Playing Electrically Recorded Records with a Mica Reproducer

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audiophile102
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Playing Electrically Recorded Records with a Mica Reproducer

Post by audiophile102 »

I collect 78 rpm hot jazz records to play on my Sonora Invincible. The phonograph has a volume control which I use for playing electrically recorded records. I would someday like to purchase a orthophonic phonograph, but in the mean time I was curious if anyone has ever adapted an orthophonic reproducer to play on an acoustic machine? I realize that without the folded horn of an orthophonic machine, much would be lost. Would the adaptation of a orthophonic reproducer on my Sonora tone arm result in any improvement in octave range? Will my mica diaphragm suffer damage if I continue to play electrically recorded records?
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Re: Playing Electrically Recorded Records with a Mica Reprod

Post by OrthoFan »

The mica diaphragm, itself, should not be damaged by playing an electrically recorded record. (This assumes that the sound box has been overhauled with fresh, soft gaskets and properly adjusted.) I can't say what happens to the records, though...

Will fitting an Orthophonic style reproducer to an older style tonearm improve the sound quality? Based on my experience with a Victor VV-80, not by much. I remember it was louder than a #2 sound box, but that was about it--still no real mid-range and certainly no bass. This is because all of the Orthophonic components -- the sound box, the exponentially tapered tonearm and the horn -- were designed to work together as a system -- http://www.gracyk.com/credenza.shtml. With a pre-1925/26 model Sonora you have the added disadvantage of a poorly designed tonearm, with no real taper.

By the way, the folding of the Credenza's Orthophonic horn has nothing to do with the improvement in sound quality. That was a compromise, done in order to fit the requisite six foot horn into a cabinet small enough to fit in the average home. It was the horn's exponential taper, coupled with sound box, that mattered, as this explains:
Whats the best loudspeaker and why.pdf
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For most antique audiophiles, today, the Credenza seems to be the end goal, but even a relatively inexpensive, small Consolette -- http://www.victor-victrola.com/4-3.htm -- which was fitted with the non-folded (Western Electric-designed) exponential tone chamber, will vastly improve acoustic playback of electrically recorded discs. It pumps out a very solid mid-range, and even some bass, though not to the extent of the larger models. None of the YouTube videos I've seen really do it justice, but this one might give you an idea -- https://www.youtube.com/watch?v=XSKoVtW_hMA

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Re: Playing Electrically Recorded Records with a Mica Reprod

Post by larryh »

I find that although Mica diaphragms were used on portables designed well into the electrical era, they aren't able to handle the sound like a well restored Viva Tonal reproducer for instance. The mica seems to have a limit as to what volume and pitches it can handle without a harsh sound that the latter designs were able to over come. As to the small orthophonic machines, I was very surprised when I owned a Credenza and one of my neighbors had their parents smallest model orthophonic machine like the one described above. It did have a very pleasant sound, far better than one would have thought with a simple horn shape.

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Re: Playing Electrically Recorded Records with a Mica Reprod

Post by Menophanes »

In the recent past I have run an English table machine of about 1927 (H.M.V. 109) with both its original No. 4 (mica) and a No. 5B (aluminium). In terms of audible frequency-range there was very little difference that I could perceive, but I felt that the tone of the No. 4, when playing electrical recordings, had too much of an edge; it was certainly not bad and it would reproduce even post-war orchestral recordings cleanly, but it seemed to throw the sound at me instead of allowing this to emerge with its own natural force. (I realise that this is not scientific terminology; if the sound-quality could be analysed, it would probably be found that the older box was favouring frequencies in [at a guess] the 1000-3000KHz range, to the detriment of those lower down the scale.) The 5B seems better balanced overall; it still lacks some lower frequencies which are undoubtedly present in the recordings (this is clear from modern digitisations), but I suspect that this is inevitable given that (as OrthoFan has said) one really needs the re-entrant horn and wider tone-arm of the post-1929 system for the best results.

I now use a Meltrope III sound-box on a home-made gramophone with a fairly large, if crudely shaped, external horn - this for the sake of more overall volume, since the 109 is simply too quiet for certain records of renaissance and baroque music. This arrangement gives a slightly more penetrating tone than the 5B and I have had to put a piece of cotton-wool in the elbow of the horn to restore the balance. The weakness in the bass remains. Because of limitations of funds, space and physical strength, I have to compromise.

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Henry
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Re: Playing Electrically Recorded Records with a Mica Reprod

Post by Henry »

Menophanes wrote: if the sound-quality could be analysed, it would probably be found that the older box was favouring frequencies in [at a guess] the 1000-3000KHz range, to the detriment of those lower down the scale.) Oliver Mundy.
You mean 1000-3000Hz, not KHz. For reference, the lowest note on the piano, subcontra A, is 27.5Hz; the highest, five-line C, is 4186Hz (one Hz is is one cycle per second). My numbers assume a'= 440Hz

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Re: Playing Electrically Recorded Records with a Mica Reprod

Post by Cody K »

If playing electrically recorded records on an acoustic-era Victor machine, I find that switching out the Exhibition soundbox with an Orthophonic-era Thorens "Primaphonic", which uses the same mount as the Exhibition, betters the sound quality to a degree probably very similar to what an adapted Orthophonic could do on an acoustic machine.
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Re: Playing Electrically Recorded Records with a Mica Reprod

Post by Menophanes »

Henry wrote:You mean 1000-3000Hz, not KHz. For reference, the lowest note on the piano, subcontra A, is 27.5Hz; the highest, five-line C, is 4186Hz (one Hz is is one cycle per second). My numbers assume a'= 440Hz
Thank you! I know there is an instance where the name of a scientific unit is popularly used with reference to a value a thousand times greater, so that people say 'x' when they actually mean 'kilo-x', and I thought the unit in question was the herz. Obviously not!

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Henry
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Re: Playing Electrically Recorded Records with a Mica Reprod

Post by Henry »

Menophanes wrote:
Henry wrote:You mean 1000-3000Hz, not KHz. For reference, the lowest note on the piano, subcontra A, is 27.5Hz; the highest, five-line C, is 4186Hz (one Hz is is one cycle per second). My numbers assume a'= 440Hz
Thank you! I know there is an instance where the name of a scientific unit is popularly used with reference to a value a thousand times greater, so that people say 'x' when they actually mean 'kilo-x', and I thought the unit in question was the herz. Obviously not!

Oliver Mundy.
Not to worry! Personally, I favor the old terminology whereby the rate of recurrence of sound vibrations ("cycles per second') is expressed as "cps," rather than Hz (with all due respect to Heinrich Hertz, https://www.britannica.com/biography/Heinrich-Hertz, whose work was concerned with electromagnetic waves, rather than with the audible spectrum.)

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PeterF
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Re: Playing Electrically Recorded Records with a Mica Reprod

Post by PeterF »

Good luck with plumbing up an orthophonic reproducer to your Sonora. Be sure to maintain tracking angles and all the other geometry to match the original.

On a Sonora such as yours, with the beautiful wooden tonearm, you have another issue specific to the machine. The orthophonic system works best when the entire air passage from diaphragm to horn opening is as airtight as possible. The Sonora tonearm pivot is quite leaky in that regard, due to patent restrictions, and you will thus lose quite a bit of efficiency and frequency response. You might try carefully experimenting with Vaseline (or some other thick grease) that allows free movement while creating and keeping a seal through the full range of the tonearm's motion.

Just be careful to not glop in on in a way that it mars the finish or shows - and if you live in a place where it gets hot enough to melt Vaseline, consider some automotive type grease that won't melt. You want to place it in a way that there is plenty enough to keep that seal through repeated cycles of the tonearm's swing.

As the market declines you may find that orthophonic machines pop up locally at good prices, and one of those would be far more preferable to the kludge we're discussing here. This is because the horn is also a big part of the system and will make a big difference in the overall sound. Haunt craigslist and search on "Victrola" and "phonograph" and "record player" and even "turntable" and you may be pleasantly surprised.

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