01-26-2026, 03:57 PM
Hi Marsupial,
The turntable that you removed has a magnetic cartridge. Does the new turntable have a magnetic or ceramic cartridge?
Magnetic cartridges needed more amplification but generally had much less distortion than ceramic pickups and much, much less than crystal pickups.
I don't think that the transformer is the issue. This set has a "Phono Preamp" stage that is needed for magnetic pickups but would not be used for a crystal or ceramic pickup. You may be overdriving this preamp, as there is no volume control for it. The phono connects directly to this preamp stage. The output of the stage goes to the radio / phono switch.
You may want to eliminate this stage and connect a jack to the radio-phone switch phono circuit instead of the preamp. See the schematic below: If you had a magnetic cartridge (GE RPX, Shure M3D or M7D wired for mono, etc.), then you would use the preamp stage.
Check the turntable on another amp to verify that the cartridge is good. Is this a mono cartridge (2 leads)? If this is a stereo cartridge, make sure that you have it phased correctly. Reversing one channel will attenuate the output unless you were playing Edison records.
Attached below is a partial schematic that I marked up for clarity (or confusion):
The turntable that you removed has a magnetic cartridge. Does the new turntable have a magnetic or ceramic cartridge?
Magnetic cartridges needed more amplification but generally had much less distortion than ceramic pickups and much, much less than crystal pickups.
I don't think that the transformer is the issue. This set has a "Phono Preamp" stage that is needed for magnetic pickups but would not be used for a crystal or ceramic pickup. You may be overdriving this preamp, as there is no volume control for it. The phono connects directly to this preamp stage. The output of the stage goes to the radio / phono switch.
You may want to eliminate this stage and connect a jack to the radio-phone switch phono circuit instead of the preamp. See the schematic below: If you had a magnetic cartridge (GE RPX, Shure M3D or M7D wired for mono, etc.), then you would use the preamp stage.
Check the turntable on another amp to verify that the cartridge is good. Is this a mono cartridge (2 leads)? If this is a stereo cartridge, make sure that you have it phased correctly. Reversing one channel will attenuate the output unless you were playing Edison records.
Attached below is a partial schematic that I marked up for clarity (or confusion):
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
Best Regards,
MrFixr55
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