[gerG]

I needed to change the cable on my Ultrasones. I took out the little circuit board in the left cup, assuming that it was just a connection point for the wire junctions. When I turned it over I found what I think are diodes. There are 2 for each channel, set up in series, between signal and ground. Basically they are in parallel with the driver. I measure 2.0 V drop through a pair (diode test on a Fluke meter) either direction. Any guess what they do?


gerG

 

[bangraman]

I was wondering the same.

 

[Banfi T.]

Maybe driver protection. At least I can't think of anything else. I would remove them

 

[kin0kin]

my guess is that it is there to prevent the drivers from frying if you happen to turn the volume of your amp too high. higher volume = more power = more current. so if you turn the volume too high, or for whatever reasons your amp sends a current surge out...it will fry the diode before the drivers....helps to reduce replacement cost too

....however huge a company is, replacing a couple of diodes is cheaper than replacing the drivers.

 

[kramer5150]

Are you certain its a diode?
Could be a funly looking resistor, to alter the impedence??

Some audio technicas have resistors in series to add resistance and present a different impedence load to the amp.

Garrett

 

[Oink1]

Quote:

Originally Posted by kramer5150 Are you certain its a diode? Could be a funly looking resistor, to alter the impedence?? Garrett

That sounds nearer the truth to me Garrett

 

[gerG]

That was my first thought, but they measure in the megaohm range, and have different resistance in each direction. Not caps either. Definitely transistors. The stripe on one end is a hint as well. I will post pics later.


gerG

 

[gerG]

It would make sense as a protection device. Wouldn't the diodes act as a short over 2 V or thereabouts? That would protect the drivers, at the expense of the amp.


gerG

 

[nikongod]

Quote:

Originally Posted by gerG It would make sense as a protection device. Wouldn't the diodes act as a short over 2 V or thereabouts? That would protect the drivers, at the expense of the amp. gerG

tangent drew up a volume limiter that looks just liek that, 2 diodes in opposite directions between signal and ground. when the voltage necessary to "close" them is exceded they short to ground.

you shouldent be playeng em loud enough that it matters anyways (say "yes mother")

 

[Potatoe1313]

You know, I caught the title of this as I was hastely scrolling up, and I could have sworn it said "Why do my Ultrasones have (inappropriate spelling of diodes) inside?"

[size=xx-small]edited by jerb's request[/size]

 

[jerb]

lets keep it 'G' i here, smaller ones browse these forums too

 

[gerG]

I did a quick read on diodes, and it is a classic voltage clamp. I listen at such low levels that it is not an issue.

So, my HFI-650 now have a very nice twin Mogami cable. I set them up for portable listening, so the cable is only 6 ft, and has a Canare mini plug. It really killed me to put a damned mini on there, but all of my portable stuff has minis for outputs.

So far I am not missing the diodes, and I learned a lot about how the Ultras are tuned.


gerG