[jiggler]

That title got at least the attention of some of you.

I wanted to add a switch to the output of an amp (RA-1 clone) to avoid the on-off pop. Will a SPST on the ground do it or do I need to switch left and right or all three?

 

[KTpG]

I would think a switch to ground would be bad.... wouldn't it short somehting? An inline DPDT or something would probably work better- inline between output and headphone jack... but i habe been known to be wrong... who knows...

 

[fyleow]

If you ground the switch I don't see why you would have a popping problem.

 

[stereth]

I think the pop is the caps charging up. Check your output and voltage to make sure there's no DC offset and your ground's in the right place. If that's the case, I would think you could put a switch to disconnect the ground to the output jack, as long as it's a SPST in line with the ground. Some people add a relay to delay turning on the output jack until the caps have charged...delays the startup by two seconds or so.

 

[grinch]

the ra-1 comes with a card that same something along the lines of "the popping noise made by power turning on/off will not hurt the headphones. we attempted to change the amp so that it wouldn't do this, but felt it was sonically inferior."

it probably isn't worth it. just keep your headphones off while you turn the amp on/off.

 

[jiggler]

I think my question has been misinterpreted. I simply was contemplating a switch between the output of the amp itself and the headphone jack so that, in use, I could throw the power switch on and then the headphone jack on. The natural time between those two actions would be enough to avoid the pop in the ears. I know I could leave them off my head while switching on but my goal is to completely eliminate the pop. I know Grado claims it will not hurt the headphones, but what else would you expect Grado to say? Perhaps it actually does damage a few headphones but not enough for them to be concerned about it.

I guess I will just put a DPST switch on the right and left channels to the headphone jack and see if it works. This is for my Mack Daddy RA-1 project so, when it is done, I'll post photos, etc. and we'll know the answer to my question.

 

[Haoleb]

Talk about ressurecting an old thread, but i think the pop comes from the DPDT switch used on the main power, ive made a couple versions myself and from what i can tell, if the positive and negative voltages are not switched at EXACTLY the same time it results in a pop. I would think this could be overcome with possibly some other circuitry, such as maybe solid state switches. But... havent come up with any designs myself.

Anyone ?

 

[dhp]

a jackoff switch eh?

 

[vixr]

What you are looking for is AMB's epsilon 12 muting PCB... Go to www.amb.org and look for his e12 board. I built it for my millett and it works like a charm. It uses a tiny relay, lytic cap and resistors. It delays turnon for whatever time you want by the values of the components, and all you hear is a tiny click when the relay closes...

 

[Uncle Erik]

Instead of just turning off the jack, why not have the switch select between the jack and a dummy load? Amps are generally happy when switched to a dummy, so it'd be pretty easy to do.

The other benefit would be for testing. A flip of the switch would put it into "test" mode.

Hmmmm... I'm building a few amps right now, and never even considered turning off the jack or wiring in a dummy load. Thank you for this thread! Something to think about tonight, for sure. What does everyone else think?