a total of $28. Not sure how much a pair of the complementary Toshibas would cost if one could find a willing seller.
Cheers,
Bob
Jan:
Just got issue 4. Each gets better and better; how long can you keep that up?
Bob Cordell:
I especially enjoyed your RIAA preamp article and look forward to the supplemental info.
(poke, poke
My next one will definitely use this architecture. Are you planning to start a topic for VinylTrak? (Dick Marsh has one going for his clever headphone amp from issue 3).
Good job guys!
mlloyd1
Thanks for your kind words about the VinylTrak phono preamp. I'll try to get the supplemental information up on my site as soon as I can, maybe in stages.
I would feel a bit presumptuous in starting a thread on my own piece of equipment, but if you or someone else wanted to, based on wanting a dedicated thread where more could be discussed, by all means go for it. I would be happy to participate in that thread.
A VinylTrak thread would probably be best put in the Analog Line Level forum where some other preamps are discussed, but here would be fine as well.
Thanks again for your interest.
Cheers,
Bob
Jack Walton (jackinnj) has an article in Vol 4 comparing many low voltage supply regulators (the 'superreg' type of regulator and others). Comparisons include measurements and controlled listening tests by the New Jersey Audio Club.
Some of the comparison graphs are quite busy with a dozen curves in various shades of grey, and to improve legibility I converted them to color and placed them online here.
Enjoy!
jan
Some of the comparison graphs are quite busy with a dozen curves in various shades of grey, and to improve legibility I converted them to color and placed them online here.
Enjoy!
jan
What is really surprising is that the LT1963A/LT3015 scored subjectively in the top 4 although they did not have very good line rejection and rather high output impedance.
Also one of the best measuring scored on pace 11 only.
How can that be explained ? Are we back to the situation that we can not measure sound quality ? I know that some equipments sounds great although it does not have PPM distortion but i thought concerning PSU that situation was clearer. After reading this that does not seem to be the case.
Also one of the best measuring scored on pace 11 only.
How can that be explained ? Are we back to the situation that we can not measure sound quality ? I know that some equipments sounds great although it does not have PPM distortion but i thought concerning PSU that situation was clearer. After reading this that does not seem to be the case.
Joachim,
I will defer to Jack for taking this on (if he wants) but just want to note that the test amplifier (the Borbely line stage) was deliberately selected because it does not have a great PSRR. Selecting a test amp with 120dB PSRR in the audio band would have been rather pointless.
So we are more or less speculating how a specific power supply 'anomaly' would manifests itself in the sound output of an audio stage.
jan
I will defer to Jack for taking this on (if he wants) but just want to note that the test amplifier (the Borbely line stage) was deliberately selected because it does not have a great PSRR. Selecting a test amp with 120dB PSRR in the audio band would have been rather pointless.
So we are more or less speculating how a specific power supply 'anomaly' would manifests itself in the sound output of an audio stage.
jan