A reverb pedal without Belton brick or FV-1?

[sajy_ho]

Guys, the hand-drawn schematic worked!! I just breadboarded it and it gives a something near to reverb, but after changing pin6 resistors with trimpots and tweaking them a bit it worked great!

[deadastronaut]

cool...

[Adventure_Audio]

Awesome! Can't wait to try it out!

How close did you stay to the original values? Mainly the 11.8Ks and the 4.99Ks. I was going to sub them for 12Ks and 5Ks.

Also did you end up using the Schmitt Trigger IC?

I want to hear a sound sample! Awesome work!

[sajy_ho]

Awesome! Can't wait to try it out!

How close did you stay to the original values? Mainly the 11.8Ks and the 4.99Ks. I was going to sub them for 12Ks and 5Ks.

Also did you end up using the Schmitt Trigger IC?

I've used 12k and 5k1 resistors instead of 11k8 and 4k99, but used 5k trimpots in place of pin6 resistors and adjusted it to given values.
Also I used pin 1 and 2 of 74hc14 as Schmitt trigger, but don't forget to connect all the other odd number pins (3,5,7,9,11 and 13) to ground.
As for the opamp I used a 741 single opamp; the rest is exactly like the hand-drawn schematic (not the first one because it didn't work for me!)

I want to hear a sound sample! Awesome work!

Oh sorry! I've just disassembled the breadboard for using the parts, but I'm designing a PCB for it and I will record a sample ASAP.

[Adventure_Audio]

Oh sorry! I've just disassembled the breadboard for using the parts, but I'm designing a PCB for it and I will record a sample ASAP.

[/quote]

No problem! I look forward to it and am very excited to try it myself. A friend suggested configuring a schmitt trigger from an op amp rather than trying to use that huge IC. That will be the next step...

[sajy_ho]

Oh sorry! I've just disassembled the breadboard for using the parts, but I'm designing a PCB for it and I will record a sample ASAP.

A friend suggested configuring a schmitt trigger from an op amp rather than trying to use that huge IC. That will be the next step...
[/quote]
That's a good idea, speacially for pcb designing I can use a dual opamp, but how can an opamp be used in place of the Schmitt triger?

[Adventure_Audio]

Here is an awesome site that explains how the schmitt trigger works

http://www.talkingelectronics.com/pay/BEC-3/Page76.html

and according to wiki - http://en.wikipedia.org/wiki/Schmitt_trigger

the idea is "any active circuit can be made to behave as a Schmitt trigger by applying a positive feedback so that the loop gain is more than one"



So this can be done with a network of transistors or an op amp configuration explained further on the wiki page. I believe a bit of experimenting is in order though! 

[sajy_ho]

Here is an awesome site that explains how the schmitt trigger works

http://www.talkingelectronics.com/pay/BEC-3/Page76.html

and according to wiki - http://en.wikipedia.org/wiki/Schmitt_trigger

the idea is "any active circuit can be made to behave as a Schmitt trigger by applying a positive feedback so that the loop gain is more than one"



So this can be done with a network of transistors or an op amp configuration explained further on the wiki page. I believe a bit of experimenting is in order though! 

Thanks man, so I guess I need to breadboard the whole thing again

[Adventure_Audio]

You could do that to be safe! Or just try constructing the inverting schmitt trigger and using it for a similar application. It would help if we had the exact values of the components in the 74HC14 IC. I will post my results in the next week or so and we can compare. I am very excited someone else is attempting this circuit at the same time as me!

[deadastronaut]

Add another pt2399...

[sajy_ho]

Add another pt2399...

That's an awsome idea man; how about a new reverb project with 4 pt2399's and more knobs like decay control?

[deadastronaut]

Yeah that would be cool,

control each pt delay, decay etc....

[sajy_ho]

How can we add a decay control to it?
I'm thinking about a variable resistor in the place of the 4th pt's pin 6 resistor...

[samhay]

> I'm thinking about a variable resistor in the place of the 4th pt's pin 6 resistor...
You can do that with your 3-PT2399 design.

I spent some time thinking about building a reverb based on the patent schematic that you have used. I eventually concluded that the main benefit would be to be able to vary the delay time(s) of the PT2399(s). You can now do with the new BTDR-3 brick, so I figured that if I wasn't going to add any new functionality, then it was not going to be worth my effort. Your initial reasons for building this probably differed to mine, but I still encourage you to think about how you can make a better version of the BTDR bricks with a discrete design - more control, different filtering, different use(s) of the LFO, etc.

[Adventure_Audio]

I spent some time thinking about building a reverb based on the patent schematic that you have used. I eventually concluded that the main benefit would be to be able to vary the delay time(s) of the PT2399(s). You can now do with the new BTDR-3 brick, so I figured that if I wasn't going to add any new functionality, then it was not going to be worth my effort. Your initial reasons for building this probably differed to mine, but I still encourage you to think about how you can make a better version of the BTDR bricks with a discrete design - more control, different filtering, different use(s) of the LFO, etc.

I totally agree. Also a 4th 2399 with decay control would be wicked. So here's a thought:

If we were to alter the patented schematic i.e. Different filtering/values/etc. would that expel the patent? I guess what I'm trying to say is, would it make it a "free", DIY enabling circuit? I'm not a lawyer but it would be interesting to know.

[sajy_ho]

If we were to alter the patented schematic i.e. Different filtering/values/etc. would that expel the patent? I guess what I'm trying to say is, would it make it a "free", DIY enabling circuit? I'm not a lawyer but it would be interesting to know.

I think we should do this, because otherwise it would be called "Copywrite" or something like that; but what about people like me which don't have access to the reverb modules?!
My idea is: four PT's with adjustable delay switch (short/long) and a decay knob, with input and output buffer/mixer all in one PCB!
I know it will become huge, but I think it still can fit in a 1590BB enclosure; so what do you think?

[samhay]

Why do you want a 4th PT2399? There is plenty enough reverb in a BTDR chip for most peoples liking.

[sajy_ho]

Why do you want a 4th PT2399? There is plenty enough reverb in a BTDR chip for most peoples liking.

I just want something different so we could call it a "DIY" reverb, but 3 chips would be enough, but how can we add a decay knob to it?

[Adventure_Audio]

When you say decay control you mean being able to seemlessly switch between the Short, Medium, Long bricks right? I would think that would amount on the feedback trim pots you spoke about earlier. Not 100% sure though

[sajy_ho]

When you say decay control you mean being able to seemlessly switch between the Short, Medium, Long bricks right? I would think that would amount on the feedback trim pots you spoke about earlier. Not 100% sure though

Exactly, thanks for correction. something like delay time but in the terms of reverb, if you know what I mean...