Quadromaniac
New member
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
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