Ok, Im loving my SHC-8 (the famous, nay, infamous out of phase dual amp of the 1st generation stereo consoles). The AM is booming and has great fidelity, and I expect the FM will be too (waiting on a tube...), the Ipod input through the tape input (with a specially created plug) sounds almost as good as my wife Sony tuner/amp with Bose speakers. But... I put on a mono record, and I get a ton of surface noise (almost like a 60 cycle hum), pops, and thin sound. Oddly enough, the 78s I've played seemed louder and with more punch than the Lps. With the back switch on "internal" there is no difference between the MONO and STEREO phono dial setting, but with the back switch at "EXT" and the dial at STEREO, the sound doubles and has punch. I hooked up a spare speaker (not a real RCA companion type) and it still sounded good at STEREO, and cut by half and thinned out when turned to MONO.

So that is the PHONO. When I go to tape, the sound quality changes from STEREO to MONO, but the volume change is much less noticeable. So, is my TT rumble and near cancellation of sound at MONO a function of the cartridge or the amp, or both?

Sounds to me like you do not have the special out-of-phase cartridge this set needs, you have a regular one. If it is a non-RCA 4-terminal cartridge it can be wired out-of-phase and will work properly.

-David

When the back switch is in the "Internal" position, the amp is bridged to mono and the main selector switch will still be bridged to mono even in stereo tape or stereo phono positions. That all sounds very normal.

It seems like someone replaced the out of phase cartridge with an in phase version. You can prove it by removing one of the outer cartridge clip leads and running it in mono with only one cartridge channel connected so there can't be any cancellation. If the sound doesn't thin out and distort in mono then you probably have the wrong cartridge.

I had that player two owners before Basilio and I put a NOS RCA 106771 cartridge in it. I still have the original box from it. I could be mistaken, but at the time, I thought I had confirmed that it was indeed an out-of-phase version. Printed on the cart was RMP-200-1, which I thought was the very first version of the cart, which was the out-of-phase one.

Mitch if you want you can bring that TT and amp down sometime and we can fiddle with it a bit and see what is going on. I never had the TT going but the amp and tuner were. I have a couple out of phase units here up and fully working and we could do some testing with another TT if needed and figure the issue out.

T

Im going to test out the pulling one lead and see how it sounds, and then go from there. I could also do what you did and put in a P-226 wired for out of phase (0nly $18 at VOM!), but on the plus side I replaced the tube and the FM sounds great (though it needs alignment since the stations are about 3 mc off, ie 90.9 is at 92.7 on the dial..)
Now, this may affect things, I had to re-solder the leads into the 3 prong phono plug. If I accidentally reversed the right and left (red and white) but not the ground (center prong), would it create this problem?

Nah, it would only reverse the channels and sound like you were listening to records through a mirror. (sorry)...(no i'm not)