[Templar-kun]

I'm not good in electronics or audio, so I have a question:
I have Denon AH-D2000 headphones, which are 25 ohm.
Found a bargain and can buy G&W TW-J1 amp quite cheap. But from specifications I saw that amp is powering headphones with impedance 32 to 600 ohm.

Will D2000 work with this amp? And if yes, will there be any side effects, like sound distortion, quality loss and etc? Should I better buy amp with specially low impedance support instead of this one?

 

[tomb]

Quote:

Originally Posted by Templar-kun /img/forum/go_quote.gif I'm not good in electronics or audio, so I have a question: I have Denon AH-D2000 headphones, which are 25 ohm. Found a bargain and can buy G&W TW-J1 amp quite cheap. But from specifications I saw that amp is powering headphones with impedance 32 to 600 ohm. Will D2000 work with this amp? And if yes, will there be any side effects, like sound distortion, quality loss and etc? Should I better buy amp with specially low impedance support instead of this one?

Will it work? Yes.

Is it optimum? Hard to say.
Looking at the Denon's specs, it has 106dB/mW, which is extraordinarily efficient. That may be a reason why this thing seems to be popular lately - because it won't take much of an amp to drive it and it may sound pretty good out of typical portable players.

That said, the impedance is quite low. Plus, power handling is up to 1.8W! For instance, maximum input power for both an AKG K701 and a Sennheiser HD600 are only 200mW. At that low impedance for the D2000, it sounds like it might be able to handle some whopping current and would prefer an amp to deliver it.

Looking at the G&W TW-J1, it appears to be a totally discrete, two-stage input amp. It uses dual-rail voltage regulation in the power supply, with a FET front end (they call it a MOSFET) and a BJT push-pull output stage. Power is listed as 800mW per channel, which is fairly good power, but not a blockbuster. Looking at the internals pic, the voltage regulators appear to be heat-sinked, but I can't see any on the output. A high current output amp would have output sinks to reject the heat caused from high current and Class A bias. So, it may be that it wants to swing a lot of voltage instead of bursting a lot of current. It would also need lots of ventilation (the G&W TW-J1 appears to be totally sealed - another indicator of low current).

Just guessing here, but there may be better choices. I'd look for something that has a high current output - perhaps a MOSFET output stage or something with a lot of ventilation slots/holes (not counting tubes). It may do fine because of the D2000's high sensitivity, but that can be misleading on high-efficiency phones that also happen to be low impedance: high current may be needed to get the best bass. IOW, it might be a bit bass-shy or have muddy bass without an amp that has good, high current control.

This was quite a bit of speculation, so please don't hold me liable.

 

[Templar-kun]

tomb
Thank for your reply.
If you saying this amp is not the best for me, it means it’s not the worst. This is still good enough for me, considering I’m getting it with good price.
I’m actually afraid that I may not be able to use them, or using them will give me nothing. Because of the low impedance.



Maybe someone experienced with familiar situation? What worse can I expect from this duel?

 

[roethlar]

You might get some hiss, but other than that it should be ok. You can always get an impedance adapter if it's a problem.

 

[eeerie1]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Will it work? Yes. Is it optimum? Hard to say. Looking at the Denon's specs, it has 106dB/mW, which is extraordinarily efficient. That may be a reason why this thing seems to be popular lately - because it won't take much of an amp to drive it and it may sound pretty good out of typical portable players. That said, the impedance is quite low. Plus, power handling is up to 1.8W! For instance, maximum input power for both an AKG K701 and a Sennheiser HD600 are only 200mW. At that low impedance for the D2000, it sounds like it might be able to handle some whopping current and would prefer an amp to deliver it. Looking at the G&W TW-J1, it appears to be a totally discrete, two-stage input amp. It uses dual-rail voltage regulation in the power supply, with a FET front end (they call it a MOSFET) and a BJT push-pull output stage. Power is listed as 800mW per channel, which is fairly good power, but not a blockbuster. Looking at the internals pic, the voltage regulators appear to be heat-sinked, but I can't see any on the output. A high current output amp would have output sinks to reject the heat caused from high current and Class A bias. So, it may be that it wants to swing a lot of voltage instead of bursting a lot of current. It would also need lots of ventilation (the G&W TW-J1 appears to be totally sealed - another indicator of low current). Just guessing here, but there may be better choices. I'd look for something that has a high current output - perhaps a MOSFET output stage or something with a lot of ventilation slots/holes (not counting tubes). It may do fine because of the D2000's high sensitivity, but that can be misleading on high-efficiency phones that also happen to be low impedance: high current may be needed to get the best bass. IOW, it might be a bit bass-shy or have muddy bass without an amp that has good, high current control. This was quite a bit of speculation, so please don't hold me liable.

Even though this was just speculation, it is very educational for those of us who know little about amplifiers... thanks!!!

 

[Templar-kun]

Quote:

Originally Posted by roethlar /img/forum/go_quote.gif You might get some hiss, but other than that it should be ok. You can always get an impedance adapter if it's a problem.

Thx. But what is a adapter? How does it look or where can I found on if needed? =]

 

[roethlar]

Check this thread: http://www.head-fi.org/forums/f4/whe...daptor-303885/

 

[mace2]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Will it work? Yes. - snip -

This was a great post. Very informative, thanks!

 

[AT0]

What if the impedance of your headphones is above the impedance of the source? Say a Sony NWD-B105 digital music player to headphones with an impedance of 50 ohms.

 

[jpelg]

Quote:

Originally Posted by eeerie1 /img/forum/go_quote.gif Even though this was just speculation, it is very educational for those of us who know little about amplifiers... thanks!!!

Quote:

Originally Posted by mace2 /img/forum/go_quote.gif This was a great post. Very informative, thanks!

x3.

Great post - thanks!

 

[QQQ]

Quote:

Looking at the Denon's specs, it has 106dB/mW

Nowhere near. I can't understand why people continue to look at these specs. How do you now under what conditions those results were received?
For example, AKG K701 listed sensivity are 105 dB/mW. If this true, k701 works fine out of any dap with its' 62ohm impedance rating...The truth is k701 has around 91db\mw...

 

[Headdie]

Interesting thread ! So far, I understand that impedance mismatch may and may not cause SQ problems. You'll have to try with an adapter and see for yourself... right?