[gurus]

Quote:

 
 
 
One should also realize that while this listener's impressions regarding SQ are certainly not definitive, it is probably better to equalize the impedance when using a tube-amp with the HE-6 by using resistors.
 
 

 
Definitely yes unless the manufacturer states otherwise, even then I would be careful.  Ayon, Marqules and Octave Audio have said in emails that their amps can drive a 50 ohm load with no problem, no resistor needed while the likes of JE Audio, MasterSound do not recommend using their amps to drive the HE-6 even with the resistors added to balance the load  to 8ohms. Pathos recommends using a resistor.

 

[drez]

If you're any good at soldering you can do this:

This looks awesome, I might do this in the future but I have no idea how to do a secure strain relief. Do you have any tips?

 

[Dr. Roberts]

Quote:

 
Definitely yes unless the manufacturer states otherwise, even then I would be careful.  Ayon, Marqules and Octave Audio have said in emails that their amps can drive a 50 ohm load with no problem, no resistor needed while the likes of JE Audio, MasterSound do not recommend using their amps to drive the HE-6 even with the resistors added to balance the load  to 8ohms. Pathos recommends using a resistor.

 
From the man himself, the designer of all BAT gear..........
 
[size=11pt]The amp does not care whether you have a resistor there or not. That is from the operating stand point. Whether its presence will affect the sound through your head phones – I don’t know, but you can easily try that. You can even try a heavier load.[/size]
 
[size=11pt]Regards,[/size]
 
[size=11pt]Victor[/size]

 

[Terja]

First of all sorry for jumping ships but this is far more relevant knowledge for HE-6 users.
 
I have a Hifiman HE-500 that I have been using via the speaker taps of a transformer coupled tube amp (musical paradise mp-301 mk2). I am well aware of the need to use resistors with such tube amps to keep the transformers cool and happy. Based on the parallel resistors equation ( combined resistance = R1xR2 / R1+ R2 ), I have a combined resistance of 5.68 ohms from both my HE-500 resistance of 34.5 ohms (measured) and parallel resistor of 6.8 ohms.
 
The resistors I am using have a power rating of 10 watts (based on forum recommendations, including Garry the designer of the MP-301). Here is my question: Why does the resistor have to have a 10 watt rating? Can I get away with say a 1 watt resistor (or less)? Would a 1 watt resistor soak up less power leaving more for the headphone? The amp outputs 6.5 watt per channel only so I would like as much of that pumped to the headphone. With a higher output amp this wouldn't be such a concern. Thanks for any input.

 

[wuwhere]

Quote:

First of all sorry for jumping ships but this is far more relevant knowledge for HE-6 users.
 
I have a Hifiman HE-500 that I have been using via the speaker taps of a transformer coupled tube amp (musical paradise mp-301 mk2). I am well aware of the need to use resistors with such tube amps to keep the transformers cool and happy. Based on the parallel resistors equation ( combined resistance = R1xR2 / R1+ R2 ), I have a combined resistance of 5.68 ohms from both my HE-500 resistance of 34.5 ohms (measured) and parallel resistor of 6.8 ohms.
 
The resistors I am using have a power rating of 10 watts (based on forum recommendations, including Garry the designer of the MP-301). Here is my question: Why does the resistor have to have a 10 watt rating? Can I get away with say a 1 watt resistor (or less)? Would a 1 watt resistor soak up less power leaving more for the headphone? The amp outputs 6.5 watt per channel only so I would like as much of that pumped to the headphone. With a higher output amp this wouldn't be such a concern. Thanks for any input.

 
The amount of power that the resistor absorbs is not related to its power rating. Its related only to its resistance value. Because it has a lower resistance value, it gets more power than the HE-500 and its proportional to its resistance and the total resistance of both. So yes, you can use a lower power rating resistor.

 

[gurus]

Quote:

First of all sorry for jumping ships but this is far more relevant knowledge for HE-6 users.
 
I have a Hifiman HE-500 that I have been using via the speaker taps of a transformer coupled tube amp (musical paradise mp-301 mk2). I am well aware of the need to use resistors with such tube amps to keep the transformers cool and happy. Based on the parallel resistors equation ( combined resistance = R1xR2 / R1+ R2 ), I have a combined resistance of 5.68 ohms from both my HE-500 resistance of 34.5 ohms (measured) and parallel resistor of 6.8 ohms.
 
The resistors I am using have a power rating of 10 watts (based on forum recommendations, including Garry the designer of the MP-301). Here is my question: Why does the resistor have to have a 10 watt rating? Can I get away with say a 1 watt resistor (or less)? Would a 1 watt resistor soak up less power leaving more for the headphone? The amp outputs 6.5 watt per channel only so I would like as much of that pumped to the headphone. With a higher output amp this wouldn't be such a concern. Thanks for any input.

If you want more power to your headphones use a 15 OHM resistor in parallel. That will give you a impedance load of about 10  ohms and a power of about 2 watts to the HE-500.  And I would use a 5 watt resistor.

 

[wuwhere]

Yes, you can increase the resistor value to increase the power going to your HE-500. The rule of thumb is you can go as high as twice the value of the speaker tap, e.g., if you are using the 8ohms, you can go up to 16.

 

[Terja]

So I'm assuming at say 5.68 ohms the total power available from 6.5 watts @ 8ohms would be 9.15 watts (or should that simply be 6.5 watts - the max output that the amp is rated for?). To make it easy let's assume 6.5 watts available. Of that, the resistor at 6.8 ohms would get 5.43 watts ( 6.5watts x 5.68ohms / 6.8 ohms) and the headphone at 34.6 ohms would get 1.07 watts (6.5watts x 5.68ohms / 34.6 ohms).
 
I need the power that the headphone sees to be higher. So a higher ohm resistor like gurus suggests would be best. Still have a question though. What's the importance of the resistor wattage? Gurus, why do you suggest a 5 watt resistor? Why not 1 watt or 1/4 watt even?
 
 
Quote:

 
The amount of power that the resistor absorbs is not related to its power rating. Its related only to its resistance value. Because it has a lower resistance value, it gets more power than the HE-500 and its proportional to its resistance and the total resistance of both. So yes, you can use a lower power rating resistor.

 
Quote:

If you want more power to your headphones use a 15 OHM resistor in parallel. That will give you a impedance load of about 10  ohms and a power of about 2 watts to the HE-500.  And I would use a 5 watt resistor.

 

[gurus]

The resistor will not be able to handle the heat dissipation and would go Poof! You might get by with a 2 watt one but generally to be on the safe side double that.
 

 

[wuwhere]

Also, wouldn't you rather burn the resistor than your HE-500?

 

[Terja]

Okay, I think I get it. So I should try to somewhat match the power that the resistor is seeing with its power rating. Sounds so simple now

! Thanks wuwhere, gurus. I think I will go with a 5 watt, 15 or 16 ohm resistor to be on the best safe side and maximum power for the HE-500. Sweet.

 

[wink]

Quote:

Here is my question: Why does the resistor have to have a 10 watt rating? Can I get away with say a 1 watt resistor (or less)? Would a 1 watt resistor soak up less power leaving more for the headphone? The amp outputs 6.5 watt per channel only so I would like as much of that pumped to the headphone. With a higher output amp this wouldn't be such a concern. Thanks for any input.

If you run the resistor at or close to it's power rating it gets very hot.
In the interest if keeping it cool, it's best to run it at about half or less of its power rating.
That way you don't get any surprises such as  burn marks on the furniture or your hands.

 

[Terja]

Mmm ... that makes sense. A 16 ohm resistor will be seeing roughly 4.44 watts. I will go with a higher rated resistor. Would the 5 watts be adequate? It looks like the ratings jump from 5W to 10W. If I find an intermediate I will go for that. Thanks for the heads up.

 

[alota]

i don´t understand the need to put resistors that degrade the sound.
a dedicated amplifier is not better?

 

[gurus]

Quote:

i don´t understand the need to put resistors that degrade the sound.
a dedicated amplifier is not better?

No real dedicated amps for the HE-6 except for a couple.
 
Even with the resistors the speaker amps blow away similarly priced dedicated amps. And  you are getting two for the price of one. The same amp does double duty as a speaker amp and also drives the HE-6. So if you have a good speaker amp already at home the cost is zilch.