Modding a delay for more feedback?

Hi guys... well I'm sitting here with an old Aria APE-4 multi fx unit (non programmable) that I bought for cheap, and I really like the gritty old style digital delay. Thing is, it won't self oscillate.

I've had the aria APE-2 which is kinda similar and tweaked the internal trimmers to obtain a three second heinously dirty oscillating delay from hell, but can't seem to do it with the trimmers in here (which effect the delay time and FX depth of the chorus)

Anyway - long story short.... are there any general 'themes' or avenues to explore for hacking a delay so it will self oscillate? Is it a case of changing resistor or pot values? Or are all delays different in this regard? If so what gives a delay circuit more feedback more resistance or less???? All i've ever previously done to pedals is tweak pre-installed trimmers.

Anye help would be much appreciated.

Cheers!

I can think of two ways without knowing the schematic or anything. it's true for most delays.

trace the schematic from the feedback knob. if you find a resistor, try shorting it, or reducing its value. you could even change it to a trimpot! if there's a resistor in series with the feedback pot, then playing with it will offset the feedback range.

another way is to feed the delay output back into the input through a pot. 500k will do, and put a resistor in series with it so that it doesn't get too harsh.

there are no "perfect values" for either the pots or the resistors, since most delays work differently.

Awesome... thanks alot!

ops, I meant trace, not trade (the schematic)

So I cracked it open last night and found that all the resistors in the circuit were tiny SMC ones.... so I found one that was in series with the feedback pot and jumped it with a little bit of wire.

Boom!

Worked a treat.

Thanks for the infos!

cool! glad it helped.

SMC are a pain in the neck

if it were me, I'd go ahead and replace both the bot and the resistor with just a pot of higher range