STAGE CENTER REVERB version 2017

[tedsorvino1]

Hello everyone.
I've decided to build a tank reverb pedal (driver and recovery circuit).
I wanted to avoid new power transformers and wanted it to be powered by a simple 9V Dc supply.
I found this schematic on the GGG site (I ve read good comments about this classic design), but I couldn't find their PCB so I 've decided to build my own board.

http://www.generalguitargadgets.com/pdf/ggg_sc_verb_mod_sc.pdf

I've started building it but I 'm already facing a problem. The MAX 1044 IC gives 9v on the positive side, but only -4,5V on the negative (after the negative end of the 10uF cap). The schematic shows that the board demands -9v.
Is this a natural behaviour of a Max 1044 ic or is my IC faulty. Or is the schematic wrong?

[tedsorvino1]

Sorted for the time being. Grounding issue.

[jubal81]

My advice is to skip the Stage Center and get a kit from Surfy Bear.

https://www.surfyindustries.com/surfybear-pcb-diy-kit-faceplate

[tedsorvino1]

i may try it at a later stage. i ve read about it

[Mark Hammer]

Reverb pans are normally driven by higher output-current - a power tube in the case of the Fender reverb unit.  So I'm curious about what the current requirements are for the Stage Center unit, and whether a 1044 charge pump is capable of providing the needed juice.  It might be.  I just don't know.

[BetterOffShred]

Apparently the Ruthenium reverb uses the little blue accutronics reverb tanks and sounds pretty good.   Not sure if you guys had seen that.

[tedsorvino1]

A lot of different DIY projects use alternative tanks (the blue one, beltons etc). The thing is that nothing can beat a real tank. I own a Twin and I know. I also own some hammond tanks, really good for older transistor amps.
But I just want to build this pedal, for building's sake and for easy of use with other small amps.

[BetterOffShred]

The blue one is a real spring reverb tank whereas the belton bricks are 2399 arrays eh?  My old Peavey had a copy of the twin reverb in it and yes it's incredibly lush. 

Not to say the accutronics tank will sound as good as your twin, but it IS a real tank

[tedsorvino1]

It is a real spring reverb...but I think it's really second rate. Even the 1 type of reverb is not really good...I mean the 4 or 8 type of accutronics tanks are brilliant and they are what I 've owned, but the pure fun ones are the 9 type ones, like the Fender vintage unit. I mean really over the top , pedal steel, surf, or even ambient- shoegaze (or even old studio- vocal effect)  type of thing. I mean...Fun but not useful. Go with the 4 or 8 type if you 're using spring reverb normally and you want classic quality sounds.

Hopefully I will make this circuit work.

[PRR]

> I'm curious about what the current requirements are for the Stage Center unit, and whether a 1044 charge pump is capable

A class B power amp driving 800 Ohms with full sine acts-like about 4,800 Ohms to its power supply. At 18V total this is about 4mA.

Add on the idle currents of the several chips, it is still maybe 10mA from the '1044.

The LED alone is 7mA, turn-on Q1 is another 1mA, but these are not fed from the '1044.

[Elektrojänis]

Is it just me or does that bypass switching on that GGG schematic look a bit odd?

To me it looks like the effect on side would be ok, but on bypass it connects the output jack to the input of the circuit, and input jack to the ground.

Edit: The connections on the GGG parts layout look more sensible to me.

[tedsorvino1]

I think I'm nearly finished and it seems to work.
Checking with an oscilloscope everything seem to work as they should...Of course I cannot be certain since I haven't got a proper pan...But with a really unsuitable one, it seems to drive it (not properly but still it drives it). I ordered a proper impedance one and I 'll know soon.
But the schematic is functional.
I have to add that I didn't use a true bypass switching scheme. I used an old DPDT Non-True-Bypass with LED, Input Not Bypassed one.