Add Phono Input To Tube Amp
Aug 04, 2013 I was speaking with a dealer the other day and he recommended that I put a solid state phono stage into a tube amp to reduce the amount of noise to the amp. I am in the market to purchase a tube amp (from a different source) and had figured I'd pair it with a tube.
After its all put back together the only way anyone can tell anything has been done is by an almost invisible jack below the antenna. other than that one wire soldered onto the tube terminal this radio now had an AUX input that almost zero changes have been made to the radio. i didnt cut any wires or alter the circuit in any way whatsoever. i could have just soldered a headphone plug on it and been done but it would always be there in view.. this way i can unplug the cord like its never been there and no one would really know. and if one day the FM decides to start working again on its on by some miracle it will be able to.
i tried my CD player, IPOD, and cell phone on this radio with the input and it all sounds great. it has clear sound with no hum or any annoying tones at all. it still has the distinct tube radio sound like it should, the volume can be controlled by its own knob. the AM works perfectly like it should, no static from the volume control either. out of curiosity i plugged a mircrophone into the input and i could hear my voice coming over the speaker too. i dont see a use for this but it can be done.
this couldnt have had a better outcome than what has happend. everything works as it should and almost as if it was designed with this and originally had it. all tubes work and are operating at max quality with new capacitors. ive had this radio on for almost 3 straight days before i wrote this and it has worked perfectly, still no hum, or funny stuff. im in the clear.
here are a few resources that i used to accomplish this. all credit goes to them.
- http://www.nostalgiaair.org/PagesByModel/238/M0001238.pdf service manual, schematics, parts list for my radio
- http://tubedata.tubes.se/sheets/093/6/6T8.pdf tube data for my 6T8 tube
- http://antiqueradio.org/recap.htm how to replace capacitors in a radio for beginners
- http://antiqueradios.com/ antique radio resource website
- http://instructables.com everyone's help and their projects helped me alot