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Phono Stage For 78s?

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Phono Stage For 78s?

Postby Brick » 25 Sep 2011 22:09

I've got a few boxes of 78 I'd like to listen to and digitize. I'll be buying a Shure 78 cartridge soon for my Dual 1019, and want to know if I should look into a dedicated phono stage with more equalization options as well.
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Re: Phono Stage For 78s?

Postby Coffee Phil » 28 Sep 2011 21:59

Brick wrote:I've got a few boxes of 78 I'd like to listen to and digitize. I'll be buying a Shure 78 cartridge soon for my Dual 1019, and want to know if I should look into a dedicated phono stage with more equalization options as well.


Sorry it took so long to reply. I have been through two identy changes since you posted and now I am back in for now.

I use a Shure M44C with an N44-3 stylus for 78s. It is a stereo cartridge which I sum to mono. I'm pretty happy with it. I don't think the dedicated 78 cartridge which Shure has been selling recently has gotten much love in the 78 community so you may want to check reviews. I am not sure if it is a "real" mono cartridge or a stereo cartridge strapped to mono.

Now to your question.
If your interest is primarly in late 78s (late 1930s and newer) I would say you can get by with your standard RIAA preamp. While these records may not be RIAA EQ'ed they do have have equalization which was applied for pretty much the same reasons. The curves will not match RIAA but they won't be so vastly different that the records won't sound good.

If on the other hand you want to play records going back to the early electrical recordings and acustic recordings you will be happier with a preamp which can accommodate the various turnover and roll off frequiencies.

I built a mono preamp which sums the two channels in phase for lateral records (78s and Lps) or out of phase for vertical records (Edison, Pathe, and others). It also offers six turnover frequencies and seven roll off frequencies as well as flat gain.

I can give you a schematic for you to build for your own use.

I linked some photos and a description of my preamp. http://db.audioasylum.com/mhtml/m.html?forum=vinyl&n=916343&highlight=preamp+coffee-phil&search_url=%2Fdefault.mpl%3Fsearchtext%3Dpreamp%26b%3DAND%26topic%3D%26topics_only%3DN%26author%3Dcoffee-phil%26date1%3D%26date2%3D%26slowmessage%3D%26sort%3Dscore%26sortOrder%3DDESC%26forum%3Dvinyl

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Re: Phono Stage For 78s?

Postby Brick » 29 Sep 2011 05:57

That unit looks awesome! If you are willing to share the schematic it would make a great winter project.

Most of the 78's I have are from the 20's and 30's. I have some Edison disks as well, but don't know the first thing about what it takes to play those. I was planning to purchase the M78S, but will look for reviews, thanks for the tip. Right now the only 78 stylus I have is for a USB table I started digitising with before I started taking it more seriously.
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Re: Phono Stage For 78s?

Postby Coffee Phil » 29 Sep 2011 07:43

Brick wrote:That unit looks awesome! If you are willing to share the schematic it would make a great winter project.

Most of the 78's I have are from the 20's and 30's. I have some Edison disks as well, but don't know the first thing about what it takes to play those. I was planning to purchase the M78S, but will look for reviews, thanks for the tip. Right now the only 78 stylus I have is for a USB table I started digitising with before I started taking it more seriously.


Hi Brick,

A 2.5 stylus works for the Edison diamond discs. They spin at 80 RPM and are vertically recorded. Theoretically I believe they should play back flat but I use about a 300 Hz bass turnover to enhance the base and as much treble cut as required to make the noise acceptable. A stereo cartridge is needed to play these. I think the M78S is sold as a mono cartridge but I have to believe it is a stereo body with the channels strapped together. I don't know if the short is external and can be removed or not. Hopefully someone with experience with it will chime in. If you are really getting into this, there is a Pickering which may be a better choice as there are a plethoria of styli available for it. Different vintages of 78s take different styli for optimum results. You are stepping onto a slippery slope.

I will attach the schematic of my Legacy Preamp. It so far is not production friendly in that for the eq I first chose the resistors then calculated the cap values with no regard of their availability. I made them up by measuring caps which I bought at surplus stores and parralleling them to make up the calculated values. I did use decient film caps and COG ceramic to makeup the values.

I would be happy if you built one of these for youself and let me know how you like it. Of course if you are going to make this production ready and sell them we should talk.

The schemo is hand drawn and scaned (I still need to develop CAD skills) so some of it may be unclear. Do ask if you have questions.

I have no idea what happened to crop this image. Maybe JaS can fix it. The uncroped image is in the DIY section of the Gallery.

Phil

[img]18919[/img]
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Re: Phono Stage For 78s?

Postby JaS » 29 Sep 2011 08:39

Images posted in the forum are cropped to stop them breaking the layout. You can view the full size image by clicking on the image once to see the gallery page, then again to see the original version if it's still not big enough (I haven't checked this with a normal user account).

Regards,
JaS

PS IMG tags are only needed for externally hosted images, ALBUM tags are used for galley images
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Re: Phono Stage For 78s?

Postby Brick » 29 Sep 2011 14:32

Thanks Phil. No worries about me going into production, I already have one unprofitable business on my hands, lol.

What model is the Pickering? I have had great experience with their carts on other tables and am kind of partial to them.
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Re: Phono Stage For 78s?

Postby Coffee Phil » 29 Sep 2011 17:56

Brick wrote:Thanks Phil. No worries about me going into production, I already have one unprofitable business on my hands, lol.

What model is the Pickering? I have had great experience with their carts on other tables and am kind of partial to them.


Hi Brick,

I screwed up. The cartridge is a Stanton 500 AL. I think Stanton and Pickering are somehow related. The big deal about that cartridge is that an outfit named Expert Stylus makes a whole array of vintage record Styli for them.

I am linking a site with a whole lot of vintage record info including contact info for Expert Stylus.

Phil

[url]
http://www.videointerchange.com/vintage_78s.htm
[url][/url][/url]
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Re: Phono Stage For 78s?

Postby J. S. Bach » 01 Oct 2011 18:26

JaS wrote:Images posted in the forum are cropped to stop them breaking the layout. You can view the full size image by clicking on the image once to see the gallery page, then again to see the original version if it's still not big enough (I haven't checked this with a normal user account).

Regards,
JaS

PS IMG tags are only needed for externally hosted images, ALBUM tags are used for galley images


It does work with my account, which I suspect is a normal user account.
Later gator,
Dave

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Re: Phono Stage For 78s?

Postby sanfranphono » 04 Oct 2011 20:03

Also - if I may chime in:

The Stanton 500 is the de facto standard of professional 78 rpm transcribers, Ed Saunders just made new 3 mil 78 rpm styli in the original Stanton suspension that to my ears sound much quieter than the usual 2.8 mil stylus. I can only recommend this combo.

And a warning for non-stanton users: 78s should be played at 4 - 5 grams. It is advisable to put an additional weight on the 78 headshell (a penny or two do just fine). Many of the more sophisticated cartridges can't take the additional weight.

The reason is that 78s are often eccentric or slightly warped. At 78 rpm a 2 gr stylus may not be able to track the irregularities of the record.
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Re: Phono Stage For 78s?

Postby Whitneyville » 05 Oct 2011 04:18

I've been using an elderly Pickering VX-15 with a 3 mil conical with excellent results, but my Dual 1226 only plays at 33 and 45 so I'm "fixing" that with Audasity in "post", or using my beast of a transcription TT with an Astatic playback/cutterhead when it's not sweltering or freezing in my garage where it has to live. The Stanton 500 does have a set of 6 stylii available for different "cuts" and wear stages on 78's, and as far as I know, it's the only cartridge that does. The "specs" say VTF 2-5 grams, but 5 grams is a better point to aim for.
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Re: Phono Stage For 78s?

Postby Phoca » 19 Dec 2011 03:29

There are some worthwhile kits out there too. Elliot Sound Labs has a board for sale which he provides info about converting to a multi-eq 78 stage, here (http://sound.westhost.com/project91.htm). Also there's the Hagtech Bugle, a stereo RIAA which can be split to provide two mono 78 eq options (something I will eventually do with my Bugle). Their forum has info about converting. Hagtech also offers the Cornet which can be modified for 78s with help from this article by Jim Hagerman (http://www.hagtech.com/pdf/monogram.pdf).

No connection to either company other than my owning a Bugle, which is a pretty dang good RIAA on the cheap.
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Re: Phono Stage For 78s?

Postby Coffee Phil » 19 Dec 2011 04:29

I don't want to sound too much like I'm braging on my circuit but it has some features which the Elliot lacks.

The Elliot has a mono input vs. a stereo input in mine which is summed in phase for lateral records or out of phase for verticals. With The Elliot you have to do that in the wiring before the preamp or have a mono cartridge.

In the Elliot part of the EQ is at the output and therefore can conceivably be effected be the load. In my circuit the EQ is buffered by the output amp which has a very low output impedance.

I do not however have a board so the effort to build mine will be greater.

Phil


Phoca wrote:There are some worthwhile kits out there too. Elliot Sound Labs has a board for sale which he provides info about converting to a multi-eq 78 stage, here (http://sound.westhost.com/project91.htm). Also there's the Hagtech Bugle, a stereo RIAA which can be split to provide two mono 78 eq options (something I will eventually do with my Bugle). Their forum has info about converting. Hagtech also offers the Cornet which can be modified for 78s with help from this article by Jim Hagerman (http://www.hagtech.com/pdf/monogram.pdf).

No connection to either company other than my owning a Bugle, which is a pretty dang good RIAA on the cheap.
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