Edison C-4 record sound question.

[marcapra]

I just had my Edison C-4 1929 radio-phono rebuilt. The sound from the phono is a little weak. The volume control for records doesn't really do much. When I connected the tonearm leads to a 1930 Edison R-6 radio, the record sound was absolutely fantastic! Would replacing the volume control in the C-4 fix the problem?

[gregbogantz]

If your C-4 radio sounds good with plenty of volume, it sounds like your phono volume control is either defective or miswired. It should control the volume from full loudness to completely quiet, just as any other volume control. Another possibility is a radio/phono switch problem or a wiring problem in the phono input circuit of the radio chassis. The R-6 and R-7 chassis have an additional stage of audio gain which could be why the phono plays louder thru the R-6. But the lack of proper operation of the C-4 volume control is a telltale sign that something is wrong there.

[marcapra]

My radio man wanted to see a schematic for the phonograph, but none exists for the C-4. I just have the radio schematic from Nostalgia Air. My radio man was further confused by the fact that the volume control only had two leads, when most vol. controls have three. So he wired the control the way he thinks it should be. When I jumped the vol. control, I still got fairly weak sound from the C-4 phonograph. As my radio man said, replacing the vol. control is not going to give me louder sound. I should say here that George Epple rebuilt the pick-up, so there is no problem there. The beautiful sound I got from the R-6 proves that. It would be good to know if there are any owners out there of a C-4 that gives out loud, satisfying sound for records?

[HisMastersVoice]

My C-4 will blow you out of the room if it is turned up all of the way, and it sounds great. One problem I've had with mine is the radio/phono switch (the one on the front to the right). Sometimes the switch will not fully engage the phono and I have to jiggle it a bit to get the phono to work (then I usually leave it). I guess this is a common problem with these and a replacement switch is not readily available. I have the schematics and other documentation if you need it.

[marcapra]

Yes, I need the schematic that includes the phonograph if you have it. That's good to know that the C-4 is capable of great sound on records. My phono/radio switch on the volume control seems to work OK. I just don't get much sound from the phonograph. I will PM you my contact info.

[marcapra]

Did you mean that your C-4 will blow you out of the room on a radio station or a record. My C-4 is loud on radio stations, but not on records where it only goes up to a pleasant medium loud. My radio man and I just spent seven hours on it and repaired the volume control and other things, but the volume of record reproduction would not go up. The fact that the R-6 1930 radio has an extra tube and an extra stage of gain is I think what makes the R-6 superior in record reproduction. So I think I will make some long tone arm leads that will go over the R-6 when I want to play records at a louder level.

[HisMastersVoice]

Yes, I mean when playing a record. I don't really ever use it as a radio. You say the radio plays loud and clear? George Epple rebuilt my pickup as well, so I trust that is not the problem. Were the pickup leads replaced? Maybe a good signal is not getting through?

[marcapra]

Yes, the pickup leads were replaced and the speaker was replaced with one that has been re-coned. He basically checked everything and said that was the best that a C-4 can do because it had only one 27 tube to give it gain. I even checked it with other 29 Edison receiver units, but the sound from records didn't change.

[Phototone]

All the phonos of this early period with a horseshoe magnet pickup (like the Edison) don't need a lot of gain in the amp. Unlike the modern magnetic pickups whose output is in millivolts or microvolts, these older pickups put out VOLTS. My opinion is that there is something wired up wrong in the receiver chassis.

[marcapra]

I wonder if the pick up may have lost some magnetism. They were rebuilt several years ago, but not used until now. I have two rebuilt pickups for the Edison and they both sound weak. But when I plug the tone arm into my 1930 R-6 radio, records sound fine.