Hi, after adding a new motor to my mixer/tape echo unit and getting it working. I'd like to make a few modifications to it... It sounds so nice and yet it looks very simple on the inside... I'm far from knowledgeable at this matter, but understand some basics, or a bit less. But I hope with your help I may succeed.
Unfortunately I can't find the schematics, but it is point to point wiring and looks fairly simple.

1. I'd like to add an output jack which would output separate channels (or just one separate channel for a start). That kind of output would be called "INSERT" on modern mixers, just a clean preamp output.

Here is an image of the first 3 preamps, there are 8 altogether, the amp/mixer is mono. One (or 2)of the horizontal wires goes to the summing amp/master eq, All the preamps are directly connected to this wire as you can see on the photo.

My question is, where could I connect my new single channel output jack wire to get only the signal from 1 preamp? Can I just solder wires before it connects to the horizontal wire, or that way I'll hear all the preamps?



2. I'd like to somehow make an output just for the WET (tape echo signal) without the original audio signal.
I'll try to find tomorrow where it sums the echo signal, hopefully it will be an easy mod.

Also the spring reverb doesn't work, don't know why, but I suspect someone has fiddled with it and it might be disconnected I'll look into that later...

Thanks

 

This is an interesting quest indeed. Tape echo systems seem to be two different family types, quite different from each other. The simple variety is similar to a simple three-headed tape machine, except it may have a variable speed motor tape drive. A signal is recorded by the first head and then played back with the second head, and the played back signal is mixed with the input signal to produce the echo effect. The third head is then the erase head.
The other scheme has multiple playback heads, and the different playback signals are all mixed to form the output signal. Some of those echo/delay machines can also be used to simply delay a signal, as was used to sensor telephone conversations for live broadcasts on AM radio stations "long ago".
I am not at all familiar with the model in question, but since it appears to use Integrated circuit technology rather than vacuum tubes, it is a much more modern device.
Without a circuit schematic it will be much more challenging to locate the various points to tap the different signals requested. So a more detailed description, including the number of tape heads, is needed.