So what does the pacemaker software do then? Up the heart rate to help getting up?
jan
Why not connect it to the stylus and a second to the tonearm. The difference would be the output and the second one would have an error component relating to everything from warp to VTA to tracing correction.
Actually, if there were a real market a MEMs stylus-transducer would be the way to do it today.
i'm not sure, I guess there is some correlation though yes? you'll have to excuse me I really dont know much about turntables and the specific mechanical and thermal distortion mechanisms.
I just figured there would be a difference in heat, distortion and possibly tone depending on the friction and vibration; thus relative weight/deflection caused by the bobbing up and down, but for real usefulness there needs to be another reference location.
I have no idea how you would isolate and remove that distortion, as that would correlated and specific to the individual pressing, its wear/deformation and recording though. maybe a digital reference file that was only mixed in when the playback deviated sufficiently from the reference?
but then you wouldnt need the accelerometer really. complex area turntables when you look that closely, covers a lot of disciplines. the query was simply a curiosity, since the conversation was about installing existing features into a different spot, I thought why not think about leveraging other benefits related to that new location, using new, lightweight technology and find some new functionality while you're at it. i'm sure the feedback would have something to say about the deflection, but making something useful out of it ...
ahh Demian's onto it, interesting puzzle.
Last edited:
I have been patient, but nobody seems to talk about issues related to the pursuit to hi end audio, of which the CTC Blowtorch is one example.
I, too, am rather tired of designing preamps, but that is not all there is to reproducing quality audio electronics. And even if power amps can and will be improved over time, there remains a critical 'weak link' audio reproduction. It is not necessarily digital, itself, BUT the interface between converting the output of a first class D-A, to a final audio signal that would go either to a quality preamp or a first class power amp.
This is usually done with IC's, and pretty good IC's at that. However, problems remain.
First, the IC's are often loaded with a difficult load, due to gain reduction requirements.
This makes the IC's put into a less than optimum situation, and I think that this is a real problem. I hope to research this in future.
Of course, I personally have little faith in CD reproduction for useful evaluation, except 'hit and miss' but even DVD and SACD are compromised by these IC's and their loading. My evaluations start with higher bit rate, high bit inputs, just to see what can be done. From my initial evaluations, high quality phono of the same music is still better.
I, too, am rather tired of designing preamps, but that is not all there is to reproducing quality audio electronics. And even if power amps can and will be improved over time, there remains a critical 'weak link' audio reproduction. It is not necessarily digital, itself, BUT the interface between converting the output of a first class D-A, to a final audio signal that would go either to a quality preamp or a first class power amp.
This is usually done with IC's, and pretty good IC's at that. However, problems remain.
First, the IC's are often loaded with a difficult load, due to gain reduction requirements.
This makes the IC's put into a less than optimum situation, and I think that this is a real problem. I hope to research this in future.
Of course, I personally have little faith in CD reproduction for useful evaluation, except 'hit and miss' but even DVD and SACD are compromised by these IC's and their loading. My evaluations start with higher bit rate, high bit inputs, just to see what can be done. From my initial evaluations, high quality phono of the same music is still better.
John, thats really funny, you interrupted a fairly interesting conversation about the possibility to leverage new technology to improve analogue playback mechanisms, to launch yet another boring, recycled tirade against ICs and digital ...
Do you think thats the most interesting topic in high end audio? you certainly know the ground and material well.
the result of this is possibly provoking yet another round of discrete and analogue versus Ics and digital, cycling around, mimicking a record.
perhaps you dont realise that there were rather analogue mechanisms under discussion? for improving the analogue playback? what new and positive discussion did you hope to provoke with that, that you might find more satisfying?
Do you think thats the most interesting topic in high end audio? you certainly know the ground and material well.
the result of this is possibly provoking yet another round of discrete and analogue versus Ics and digital, cycling around, mimicking a record.
perhaps you dont realise that there were rather analogue mechanisms under discussion? for improving the analogue playback? what new and positive discussion did you hope to provoke with that, that you might find more satisfying?
Last edited:
You will probably be surprised to hear that fully complementary, j-fet input, open loop OTA's have been used in that place some 20 years ago
In the 2/92 issue of The Audio Amateur, Walt Jung shows on pages 16 and 17 how good the AD811 is for an I/V converter. And I know John will like this, the 811 has on open loop bandwidth of 21Khz.
I feel that the 811 is an excellent IC for an I/V stage. I like to use some LC filtering in front of it to lower the RF going into it from the DAC chip.
I feel that the 811 is an excellent IC for an I/V stage. I like to use some LC filtering in front of it to lower the RF going into it from the DAC chip.
I think you are on the right track with a current-feedback opamp, as the inherent inverting input impedance is so low to begin with, and feedback enhances it. The DACs that are misleadingly described as "current output" I've remarked elsewhere should be called "DACs whose outputs should be terminated in a very low impedance". It is unfortunate that few manufacturers reveal what their output impedance really is, and in particular how much it may be code-dependent.
Brad
yea no progress in op op amps in 20 years, no sir, never happened...
nor would anyone think to put a feedback cap across the I/V R - making the low Z of the output dominant at high frequency with VFA I/V - or write up the advantages say back when AD was still building DACs in potted boxes...
Last edited:
It's a bit more complicated than that.
To start with a low impedance open-loop, and then enhance that with feedback, is an attractive approach. For some reason a great many people are not thoughtful about this, and continue to apply voltage-feedback opamps to this particular task. Indeed, virtually all of the app notes I've seen are still using voltage feedback amps. Yes, the results are acceptable, just suboptimal.
- Status
- Not open for further replies.