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Speaker amps for headphones
Dec 19, 2013 at 10:44 PM Post #1,981 of 3,871
alrainbow said:
What is there to be confused about . I followed what was given , it's not the volume I care about it's why was the resister overloaded. It's a ten watt resister. The way the circuit is destined the power for the headphone and the total power goes through that resister but regardless how odd I achieve excess of 10 watts . Now that the headphone is out of the circuit it's fine ice cold . So the headphones were using some serious power .
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Just because the resistor got hot doesn't mean it was dissipating more than 10W.  Cement wire wound resistors get quite warm at rated load.. burn your finger warm... That's how they are designed.
 
Dec 19, 2013 at 10:45 PM Post #1,982 of 3,871
potterma said:
  Just because the resistor got hot doesn't mean it was dissipating more than 10W.  Cement wire wound resistors get quite warm at rated load.. burn your finger warm... That's how they are designed.
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I run a similar setup (same amp too) and my resistors always stay nice and cool. I used 100ohm and 3 ohm.
 
Dec 19, 2013 at 10:51 PM Post #1,983 of 3,871
Well I know they can get warm or very warm to the touch but it's a new amp and 1500 headphones so I'm not happy.

And ohh , sis not hot and I am. Guessing it's because he is at 100 ohms and I am at 10 ohms . My point is this happened in about 15 mins and I would not go any longer.. I will measure the voltage if I can in the morning. Playing some kind of steady sound . But I am thinking that the total load across the resister and the added load of the headphone is exceeding or getting close to the max of the resister . AnywAy it's fine now.
 
Dec 19, 2013 at 11:36 PM Post #1,984 of 3,871
ohhgourami said:
 
I run a similar setup (same amp too) and my resistors always stay nice and cool. I used 100ohm and 3 ohm.
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Wow, that's a lot of attenuation.  Do you really need that much attenuation with the Krell?
 
Dec 19, 2013 at 11:42 PM Post #1,986 of 3,871
In reply to those 10w wirewound resistors getting hot. Those things will literally glow orange in the dark, and start to yellow/blacken when being overloaded. They will melt the skin right off your finger. They can take a real beating, so if you're touching them and not cussing at yourself from a burn, you're fine 
tongue.gif

 
Yes, I like to watch things blow up 
devil_face.gif

 
Dec 19, 2013 at 11:55 PM Post #1,987 of 3,871
ohhgourami said:
With +36dB gain, I sure do. I listen at ~32/151 volume with resistors.

Without resistor's I have to listen at 2/151.
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OK, good to know!  That is a lot of gain.  I seem to remember now that the input sensitivity was very low (meaning high gain) on that amp, but didn't realize it would require that much attenuation.  Was the gain accompanied by a high noise floor, or is it just volume knob adjustment you were after?
 
brunk said:
  In reply to those 10w wirewound resistors getting hot. Those things will literally glow orange in the dark, and start to yellow/blacken when being overloaded. They will melt the skin right off your finger. They can take a real beating, so if you're touching them and not cussing at yourself from a burn, you're fine 
tongue.gif

 
Yes, I like to watch things blow up 
devil_face.gif
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Keep flammable objects away!  
 
Dec 20, 2013 at 12:01 AM Post #1,988 of 3,871
potterma said:
 
Keep flammable objects away!  
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But that's no fun 
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EDIT: Seriously though, I do these things in a controlled environment with an extinguisher handy.
 
Dec 20, 2013 at 12:07 AM Post #1,989 of 3,871
brunk said:
  But that's no fun 
very_evil_smiley.gif
 
 
EDIT: Seriously though, I do these things in a controlled environment with an extinguisher handy.
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OK, good.  I was thinking of the window drapes!  Controlled destruction is fun :)
 
Dec 20, 2013 at 12:12 AM Post #1,990 of 3,871
potterma said:
  OK, good.  I was thinking of the window drapes!  Controlled destruction is fun :)
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Hehe it sure is! Depending upon the potential, I will do it outside, or in the bath tub with a basin of sand lol 
tongue.gif

 
Dec 20, 2013 at 12:20 AM Post #1,991 of 3,871
potterma said:
   
OK, good to know!  That is a lot of gain.  I seem to remember now that the input sensitivity was very low (meaning high gain) on that amp, but didn't realize it would require that much attenuation.  Was the gain accompanied by a high noise floor, or is it just volume knob adjustment you were after?
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Both. Very happy with the resistor setup. The HE-6 is only receiving 0.17Wpc compared to ~30Wpc. There has been no change in sound quality after carefully ABing for an hour.
 
Dec 20, 2013 at 4:38 AM Post #1,992 of 3,871
Yesterday I compared the Millenia with and without the resistor box. Directly from the speaker tap the sound is more dynamic and open. Now either the resistances I used are bad quality ones or attenuating the sound just kills the dynamics. I read that adding a bleeder cap may help with this. 
I do get a hum without the resistor box but it's not too bad, I think 6db attenuation would be enough to remove the hiss, 12db is overkill. 
I will try all kinds of setups I can think of over the weekend and I will use alligator clips to add remove resistances with ease.
 
If there is a will there is a way.
 
Dec 20, 2013 at 6:28 AM Post #1,993 of 3,871
I can say that for me removal of the attenuation had no effect on the sound. I am sure it has become louder but the krell kav 400xi. Is dead silent with just the 10 ohm across the speaker terminals .
Over today and the weekend I plan to do some better testing , and compare to some other amps as well. But for now bliss and thanks for all the work yup people have put into this..
 
Dec 20, 2013 at 7:03 AM Post #1,994 of 3,871
alrainbow said:
First of not all wire wound resisters are the same. As the ones with more space between them will have no inductance.
As for lands yes not intended for us. And they are a transformer as i said . The purpose of it is to keep the same load on the amp and allow for controlling the volume they are rated as well about 80 watts for a good one . And you can smoke them too . Lol I have. As I amusing the resister network you people were so kind to design , I have an issue.

I have an amp solid state rated at about 100 watts at 8 ohms . And using the HE6 headphones .

So I have a 8 ohm and 2 ohm in series with tap in the middle of them. As shown in this thread . Well the attenuation was fine but the 8 got hot , too hot. They are 10 wire wound in ceramic . So after this I just left the two resisters connected to the speaker terminal and connected the headphones directly to the speakers terminals so they all are in parallel .

The sound level seems to be the same and all is well . So does someone here know what I did that was wrong ?
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All resistors have inductance.
You can't get rid of it.
Even a piece of wire has inductance.
I assume you meant Low Inductance?

But In practice, if it's small enough, you can ignore it, especially at audio frequencies.

BTW, I've seen very hot ceramic resistors in the field. As a few posters have pointed out, some types do run extremely hot at full power, so may seem pretty damn hot at say 25% of their power rating.
 
Dec 20, 2013 at 7:14 AM Post #1,995 of 3,871
Yes I did sorry . It's just low enough to be ignored. So far very happy with the amp right now. I have two more to try out , when I can. But I do not expect to get anything more out of ot , maybe less. After what I heard yesterday I think my stax rig can in some ways do it better. I see you are up late .
 
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