Manual mute switch

[Mikhail Vorozhtsov]

Hi all,

I'm getting ready to start soldering the kit (my first DIY project, be gentle) up. I've read that it is highly recommended to unplug headphones before turning the amp on/off and I find it somewhat inconvenient.  So I'm thinking about opting for a DPDT ON-ON switch (I have NKK's S6A, rated for 30VDC) before the jack ("mute" position would short both channels to the jack ground terminal). Does it make sense, can the overall SQ suffer from such modification? Would it be prone to "thumps" on (un)muting?

Thanks.

[Paul Birkeland]

The need to plug/unplug headphones will depend on the impedance of the headphones, and whether you have the Speedball.

For my own Crack with Speedball, I have turned it on and off with my HD-800's plugged in plenty of times, and I haven't had any issues (this should be about the worst combo).

Otherwise, you could use a DPST (or DPDT) switch to force a ground connection to the headphone jack outputs until the switch is opened. 

[Mikhail Vorozhtsov]

The need to plug/unplug headphones will depend on the impedance of the headphones, and whether you have the Speedball.

For my own Crack with Speedball, I have turned it on and off with my HD-800's plugged in plenty of times, and I haven't had any issues (this should be about the worst combo).

I have HD-650 and Speedball (building a plain Crack first), I also plan to get film caps sometime next year. I realize that leaving headphones plugged in doesn't necessarily mean that the drivers gonna blow up, but I want to be on the safe side.

Otherwise, you could use a DPST (or DPDT) switch to force a ground connection to the headphone jack outputs until the switch is opened. 

Hm, wouldn't the headphones still be connected, just in parallel with the switch and bleeder resistors? I was thinking about connecting red and white wires to the switch first, then connecting "not muted" switch terminals to R and T of the jack and "muted" terminals to S.

[Paul Birkeland]

You can do it either way if you like.  Wiring it the way I suggested keeps the signal current from flowing through the switch while you're listening.

If the headphones/bleeder resistors are shorted to ground during startup, there is no need to unplug the headphones. 

[Mikhail Vorozhtsov]

If the headphones/bleeder resistors are shorted to ground during startup, there is no need to unplug the headphones. 

Thanks, I'll go with it then.