I have been pondering this. The big uncontrolled variable seems to be the capacitance of the deck-preamp cable. That can be reduced to effectively zero by driving the cable screen as a guard, as in the Neumann PUE-47 phono amp. Is anyone aware of any other guarded phono inputs?
(Audio noob here.) I was wondering with availability of modern high gain devices if it is possible to discard step-up transformer for low output moving coil cartridges ? And if possible then a circuit design for that perhaps ?
Also if it is possible to design a circuit independant of resistive load and capacitance (that cartridge manufacturers talks about) ?
Thanks and regards.
Also if it is possible to design a circuit independant of resistive load and capacitance (that cartridge manufacturers talks about) ?
Thanks and regards.
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Motor controllers for DC, single and multi phase motors. Maybe even servo/regulator circuitry utilizing tacho signals derived from strobes. Also, line filtering for motors.
Strobes.
DIY arm lifts and/or limit switching circuitry.
MC head amps of varying complexity.
A bit more on electric load synthesis, maybe with discrete circuitry, I really liked that approach.
Strobes.
DIY arm lifts and/or limit switching circuitry.
MC head amps of varying complexity.
A bit more on electric load synthesis, maybe with discrete circuitry, I really liked that approach.
What would be useful for me is how to use a good test record for calibrating the R and C loading of the MM cartridge. I'm convinced that that is more important than getting the RIAA curve within 3dB of correct. A good discussion of MC cartridge issues and loading too. A phono preamp circuit project would be a fun way to explore each issue, and give something to a newbie who really just wants to copy a known good circuit. There's tone arm mechanical adjustments that should be talked about in full detail (azimuth, antiskating, etc.). Preamp noise measurements too.
What would make the book more interesting to me (as opposed to useful), would be stories about the history of the development of records, record players, etc. Lots of pictures of the Engineers in their labs, etc.
I don't recommend excluding issues related to any of the things I mentioned just because other books do a perfectly good job of explaining them. Write a book that is all a tech would need for anything related to cartridges, tonearms, phono preamps and calibration.
Also maybe a section on early EQ variations for those who want to play very early records, to hear music that may never have been copied onto a regular RIAA record or CD or whatever. Many musicians thrive on very early recordings from the 20's and 30's. I've been asked about this and had no real answers.
What would make the book more interesting to me (as opposed to useful), would be stories about the history of the development of records, record players, etc. Lots of pictures of the Engineers in their labs, etc.
I don't recommend excluding issues related to any of the things I mentioned just because other books do a perfectly good job of explaining them. Write a book that is all a tech would need for anything related to cartridges, tonearms, phono preamps and calibration.
Also maybe a section on early EQ variations for those who want to play very early records, to hear music that may never have been copied onto a regular RIAA record or CD or whatever. Many musicians thrive on very early recordings from the 20's and 30's. I've been asked about this and had no real answers.
I published an amplifier that meets these requirement in December 1987 in Electronics World. An updated version appears in my book Small Signal Audio Design (both editions)
Since cartridge makers seem to depend on the HF resonance to get a decent freq response I don't see how this is possible.
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Deep Learning is a buzz word for the generation of processing algorithms who's parameters are generated from the statistics of real-world data. As a method, it side-steps the need to develop a clearly defined analytical model of the problem up-front and then trying to 'fix' it where it meets the real-world.
In practical terms, you'd develop a processing algorithm that would edit the sound track to remove pops and ticks based on a set of parameters. These parameters would be determined by having the system 'listen' to many many many examples of pops and ticks. This is the 'learning' step and it would be performed by the manufacturer; the parameters would represent the IP of the manufacturer.
That's my take on it. Google the term and you'll be rewarded(?) with more reading material than you can handle.
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I realize that, which is why I suggested your seek 'guest authors' for those chapters. At the end you would have the 'bible' on vinyl. Without it you have a very desirable book, but not the 'bible' on vinyl.
With all due respect, the motor related parts could be a whole book in itself. Today's turntable motors/mechanisms may have common elements, but the turntables of the past seem fairly diverse, based on what I've seen. When I refurbished my RCA 9-JY 45 changer, I just went on the web and researched until I could find the parts I needed, and procedural info. What are the chances that any one book would cover most turntables in this way? Today's motor/mechanisms are probably microcomputer controlled, and therefore may involve code burnt into a PROM memory (?)...
I don't know enough to say if it's a Neumann pole. Here's the text
http://www.hagtech.com/pdf/riaa.pdf
Why more than one iRIAA circuit? Same reason I guess that there are more than one RIAA circuits. I've seen 2 inverse circuits - one passive and the other active using opamps.
My opinion is hardening against the mechanical stuff. It needs a separate book. Putting together phono amps is one thing, but building electric motor systems is another.
Both already on my tentative list/ Not sure about discrete load-synthesis: can see no advantage and lots of snags. To name one, you need a very high-impedance pickoff for the synthesis signal.
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Doug, what about actively driven shielded phono cable, virtually eliminating the capacitance of the cable, then using a known value of capacitance at the input of the phono amp so that the FR becomes more predictable. I've been thinking about making something like this myself, after Christmas.
The trouble with an active cable driver (impedance converter) is that once you've got an active circuit in the turntable, it only takes a few more parts to turn it into a complete hi quality RIAA preamp... Why not just do that?
If I wrote such a book, I'd start with trying to answer the question: Why does vinyl ever seem to sound better than digital? I'd talk about compression, and the way the reactive needle vibrates the record that is often held only by the edge (and maybe one other place), thereby causing a very short term reverb effect that "warms" the sound... I'd also talk about early digital problems (aliasing distortions and low effective bit counts on low level material such as soft piano) that remind me of early transistor circuit problems (phase margin and crossover distortion in PP output stages).
I'd also mention the effect of the graphics of the record album cover. Not just for art sake, but it gets you more involved with what you're hearing. It's part of the entertainment value. Once music is all digital downloads, there's almost nothing left of that... A little off subject maybe, but perhaps part of why people love vinyl. Some people (me) also loved watching the mechanical magic act of a record changer.
If I wrote such a book, I'd start with trying to answer the question: Why does vinyl ever seem to sound better than digital? I'd talk about compression, and the way the reactive needle vibrates the record that is often held only by the edge (and maybe one other place), thereby causing a very short term reverb effect that "warms" the sound... I'd also talk about early digital problems (aliasing distortions and low effective bit counts on low level material such as soft piano) that remind me of early transistor circuit problems (phase margin and crossover distortion in PP output stages).
I'd also mention the effect of the graphics of the record album cover. Not just for art sake, but it gets you more involved with what you're hearing. It's part of the entertainment value. Once music is all digital downloads, there's almost nothing left of that... A little off subject maybe, but perhaps part of why people love vinyl. Some people (me) also loved watching the mechanical magic act of a record changer.
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I didn't explain - you drive the shield of the cable from the amplifier end of the cable. You take the signal from the inner conductor and buffer it and use that to drive the outer shield. This is a standard technique for some instrumentation probes. Think of it as a bootstrap. Again, it's a common technique in electronics systems.
> I suggested your seek 'guest authors' for those chapters.
No clue what Mr. Self's contract says, but typically a tech book is a straight $2K delivered (old contract, but rates have been flat). So paying guest authors leaves Doug hungry. Not-paying them is bad karma.
If this sells good, he could be the person to organize a mini Audio Cyclopedia totally paid-guest-authored. But a demand must be proven first.
No clue what Mr. Self's contract says, but typically a tech book is a straight $2K delivered (old contract, but rates have been flat). So paying guest authors leaves Doug hungry. Not-paying them is bad karma.
If this sells good, he could be the person to organize a mini Audio Cyclopedia totally paid-guest-authored. But a demand must be proven first.
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