I have been trying to find a decent product, with no luck so far.
I cannot find any datasheet claiming, that no shortcircuit is present, when plugging/unplugging. -Next step is to write to neutrik, asking them directly?
Another option i consider is to use normal XLR plug's (Male+female), and just solder those types on our headset.
But i would like to keep it original through if possible.
Jesper.
I cannot find any datasheet claiming, that no shortcircuit is present, when plugging/unplugging. -Next step is to write to neutrik, asking them directly?
Another option i consider is to use normal XLR plug's (Male+female), and just solder those types on our headset.
But i would like to keep it original through if possible.
Jesper.
Hi all here 
I was digging into this jack phenomena thing.
After i did some research, and looking into severel datasheets, i took contact with Neutrik.
After a little while, someone really kind there, was replying my quistion.
This was some of the reply, which i also expected myself.
Anyway, could it be that it's just like this, and no equipment will fail for such a shorttime shortcircuit ? -Or am i crazy
I will not go offtopic here, but i think it is a good thing to know, that jack sockets really have to be selected carefully.
Jesper.
I was digging into this jack phenomena thing.
After i did some research, and looking into severel datasheets, i took contact with Neutrik.
After a little while, someone really kind there, was replying my quistion.
This was some of the reply, which i also expected myself.
Anyway, could it be that it's just like this, and no equipment will fail for such a shorttime shortcircuit ? -Or am i crazy
I will not go offtopic here, but i think it is a good thing to know, that jack sockets really have to be selected carefully.
Jesper.
If you are really worried about it (and I am not), the solution is 4 pin XLR or something with a 1/4 adapter. Unplug the 4 Pin from the headphone amp first, then the 1/4 to 4 pin adapter from the headphones.
I have a Pass F5-based headphone amp that in theory does not like the output shorted. I usually turn the volume down all the way and make sure the source isn't playing when changing phones. But I have forgotten many times. I usually unplug and plug real quick though. No problems yet.
I have a Pass F5-based headphone amp that in theory does not like the output shorted. I usually turn the volume down all the way and make sure the source isn't playing when changing phones. But I have forgotten many times. I usually unplug and plug real quick though. No problems yet.
Yes... I will proberly use an female XLR 3pin (what i got in drawer) on pre. chassis-front. Then make adaptors for both 6.35mm and 3.5mm. male jacks.
Jesper.
headphone outputs that had a 100r in the line would be impervious to this momentary shorting.
But the fashion now seems to be to go for very much lower output impedances. I adopted 10r in my last build (it had no location on the PCB) and even that is frowned on by many Members of this Forum.
Shorting the output when Zo<<1r is a risk.
But the fashion now seems to be to go for very much lower output impedances. I adopted 10r in my last build (it had no location on the PCB) and even that is frowned on by many Members of this Forum.
Shorting the output when Zo<<1r is a risk.
the curve on the contacts may make this a break before make as the plug slides in/out.
Interesting topic.
In 14 years listening to headphones only, with expensive headphones on a good dozen of different amplifiers I never had a problem with connecting/disconnecting the headphones with the equipment switched on (sometimes not even the volume turned down all the way).
No damage, no strange noises, so I safely assume that this is a non-issue?
But maybe I was just being lucky...
In 14 years listening to headphones only, with expensive headphones on a good dozen of different amplifiers I never had a problem with connecting/disconnecting the headphones with the equipment switched on (sometimes not even the volume turned down all the way
).No damage, no strange noises, so I safely assume that this is a non-issue?
But maybe I was just being lucky...
Funny that now that the group buy is on we seem to see a lot less uPA68h on eBay...still some left though. Can't wait to get my pcb.
Sorry if this was asked before but should uPA68h be matched channel to channel? I understand dn2540 needs to be matched to maintain similar bias channel to channel but does the varying idss of uPA68h between channels effect gain?
Sorry if this was asked before but should uPA68h be matched channel to channel? I understand dn2540 needs to be matched to maintain similar bias channel to channel but does the varying idss of uPA68h between channels effect gain?
I have played with adding resistance to my f5-based headphone amp. The results are certainly interesting. I might actually prefer 20r or so in series even with low impedance headphones. Adds some ambiance, sounds more like speakers in a room with more bloom. I know it's not accurate and the people used to the clinical sound of headphones (compared to speakers) might disagree. But it certainly changes to sound. It's kind of like the difference between speakers in a really well treated damped room and speakers in a typical living room. Iam used to the living room.
So, why do we typically add resistance to a preamp out but strive for near zero with a headphone amp? I realize the preamp drives a much higher impedeance next stage (a power amp) but does the added resistance provide some decoupling or filtering? What is the benefit?
No need to match the uPAs channel to channel. They will be bias controlled by J3s. They could just be relevant like within 2mA from each other.
Great. You just saved me from buying 10 of them. Now I can buy 2 instead. Thank you.
That is why I put a place there for an Rz or a jumper. Its a subjective area but its good to have the option.
The line output resistance gives some extra phase margin to that output and some damping to capacitive loading.
Near zero for headphones its the same damping factor logic as near zero for loudspeakers but adding some its the same like a tube amp of zero or little feedback might be preferred for giving a looser sense to a dry small full-range speaker or whatever is on the lean side. Further frequency response aberrations come with the high Zo & the load impedance shape interaction.
Good thing is that we can add some here but the circuit does not have a high intrinsic one that we can't further reduce.
Morning all.
In post number 204 & 205, Salas was writing something about lifting and pseudo coax shield.
I am trying different, while i am waiting for my Polish torrids, and some Alps 50K potentiometer to arrive.
I allway's had a hard time understanding howto layout a humfree preamp.
Will someone care to explain a little further, how this lifting shield (pseude shield) is done ? And perhaps some other tricks to try.
I have a little bit of slight hum still i am trying to get rid off.
Jesper.
In post number 204 & 205, Salas was writing something about lifting and pseudo coax shield.
I am trying different, while i am waiting for my Polish torrids, and some Alps 50K potentiometer to arrive.
I allway's had a hard time understanding howto layout a humfree preamp.
Will someone care to explain a little further, how this lifting shield (pseude shield) is done ? And perhaps some other tricks to try.
I have a little bit of slight hum still i am trying to get rid off.
Jesper.
One thing to test is if you have the same in headphones. If not so then its in the whole hi-fi system. You may get it from the big transformer field its another thing. Your PSUs share the same secondaries also. Wait to have the double mono shielded ones before you will see about final grounding IMHO. Then make it hum free on headphones as a unit first. When two signal lines refer to same ground return sometimes one channel's shield can be connected at one end only if there is a ground loop. You should mains earth your Aluminum plate anyway.
Good idea with headphones only!
Thanks for nece clear answer. / I will wait for the torrid's and then look into it.
(But what to do in waiting time
)Jesper.