The new pot that I suggested in posts #24 and #29 does exactly that.What I want to do is:
Determines the level of original, unprocessed audio.
Existing pot R11.Wet Out
Determines the level of delayed, processed audio.
Not possible, you need to adjust the length of tape between the record and play heads to do that, although altering the tape speed will give a crude limited similar effect, but will lower quality.Delay(echo)
Specifies the delay length.
Existing pot R10 - set it too high, and the entire system will oscillate (this is normal for echo units).Feedback
Creates repeating echoes by resending delayed audio through the delay line
Existing pot R16 (output level, rather than gain).Gain
Why suddenly 1K?, it should be 10K like the other one. Also you have C14 the wrong way round, it need to be the same as the other capacitor.Thank you so much! Really appreciate it and cant wait to get this done.
I understand I need to modify the unit to put in a pot that makes it possible to adjust the motor. Think I remember reading about just that mod somewhere.
Is this looking better?
View attachment 109820
And should all pots be log pots? Or just the output level? Can I buy 1K log pots?
Not really a problem, and if it concerned you simply alter the 22K resistors and associated feedback resistors - but the design already uses 10K in the exact same way.I advised the 1k as the impedance the output of the pot goes to a 22k load, 10k will work but it wouldnt be linear.
I already suggested changing the speed, but it alters quality as well - and as you say, if the controller is built-in the motor it makes it more difficult.No disrespect to nige, however some change in delay time would be possible if you change the speed of the tape motor, though that would mean serious mods to the motor if the speed control is built into it.
The Watkins Copycat was the most famous (and popular) of the echo systems, nice and easy to repair as well.Hi Nige, have a look at post #3, copycat is one of the machines your talking about, I repaired a few too back in my apprentiod days.
Not something I've ever been involved in, but I remember the BBC Radiophonic Workshop used to make long delays with two reel to reel machines at either sides of the room and the tape fed across between them. But their 'real' echo system was the best - from the Radiophonic workshop they had cables down to a large room 'down in the depths' of the BBC - they had speakers and multiple microphones in this large room, and used it as an echo chamber.If you have 10k rorut try it it'll probably work fine I might have been a bit too picky.
Looks like the motor speed control is onboard rather than in the motor, some tape players had a variable speed control fitted.
Have you considered modding a tape to an endless loop, or even using 2 decks with 1 tape?