Powering Eden pedals (e.g. the WTDI) - not straightforward

[laurie]

I have two Eden pedals in my bass rig now - a WTDI, and an I-90 chorus.

These pedals do not play well when powered with other pedals.

There are many (many) threads on other forums talking about power supply issues, with the consensus that "most power supplies do not have enough milliamps - that's why it isn't working".

NOT TRUE.

In case anyone is looking for an answer sometime in the future, I traced the circuit in my WTDI and here is the definitive reason there are issues with powering Eden pedals in a multi pedal rig, and the way to do it properly.

[laurie]

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[laurie]

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[laurie]

Also note - because the "point A" potential will not be exactly identical between Eden pedals you cannot daisy chain the 15V supply to multiple Eden pedals.

The proper (and only) way to power an Eden pedal is with a single external supply, or with a fully isolated output from a multi supply.

THE FOLLOWING IS GIVEN WITH NO GUARANTEE
Because the Eden pedal analyzed has a bridge rectifier plus a 12VDC regulator...

• Not using a polarity changer should be OK.

• An 18VDC supply should be OK.

• A 12VAC supply should be OK.

[laurie]

Also note that there is no "mod" that can be done to the Eden pedal to allow it to be powered by a multi pedal power supply that does not have isolated grounds.

[laurie]

One more factoid...

My WTDI draws 35mA, measured with a Fluke meter. Additionally, because the pedal is powered through a 78L12 regularor, the 78L12 has an inbuilt current limiter (around 200mA).

The 35mA is the key number. This is nowhere near the 400mA rating on the Eden power supply that comes with the pedal, and there should never be an issue with current draw with these pedals. Any supply you want to use should work, as long as it meets the criteria in the previous post above.

[laurie]

I have completed a test of my new bass board - I am powering the Eden pedals with 14.8VDC, unregulated, center negative. They are working perfectly.

[laurie]

This is the new board.

I repurposed one of my Caline power supplies:
viewtopic.php?f=13&t=880

To get the +15VDC for the Eden pedals I removed the 7809 regulators from those channels and jumpered the input pad to the output pad where the 7809 used to be. The power comes out of the power supply center-negative, which works just fine (the Eden pedals have a bridge rectifier).

I also did the 9.6VDC mod on the two channels powering the Boss pedals. The EQ-200 is on the "high power" channel - allegedly 500mA, but the EQ-200 only draws 170mA so it also works just fine.
viewtopic.php?f=13&t=10&p=8508&hilit=7809#p8508
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2024-07-21 Bass board.jpg (302.8 KiB) Viewed 7271 times

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2024-07-21 Bass board PSU.jpg (301.78 KiB) Viewed 7271 times