amp6 basic speaker turn on pop/click issue

[V-bro]

Made another drawing:



Mind you all, this circuit has not yet been tested!

Some things that might need looking after are the resistors R5 and R6 for instance, these might need to have a bit different value, maybe they are not needed at all.... The point of them is to keep the transistors in a state they are supposed to have when there is not current supplied to their base. Some transistors can go in a sort of limbo state, or even are latching (keep the state they last have been actively put in)

You may prefer using little mosfets like 2N7000 series as these have better base (gate) to collector/emitter (drain/source) isolation. I'd say first put it all on a breadboard to see if/how it works and then place it on a perf board or something...

These circuits are very basic rugged and yet effective discrete delays etc. based upon very basic NPN transistors. Many other kinds of NPN transistors will work just as well. The circuit will also basically work on any of the amplifiers as long as you keep an eye on the operating voltage. Delays can also be adapted by either increasing the C values or decreasing/increasing R values.

On other amplifiers pins may have other names, I name HMUTE before, but the TA2020 doesn't have that pin, it uses the FAULT pin for just about the same logic function (protection or fault indication purposes)

Good luck and if you have any questions just ask!

[xrayspex]

Nice one! will look in to the error-input implementation.
Personally I have successfully used a simple delay-on instant-off circuit seen below.
The amp turns on and off dead silent

Screen Shot 2012-08-04 at 12.00.47 .png

[V-bro]

Yes, the protection would fit right in your circuit as well...

The simplest yet is using the right input caps and to my experience these amps then too turn on/off dead silent. Though the speaker relay is definitely the most secure and fancy solution with extra protection options.... Basically you can connect any kind of current towards the base of the transistor for the speaker relay (T2) The point is to give the right of way to the most important one. In this case the transistor T3 will pull down the base, no matter if there is current coming from Vin through R2. This current will simply be shunted to ground and keep T2 in a low state, to keep the relay contacts open....

I have drawn my circuit based upon the tested circuit in the youtube link one page back, and the rest in the circuit above just imagined how it should work. I haven't looked in to how much current the FAULT pin from the TA2020 will give and how it would relate to a 120R load. To pull T3 down even higher values would suffice and might make it easier for the FAULT pin to operate the transistor.

Then the old circuit worked fine without R5 and the 2N3904 transistors, but it is not a bad idea to place it to ensure that T2 stays low when there is no base current.

I am 100% certain it will work great one way or another, and it is definitely safe to build and use it as drawn above...

If I find some time somewhere soon I shall hack it together to test the functioning.