Channel Switiching for SANS AMP GT2 CLONE

[paku5535]

Hello,

I am currently making my hand made DIY amplifier. I have decided that I will use sansamp gt2 as my preamp(dont know how it will be!). I want to change various parameters by foot switches. So I have already built a micro controller board having relay drivers(uln2803). Now I have separate relay board. Can you please verify and suggest me with corrections,improvements...

http://imageshack.us/f/855/38978329.jpg/

[paku5535]

Circuit Description:
please refer to the image
for any relay pin 1 and 2  are power pin. Vcc is common and the other power pin will be connected to U/C for ground.Each column (3 vertical relays) is acting like 3pdt. only 1 out of 3 (in each col) will remain on at a time and other two will be disabled. I have only one momentary switch for each column(Tweed/British/California etc). For each press of the switch it will alternate between the three states like 1 2 3 1 2 3 1 2 3 ......(Tweed/British/California/Tweed/British/California/Tweed/British/California.....). I have good quality Lan wire(10~12 wire and a common shield). I will require three such small pieces to connect from circuit board to relay board.

[paku5535]

any suggestion?

[armdnrdy]

Post a schematic

[paku5535]

already poste

http://imageshack.us/f/855/38978329.jpg/

[paku5535]

[armdnrdy]

What you uploaded to imageshack is called a board layout.

A board layout has the actual components, traces, and solder pads. A schematic has component symbols and connections. Schematics exist because they are the blue print of the circuit. With a schematic is usually easier to understand what is going on in the circuit.

With that being said, do you have a schematic? I would like to help

[paku5535]

Sorry for being misunderstood. Actually I had marked necessary pin for understanding. Never mind here is the schematic.. I have only mentioned for one switch only and at a  time only one relay will be switched on..

http://imageshack.us/f/715/paku.png/

Do you know how can we upload picture directly in this forum topic?

[paku5535]

[paku5535]

No reply!!!!

[armdnrdy]

Sorry for not getting back to you sooner. I've been working on issues in one of my designs.

Okay, there are a few different ways to do this. I would prefer the CMOS switching i.e.: CD4053. Mechanical relays are easier to implement on the surface, but do come with drawbacks. One major drawback is size! As you have observed in your component layout, the relays make for a whole board by themselves.

If size doesn't matter, then you have to tackle a few other issues. One is related to the other. With mechanical relays comes contact bounce. Contact bounce all by itself may or may not pose a problem in your particular circuit. In logic circuits the bounce can cause multiple false triggering until the contact settles down. This can result in faulty operation of system processes .

The other issue related to bounce is a loud pop when switching between channels. That's something that you will encounter in your circuit. There are a few different ways to lesson or eliminate that problem. Google is your friend for that fix. There's also the issue of an inductor or coil being utilized in the circuit. There's an issue called flyback that you may need to attend to.

I hope that this info will lead you in the right direction.

[paku5535]

i have used uln2308 for powering the relay!

[paku5535]

sorry uln2803a

[armdnrdy]

Paku,

I didn't catch that in your first post. That will take care of the flyback diode problem. Now on to the contact bounce issue.

[paku5535]

Thanks armdnrdy. You are right. This bouncing can cause 'pop' sound mainly during release time as I have already encountered.

Acually my amp contains the following..

Buffer---->Phaser---->Compressor---->GT2 Clone---->Delay---->Noise Gate. For bypass every circuit(except Gt2) contains a relay. and GT2 has 9 relays!! Every relay will be controlled by Micro controller. Interface----


Remote Foot Switches---->Encoder---->Microconroller---->serial communication to amp---->Microconroller---->(Decision)---->Latch---->Uln2308.

Since during start up time all the latch momentarily remain in 1 state. So all the relay will be on. So I have used relay delay at the last stage to disconnect the speaker initially for 2-3 seconds to avoid initial pop and to settle all the relays to their intended state.


So can u suggest some ways, I can momentarily make the amp silent while changing any of the 15 relays in my circuit (Making software delay will not be a problem!) 

[paku5535]

Hello,

I am afraid that only one member is replying my tread