barclaycon
Well-known member
I don't normally rave about aspects of analog circuit design, but whilst looking at delay circuits I came across the MXR 118 delay. (Stephen Giles very kindly upped a copy here).
I was impressed with the way they had incorporated 4016 transmission gates into the input and output filters so that they were switched by the clock. This means that they are being used as 'chopper' resistors i.e. the resistance they present varies according to the clock frequency.
It's a technique that the Pye compressor used and also the EMT 165 limiter - albeit without CMOS chips!
In the MXR the resulting sound therefore gets darker the longer the delay, because the clock frequency is switching the 4016's and lowering the cutoff of the filters. It also gives a the delay a characteristic sound.
I wonder if the Carbon Copy model usse the same technique. It's a analogue design but I haven't seen any schematics.
I was impressed with the way they had incorporated 4016 transmission gates into the input and output filters so that they were switched by the clock. This means that they are being used as 'chopper' resistors i.e. the resistance they present varies according to the clock frequency.
It's a technique that the Pye compressor used and also the EMT 165 limiter - albeit without CMOS chips!
In the MXR the resulting sound therefore gets darker the longer the delay, because the clock frequency is switching the 4016's and lowering the cutoff of the filters. It also gives a the delay a characteristic sound.
I wonder if the Carbon Copy model usse the same technique. It's a analogue design but I haven't seen any schematics.