IQ Systems Spring Reverb (low output)

Hi!

Ive got this spring reverb made in Holland. I wonder if some one got a schematic for this one, or a manual...or some history.
I think it has a low output. I use it through my FCA1616 behringer, in logic x i use the I/O plug an have to give it +10dB on the input and output fader. If i boost the output on the reverb itself its get to noisy, more than it already is
Have compare the levels with my au reverbs and my dynacord tape echo which and both have more reasonable levels when they return.
Any thoughts?

As you already wrote, this spring-reverb  was made in Holland - in the mid-80's, until the company busted due to malversations of the owner who is now trying his luck with obscure esoteric "medical" goods.

The spring-reverb itself should deliver enough signal (up to +10dbm) with an output impedance of 100 Ohm.

If the spring and its driver are working correct, then there is not much what can be wrong.  There is the recovery amp (after the spring), a TL072 with a 180k resistor in the fedback loop and a 1k8 from  inverting to ground via a 680n cap.  So the gain there is about 100.  (Yes, the noise here can be improved by reducing the resistor values by the factor of 10 and increasing the capacitor values by the factor of 10.)

After this is a baxandall-tone-control, followed by the output volume-control, mixing-stage and output-driver with a gain of 2 for the reverb-signal and a gain of 36 for the input signal.  Yes, there could be made some improvements too, but it should not be a problem. 

The output driver is a standard non-inverting circuit similar to this:


http://www.next.gr/uploads/3-8bcda3cc31.gif

So if you press the MIX-button, turn the OUTPUT control fully CCW and the INPUT control at approx. 2 o'clock and you feed a signal to the input so far, that the NORMAL LED is lighting but the OVERLOAD LED does just not light, then you should have approx. the same signal level at the output as at the input.

Then the mix&output-stage should be working fine and the problem could be in the recovery amp or baxandall-tone-control-stage (if the spring driver is working correct).

;D
Thanks!
It looks like this when the input control is fully open, its just before overload.  Its the same on both channels.
Do you know how the stereo depth control works. I thought the two channels where fully separated...maybe you just keep it down when you use it for to different/mono signals?

phelar said:

;D
.....
Do you know how the stereo depth control works. I thought the two channels where fully separated...maybe you just keep it down when you use it for to different/mono signals?

Click to expand...

The input is wired that if you connect only one input (left OR right) the signal appears on both channels and there are generated two independent reverb signals from the input signal.

The depth control is nothing else than a  "stereo spreader" where the reverb signal from the left channel is mixed - out of phase - with the right channel and the reverb signal from the right channel is mixed - out of phase - with the left channel.  When you want two individual signals you have to turn the depth control fully CCW and you get 2 independent channels.