A delay "line-box" project for a Hammond style vibrato

This device will be a standalone scanner vibrato unit suitable for guitar or organ sound sources. I have already bought a scanner unit from Ebay. I personally love the old style scanner vibrato chorus and I think the line-box is responsible for the pleasant sound quality of it.

I'm building the line-box now. So far I've made four coils with my CNC wire winder.

They are made with 0.1mm copper wire and wound about 4200 turns in order to get the 500mH inductance used by Hammond style line-boxes. I've read on an organ forum that the DC resistance of the original foil inductors are about 435 ohms but with my wire I got down to around 400 ohms at 4200 turns. Below is a photo of the original foil inductors mounted below the capacitors.

I've had some problems with some coils that the inductance got to 500mH already at 4020 turns and also led to reduced DC resistance (leftmost of top photo).

I have checked the amount of turns and degaussed the cores. Below degausser arrangement and mechanical counter.