78 noise

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Bob Dillon
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Re: 78 noise

Post by Bob Dillon » 29 Aug 2019 00:56

I have a high output MC 78 cartridge. It's the Audio-Technica SP series 78 cart. It has a 2.5 mil stylus tip. I think that if the smaller stylus profile is suitable for the grooves on an acoustical 78, which is not always the case with acoutical records, I get reproduction with more lifelike 'body' than I do playing the records with my various MM carts, regardless of the EQ chosen. I wonder how the MC vs. MM debate stacks up in all this.

Coffee Phil
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Re: 78 noise

Post by Coffee Phil » 31 Aug 2019 19:01

Hi Bob,

I'm not sure I get the mm vs mc thing. I think current mm cartridges can have at least as low moving mass as mc cartridges. I wonder if the low output impedance making them less effected by load capacitance is the "big deal". I am however agnostic about the subject. One thing sure is having an arsenal of different size styli is less convenient with a moving magnet cartridge.

I have a 1/3 octave equalizer on the way. It was used and only cost me $40 plus shipping so I'm not risking much. Here is one like it:

https://www.ebay.com/p/Alesis-M-eq230-D ... 1907933686

It is ugly as sin but if it does good things with the acoustic records I'll find a way to keep it out of prominent view. If it doesn't do magic with the old records I can return it within 40 days so I'm just risking the shipping.

Phil
Bob Dillon wrote:
29 Aug 2019 00:56
I have a high output MC 78 cartridge. It's the Audio-Technica SP series 78 cart. It has a 2.5 mil stylus tip. I think that if the smaller stylus profile is suitable for the grooves on an acoustical 78, which is not always the case with acoutical records, I get reproduction with more lifelike 'body' than I do playing the records with my various MM carts, regardless of the EQ chosen. I wonder how the MC vs. MM debate stacks up in all this.

Bob Dillon
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Re: 78 noise

Post by Bob Dillon » 31 Aug 2019 19:57

Coffee Phil wrote:
31 Aug 2019 19:01
Hi Bob,

I'm not sure I get the mm vs mc thing. I think current mm cartridges can have at least as low moving mass as mc cartridges. I wonder if the low output impedance making them less effected by load capacitance is the "big deal". I am however agnostic about the subject. One thing sure is having an arsenal of different size styli is less convenient with a moving magnet cartridge.

With a removeable headshell, it's not that much more trouble to swap them out than it is to change styli on the carts themselves, and there is less risk of a 'butterfingers moment' damaging a delicate stylus assembly. For 78 rpm I have two dedicated Stanton carts, one Shure and one Audio-Technica on different headshells. Those are ready to go with my most used 78 styli, (the A-T MC of course has a non removeable stylus). Then I have one other 78 rpm stylus size for one of the Stantons, requiring swapping styli. Then I have a Nagaoka MP-110 on another headshell which I've also purchased Nagaoka 4.0 mil 78 rpm stylus for, which I use not that much, because it's a larger size. All in all I have ten cartridges mounted on seperate headshells for playing microgroove and wide groove records and a few carts can do double duty with a stylus swap. A turntable with a removeable headshell is a requirement for me.

Good luck with the EQ !

Coffee Phil
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Re: 78 noise

Post by Coffee Phil » 07 Sep 2019 08:45

The 1/3 Octave EQ arrived:

https://www.vinylengine.com/turntable_f ... 629/medium

It was a bit of effort to get it up and working. First off they sent a 9 volt DC wall wart. The unit calls for 9 volts AC. If the power just fed a bridge rectifier it would have worked. No joy. It turns out that power goes to two 1/2 wave voltage doublers feeding three terminal regulators to provide + and - 12 volts. I found a 9 VAC transformer but then had to reflow the solder around the power connector to bring it to life.

I then put it after my mono phono stage and tweaked it to EQ out the resonant peaks seen in the post above from the 1929 book. Playing with the EQ sliders I think it makes a noticeable improvement on a couple of acoustic records which I tried with it.

I think the unit is ugly as sin with the the huge brand and model number all over the front panel. As ugly as it is, I think it is a keeper as the difference with acoustic records makes it worth the bother.

Phil

PS: Bob, I agree with you on the detachable head-shells. I have real SME head shells for my Sonus Blue and Shure M44. I use knock-offs for other cartridges including an RPX triple play. I was not about to drill a hole in the top of a real SME head shell for the stylus change knob of the RPX.

Bob Dillon
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Re: 78 noise

Post by Bob Dillon » 09 Sep 2019 02:34

What were the settings used on the 1/3 octave EQ unit ? I might try to duplicate it with audio software to hear the result for myself. \:D/ Audacity has a 31 band EQ that are a close match at the frequency points.

It would also help to know if you were running the signal through your phono stage 'flat' or...

Coffee Phil
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Re: 78 noise

Post by Coffee Phil » 09 Sep 2019 05:52

Hi Bob,

I set my mono phono stage to 400 Hz bass turn and treble cut of 3180 Hz and followed it with the one channel of the EQ. The settings on the EQ were 200 Hz +2dB, 250 Hz + dB, 320 Hz + 4 dB, 400 Hz +2dB, 800 Hz +2dB, 1 kHz -4dB, 1.3 kHz -6dB, 1.6 kHz -6dB, 2 kHz -3dB, 2.5 kHz + 5dB, 3.1 kHz +9 dB, 4 kHz +8 dB, 5 kHz and above -12 dB.

I started with the phono stage as above and set the EQ to “tweak” out the ripple in the acoustic curve from the book, then tweaked to taste.

I called the folks I bought the EQ from and they are sending me the proper wall wart.

We are going on vacation, soon so more playing with this thing will have to wait. When we return I’ll have to arrange my system to make room for the EQ. I only envision using this with acoustic records so I may cascade the two channels and put it between my mono phono stage and the aux input of my preamp. I can then use one or both sections of the EQ. I expect that using both with the same frequency selected in each channel will make the bands sharper for what that may be worth. I also plan a passive switch around the EQ as I like my audio path as simple as possible.

Please do report on your results.

Phil
Bob Dillon wrote:
09 Sep 2019 02:34
What were the settings used on the 1/3 octave EQ unit ? I might try to duplicate it with audio software to hear the result for myself. \:D/ Audacity has a 31 band EQ that are a close match at the frequency points.

It would also help to know if you were running the signal through your phono stage 'flat' or...

Bob Dillon
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Re: 78 noise

Post by Bob Dillon » 09 Sep 2019 19:22

Coffee Phil wrote:
09 Sep 2019 05:52

I set my mono phono stage to 400 Hz bass turn and treble cut of 3180 Hz and followed it with the one channel of the EQ. The settings on the EQ were 200 Hz +2dB, 250 Hz + ? dB, 320 Hz + 4 dB, 400 Hz +2dB, 800 Hz +2dB, 1 kHz -4dB, 1.3 kHz -6dB, 1.6 kHz -6dB, 2 kHz -3dB, 2.5 kHz + 5dB, 3.1 kHz +9 dB, 4 kHz +8 dB, 5 kHz and above -12 dB.



So I duplicated the curve in Audacity (assuming + 2 db at 250 Hz) and the 3180 Hz treble cut. Did 500 Hz bass turnover because that's what my phono stage offers. Could have done 300 too, don't have 400 available.

Interesting result. It sounds pretty integral but can't help thinking that it still sounds a trifle dull for what I find pleasing. Will have to experiment more in the future with some different records.

Coffee Phil
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Re: 78 noise

Post by Coffee Phil » 09 Sep 2019 23:20

Hi Bob,

I don’t think 300, 400, or 500 Hz bass turn makes a huge difference on these records. There really is not much bass there. I started with the fairly politically incorrect “Go To Sleep My Dusky Baby” which is the lullaby setting of Dvorak’s Humoresque #7. Pre-1/3 octave EQ with out the sheet music I don’t think I could have understood the lyrics. Now after tweaking the lumps and bumps shown in the book:
https://www.vinylengine.com/turntable_f ... 488/medium

I think I could discern most of the lyrics. Still no-one would mistake this for a modern recording. There is really not much of value above 5 kHz so turning down all the sliders above 5 kHz keeps things more quiet.

I’m guessing that the curve from the old book is typical and even things in the near vicinity of the recording horn could alter the curve. I think for each record some tweaking will be required. I guess I’ll just write down what I settle on for each record and keep it with the record.

Phil

PS: Woops! I just looked at the EQ box. The 250 Hz setting is a bit over + 2 dB.

Bob Dillon
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Re: 78 noise

Post by Bob Dillon » 13 Sep 2019 19:14

I almost always like the slightly fuller sound that the 500 Hz turnover provides for the acoustically recorded records. It's not just bass, there is some of the important midrange there too. Acoustically recorded 78's are basically all midrange, with occasional shades of the outer edge of the bass range on some.

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