KrammeAcoustics wrote:
That looks fine and simple ...good work, thanks for sharing

I'm going to find out, how to make a "turn off circuit" to, because it's not fun only having a turn on circuit, as i've got now ( only half done ). Something is going to happen soon. If not possible, i'll go back to two switches, one for the supply and another for the headphone-output.
Hi Kramme
How did you get on with the off circuit how loud is the thump i have not build my NP-100v12 yet ? i was thinking of a 3 way switch on at the top with off at the bottom as it passes center it disconnects the headphone jack but i havent really looked into it or thought what type of switch on/off/on toggle or something any ideas ?
i refined the Delay circuit as i got more use to eaglecad and now includes and input for audio and a pcb headphone jack so its a one stop solution for headamps i have included the board files for eagle if anyone wants to tweek it also the schematic,etch file,component layout pdf
you can find the files here
http://homepage.ntlworld.com/ruperthirst/Recent%20DIY%20Projects/Audio%20Projects/the updated Schematic gives up to 55 secs of delay but this can be increased by changing the pot value.
heres what it looks like unfortunately the relay has not arrived yet or the trim pot so i ghetto soldered one to the bottom to test the prototype pcb design 100mm x 40mm.



on power up the led will illuminate till the timer runs out then will extinguish at which point the relay will turn on connecting the right and left channels in to the PCB headphone jack .
The board layout is designed for a Neutrik jack which are cheap but of good quality there are around £2 delivered on ebay
the 555 was rescued from a commodore plus 4 computer just for nostagia

good thing is with this circuit is it will take anything from 5-18v its only dependent on what relay voltage you use remember to use caps of 25v+ though if anyone decides to hit the 18v end but since relays tend to jump to 24v after 12 this shouldnt be an issue.
i designed this with regards to the NP-100v12 headamp project so ill prob post something in there also
Thanks for reading my boring txt

Koog