Pete's Humble Pi - For Ceramic Cartridges

Pete’s Humble PI is an attenuator for use with ceramic turntable cartridges that may have some degree of built-in mechanical equalization. As you can see, it uses Pete's PI resistor network. If you want to connect a ceramic/piezo cartridge to a standard RIAA preamplifier, then this attenuator will do the job well. It is just something I designed and knocked up over the weekend to test the cheap ceramic cartridge I recently bought. The humble pie was of course food for the poor, and you cannot get any poorer than me, so if you are on a shoestring budget like me, then this is something you can make yourself at home.

As you can see, I placed 47-kΩ metal-film resistors at the input and output ends for impedance correction. The 1-MΩ resistor in the signal path provides the necessary signal attenuation. Connect the ceramic/piezo cartridge at one end, and the other end goes to your amplifier turntable phono input. The circuit diagram shows only one channel, hence you will have to build two for stereo. I was very pleased with this and it sounds surprisingly good. It certainly made me a convert to ceramic cartridges and I decided to get some more in case the price increases!

As you can see, the circuit is something you can knock-up on a weekend within a couple of minutes. All you need are a pair of phono sockets and plugs, four 47-kΩ resistors, and two 1-MΩ resistors. In addition, you will need a small piece of strip-board to mount the components. These are all the things most hobbyists and hi-fi enthusiasts usually have.

I do not have access to a Chinese factory or facilities in the UK to manufacture this, I am just a poor Brit publisher, however if you make these, I am sure you could sell millions with the ceramic cartridge. You can also call it Pete’s Humble PI, providing you send me a link!

This Article Continues...