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Hi, I recently got into electronics and pedal construction, and so far have built three projects - A delay, reverb, and fuzz. Right now i'm working on custom tape echo.
Basically, I bought two mini 3" reel to reels from ebay, and am modding them to run as a tape echo. I scribbled out the schematics for the two reel to reels and dissasembled them. I mixed the parts and created a track on top with a record head and play head, and then wired one circuit to always record and one to always play. Simple concept, once I get that working, I will then mod the circuits to create a feedback loop, motor speed control, etc.
So, I merged the two reel to reels into one casing quite successfully, but I ended up with something very strange that I cannot explain. The two play/rec circuits are completely seperate electronically. However, when I insert the mic into the rec circuit and connect the play circuit to a speaker, I get this weird sci-fi sounding high pitch noise that depends on the distance of the mic to the speaker. When I move it closer and closer, the pitch ramps up for a sec, then suddely drops, ramps up slowly, then drops, etc. Eventually when I get within two centimeters of the speaker it goes to a altogether different flat tone. The distance of the mic ONLY changes the pitch of the sound, not the volume.
And remember, the two circuits are COMPLETELY seperate. I even unscrewed everything and physically seperated the circuits across a distance and it still happened, albiet decreasing in volume based on the distance between.
Some additional info:
- Both reel to reels are wired up strangely - ground is in place of where the power supply (9VDC) should be and 9VDC is where the ground usually is. So, the whole case is at 9VDC. Why would they build it this way?
- Same effect happened when both were connected to the same power supply
- No wiring alterations were done except removing the switches and freezing the circuit in the place of a certain combination of settings. I triple checked every change both while doing it and afterwards.
- I had both reel to reels running side by side in a "frippertronics" stlye setup before the modding began and they worked fine sitting next to each other.
-The effect is still noticably loud even when the circuits are as far as three feet away from each other!
I hope someone can help. I am totally lost as to what I should do. I can't think of any possible way there is that strong of whatever field-effect it might be and how they might be connected through it.
Basically, I bought two mini 3" reel to reels from ebay, and am modding them to run as a tape echo. I scribbled out the schematics for the two reel to reels and dissasembled them. I mixed the parts and created a track on top with a record head and play head, and then wired one circuit to always record and one to always play. Simple concept, once I get that working, I will then mod the circuits to create a feedback loop, motor speed control, etc.
So, I merged the two reel to reels into one casing quite successfully, but I ended up with something very strange that I cannot explain. The two play/rec circuits are completely seperate electronically. However, when I insert the mic into the rec circuit and connect the play circuit to a speaker, I get this weird sci-fi sounding high pitch noise that depends on the distance of the mic to the speaker. When I move it closer and closer, the pitch ramps up for a sec, then suddely drops, ramps up slowly, then drops, etc. Eventually when I get within two centimeters of the speaker it goes to a altogether different flat tone. The distance of the mic ONLY changes the pitch of the sound, not the volume.
And remember, the two circuits are COMPLETELY seperate. I even unscrewed everything and physically seperated the circuits across a distance and it still happened, albiet decreasing in volume based on the distance between.
Some additional info:
- Both reel to reels are wired up strangely - ground is in place of where the power supply (9VDC) should be and 9VDC is where the ground usually is. So, the whole case is at 9VDC. Why would they build it this way?
- Same effect happened when both were connected to the same power supply
- No wiring alterations were done except removing the switches and freezing the circuit in the place of a certain combination of settings. I triple checked every change both while doing it and afterwards.
- I had both reel to reels running side by side in a "frippertronics" stlye setup before the modding began and they worked fine sitting next to each other.
-The effect is still noticably loud even when the circuits are as far as three feet away from each other!
I hope someone can help. I am totally lost as to what I should do. I can't think of any possible way there is that strong of whatever field-effect it might be and how they might be connected through it.
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