You should come here and ask a maker, what he wants to do this.
Labour rate for mechanics is apx. 90 CHF plus machining cost plus raw material plus 5 bucks for a box to put it in.
My car mechanic guy actually costs 215.- CHF /h plus 8 % VAT.
The LT1364 (and its near family members) is really an exceptional IC op amp. My former CTC business partner auditioned it more than 10 years ago, and found it much better than standard IC op amps. It was used awhile ago by several audiophiles who knew Bob Crump. I would never have found it, normally. It is subjectively one of the better IC's ever made for audio circuitry. The circuitry is elegant, the open loop bandwidth is outstanding, AND they are not trying to starve it to death, current wise.
Of course, the AD797 would be better for measuring equipment due to its static linearity, but the AD1364 is better than most for audio circuitry. I might compare it to the AD825 subjectively, if I needed an IC for general line level operation. I haven't compared the two, but they would be my leading contenders. I do use the OPA2134 in the JC-3 phono second stage and it works fairly well, BUT I have a 2KHz, 6db per octave passive filter in front of it, so it gets a fairly slow audio signal, which seems to help it along, so that any compromises are not very obvious. Otherwise, I would not necessarily use it.
Of course, the AD797 would be better for measuring equipment due to its static linearity, but the AD1364 is better than most for audio circuitry. I might compare it to the AD825 subjectively, if I needed an IC for general line level operation. I haven't compared the two, but they would be my leading contenders. I do use the OPA2134 in the JC-3 phono second stage and it works fairly well, BUT I have a 2KHz, 6db per octave passive filter in front of it, so it gets a fairly slow audio signal, which seems to help it along, so that any compromises are not very obvious. Otherwise, I would not necessarily use it.
Morinix thanks for you answer ,
but IMHO that round chunk of aluminium real price is max 5$ even if is produced in US ,
and one more question to you ,
by adding that extra 375gram weight on the top of turntable life expectation of main axial bearing will be
-unaffected?
-shortened?
-extented?
Depends what you compare it with. My countryman above is aware of local prices, and I paid for my all aluminum, 385 gram, finely machined, all of 2,100 dinars (app. USD 3, rounded off). So, from our perspective, $45 is crazy, man.
On the other hand, having been in manufactuting myself for 12 years, I perfectly understand and support morninix' math and pricing. That's a text book example of forming a sales price, only the cirumstances and the environment are such that it's on higher level.
This is a very typical discussion between a manufacturer and a DIYer, with very typical questions and answers. Not to worry.
I don't see what's so exceptional in it. It has a huge slew rate that can't be leveraged for audio anyway, and everything else is mediocre. The noise is 10X the 797, for example. Linearity/distortion so-so. Almost all specs are below the $ 0.50 5532.
Jan
Not clear that JC sees what's exceptional. He may hear something exceptional.
If so, it could be that in cases when it does produce a small amount of audible distortion, the distortion sounds less objectionable than some other op-amps with better specifications.
EDIT: Wonder if there could be something like sighted-listening without listening? A different view on same phenomenon, or something else? (Must be too early in the morning, don't know why else this type of thinking.)
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One might wonder why we have never gotten there. Bear's going to try ,we'll see. Every, truly blind and by any protocol test has been backed out of or faded away unfulfilled.
Lots of those around. I love the cap load drive crossover distortion enhancer (Rc,Cc) it shows up on the data sheet BTW and I can see that maybe it could get audible with a bad enough load.
BTW This "feature" was fixed in later parts IIRC as drawn Cc injects load dependent distortion directly into the gain node.
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Understood. One thing I have noticed is that when small distortion is audible, often it is complex, hard to describe in words for people who haven't heard it (like describing "yellow" to someone who is color blind for that -- we only learn what the word refers to when someone says it and point to a bus or a banana), and not particularly memorable.
In the later sense, suppose somebody gave a test subject a funny little barely detectable electric shock that was pulsating and vibrating in some little way, maybe prickly, tingling, itching, and whatever else a little at the same time in some odd way, how long and how well can someone be expected to remember the exact sensation in order to be able to reliably discern it from a similar experience later. I don't know, myself. Easy to imagine cases where it would be hard, though.
For an example of not being able to remember even a powerful experience, people can remember they were once in so much pain they could barely walk to the bathroom, but they can't re-experience the pain itself from memory, all that's left is a memory that pain occurred.
My thoughts on this remain about as I have expressed before. If I can hear something, but found that I failed an ABX test for it, then I would be in the position of having to work on trying to devise an experiment to demonstrate there was some real effect.
Beyond that, in reference to the Tambourine test, I find myself wondering about two things, (1) is -70db THN+N, or even a little better, from a DAC/headphone-amp good enough playback performance to sufficiently discern dither for most people, or for anyone? How much does the particular traducer used matter? At some point the dither and quantization noise could get buried under other distortion, right?
And, (2) for people that don't hear dither that most mastering engineers do claim to hear, how much might coaching on a very high resolution playback system help develop the ability?
Returning to opamps, if mastering engineers can hear dither in the lower bits of 16-bit audio, an opamp producing a similar level of distortion might reasonably be expected to be audible as well, roughly speaking at least, and depending on the spectrum. If the distortion were some amount lower, or perhaps of a less objectionable type, then it would make more sense if it were inaudible to everyone.
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This came up in one of the interviews with Bob Ludwig, he stated that visitors sitting down cold and listening even through his personal mastering system don't hear the differences reliably at first. My problem here is that first and foremost this stuff is subtle at best and yes you can listen long term and with training maybe hear differences. But now you are concentrating on simply difference i.e. where does a personal judgement of where the differences stop affecting preference figure in?
Op-amps that produce ppm levels of distortion by ANY measurement in the audio range are readily available. The "we can hear it and you can't measure it" will not go away. This is a red herring as I stated re the LT op-amp, it actually makes distortion so all I can conclude is folks want an effects generator.
Frequency dependent compression a.k.a. Tales from an Obsolete Universe...
OK, another boring story from an old fart...Years ago (in a galaxy far far away...) I was the Dir. of Engineering for the AMI Cassette replication facility. The biggest problem with the fidelity of cassettes in the mid-1980s was the 1/2" 3-3/4 ips master tape and the loop bin. For those who have never seen it, the loop bin was a monstrosity which took the 1/2" 4-track tape recorded at 3-3/4 or 7-1/2 ips and ran it by the play heads at 240 or 480 ips. It was the single largest source of fidelity loss with mass-produced cassettes and introduced high-frequency instability, rapid phase modulation, tape wear loss and noise. In 1990 we introduced the 16-bit digital bin to replace the tape bin and eliminate the associated issues. You will have to take my word for it when I say any artifacts of transferring to digital were inaudible compared to the disaster which was the loop bin master process!
The cassette tape saturation characteristics and recorder itself became the next limitation to high fidelity. Since we manufactured cassette loaders we had relationships with both TDK and Maxell, so I spoke with their engineers and we and we became the first high-speed replicator to use both Co doped Fe and Metal tape pancakes in a high-speed duplication facility.
What does this have to do with frequency dependent compression? Well, we sold our DAAD digital bins to many competitors but we were able to transfer as much as 3-6 dB more level on our tapes giving a blacker background than our competitors...how? A brainstorm I had which became our secret weapon was to model the frequency-dependent saturation characteristics of each tape, and then create an RC network with identical slopes to drive the detector inputs of broadband compressors. The fact that we compressed broadband eliminated any spectral shifts, and we were able to utilize all of the saturation characteristics of each tape type. It was transparent enough that Sheffield, Telarc, DMP and others did not ever suspect we were using any compression when we made cassettes for them. I assume with AMI gone it is safe for me to reveal this at this time...LOLOL
It was this technique in conjunction with precisely tweaked Dolby HX which allowed us to make cassettes at an 64:1 speed ratio which sounded better than those made in ANY cassette deck at real time, and we were Nak pro dealers and had 1000ZXLs as reference reproducers. There are many other reasons why recording at high-speed out of the shell can give quality superior to real-time decks, but that is another large subject.
Sorry for the long post, but I though the preliminaries were necessary for the (somewhat) related content...and yes, this is frequency dependent broadband compression which was not Scott's topic, but I thought it an interesting related topic.
Cheers and Happy New Year all! Keep up the creative bickering!
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
WXYC Chapel Hill, North Carolina - 89.3 FM
OK, another boring story from an old fart...Years ago (in a galaxy far far away...) I was the Dir. of Engineering for the AMI Cassette replication facility. The biggest problem with the fidelity of cassettes in the mid-1980s was the 1/2" 3-3/4 ips master tape and the loop bin. For those who have never seen it, the loop bin was a monstrosity which took the 1/2" 4-track tape recorded at 3-3/4 or 7-1/2 ips and ran it by the play heads at 240 or 480 ips. It was the single largest source of fidelity loss with mass-produced cassettes and introduced high-frequency instability, rapid phase modulation, tape wear loss and noise. In 1990 we introduced the 16-bit digital bin to replace the tape bin and eliminate the associated issues. You will have to take my word for it when I say any artifacts of transferring to digital were inaudible compared to the disaster which was the loop bin master process!
The cassette tape saturation characteristics and recorder itself became the next limitation to high fidelity. Since we manufactured cassette loaders we had relationships with both TDK and Maxell, so I spoke with their engineers and we and we became the first high-speed replicator to use both Co doped Fe and Metal tape pancakes in a high-speed duplication facility.
What does this have to do with frequency dependent compression? Well, we sold our DAAD digital bins to many competitors but we were able to transfer as much as 3-6 dB more level on our tapes giving a blacker background than our competitors...how? A brainstorm I had which became our secret weapon was to model the frequency-dependent saturation characteristics of each tape, and then create an RC network with identical slopes to drive the detector inputs of broadband compressors. The fact that we compressed broadband eliminated any spectral shifts, and we were able to utilize all of the saturation characteristics of each tape type. It was transparent enough that Sheffield, Telarc, DMP and others did not ever suspect we were using any compression when we made cassettes for them. I assume with AMI gone it is safe for me to reveal this at this time...LOLOL
It was this technique in conjunction with precisely tweaked Dolby HX which allowed us to make cassettes at an 64:1 speed ratio which sounded better than those made in ANY cassette deck at real time, and we were Nak pro dealers and had 1000ZXLs as reference reproducers. There are many other reasons why recording at high-speed out of the shell can give quality superior to real-time decks, but that is another large subject.
Sorry for the long post, but I though the preliminaries were necessary for the (somewhat) related content...and yes, this is frequency dependent broadband compression which was not Scott's topic, but I thought it an interesting related topic.
Cheers and Happy New Year all! Keep up the creative bickering!
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
WXYC Chapel Hill, North Carolina - 89.3 FM
Or once harmonic distortion is below a certain level it is no longer perceptible, but there may be some other issue that still is perceptible. Maybe only to a few, under particular circumstances, I.E. a low noise floor and a system that either is clean enough in other details or perhaps one that exaggerates the issue.
Howie,
One of the local universities used to record the master degree performances on cassettes. I sold them a tweaked high speed duplicator after they tested it.
The fellow doing the recording gave the original and a duplicate to the faculty member in charge. He returned the original saying he was impressed with how good the copy was but that he could tell the difference and so he would keep the one he thought was the original... (A bit too much HF boost on the copy.)
ES
One of the local universities used to record the master degree performances on cassettes. I sold them a tweaked high speed duplicator after they tested it.
The fellow doing the recording gave the original and a duplicate to the faculty member in charge. He returned the original saying he was impressed with how good the copy was but that he could tell the difference and so he would keep the one he thought was the original... (A bit too much HF boost on the copy.)
ES
For people who do hear it, the problem I think is that it might be classified as a noxious stimulus, as are things like mild electric shocks, fart spray, etc. In other words, the sound is objectionable out of proportion to its loudness.
As an somewhat related aside, I have mostly gotten used to listening to music or video soundtracks on my cell phone when that's all that is available. Recently, while doing so I accidentally thought of the discussions we have been having here. Immediately, I noticed how horrible the cymbals sounded, and it was impossible to ignore them for awhile. Eventually, I was able to let go of it and just listen to the music again. Apparently, meditation and relaxation techniques may have practical benefits for cell phone audio, at least for me.
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