Shouldn't a Phono Stage Be Like a DAC? Why so expensive?

[Cosmik]

Placing the tape near a magnet can do it, too. When I was a kid I inadvertently placed a precious reel-to-reel recording near a speaker, I think, and from then on you heard several layers' worth of print-thru - very clear because it wasn't music but speech. Might be able to remove it with some careful DSP manipulation these days...

 

[DonH56]

A magnet will erase the tape but not well... Unfortunately well enough to make it unplayable, not well enough to get it anything like a virgin tape.

 

[Sal1950]

Unfortunately well enough to make it unplayable, not well enough to get it anything like a virgin tape.

Do you believe a tape can never be erased to the equivalent of virgin, or only not by a using a permanent magnet?

 

[DonH56]

Do you believe a tape can never be erased to the equivalent of virgin, or only not by a using a permanent magnet?

Disclaimer: NOT my area of expertise, and a long time since I've dealt with this in the studio or at home! Take with block of salt, totally off-the-cuff comments follow...

How close you can get to a fresh tape is one of those debatable things... But what it usually takes is an alternating field strong enough to thoroughly scramble the field imprinted on the tape; most tape recorders use the bias oscillator with no signal impressed (about 60 kHz IIRC though different machines used different frequencies). Cheap recorders did use a permanent magnet and just let it erase the tape as it went by. IME that did not work well; not enough energy, and imposed sort of a DC "offset" on the tape. Some off-deck erase units were just a transformer in a box, ditto some demagnetizing probes. I sometimes used a TV degaussing coil.

Here is an example of something like I used to play with:

 

[Wombat]

In what way is the fact that one can hear the stylus/cantilever play the record if one gets their ear really really close to it like scratches. pops and clicks? And how is the fact that one can hear the stylus/cantilever play the record if one gets their ear really really close to it a "weakness" in and of itself and not just an artifact of the fact that the thing is moving in the open air?

That audible vibration feeds-back to the stylus with an under-damped lower level version of the groove signals. This will be included in playback signals. It shouldn't be there in an accurate reproducing medium.

 

[Frank Dernie]

That audible vibration feeds-back to the stylus with an under-damped lower level version of the groove signals. This will be included in playback signals. It shouldn't be there in an accurate reproducing medium.

Yes, it shouldn't be there but along with mechanical and acoustic environmental pickup it adds a bit of extra reverb, which isn't on the recording but may well sound nice. IME all the shortcomings of record players are euphonic apart from speed fluctuations and rumble.
I have reported this often before but when I was a young R&D engineer at Garrard in the mid 70s one of the first jobs I was given "to familiarise myself with the equipment" was to measure the rumble of a 401. In fact I was very familiar with the Bruel & Kjaer analysers since I had used them daily before in my previous job. What I learned then was how sensitive a record player is at picking up environmental vibration.
The deck was on a heavy oak work bench on the 4th floor (5th floor for US speakers) of a concrete factory building. I couldn't get consistent results at all (this was the lesson I was being taught). I was then shown that if you watched the cartridge output on the analyser you could see clearly the vibration of buses passing on the road on the other side of the factory carpark!
The bass output of most record players is considerably boosted by this effect, which most people, including me, like IME.
I did experiment at home by putting record players in a different room to the speakers and did not prefer the sound I got...

 

[Blumlein 88]

Yes, it shouldn't be there but along with mechanical and acoustic environmental pickup it adds a bit of extra reverb, which isn't on the recording but may well sound nice. IME all the shortcomings of record players are euphonic apart from speed fluctuations and rumble.
I have reported this often before but when I was a young R&D engineer at Garrard in the mid 70s one of the first jobs I was given "to familiarise myself with the equipment" was to measure the rumble of a 401. In fact I was very familiar with the Bruel & Kjaer analysers since I had used them daily before in my previous job. What I learned then was how sensitive a record player is at picking up environmental vibration.
The deck was on a heavy oak work bench on the 4th floor (5th floor for US speakers) of a concrete factory building. I couldn't get consistent results at all (this was the lesson I was being taught). I was then shown that if you watched the cartridge output on the analyser you could see clearly the vibration of buses passing on the road on the other side of the factory carpark!
The bass output of most record players is considerably boosted by this effect, which most people, including me, like IME.
I did experiment at home by putting record players in a different room to the speakers and did not prefer the sound I got...

Early on when doing a digital needle drop for a friend, we did some and he was pleased. He then did some on his own. And said they weren't quite right. He had an exemplary TT, and a nice tubed phono stage feeding a tubed amp. Trying to find out what was wrong he described doing the needle drops with amp and speakers off. He assumed that would be cleaner and sound even better. I told him how that wasn't the same the feedback was part of the sound he liked. He rather didn't believe me. I had him play a CD, while I recorded his TT with cartridge sitting on a non-spinning disc. While low in level the music being played was clear. I told him part of the sound he loved was acoustical feedback in the TT, the preamp, and likely even the tubed amp. He recorded with the whole system going and things sounded right on these digital recordings.

Man I am glad I don't have a TT anymore.

 

[Frank Dernie]

Early on when doing a digital needle drop for a friend, we did some and he was pleased. He then did some on his own. And said they weren't quite right. He had an exemplary TT, and a nice tubed phono stage feeding a tubed amp. Trying to find out what was wrong he described doing the needle drops with amp and speakers off. He assumed that would be cleaner and sound even better. I told him how that wasn't the same the feedback was part of the sound he liked. He rather didn't believe me. I had him play a CD, while I recorded his TT with cartridge sitting on a non-spinning disc. While low in level the music being played was clear. I told him part of the sound he loved was acoustical feedback in the TT, the preamp, and likely even the tubed amp. He recorded with the whole system going and things sounded right on these digital recordings.

Man I am glad I don't have a TT anymore.

Absolutely right. Mind you having worked in the business I have been well aware of this personally for decades so listening to my old LPs, which I don't do all that often, will always be part of my life.
Most LP enthusiasts seem to be actually convinced that there is something superior about them though, rather than the euphonic colourations we know about, and can get quite antsy when told the facts...
Sometimes I think I should sell some of the LPs an turntables I still have but I don't need the space just yet, and the LPs form a nice uneven reflecting surface on the side of my listening room

 

[Soniclife]

IME all the shortcomings of record players are euphonic apart from speed fluctuations and rumble.

I think you need to be careful with that statement, lots of people probably do think that, but I always struggled with vinyl as it never seemed accurate, once I embraced digital I realised I was right, and what you refer to as euphonic I mainly hear as wrong. That's not to say I don't love the sound of some of my vinyl, and some records do seem to have something the digital version is missing, and I do think they are being euphonically enhanced in some cases not just better mastering, but it's a low percentage.

 

[Analog Scott]

Yes, it shouldn't be there but along with mechanical and acoustic environmental pickup it adds a bit of extra reverb, which isn't on the recording but may well sound nice. IME all the shortcomings of record players are euphonic apart from speed fluctuations and rumble.
I have reported this often before but when I was a young R&D engineer at Garrard in the mid 70s one of the first jobs I was given "to familiarise myself with the equipment" was to measure the rumble of a 401. In fact I was very familiar with the Bruel & Kjaer analysers since I had used them daily before in my previous job. What I learned then was how sensitive a record player is at picking up environmental vibration.
The deck was on a heavy oak work bench on the 4th floor (5th floor for US speakers) of a concrete factory building. I couldn't get consistent results at all (this was the lesson I was being taught). I was then shown that if you watched the cartridge output on the analyser you could see clearly the vibration of buses passing on the road on the other side of the factory carpark!
The bass output of most record players is considerably boosted by this effect, which most people, including me, like IME.
I did experiment at home by putting record players in a different room to the speakers and did not prefer the sound I got...

Has there actually been any tests of vinyl playback that actually isolates this particular acoustic energy as a source of feedback? I am very skeptical that such a low level of kinetic energy would have any audible effect. Mechanical feedback for sure, acoustic feedback from the speakers yeah, slightly. the mechanical feedback of the stylus groove interface, no doubt. But the acoustic output of the stylus/cantilever? I really doubt it. And given that we are talking about 3 different sources of feedback that are orders of several magnitudes larger in actual kinetic energy AND are derived from the exact same source, I'd like to know how anyone has managed to isolate the effects of the acoustic energy of the stylus/cantilever from the mechanical feedback fromt he styluc/cantilever interface, the acoustic feedback from the speakers and the mechanical feedback from the speakers? Seems to me the only way one could test for such feedback would be to do comparisons between the signal by putting the TT rig in a vacuum chamber and comparing it to the signal when played in the open air with no speakers playing while the record is being tracked. Has this been done? Is there an alternate way to isolate that particular alleged source of audible feedback?

 

[Wombat]

Chalk and fingernails.

http://www.physlink.com/education/askexperts/ae110.cfm

https://www.newscientist.com/articl...t-when-nails-scratch-a-blackboard-has-a-name/

Mechanical action producing sound energy. In vinyl record replay this happens and the energy feeds back to the stylus. It is measurable but why bother? Technology has moved on from there.

However, if proponents of the superiority of vinyl playback would do their own homework instead of asking others to do it they may gain some credibility.

 

[Analog Scott]

Mechanical action producing sound energy. In vinyl record replay this happens and the energy feeds back to the stylus. It is measurable.

How do you know?

 

[Wombat]

How do you know?

Do some homework for a change. Hint: mechanical/acoustical energy transfer.

Repeat, why bother?

 

[Analog Scott]

Do some homework for a change. Hint: mechanical/acoustical energy transfer.

Repeat, why bother?

The question was how do you know. Looks like you don't have an answer. No surprise.

 

[Wombat]

The question was how do you know. Looks like you don't have an answer. No surprise.

I have an answer but I won't waste my time.

When you start justifying your own opinions with substantial support, then you can expect the same from others.

Technical ignorance may lead you to think your reactive questions can be answered quickly in a few lines. Get past it!!

 

[Frank Dernie]

Has there actually been any tests of vinyl playback that actually isolates this particular acoustic energy as a source of feedback? I am very skeptical that such a low level of kinetic energy would have any audible effect. Mechanical feedback for sure, acoustic feedback from the speakers yeah, slightly. the mechanical feedback of the stylus groove interface, no doubt. But the acoustic output of the stylus/cantilever? I really doubt it. And given that we are talking about 3 different sources of feedback that are orders of several magnitudes larger in actual kinetic energy AND are derived from the exact same source, I'd like to know how anyone has managed to isolate the effects of the acoustic energy of the stylus/cantilever from the mechanical feedback fromt he styluc/cantilever interface, the acoustic feedback from the speakers and the mechanical feedback from the speakers? Seems to me the only way one could test for such feedback would be to do comparisons between the signal by putting the TT rig in a vacuum chamber and comparing it to the signal when played in the open air with no speakers playing while the record is being tracked. Has this been done? Is there an alternate way to isolate that particular alleged source of audible feedback?

I would expect the amount of cartridge output due to this, one of many, bit of spurious vibration, will depend on the record support. Something with vacuum hold down or a properly engineered clamp system will have the least, something with a felt mat perhaps the most (perhaps why so many people like Linns and Roksans ???)
But why bother about quantifying it?
AFAIK there hasn't been any published engineering analysis of the distributed mass dynamic response of a record player system since computer power and software cost made such a thing plausible. I don't see any likelihood of one being done by any company currently in the business, which proceeds with marketing phrases not far removed from witchcraft and technically erroneous statements based on applying static thinking to a dynamic system. If one has been done it has not been published. A well known cartridge manufacturer did approach a friend of mine to do an analysis of the dynamics and magnetic linearity of their cartridges. The first look showed significant areas of error so they decided not to go ahead with the engineering work... Neat and inexpensive solution.
I don't concern myself with the relative magnitude of spurious vibration pickups inevitable in my record players. Experiments when I did work in the business showed that eliminating all of them was not possible anyway.
I rejoice in the ability to tune the sound of record players to taste, if that is what one likes, which isn't feasible with CD. If one doesn't want the faff LPs are no longer the only low cost music carriers they were when I started buying recorded music in the mid 1960s so there is another choice.
Mostly I listen to CDs but still enjoy my old LPs whenever I feel like listening to them. I probably won't ever buy a new one again unless part of a set with compelling artwork like a Laura Marling set I bought.

 

[Analog Scott]

I would expect the amount of cartridge output due to this, one of many, bit of spurious vibration, will depend on the record support. Something with vacuum hold down or a properly engineered clamp system will have the least, something with a felt mat perhaps the most (perhaps why so many people like Linns and Roksans ???)
But why bother about quantifying it?
AFAIK there hasn't been any published engineering analysis of the distributed mass dynamic response of a record player system since computer power and software cost made such a thing plausible. I don't see any likelihood of one being done by any company currently in the business, which proceeds with marketing phrases not far removed from witchcraft and technically erroneous statements based on applying static thinking to a dynamic system. If one has been done it has not been published. A well known cartridge manufacturer did approach a friend of mine to do an analysis of the dynamics and magnetic linearity of their cartridges. The first look showed significant areas of error so they decided not to go ahead with the engineering work... Neat and inexpensive solution.
I don't concern myself with the relative magnitude of spurious vibration pickups inevitable in my record players. Experiments when I did work in the business showed that eliminating all of them was not possible anyway.
I rejoice in the ability to tune the sound of record players to taste, if that is what one likes, which isn't feasible with CD. If one doesn't want the faff LPs are no longer the only low cost music carriers they were when I started buying recorded music in the mid 1960s so there is another choice.
Mostly I listen to CDs but still enjoy my old LPs whenever I feel like listening to them. I probably won't ever buy a new one again unless part of a set with compelling artwork like a Laura Marling set I bought.

OK so we don't really know, it hasn't been measured and it's nothing to worry about. Fair enough, What Laura Marling set did you buy? I'm a big fan of hers. Seen her live many times.

 

[Analog Scott]

I have an answer but I won't waste my time.

When you start justifying your own opinions with substantial support, then you can expect the same from others.

Technical ignorance may lead you to think your reactive questions can be answered quickly in a few lines. Get past it!!

And yet you have already wasted your time with four posts on this subject. Why stop wasting your time now?

 

[Wombat]

And yet you have already wasted your time with four posts on this subject. Why stop wasting your time now?

I don't consider countering your typical response to be a waste of time. Work on your credibility. Next question, please.

 

[Frank Dernie]

OK so we don't really know, it hasn't been measured and it's nothing to worry about. Fair enough, What Laura Marling set did you buy? I'm a big fan of hers. Seen her live many times.

"The Beast was a creature I did not know". I have several of her CDs
Spurious vibration pickup in record players is not worth worrying about because it is inevitable.