Joseph Grado speaker output to headphone adapter

[rickcr42]

for an alternate take check out the speaker/headphone junction box here :

http://www.avahifi.com/root/audio_ba...pdf/ab1987.pdf

Not too big at 281K but right click and "save as" is probably best.
This is how i configure my boxes that have headphone resitor matching networks but I take it a step further by making one headphone output and switch optimised for high Z cans and the other uses the above Joe Grado resisitor matrix.

Another thing it is my habit to do is to switch in the headphone matrix THEN switch off the speakers so the amp always "sees" a load at its output.
Some amps do not take kindly to having a no load situation and have been known to self destruct,especially some tube amps.
The fix is not easy and not cheap so i take no chances and the additional load in parallel with the speaker load will do ZERO harm.A nice thing if you are running extension speakers in another room for someone else and want to listen to headphones locally.

so my "box" is a set of four toggles :

Toggle Switch 1-speaker A

Toggle Switch 2-speaker B (in my case goes to my "dynaquad" style Hafler QD-1 MKll passive surround system)

Toggle Switch 3-high impedance cans

Toggle Switch 4-low impedance cans

Gadgetised and assessorised Rick



[size=medium]BAN THE SPRINGCLIP !!!!!!!!!!![/size]

 

[dsavitsk]

Quote:

Originally Posted by rickcr42 Another thing it is my habit to do is to switch in the headphone matrix THEN switch off the speakers so the amp always "sees" a load at its output. Some amps do not take kindly to having a no load situation and have been known to self destruct,especially some tube amps. The fix is not easy and not cheap so i take no chances and the additional load in parallel with the speaker load will do ZERO harm.A nice thing if you are running extension speakers in another room for someone else and want to listen to headphones locally.

Would a make before break 4pdt work for this, and if so, does anyone make one? I would love to put a headphone jack into a gainclone.

-d

 

[rickcr42]

two 4PST or 4PDT (nothing conected to the bottom posts) would work fine then you would just sequence headphones "ON" then amp "OFF".

simple is good

simplyRick

 

[dsavitsk]

Quote:

Originally Posted by rickcr42 two 4PST or 4PDT (nothing conected to the bottom posts) would work fine then you would just sequence headphones "ON" then amp "OFF".

Does this require the user to switch the switches in the correct order? Seems confusing to me.

 

[rickcr42]

simple really-

to listen to headphones just switch the headphone toggle to "ON" .Then toggle the loudspeaker to "OFF"

the only place you can get into trouble like this is if you are playing inefficient loudspeakers LOUD and you switch on High efficiency heaphones.The power blast could cause damge in some rare cases so back off on the volume before switching (a good idea anyway).The same would be true of a sinle 2PDT switch used as a straight Spkr/Hdpn switch.

My personal preference is for individual switching due to more options being available .There ARE times when both speakers and cans are active.
Same with my multiple Speaker/Headphone Sitch box.If it were a simple Spkr/Hdphn + low Z/high Z box i would be limited to one single output at a time.since my surround system is passive and connects to my amp that will not do so it is a simple flick of a switch to bring it online and if i want to listen to two sets of can for whatever reason i cam.

 

[dsavitsk]

Quote:

Originally Posted by rickcr42 simple really- to listen to headphones just switch the headphone toggle to "ON" .Then toggle the loudspeaker to "OFF" the only place you can get into trouble like this is if you are playing inefficient loudspeakers LOUD and you switch on High efficiency heaphones.The power blast could cause damge in some rare cases so back off on the volume before switching (a good idea anyway).The same would be true of a sinle 2PDT switch used as a straight Spkr/Hdpn switch. My personal preference is for individual switching due to more options being available .There ARE times when both speakers and cans are active. Same with my multiple Speaker/Headphone Sitch box.If it were a simple Spkr/Hdphn + low Z/high Z box i would be limited to one single output at a time.since my surround system is passive and connects to my amp that will not do so it is a simple flick of a switch to bring it online and if i want to listen to two sets of can for whatever reason i cam.

I see where you would prefer this set up, but I think I'll respectfully disagree and leave it at that. I have never wanted to use phones and speakers at the same time, and I would feel uncomfortable with a self destruct switch on my amp.

So, back to my original question, is a make before break switch what I should use assuming I only ever want one signal at a time from my power amp? Really I am just asking about the terminology -- I am assuming that make before break means that the switch makes the next connection before breaking the first, in essence allowing there to be 2 completed circuits for a short amount of time, but i want to make sure this is correct. Also, I am looking to find out if there are 4 pole toggles that do this, or if I need to use a more substantial rotary switch.

Thanks,

-d

 

[rickcr42]

Quote:

So, back to my original question, is a make before break switch what I should use assuming I only ever want one signal at a time from my power amp? Really I am just asking about the terminology -- I am assuming that make before break means that the switch makes the next connection before breaking the first, in essence allowing there to be 2 completed circuits for a short amount of time, but i want to make sure this is correct. Also, I am looking to find out if there are 4 pole toggles that do this, or if I need to use a more substantial rotary switch. Thanks,

your best shot at finding a great high current "shorting" switch at a rational price,either toggle or rotary,is one of the surplus dealers like Nebraska or one og the others.

check the DIY links section for web addresses

 

[dsavitsk]

Quote:

Originally Posted by rickcr42 your best shot at finding a great high current "shorting" switch at a rational price,either toggle or rotary,is one of the surplus dealers like Nebraska or one og the others. check the DIY links section for web addresses

Thanks Rick,

-d

 

[rickcr42]

you got it man

[size=small]Up , Up , and AWAAAAY ![/size]