Brick Reverb DIY for Whistling street musician

[jjj333]

Hi you wonderful DIY experts,
For years I'm trying to build a small, compact Demo unit for my creative whistling to music. I hate to have ten different boxes to connect etc. I bought one of these cheap Chinese (Biyang) "Tri Reverb", which sounds great, but is too big! 
The reason why I bought this Rev (Brick2H, long) was to build a small as possible Rev unit to fit into a Mini stereo speaker box (of only 16x8x8cm) for a compact Demo unit to demonstrate my whistling to music. The Mini Stereo for music (only) has got a warm bass and so, the Brick reverb is a separate unit, consisting of the electret Mic with a TA2024 Amp and a remotely placed speaker.

I already built the "Dub A Rub", but its Rev effect was too short and I wonder how I could minimize the circuit's size w/o sacrificing its Rev quality? Maybe I there's a way of adding feedback to lengthen the Rev effect? - I could reduce its physical size by soldering its components directly onto each other without a PCB.
I found an interesting circuit and need only Mono reverb, but I prefer a long reverberation, like from that China Biyang.
I would like to input an electret Mic and for that purpose configured the input OP Amp input. Will that work?
To get Mono reverb, I joint the Brick outputs (pin 5 & 6) via 5K resistors. 
I only have hobby electronics practice and so, at least I can build it as shown in  the circuit diagram.
To give you an idea of what I do, here's a Demo of my creative whistling to music:   https://app.box.com/s/6f72eb90c2002db2e9fc  or this one: https://www.mediafire.com/?t0mocnkevh9bz1c

Warm Regards, from young pensioner (74) down-under in St'go de Chile

PS. I found the circuit here:  https://www.youtube.com/watch?v=edNSO0RBLms

[cooder]

That's some hot whistling there... cool stuff!
I did a pcb design for a compact version of Rub-A-Dub that's hardly bigger than the brick itself if that would help you.
However, the circuit and the sound / length of decay is the same as the Rub-A-Dub you have built, just smaller.
Did you use the long decay brick in your first Rub-A-Dub you built?

[pogart]

That is the coolest little board. I'd love to build that one up. Cool stuff.

[cooder]

You could also consider Grindcustom's excellent "Tenebrion" reverb, gets some nice spacey sounds on higher settings.
Slightly larger pcb and three knobs, so needs a bit more physical space.
Check out http://www.grindcustomsfx.com/

[jjj333]

Thank you cooder for your responds,

Yes, I bought that long Rev Brick (2.83s) and my Dub-A-Rub circuit (direct parts soldering) was very small and flat. I used special low profile electrolytics, pots etc. and glued the IC upside down onto a piece of flat carton.
I find that "Tenebrion" Rev circuit more interesting, for it got great feedback and never seen that one before. Their YouTube Demo sounds really good!
1) The Dub-A-Rub circuit output signal was rather weak and I wonder how I could lift the signal to feed a stronger signal level to the TA 2024 Amp.
2) Also, I'm not sure if I can connect the electret Mic to the Rev's input OP Amp, just as it is?
3) Their circuit and PCB doesn't show how/ where the turn On/Off switch is connected?

[cooder]

Well both the Rub-A-Dub and the Tenebrion will work at unity gain, so the signal will not be amplified or louder at the end. If you microphone drives the amp without the reverb loud enough then the reverb soundlevel should be similar.
If you need more output maybe you also need another clean booster to drive the amp harder for more volume?

[jjj333]

Well, I can connect a small two transistor electret Mic PreAmp to the Rev's input to lift the signal.
In fact, the only reason I bought this Brick to build a small Rev.
Weird that nobody thought of building a Mini sized Rev. That would make the Brick Rev unique in size, because what's the point building this unit if ready built Revs, such as he Chinese Biyang Rev, sound as great and come cheaper? One never knows whether/ when this Brick Enigma fails...
I connected this Chinese Biyang Rev to the Aux Send/ Return Loop of my Yamaha Tyros 3 and it sounds clean & great.
I now still have to find out how to connect a noiseless On/Off switch to the (Box of Hall or) Tenebrion circuit.