IMHO, Wikipedia can be a guide but never The Authority.
Santa Claus is real. The Easter Bunny is real. The Neumann Pole is real. If you wish to believe in it. Don't let facts or logic get in the way.
You need to read Self on this. Not only does he disprove the 'Neumann pole' by reference to actual Neumann circuits, he also asks the even more relevant question: if Neumann really tried to suppress stuff beyond 50KHz, what exactly are we doing trying to put it back?
NB The original claimant, Allen Wright, provided exactly zero evidence.
NB The original claimant, Allen Wright, provided exactly zero evidence.
That was not the point. I do not particularly care about frequency response accuracy well in the ultrasonic range, as should most other people with a grand total of zero CD-4 quadrophonic records. What I do care about is the associated additional series resistor in the feedback network that (a) makes it easier to drive and (b) also permits use of non-unity-gain-compensated opamps (or being able to ease up on compensation of an external input pair). Nothing more, nothing less. If the resulting pole results in more FR deviation from ideal than you like, eliminating it via some passive RC filtering should be trivial.
Last edited:
That series resistor is also improving the phase response linearity in 10...20khz or even higher range with unity gain compensated op-amps and also with the "universal op-amp "model in LtSpice.
Were these comments in one of Douglas Self's books? ... or a posting online? Either way, it would be great to have a citation to refer to.
To answer your question, though, if Neumann tried to avoid burning out their cutting coils via ever-increasing gain in the ultrasonic region, then "what we're trying to do" is match the decoding EQ to the encoding EQ as closely as possible. In other words, don't cut frequencies above 50 kHz that weren't boosted according to RIAA spec. Whether we can hear it or not is separate from the question of whether the phono decoder stage mirrors the cutter encoding stage.
Replace of NE5532 by 2xAD825 - go to
L C Audio Technology/AD825
remove this character completely at NAD's model PP-2 - go to the second schematic in post #5 under
Head Pre for Denon DL 103
Quote from Page 106, The "Neumann Pole"
"The name of Neumann became attached to this concept simply because they are the best known manufacturers of record lathes.
The main problem with this story is that it is not true. The most popular cutting amplifier is the Neumann SAL 74B which has no such pole."
There are more comments on the actual equalisation.
Last edited:
check out this URLs:
Stereo Lab - RIAA and the Neumann Pole
Cut and Thrust: RIAA LP Equalization | Stereophile.com
Cut and Thrust: RIAA LP Equalization The Neumann 4th pole (sic) | Stereophile.com
Neumann-Konstante; Wahrheit oder Märchen? RIAA Filter, Entzerrung; Neumann Pole;
https://books.google.de/books?id=WFoPEAAAQBAJ&pg=PA106&lpg=PA106&dq="The+name+of+Neumann+became+attached+to+this+concept+simply"&source=bl&ots=3uQbMbOTZY&sig=ACfU3U2drFKn0sD4KMpR3ZVQHBjc8Vv2fw&hl=de&sa=X&ved=2ahUKEwik8d-fj93uAhVM6uAKHf-zBqkQ6AEwAXoECAMQAg#v=onepage&q="The%20name%20of%20Neumann%20became%20attached%20to%20this%20concept%20simply"&f=false
Last edited:
Swapping op amps is not as easy as direct replacement.
Usually the gain, and impedances for input and output will change, unless the op amp is a direct substitute.
So if you want to experiment, put sockets for op amps, and multi turn presets for input, output and supply voltage.
Then play the same music through different set ups, and decide what suits your liking, in that your music choice may not be my choice, and so on.
What I mean is that you decide which op amp best reproduces your preferred choice of music, and having done that, freeze the design, and on to the next project.
Usually the gain, and impedances for input and output will change, unless the op amp is a direct substitute.
So if you want to experiment, put sockets for op amps, and multi turn presets for input, output and supply voltage.
Then play the same music through different set ups, and decide what suits your liking, in that your music choice may not be my choice, and so on.
What I mean is that you decide which op amp best reproduces your preferred choice of music, and having done that, freeze the design, and on to the next project.
I put it in mine to increase the stability of the RIAA op amp, not for any EQ benefit.
5532(4) is an excellent op amp for RIAA. I used an LF353 for years as the J-FET input may be a little brighter. I am using the HA1457 which has specs similar to the 5534.
5532(4) is an excellent op amp for RIAA. I used an LF353 for years as the J-FET input may be a little brighter. I am using the HA1457 which has specs similar to the 5534.
Last edited: