So the good old 5534 will do just as well for MM as the new tech jjfet OPA1656 and possibly without the thump/pop issues of tone arm concerns re:OP. As an added bonus the 5534 also does great for MC …
Well that’s rather questionable with their relatively high voltage noise.
You better use an opamp with around 1nV/rtHz.
Hans
Noise-wise, for a 500 mH or so moving magnet cartridge, an OPA1656 will outperform an NE5534A, but only by a small amount when there is still 47 kohm across the input.
See the second paragraph of post #202, https://www.diyaudio.com/community/...split-from-opa1656-thread.377331/post-7918764
If you mean the subtle sound quality differences that are still heard with the RC damper circuit in place: could very well be, your guess is as good as mine.
If you mean the enormous bang that JRA had when the turntable's muting switch shorted the cartridge before the RC damper was added: believe whatever you want, I have no intention of repeating the first ten pages of this thread.
Don't be so assured. Not in the sense of continuous or sporadic misbehavior. The simple act of shorting or un-shorting the 1Kohm-terminated shield to center conductor of the 1m low-cap input cable sent those few opamps into a convulsion - and then it was over, albeit per my 40MHz storage scope. This "simulation" mimicked the action of the TTs muting slide switch when the fully-auto function lifted or lowered the arm. The 1656 reacted the most violently.
So, do we have a final schematic of Marvel's phono preamp?
1) Do we simply put say ~ 15nF at the output for the +1 problem?
2) Can we see a Bode plot of 40Hz and down? Is 30Hz preserved? 20Hz?
3) Can the 1KHz gain be increased by say +5dB as was part of my original wish list for a low gain system?
Hats off to all those here smarter than I!
1) Do we simply put say ~ 15nF at the output for the +1 problem?
2) Can we see a Bode plot of 40Hz and down? Is 30Hz preserved? 20Hz?
3) Can the 1KHz gain be increased by say +5dB as was part of my original wish list for a low gain system?
Hats off to all those here smarter than I!
And then there are maybe a few folks who routinely turn down the volume before touching the tone arm.
So you will have a system shielding, wiring and grounding issue. I do not experience any pops from speakers even after human ESD discharge through the tonearm, without turning volume down.
A system shielding, wiring and grounding issue that only shows up when the cable is shorted and the op-amp is fast and that is solved when you add an RC damper circuit large enough to get rid of the negative input conductance of a 53 MHz gain-bandwidth product op-amp with 9.1 pF open-loop differential input capacitance (see
https://www.diyaudio.com/community/attachments/sourceimpedance-pdf.1382244/ ). Sure...
https://www.diyaudio.com/community/attachments/sourceimpedance-pdf.1382244/ ). Sure...
Personally, I also particularly like the Altra circuit.
We can probably all design an equalizer every 15 minutes to pass the time. Unfortunately, at some point the decision as to which litter you should enjoy the music with becomes increasingly agonizing.
greetings,
HBt.
😊
We can probably all design an equalizer every 15 minutes to pass the time. Unfortunately, at some point the decision as to which litter you should enjoy the music with becomes increasingly agonizing.
greetings,
HBt.
😊
Attachments
Here you are,
Two sims, first attachment with a 2nd order and second attachment with a 3rd order rumble filter.
Gain increased to 45.5dB.
To compensate the +1 effect, a 100R+ 3.9nF has been added, keeping the outer 100R at the output intact to cope with interlink reflections.
Be aware that the 3rd order filter exceeds the 20msec@20Hz group delay that Tomlinson Holmann advices as a maximum.
Hans
