Understanding J1 and J2 and sleep/mute

[rlmoss]

Amp 6 documentation notes:

# J2 on PCB rev. 1.0, Place the jumper from J2 to Awake, otherwise Sleep mode.
# J2 on PCB rev. 1.1 + 1.2

* it has 4 pins (sticking up from board), a line around each two pins (a pair)
* the two pins closest to the TA2020 refer to Sleep, an input
* when pins are connected (jumper on/placed), AMP is 'Awake', active/working
* --------------
* the two pins closest to the output-connections refer to Mute, an input
* when pins are connected (jumper on/placed), AMP is UN-muted, active/working

On my board a jumper has been installed on the two pins at the edge of the board. (Differs from representation in top view, where J2 is to back of J1 and thus closer to 2020. On my board, the relative position of J1 & J2 are horizontal--that is they sit left to right.

So one set of pins sport a jumper--leaving me one to solder an on/off mini switch. Is it the case that AMP will only be awake if pins are connected. Also is it true that then AMP will be in mute unless the pins close to connectors are connected.

This all seems counter-intuitive to me: wouldn't you want the AMP's default to be "working" not sleeping, not muted. IOW, designed so that least possible builder intervention is required.

I assume I am missing some important safe guard of equipment.

So bottom line: the pins are arranged differently than the representation on top down view. There is a jumper installed between two pins at edge of board. For the other set of pins, I have a mini-switch: should I solder it to the set of pins behind the one that sits at the edge of the board.

I'd any words of caution or direction.

Many thanks,

Richard Moss
Washington, DC

[FFF]

You got it wrong, let me explain:
J1 is the connector-block/pad for the speakers (check component layout pics in the AI too).
J2 was only 1 jumper, now it is a 'jumperblock', consisting of two jumpers. (some amps here have a jumerblock Jx with 5-7 jumpers = 10-14 pins.
One jumper (of J2) makes all amp-circuitry go to sleep = very low power mode.
The other pins 'mutes' the amp = no power output = no sound.
Mute is usually used to prevent a/the power-up 'thump' or 'plop' sound when you power up a/the power-stage of an ampifier = this amp.
So you could connect the two 'sleep' pins on J2 and put the switch on the other two 'mute' pins of J2.
Set to mute, switch on, then un-mute + listen to sound.

So, in:
"* the two pins closest to the output-connections refer to Mute, an input",
means:
* the two pins (pair) of J2 (=mute/sleep jumperblock) closest to J1 (= output-connections = for speakers), refer to Mute, an input, for a Mute-Switch (if you wish, otherwise just connect the two pins).

I changed the AI.

OK?

[rlmoss]

FFF, thank you for explaining J1 and J2. I'm at university computer lab without my printed AI; I'll look at the layout pics and the revisions.

So far, I get this: put a toggle on/off on the 2 "mute" pins.

But you write: "mute is usually used to prevent...power/up thump." Yet the sequence noted is "Set to unmute; switch on; then un-mute,+ listen to sound." If I set to unmute and switch on, wouldn't I hear the "thump?"

Is it the designer's intention to put the amp to "sleep" (very low power) rather than to turn it off? Or is assumed that users will plug into a surge protector or wall switch and turn power "on" or "off" at the source?

I'm feeling very dense.

Richard

[Scratchy]

But you write: "mute is usually used to prevent...power/up thump." Yet the sequence noted is "Set to unmute; switch on; then un-mute,+ listen to sound." If I set to unmute and switch on, wouldn't I hear the "thump?"

I'm sure that's just a typo. It should say "Set to mute; switch on; then un-mute,+ listen to sound."
Sleep would be good for a car, where you leave the amp always connected, but just put it to sleep when the ignition key is turned off.
My 50VA toroid powered AMP6 stays on at all times & I just mute it at night when the in-wall speakers are no longer required to play music 7x24 (if that makes any sense). I never actually shut off the AC to this amp.

[mysterious]

Hey is it possible to switch Mute and Sleep at the same time? Or will there still be noise from switching on the speakers?

[Scratchy]

Yes this is possible with a double pole switch or relay, but I'm not sure of the outcome.
I think the amp must come out of sleep first and stabilize before unmuting.
Perhaps you can test this and post your results?

[tuo]

I did test this. The test rig consisted an AMP6-Basic rev 1.10 with the mute modification, a lab power supply, speakers, a mobile phone as a source and a two pole switch connected to the sleep and mute pins. As a result I can say that there's no point to connect both pins to the same switch; the sound from the speakers is exactly same when the amplifier is just powered up with both pins already connected.

I also tested turning mute off after sleep mode. The sound from this was louder than I expected. It is still smoother than the other one, like "'kaPOW" versus "kapow".

[V-bro]

Hey is it possible to switch Mute and Sleep at the same time? Or will there still be noise from switching on the speakers?

This is done on many amps. MUTE and SLEEP can both be tied together to ground, with a single jumper...

But it will give more turn no noise than switching them sequential...

[V-bro]

It's not too hard to make a sequential circuit with a pair of transistors switching SLEEP on first, then MUTE at turn on and letting MUTE die first, then SLEEP at turn off....

[tuo]

Yes. My idea is a bit more simpler: a power switch and a delayed relay after it just for the mute pin. The sleep pin would be shorted. Too bad I haven't got time yet to implement a prototype and to test with it.