Yet people seem to delight in the experience of vinyl record playback, including playback of slightly, moderately, and severely warped records. How can this be so?
Yes, where are all these horrifying LP's? It verges on FUD, you can't make a useful pre-amp unless it handles every LP made no matter how its been abused. Does anyone consider, for instance, that the extreme groove velocities quoted are not even remotely trackable and are generating so much volume and distortion that it could not matter anyway?
bill, I should caution that this is appears to be the lesser Leach variant from #311 rather than true Duraglit. But it's a simple (?!!) matter to remove 6 bits and change 2 resistors to get the, at least 3dB, Vni improvement of true Duraglit.It's likely PSR is also improved but I would want to confirm this in real life. There is no evidence that lesser variants give the advantages for World Peace and better sex life of true Duraglit.
Sorry, wrong on all counts. Do yourself a favour and save some embarrassment by looking closely to the schematic.
That's the main issue IMV. You can't stop off-centre record modulation (someone suggested and experiment with opera) which can render piano unlistenable but you can stop cone flap very effectively. I have a Manhattan Transfer vinyl (1979) that is immaculate other than a severe warp. It sounds absolutely fine, but you cannot play it without the sub-sonic filter switched in the cone flap is that severe.
Anyway, each to his own on this subject - my 2c worth.
People are happy to spend $100's on a turntable and the same again on a decent cartridge and have probably spent 1000's over the years on records.
A subsonic filter is 1 dual opamp and a handful of 1% NPO caps and 1% resistors - about 1$ per channel. Sorry, I don't see why one would not consider such a solution. A lot of folks have vinyls that date back 30 or 40 years (me for example) that are going to suffer from some of these issues unless they have been stored in ideal conditions.
Of course, if this is all too much to bear, just stream your music. But, as the standing joke goes 'I was attracted to vinyl because of the expense and inconvenience of it'
Well, blew that. Sorry guys.
Warp will excite resonances in the 7-8Hz region for one and secondly the ear is more sensitive to FM in the 4-10Hz region. And finally there is circumstantial evidence that a higher resonance is easier to damp. But this does need testing as the B&K papers had a slight cheat there.
You ever looked at the phase of the LF flap? Warp I would suggest gives mainly vertical motion. If this is the case then there might be better ways of filtering this. Or at least something to investigate that there is little in the literature about.
But if you use a 40 dB/decade sub-sonic filter these issues go away - assuming of course that the resonance issues don't cause mis-tracking.
Dunno how else you can decently filter out cone flap for less than 1$ (1 x 5532, 4x 1% resistors and 4 off caps + 2 for decoupling).
I've done the resistor trick from the RIAA amp output back to the top of the DC blocking cap - the slope below 20Hz is definitely better than a straight RC filter but you get peaking between 20~60 Hz as would be expected.
Dunno how else you can decently filter out cone flap for less than 1$ (1 x 5532, 4x 1% resistors and 4 off caps + 2 for decoupling).
I've done the resistor trick from the RIAA amp output back to the top of the DC blocking cap - the slope below 20Hz is definitely better than a straight RC filter but you get peaking between 20~60 Hz as would be expected.
Bonsai,
Bill has right, Fres of Arm/Cart causes frequency IM distortion that no filter can ever remove.
So always try to get Fres above the frequency of the warp stimulations and also try to achieve a low as possible Q at Fres.
For the same reason will subsonic movement of the speaker cause IM modulation.
But to prevent that from happening, a rumble filter is your friend.
Hans
Bill has right, Fres of Arm/Cart causes frequency IM distortion that no filter can ever remove.
So always try to get Fres above the frequency of the warp stimulations and also try to achieve a low as possible Q at Fres.
For the same reason will subsonic movement of the speaker cause IM modulation.
But to prevent that from happening, a rumble filter is your friend.
Hans
I'm not suggesting anyone should not try to minimize mechanical resonances etc. It was simply a question from my side as to why he preferred Fres up at c. 14Hz.
(Warp is at 1/33.33 - no where near the 8-12 Hz mentioned by Ortofon. You'd have to have a pretty crazy vinyl to be getting it at >8 Hz)
(Warp is at 1/33.33 - no where near the 8-12 Hz mentioned by Ortofon. You'd have to have a pretty crazy vinyl to be getting it at >8 Hz)
I just ordered a new set of boards, with some minor layout changes: I was getting annoyed to have to twist the ZTX pins to fit in the japanese transistors pinout so the ZTX and japanese devices now got separate boards, 600mA power LEDs are not required (so switched to smaller and much cheaper devices with the same spectral content), shortened a few traces.
As usual, for DIYers, the problem is not with the simulator, but with the models; I'm sick of people claiming outstanding results while using models that do not model some basic in scope parameters: simulating distortions with op amp macro models (ABM), power amplifier distortions without mosfet subthreshold modelling, passive devices without parasitics (where it matters, like RF or noise), noise in transistors with virtually zero Rbb, and with zero Kf flicker noise parameter, etc...
There is clear trend to blindly trust Spice models, the manufacturers are doing a very poor job, while other sources (like Bob Cordell) are also not helping in gaining trust, some of his models are as bad as the originals.
Funny enough, IC industry design models are also macro/behavioral models (example: based on Sij parameters for the linearized models, modified Volterra-like integral series expansion for the nonlinear case) but they are very solidly grounded in statistical measurements and process parameters. Add to this the hierarchical approach (trivial example: a finished opamp is defined as a macro cell, with it's own set of fully characterized parameters). This explains the high rate of success at the first run.
In my early life, when rubylith cutting and a photo bench were used to get the x10 reticles, it usually took at least two iteration to get an analog design right. I still remember myself patching manually the rubylith to adjust a resistor in a 5V/3A LM323K regulator, for bringing the output voltage it right in the middle of the datasheet range. This was 40 years ago, in the JC glory days
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I still remember myself patching manually the rubylith to adjust a resistor in a 5V/3A LM323K regulator, for bringing the output voltage it right in the middle of the datasheet range. This was 40 years ago, in the JC glory days
Just like roofing to many layered patches and you had to remove the whole area and do it over.
Just like roofing to many layered patches and you had to remove the whole area and do it over.
Exactly
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