[Duc]

DISCLAIMER: I in no way endorse or think it is a good idea to remove the jumpers from a Little Dot 2+ headphone amp, Nor take this amp apart. High Voltages are present and you could kill yer self. This is a really really bad idea, only a dumb-ass would do this.

Oh_Key

To remove the Jumpers...

Remove the screws at the bottom of the front panel.
Remove the screws at the bottom of the rear panel.

The entire bottom of the case will pull off.

 

[Duc]

OMG!!!
This bleepin site won't let me put up the next pic

Any who. The jumpers are up front one on the left and one on the right.
Just pull em off.

 

[Duc]

Yeah you were right. Sounds the same, just have to turn the volume up more.

Don't see the point, but i'm sure there is a good arguement out there.

B

 

[m8o]

Quote:

Originally Posted by Duc Yeah you were right. Sounds the same, just have to turn the volume up more. Don't see the point, but i'm sure there is a good arguement out there. B

LoL.... I thought I gave you that answer.

 

[m8o]

Quote:

Originally Posted by odmanca Also a side note, on page 7 of the user manual it's stated these jumpers are to be used to configure the amp for "high-sensitivity" and "low-sensitivity" headphones, high-sensitivity headphones being the HD595 and HD650 and low-sensitivity ones being the AKG K501 and K240DF.

My only complaint to David has been that they produce and English manual. Great that you can read it. I think there's an implication there in the way the manual presents it that high sensitivity goes hand in hand with low impedance then.

 

[vcoheda]

Thanks for the pics. Too bad you were unable to post the last one. I'm going to try removing the jumpers and see if there is any difference when using my K701's.

. . . Oh Wait, I was just re-reading some of these posts. So there is not going to be any benefit to taking out the jumpers when using low impedance headphones -- e.g., my K701's. No difference in sound quality or anything. Why is it an option then? I mean if there is a way, seemingly intentional, to adjust the amp to more closely match the impedance of your headphones, then you would expect some kind of resulting benefit.

Maybe I just have to try it and see.

 

[m8o]

I think it's so the amp operates at a lower voltage swing [gain] for the signal and has less risk of compression at loud passages.

 

[Dept_of_Alchemy]

Quote:

Originally Posted by m8o I think it's so the amp operates at a lower voltage swing [gain] for the signal and has less risk of compression at loud passages.

Compression being the same as clipping, just thought I'd point out the obvious.

 

[Duc]

I can email the last pic if you want

 

[ktogun]

Well, you all may have been in on my other discussion where I complained about the need for an english manual, and I subsequently have requested and received one from David. Much of the discussion being held now is answered in the English manual, which is why manuals are valuable. I think I remember some penguin whatever guy saying I was an idiot for needing an manual in english because it was plug and play. Clearly, time is saved through this process. The manual describes the jumpers and gives instructions for changing them. If you need me to, I can scan the manual in and post it.

 

[Funkdeal]

Quote:

Originally Posted by Duc /img/forum/go_quote.gif OMG!!! This bleepin site won't let me put up the next pic Any who. The jumpers are up front one on the left and one on the right. Just pull em off.

what exactly do the jumpers look like? i really have no knowledge of this kind of stuff, but it sounded easy so i figure i'd give it a try.

edit: i did a little research. are the jumpers the red and black rectangles very near the front? which ones do i take off? do i just yank them off with my fingers? thanks.

 

[penguindude]

Quote:

Originally Posted by Funkdeal /img/forum/go_quote.gif what exactly do the jumpers look like? i really have no knowledge of this kind of stuff, but it sounded easy so i figure i'd give it a try. edit: i did a little research. are the jumpers the red and black rectangles very near the front? which ones do i take off? do i just yank them off with my fingers? thanks.

For those of you who still cant figure it out, here is a big picture. The circled ones are the ones that should be removed. And they are the black ones.

 

[Funkdeal]

Quote:

Originally Posted by penguindude /img/forum/go_quote.gif For those of you who still cant figure it out, here is a big picture. The circled ones are the ones that should be removed. And they are the black ones.

thanks for the picture. i removed the jumpers. i can't tell if it sounds different, though.


edit: i've found that the volume difference has not changed since i removed the jumpers. i'm using k701s and the volume is at about 9 o'clock.

 

[Killahertz]

Quote:

Originally Posted by m8o /img/forum/go_quote.gif Now, I'm not sure you know what I mean by compression ... ...if you try to drive a low impedance in high impedance mode, the voltage swing of the signal is going to reduce (compress) on loud passages, because there's a limited amount of power the amp can deliver. I don't know if you know ohm's law. And I don't think I'm doing a good job at explaining it in regards to power in this context. But basically, there's a fixed amount of 'power' the amp can deliver. V = I*R :: Voltage = Current Times Resistance ; P = V*I or R*I*I :: Power = Voltage times Current or Resistance times Current Squared. If you try to feed a low impedance load too much voltage and the tubes can't flow the current (I) to deliver the power the voltage is going to reduce on its own across the load to a point where the amp can deliver enough current to max out the power it can provide. ...compression.

And I would agree that it does, and that it is audible. However, audibility is circumstantial, and will primarliy manifest itself at higher drive levels and/or with complex music (especially that which features considerable variations in dynamic range).

At higher drive levels and/or with complex music there is a perceptible loss of stage width, and a loss of fine detail and clarity (especially with vocals). The loss of fine detail and clarity also gave a (false) impression of increased bass warmth, albeit with a slight loss in definition.

Do bear in mind that the differences are circumstantial, and that they are not 'night and day'. However, given that the mod is a such a simple one, users of low impedance headphones should really give it a try

 

[penguindude]

Quote:

Originally Posted by Killahertz /img/forum/go_quote.gif And I would agree that it does, and that it is audible. However, audibility is circumstantial, and will primarliy manifest itself at higher drive levels and/or with complex music (especially that which features considerable variations in dynamic range). At higher drive levels and/or with complex music there is a perceptible loss of stage width, and a loss of fine detail and clarity (especially with vocals). The loss of fine detail and clarity also gave a (false) impression of increased bass warmth, albeit with a slight loss in definition. Do bear in mind that the differences are circumstantial, and that they are not 'night and day'. However, given that the mod is a such a simple one, users of low impedance headphones should really give it a try

Tried it, didnt like it. Again, the jumpers are meant for phones with really high impedance. If you can get the volume out of your regular setting, there's not much point in switching.