L.R.E./Lafayette EchoVerb II

[Rodgre]

Hi all.

I was just thinking about an old Lafayette Radio EchoVerb II spring reverb unit that I have and it got me curious as to whether this circuit could be modified to replace the pretty short and lo-fi tank inside with a Belton brick. I would obviously have to create a regulated power supply for the brick. I have never built a circuit with one and I wasn't sure if they were designed to be able to swap out any particular spring tank.

Does anyone have experience with something like this?

By the way, I am all for clangy and lo-fi springs but this EchoVerb has been in my collection for decades and I've yet to find a use for it in the studio, whereas the awful reverb in my Silvertone Twin-Twelve has made a few appearances. I'm just looking to see if there's something useful I can do with it.

For reference:


Thank you
Roger

[PRR]

The Belton module is nothing like a reverb tank.

First thought is you might put a good tank in the Lafayette except it is DC coupled and uses the tank DC resistance as a bias-sense resistor. It is too wonky-drawn for me to suss out today.

If it is truly useless, list on Reverb[.]com and CraigsList. No takers, chisel ALL the guts out and implement the Belton suggested application in the vintage box.

[PRR]

@Rodgre, we are talking about your reverb (and using your schematic) on another thread.

https://www.diystompboxes.com/smfforum/index.php?topic=131225.0

[Rob Strand]

The schematic at the top of the thread is actually for the Lafayette Radio Echo Verb (I).

You can see the Lafayette Radio Echo Verb and Lafayette Radio Echo Verb II from this 1971 Lafayette Catalog pic:



Lafayette Radio Echo Verb (I) has one knob.
Lafayette Radio Echo Verb II has many inputs and three knobs

There's no schematic for the Lafayette Radio Echo Verb II.  From what I can see it is very similar to the Lafayette Radio Echo Verb.  Differences from what I can work out (tentative):
- all the inputs and level controls are resistively mixed at the input.
- the reverb and dry signal are combined at the output node.
- there's a few other circuit and value differences here and there.

I'm pretty sure the 100nF caps are greencaps/polyesters on some units.
This is good as I can do with the info I have.

Lafayette Radio Echo Verb II



If anyone has a unit, please check/post:
- the part values, including the pots, especially those marked ?
- read off transistor gain codes (P, Q, R etc.)
- the pot tapers
- measure the DC resistance of the input and output coils
- measure the DC supply voltages