headphone bypass jack

[nukaidee]

I hope this is the right section, I am building the RUBY, namely a 386 chip based amp. I ran across the schematic of adding a headphone bypass jack to the amp here: http://runoffgroove.com/phones.png
I am having difficulties understanding it, I am wondering what am I connecting to the speaker's +? Because the amp is mono, it makes sense that the tip is connected to the output cap, the sleeve is grounded, and the ring shouldn't be used since its mono correct? so how does it disable the speaker?

Thanks!

[VictoriaGuy]

This uses a 'shorting/switching'-type phone jack.
Without a plug inserted in the jack, the + speaker lead is connected to the source. When a phone plug is inserted, the speaker is disconnected.

I've mangled the diagram to show the situation when no phone plug is inserted.

Cheers
John

[nukaidee]

this sounds like a totally different type of female phone jack altogether.. im guessing the ones i have now wont work? so will I have more pins on the back of the plug then?

[VictoriaGuy]

I'd think for most audio applications (and standard headphones) you'd want a stereo shorting jack. (3 conductors, 5 lugs)
Switchcraft Data Sheet

Switchcraft 14B jack: Mouser, Digikey Part#s

The mono version is the 12A by Switchcraft. They also make versions with longer threaded barrels, L12A, etc.

You should be able to get one of these from any decent electronics supplier. It's enough trouble connecting these up that it pays to avoid the cheaper brands, IMO.

Cheers
John

[nukaidee]

yeah, i usually go neutrik but switchcraft is okay too. where do you usually get your parts? mouser wants to charge me 20 for shipping, 8 at digikey. any other cheaper shipping suppliers in canada?

[VictoriaGuy]

Originally posted by nukaidee
any other cheaper shipping suppliers in canada?

Allied ships inside Canada, but I don't buy from them much. Prices seem a bit high, and I had a problem with some Neutrik jacks from them that didn't come with the correct washers/ferrules.

I haven't dealt with Electrosonic in Toronto for 20yrs- they used to be more set up for commercial accounts, as I recall.

justradios.com is a good ('ordinary') resistor/capacitor supplier- small family business with good service. Mostly oriented toward tube (higher voltage) caps.
TheTubeStore in Hamilton is reasonable for new tubes.

John

[nukaidee]

does anyone see this product at smallbearelec? http://www.smallbearelec.com/home.html
they've got good prices, but I dont seem to see the exact one, or am i missing something?

thanks

[VictoriaGuy]

Originally posted by nukaidee
does anyone see this product at smallbearelec? http://www.smallbearelec.com/home.html
they've got good prices, but I dont seem to see the exact one, or am i missing something?

thanks

It looks like the Neutrik NYS212 will do the job of the Switchcraft 14B- stereo and switched contacts. The standard price for these is 90 cents everywhere I looked (Mouser, PartsExpress), so take your pick.
John
BTW, I didn't answer your Q about where I buy parts- It's Digikey, Mouser,PartsExpress, apexjr, Hoffman amps for US suppliers.

[454Casull]

Originally posted by VictoriaGuy

justradios.com is a good ('ordinary') resistor/capacitor supplier- small family business with good service. Mostly oriented toward tube (higher voltage) caps.

Whoa, I pass by their house all the time.

[nukaidee]

oh! i see how they work now. for anyone who is confused you should check the wikipedia pages for TRS. they have some really good pictures there.