EPC-450C-II distortion

QuadraphonicQuad

Help Support QuadraphonicQuad:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Quadromaniac

New member
Joined
Apr 1, 2019
Messages
6
Location
Bosnia
Hello everyone this is my first post so here is a little intro. I got interested in quadraphonic and surround sound, about a year and a half ago, when I found out how many albums had been released in quad in the seventies and later in 5.1. So I made an improvised quad setup and listened to some transfers I found, only to be blown away by the discrete mixes. As someone who plays an instrument I always wanted to hear in better detail every part of a song, and now I could. Later I had a chance to listen to some albums in 5.1 recording studio which was incredible. At the same time I especially got interested in CD-4, I mean the way that stereo records work is amazing, but CD-4 is a whole other world of magic. There is something so interesting about listening to four discrete channels from a record that are obtained by demodulating the difference in real time in front of you. The technology really fascinated me and I read as much as I could find about it. Anyway I only had an AT-95E cart but as I saw a video of CD-4 working with it I decided to buy some quadradiscs to listen in stereo (which I enjoyed) and demodulate in SDR# and Audacity with nyquist prompt for fun, as I look for a Panasonic SE-405H and a strain gauge cartridge, preferably the EPC-450C-II because of the lower tracking force. It took me a year to find these at a reasonable price online, that would ship to my country and I finally got it in my hands couple a days ago.

And now we reach the problem. The seller that sold me the EPC-450C-II thought it was new, however as you can see from the photos of the cartridge that I posted the cantilever is not straight and goes to the side and seems rotated a bit, also the plastic around it was dirty and there was dust on the elements. So I put the cart on my headshell without the weight (because I don't have one) and when I zeroed it, the tonearm weight on my Technics SL-Q3 maxed out at about 2.1 grams. I then hooked it up and tried it on a Keith Jarrett stereo record to check how it sounds and it sounded fine, so I thought the needle was in good shape. Then I tried Carly Simon - No Secrets quadradisc and it sounded really good with some distortion here and there, but the innermost track on the first side sounded pretty good in quad. I also noticed that the right channel was a bit louder than the left. So as I played around with it I tried it on my Dreamboat Annie record and I could hear distortion in the right channel and when I checked the recording of my AT-95E on the same part there was no distortion. Then I changed the inputs into the demodulator to rule it out and the noise changed to the left, pointing all fingers to the cartridge. I removed the stylus and cleaned off the dust from the elements with a brush (the right side was especially dusty) and gently nudged the cantilever to see if it would change it's position but it just returned back to it's resting place. When I hooked it up again and tried the same part of the record, this time the same distortion shifted to the left channel and increased. I also tried the Keith Jarrett album again and it also had distortion where there was none the day before. It's a good thing I recorded the day before to have something to compare to. Now the funny thing is I can't hear any similar distortion when playing quadradiscs in stereo, they sound very good as you can hear from the samples of Aqualung and No Secrets. So I thought if it was a bad stylus it couldn't trace the ultrasonic frequencies so well or play fine one day and distort the next than shift distortion from one channel to the other. It could be that the stylus is not making good enough contact with the elements but I'm not sure why it would sound good on quadradiscs, maybe because of the lower recording level?

I also measured the resistance of the cartridge and it is higher than 1000 ohms that it should be. It is 1382 ohms for the left channel and 1326 ohms for the right, also the bias current from the demodulator is higher than 4mA, it is 5.5mA and 19.73V for both channels.

So I wanted to ask anyone that has used these cartridges, have you ever experienced something like this, should these measurements be a concern and is there any way to straighten that cantilever?

I uploaded the files I recorded on google drive and I would appreciate any help, after all this money and time spent searching it would be such a disappointment to find out it is damaged.

Thanks for reading and sorry for such a long post.

Neven

1.png2.png3.png4.png
 
I have two EPC-450C II cartridges, one with a used stylus with unknown hours/wear on it and one brand new I bought to get the new stylus. The used one has the same problems with tracking as you have. It plays two channel and CD-4 records fine as long as you have the demodulator set to two channel mode but distorts in CD-4 mode, especially in the inner grooves where it is more difficult for the stylus to trace the ultra sonic frequencies.

Your cartridge was not new if there was dust and dirt along the bottom. A new cartridge will, of course, be free of that and will be absolutely clean. In addition, your stylus is cocked a bit and you said possibly rotated which I take to mean the diamond not straight up and down to the record surface.

Your cartridge, itself, is probably OK and your problems are almost certainly due to the stylus. CD-4 requires pretty much perfection with the stylus being unworn or with very low wear. You may be able to coax the stylus back straight by supporting it right behind the bend and pressing carefully on the tip to bend it back. A bit tricky but I have done it several times with different styli. If it's also twisted, it may be beyond help but I have fixed that before also with a tweezers on the flattened part of the cantilever where the diamond is mounted.

Of course, you then still have the possibility that the stylus is worn beyond use for CD-4. You wouldn't know that, of course, until after you get it straightened.

Anti-skate is also critical to stop distortion in both channels. The pressure on each groove wall must be equal. You also want to super clean the diamond with high strength alcohol and stiff brush to be sure all traces of contaminants are gone. And, don't be afraid to track it at maximum VTF - 2.5 grams. You won't hurt anything. I would try to find a weight to add between the cartridge and headshell too.

My NOS EPC-450C-II tracks everything flawlessly, even worn CD-4 records.

Doug
 
Thank you Doug for the advice I'll try cleaning it with alcohol, I have a bottle of 96% ethyl alcohol that should work well I suppose. Have you ever cleaned the elements underneath and do you think it would be safe to use alcohol on them?

I am just confused how my Keith Jarrett stereo record suddenly started distorting the next day, but as you said it must be some fault of the stylus.

I will definitely get a weight for it and I'll be on a lookout for some NOS styli or at least a non genuine shibata replacement as I've seen they go for less, but I read are not as good performers as the original ones.

MOD EDIT NOTE: No links to Copyright material.
 
http://www.phaedrus-audio.com/protractor.htm^^^
The Phædrus Audio Phono-cartridge alignment protractor
is available free from Phaedrus Audio.


Phono-cartridge alignment is critical with CD-4.

In my situation, I use(d) a Shure V-15 type 3 w/MicroRidge stylus
and a Technics SH-400 demod, after aligning with what is called
the 58 mm inner radius option, CD-4 worked OK even though
the Shure isn't a CD-4 cartridge.


Kirk Bayne
 
Last edited:
Thank you Doug for the advice I'll try cleaning it with alcohol, I have a bottle of 96% ethyl alcohol that should work well I suppose. Have you ever cleaned the elements underneath and do you think it would be safe to use alcohol on them?

I am just confused how my Keith Jarrett stereo record suddenly started distorting the next day, but as you said it must be some fault of the stylus.

I will definitely get a weight for it and I'll be on a lookout for some NOS styli or at least a non genuine shibata replacement as I've seen they go for less, but I read are not as good performers as the original ones.

MOD EDIT NOTE: No links to Copyright material.

I wouldn't use alcohol in an attempt to clean the elements or cartridge itself. Just use a brush to get any debris off the elements and from between them until it is clean.

A stylus for the EPC-451C cartridge will also work with the EPC-450C-II but both are very difficult to find these days. As I said, I bought a whole cartridge just to get the new stylus. It was worth it however.

I also have an aftermarket stylus for an EPC-451C and it performs about the same as my worn EPC-450C-II stylus, fine on the outer groove but starts mistracing on the inner tracks. It's not new, however, and may be worn also. I guess if the price was reasonable, I might try an aftermarket stylus that is new, from a reputable supplier, of course.

Good luck.

Doug
 
Ok thanks Doug, I'll just clean them with a brush. Unfortunately it seems the moderator removed my links because of copyright, although they are just a one minute sample each.

Thank you Kirk for commenting, if I solve the problem with a good clean and maybe with some luck straighten that cantaliver, I'll give it a shot.

Neven
 
The price has gone up to $60 US but still worthwhile for a Pfanstiehl copy. I track mine at 3 grams with no distortion or groove damage. 672DQ

As to distortion, I have 2 450CII cartridges and a 450C4. One of my 450CII's distorts but when I move the stylus to the other cartridge it is fine. I suspect the point where the stylus meets the elements is worn or slightly out of position. It seems to work okay with the stereo conical stylus though.
 
Thanks for the information! I was just never sure about buying an aftermarket stylus for them because I once bought an aftermarket for a 4000 D/III and it didn't work at all. I think the one I have was probably good when new because, as I said, it works fine in the outer grooves and only distorts in the inner tracks which is the sign of wear with CD-4.

Yeah, 60 bucks isn't too bad, especially if they work.

Do you know what the difference is between the 450C II and 450C 4?

Doug
 
The price has gone up to $60 US but still worthwhile for a Pfanstiehl copy. I track mine at 3 grams with no distortion or groove damage. 672DQ

As to distortion, I have 2 450CII cartridges and a 450C4. One of my 450CII's distorts but when I move the stylus to the other cartridge it is fine. I suspect the point where the stylus meets the elements is worn or slightly out of position. It seems to work okay with the stereo conical stylus though.

Thank you so much for the link, $60 for a new one doesn't seem bad at all!

Yes it is probably not making good contact with the elements, when I clean them I'll gently move the stylus and see if that changes anything. Also it could be that a higher tracking force would also help the stylus in making a better contact.
 
Unfortunately I don't have any documentation for the 450C4. It c.ame from a Japanese auction attached to a broken arm. It seems some scrappers know the value of these carts even though they were frequently sold in 2 and 4 channel crumpack systems. When I do see them they are often still mounted on arms brutally ripped from crumpacks or just the headshell and cart still attached withh arm wires hanging off.
 
OK, I don't think any of us know the difference between the different 450C-451C series variations and they must be pretty minor since the styli are interchangeable. It seems my 451C has a bit different sound from my 450C II but it's nothing really definitive.

Doug
 
Back
Top