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Amps that can drive the HiFiMan HE-6 planar headphones - Page 146

post #2176 of 4932
Quote:
Originally Posted by ALRAINBOW View Post

Steve , thanks for replying. I have several more questions.

 

Sure. And first my apologies for taking so long to reply. Got a bit sidetracked.

 

Quote:
 If the first resister is to be in series to reduce the overall out voltage and allow to increase our volume pot. Does this effect factor damping factor.

 

Well, for dynamic headphones, which don't have a nice flat, resistive impedance curve, it can effect frequency response. But for orthos, which is the subject of this thread, the concept of "damping factor" isn't really relevant. The impedance curve of orthos is flat and virtually purely resistive so the resistor's only effect is signal attenuation.

 

Quote:
Second question. I am assuming the resister in parallel with the headphones is to match the nominal imp of that particular headphone.

 

No, it's not to match the impedance of the headphone, but rather to allow the headphone to see a lower output impedance from the amp than it would see if just using a series resistor.

 

Let's say you're using a 100 ohm series resistor. Then the impedance seen by the headphone would be 100 ohms. But add a 10 ohm parallel resistor and now the headphone sees an impedance of 100 ohms in parallel with 10 ohms which comes to about 9 ohms.

 

Of course you could do all the attenuation with just a parallel resistor, but it may end up being of such a low value that it could end up having to dissipate a fair amount of heat. So a series/parallel pair is a good compromise to give you a lower output impedance while not having to dissipate much heat.

 

Quote:
 Third question . Would it be better to have the resister as like 8 ohms. And resister in series from there to antenna the the output voltage and the final resister in parallel with headphone matching the headphone . At the speaker terminal the amp would see a nominal load of 8 ohms .

 

Well, as I said above, the purpose of the parallel resistor isn't to match the headphone impedance but rather to have the headphone see a sufficiently low output impedance that it won't have a significant effect on its frequency response.

 

se

post #2177 of 4932
Quote:
Originally Posted by NZtechfreak View Post
 

Thank you for that post Steve, wonderful. There is a sentiment that suggests a person doesn't truly understand something unless they can explain it simply, or stated differently, in a form that is accessible to the person receiving the explanation in a way that facilitates their understanding - your post is a wonderful example of that.

 

As a doctor, which is to say fundamentally a scientist, and also a musician, I really appreciate the fine line between appreciating sound science, while also realising that it has limits where it intersects with something subjective like music, and for me your commentary is the perfect marriage of those two sometimes difficult bedfellows.

 

My thanks sir.

 

Thank you for the very kind words, NZtechfreak. However as a caveat, just because someone seems to be able to "explain" something doesn't mean that the explanation is a sound one. I mean, I've seen some rather uh... "creative" explanations in my time. :D

 

But I enjoy explaining things when I can. When you explain something, it forces you to think about what it is you're explaining (as opposed to just regurgitating something you've read) and that can lead to a deeper understanding than you had before. Also, it helps keep things fresh in the mind.

 

se

post #2178 of 4932

@ Steve Eddy's explanation... of "Explanations."

thumbsup.gif

post #2179 of 4932
Quote:
Originally Posted by Silent One View Post

@ Steve Eddy's explanation... of "Explanations."
thumbsup.gif

Uh... Could you explain that, please? biggrin.gif

se
post #2180 of 4932

he means with you explaining it to others it should inspire you to understand your thouhgts more deeply.

he is correct to a point , at times people will ask me for an answer, in my response sometimes I come to realize my answer has holes in it..

post #2181 of 4932
Quote:
Originally Posted by ALRAINBOW View Post

he means with you explaining it to others it should inspire you to understand your thouhgts more deeply.
he is correct to a point , at times people will ask me for an answer, in my response sometimes I come to realize my answer has holes in it..

I was just funnin' with him. biggrin.gif

se
post #2182 of 4932

:dt880smile:

 

Yeah, we're just funnin'...

 

 

:wink_face: But my HE-6 amp pairings are no joke! Getting some good listening in the last couple of weeks.


Edited by Silent One - 11/25/13 at 11:04am
post #2183 of 4932
Quote:
Originally Posted by Silent One View Post

wink_face.gif  But my HE-6 amp pairings are no joke! Getting some good listening in the last couple of weeks.

Sweet! That's what it's all about! beerchug.gif

se
post #2184 of 4932

My recent listening patterns have settle into:

 

Shindo Laboratory Sinhonia monaural blocks > HE-6 (75%)

Sansui G-22000 via speaker taps > HE-6 (25%)

post #2185 of 4932
Nice! I've always loved that "industrial" green Shindo uses. And that Sansui seems to be rather interesting in that it has it's speaker outputs on its side. Must make it a little more convenient for headphone use. You're aware by the way that those old receivers typically drive the headphone outputs from the speaker outputs, yes?

se
post #2186 of 4932
Quote:
Originally Posted by Steve Eddy View Post

Nice! I've always loved that "industrial" green Shindo uses. And that Sansui seems to be rather interesting in that it has it's speaker outputs on its side. Must make it a little more convenient for headphone use. You're aware by the way that those old receivers typically drive the headphone outputs from the speaker outputs, yes?

se

 

Yes, I am aware. But with my particular model (G-22k) the headphone output is handicapped - power and sonics. The sound heard between headphone out and speaker output is night and day. Due to the receiver's broad width of 25" with taps on either side, I had my pigtails made :tongue_smile:with a 36" split.

 

I have a hunch though, that the Shindo/HE-6 pairing could be improved. Currently, I'm using the HE-Adapter and run 2.5M Auditorium A23 cable from amp to adapter. Why? Because it's all I have :confused: I just have a feeling if I swap in higher quality resistors and shorten the speaker cables, things will improve.

 

In your view, any gains to be made this way? Thanks for reading and happy listening.

post #2187 of 4932
Quote:
Originally Posted by Silent One View Post
 

 

Yes, I am aware. But with my particular model (G-22k) the headphone output is handicapped - power and sonics. The sound heard between headphone out and speaker output is night and day. Due to the receiver's broad width of 25" with taps on either side, I had my pigtails made :tongue_smile:with a 36" split.

 

Hmmm. Looking at the service manual, the headphone outs appear to be driven from the speaker outs through 220 ohm 5 watt resistors. Are you currently driving the headphones directly off the speaker outs without any resistive attenuators? If so then the only difference would just be a matter of attenuation from the headphone outs. It would be pretty easy for someone competent to simply pull the 220 ohm resistors and jumper them so that the headphone outputs will give you the same as the speaker outputs.

 

Quote:
I have a hunch though, that the Shindo/HE-6 pairing could be improved. Currently, I'm using the HE-Adapter and run 2.5M Auditorium A23 cable from amp to adapter. Why? Because it's all I have :confused: I just have a feeling if I swap in higher quality resistors and shorten the speaker cables, things will improve.

 

In your view, any gains to be made this way? Thanks for reading and happy listening.

 

For transformer output tube amps, I think it's best to have the load match the tap on the output transformer. If you're going to go messing with the resistors in the HE adapter, perhaps remove the 25 ohm series resistors and replace the 10 ohm resistors with some higher power 10 ohm resistors.

 

se

post #2188 of 4932
Quote:
Originally Posted by Steve Eddy View Post
 
Quote:
Originally Posted by Silent One View Post
 

 

Yes, I am aware. But with my particular model (G-22k) the headphone output is handicapped - power and sonics. The sound heard between headphone out and speaker output is night and day. Due to the receiver's broad width of 25" with taps on either side, I had my pigtails made :tongue_smile:with a 36" split.

 

Hmmm. Looking at the service manual, the headphone outs appear to be driven from the speaker outs through 220 ohm 5 watt resistors. Are you currently driving the headphones directly off the speaker outs without any resistive attenuators? If so then the only difference would just be a matter of attenuation from the headphone outs. It would be pretty easy for someone competent to simply pull the 220 ohm resistors and jumper them so that the headphone outputs will give you the same as the speaker outputs.

 

Quote:
I have a hunch though, that the Shindo/HE-6 pairing could be improved. Currently, I'm using the HE-Adapter and run 2.5M Auditorium A23 cable from amp to adapter. Why? Because it's all I have :confused: I just have a feeling if I swap in higher quality resistors and shorten the speaker cables, things will improve.

 

In your view, any gains to be made this way? Thanks for reading and happy listening.

 

For transformer output tube amps, I think it's best to have the load match the tap on the output transformer. If you're going to go messing with the resistors in the HE adapter, perhaps remove the 25 ohm series resistors and replace the 10 ohm resistors with some higher power 10 ohm resistors.

 

se

 

On the Sansui, I'm simply connecting direct to speaker taps no attenuation, no resistors. With the HE-Adapter box, I'm hoping to track down someone locally who'd like to touch it up for a few dollars, as I wouldn't know what's best or what works. Are you suggesting maybe I can get by without series resistors and live on the 10 Ohm parallel resistors alone?

:popcorn:

post #2189 of 4932
Quote:
Originally Posted by Silent One View Post
 

 

On the Sansui, I'm simply connecting direct to speaker taps no attenuation, no resistors.

 

Then I'd explore the option of jumpering those 220 ohm resistors and driving your headphones from the headphone jacks. Would certainly be less messy that way.

 

Quote:
 With the HE-Adapter box, I'm hoping to track down someone locally who'd like to touch it up for a few dollars, as I wouldn't know what's best or what works. Are you suggesting maybe I can get by without series resistors and live on the 10 Ohm parallel resistors alone?

 

Technically, yeah.

 

You see, the purpose of output transformers in amps like that is to present the tube driving them with an ideal load for that particular tube. So for example let's say the tube wants a 5k load on its plate. Well, in order to get that from a nominal 8 ohm loudspeaker load, the transformer has to be a step-down type with a 25:1 ratio. Transformers reflect impedances as the square of their turns ratio so with an 8 ohm load on the secondary, the tube will see 25^2 x 8, or 5,000 ohms. Now let's say you connect a 50 ohm headphone to the 8 ohm tap. Instead of seeing a 5k load on its plate, the tube will now see 25^2 x 50 or about 31,000 ohms. With the HE adapter connected to a 50 ohm headphone, the impedance on the secondary is 33 ohms so the tube will see a load of about 21,000 ohms.

 

Eliminate that series resistor and the secondary will see 10 ohms in parallel with 50 ohms, or about 8.3 ohms and now the tube will be loaded with something much closer to the 5k ohms it wants to see.

 

se

post #2190 of 4932

^ +1 to Mr. Eddy's excellent post. :)

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