May 2, 2021 at 6:33 pm #16678Doug ParkerCVRS Member
Using a Ronette Crystal Stereo 208 phono cartridge on a BSR UA14 turntable in a Viking ECC-417z 48-74 radio-phono combination. This is a transplanted turntable that was in the unit when I purchased it.
I have to turn up the volume control near maximum to hear the record and it has absolutely no bass response to the sound, just treble, i.e. it sounds horrible. The chassis was built for a mono cartridge. I have wired the two channels of the stereo cartridge in series and also in parallel and there is no notable difference in the output of the cartridge. I do not have any other cartridge to substitute. I looked on the world wide wonder and found one site said the Ronette 208 had a 2.0 Volt output. Any suggestions would be appreciated.
Attachments:May 3, 2021 at 6:18 am #16680Alistair ThomsonForum Participant
Sounds like either an impedance mismatch or a phasing issue. The ceramic cartridge requires very high input impedance and that is normally deigned in to the amplifier, but if the amp was deigned for a magnetic cartridge, you’d get these symptoms. But that’s unlikely since most record players in the 50s were ceramic.
So it may be phasing. You can check by only using one of the two cartridge channels, leaving the other one disconnected. If that sounds OK, connect the other one in parallel (not series) and if the sound dies reverse the connections in that second channel. Remember also that one of the connections to the cartridge has bias volts on it and that has to go to the correct pin in each channel.May 3, 2021 at 4:33 pm #16684John GreenlandCVRS Member
I am not sure where the info for the model 208 cartridge comes from but what I found only lists the output at 750 millivolts.
I agree with Allistair to try one channel at a time to see what happens. According to the schematic for a Viking 48-74 the cartridge feeds into a series 1 meg resistor.
You may want to check it for value. It forms a divider with a 270 K which should be checked as well.
R27 and R28 on the schematic I am looking at.
Regards John G. VO1 CATMay 5, 2021 at 8:49 am #16700Doug ParkerCVRS Member
Thanks Alistair and John. All resistors in the chassis where checked and verified and if they were out of tolerance they were replaced. I will give your suggestions a try and see if it passes the smoke test.
- You must be logged in to reply to this topic.