The "1931" transformer mentioned is the Lundahl LL1931:
http://www.lundahl.se/pdf/1931.pdf
Not from the year 1931 of course.
http://www.lundahl.se/pdf/1931.pdf
Not from the year 1931 of course.
OK, and (putting aside why anyone would care about 2 Hz distortion), what do you get at -100dBU, which is already considerably higher than worst-case for an MC cartridge? And how does this number compare to the modulated distortion in the audible range from the gross (1mm) stylus displacement?
You definitely need a set of Kopenhager hull-drafting templates
Anyone notice that this is also rather amusing ? (0.555 Hz)
Electrically at the levels sy gave, nothing.
I would be more concerned with the cantilever nonlinear modulus. The further off center the motion goes, the more the elastic is compressed. I would expect warp modulation of the resultant audio. (actually been there done that, some of the records I played in the disco were warped to about half an inch height off the platter, occasionally one was so warped it hit the cantilever, some of the 12 inch 45's the tonearm would lift off the record and were unplayable.
jn
Very nice, thank you.
What is missing is the relationship between two independent twisted wire pairs, such as line cords and balanced mike runs. If the twist pitch of one is an integer multiple of the other, near field coupling will occur. If the twist pitches are non integer related, there will be almost complete cancellation. This is how cat5e was designed. I used this to my advantage when I bundled a 125 foot line cord to a 125 foot balanced mike run AND a pair of 125 footunbalanced line out runs on one snake.
jn
The problem for me is that I have to make the best possible design, and even the 'best' transformers have real problems. In fact, there are sonic tradeoffs between metglas and mumetal, and metglas wins for the midrange and mumetal wins for the bass. That's why I quit trying. Well I guess I could use 2 transformers in parallel with a crossover above 100Hz to the metglas one. Kind of expensive, even for me.
This was exactly Scott's and my point- the transformer is the least of your worries.
I see, though, that John has now abandoned that particular handwave and moved on to another.
In any case, I hope that some good has come of this.
For me, it is the exercise of getting an approximate measurement or at least a good prediction of the transformer distortion that I am effectively removing from the phono stage. Of course, some people will never play old records, or even warped ones, but I can't count on that. I was assigned to make the best possible design, and trust me, it is a bit too expensive, even for me.
I'll trudge on with my single sided Vendetta phono stage, built into the CTC Blowtorch, probably for the rest of my life. The biggest change that I could make would be a better MC cartridge (I have it already) and maybe a better tone arm cable, but the one I have seems to be working OK.
For me, it is the exercise of getting an approximate measurement or at least a good prediction of the transformer distortion that I am effectively removing from the phono stage. Of course, some people will never play old records, or even warped ones, but I can't count on that. I was assigned to make the best possible design, and trust me, it is a bit too expensive, even for me.
I'll trudge on with my single sided Vendetta phono stage, built into the CTC Blowtorch, probably for the rest of my life. The biggest change that I could make would be a better MC cartridge (I have it already) and maybe a better tone arm cable, but the one I have seems to be working OK.
Which turned out to be negligible even for wildly awful cantilever displacements. Nice to have other people do your work for you, eh?
My engineers know to do basic analysis before they start throwing out pronouncements. All good engineers do that.
Mr John,
as it's evident that no-one takes me serious any longer, not even my dentist, can I adress my question to a fellow kitchen tile free-masonry'r ?
Keeping in-line with JD's tunnel-phobia : suppose a cable had dual screens (a bi-assed tunnel, so to speak).
Suppose one screen is in contact with Jan's scr chassis, and the 2nd tunnel has a thing for Pin-1 of the receiving chassis.
Suppose both tunnels had a pressure relief valve, situated at L/2 (not a straight wire link).
What would you expect for the corresponding rejection number ?
(I met a Texan oil guy once, who walked on two snakes and one shoelace, too fat to run)
http://www.ax84.com/static/rdh4/chapte17.pdf
has a nice bit about lateral recording and tracing. Those who can do the math can calculate what happens when you have a 1 CM bump and vertical signal components.
It might be useful to assume a worst case stereo cartridge misalignment of 5 degrees.
(Just for fun would anyone care to guess what 5 degrees does to the stereo signal?)
has a nice bit about lateral recording and tracing. Those who can do the math can calculate what happens when you have a 1 CM bump and vertical signal components.
It might be useful to assume a worst case stereo cartridge misalignment of 5 degrees.
(Just for fun would anyone care to guess what 5 degrees does to the stereo signal?)
Not without knowing cartridge vertical compliance and effective mass as well as the length of the warp (to estimate the forcing frequency).
Or you can actually look at a cartridge tracing a warp and see approximately how much the stylus/cantilever move. Crazy notion, I know. Of course, for a 1cm high warp of limited length, the stylus is likely to bounce right out of the groove.
Mr Curl,
think of yourself as the music director of an orchestra.
At the very least, you sure make 'm do physical exercise.
(pugh, even had me reach for a metal slide caliper biggy and a record)
I did BASIC MEASUREMENTS SY, before dropping the transformer input option. I kept an open mind, UNTIL I saw that I could not have 'everything' in one transformer, even at high cost. My employer, who sourced the transformers for me, was also glad that I dropped them. It seems I have kept my side happy.
For the record, while I got some very interesting and relatively complete measurements from the Jensen MC transformer data sheet, I got very poor info on distortion vs frequency from the transformers that I hoped would work. That is why I did the measurements, myself, and then confronted the transformer designer with the results.
For the record, while I got some very interesting and relatively complete measurements from the Jensen MC transformer data sheet, I got very poor info on distortion vs frequency from the transformers that I hoped would work. That is why I did the measurements, myself, and then confronted the transformer designer with the results.
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