[gurus]

Quote:

 
In the never ending quest for better SQ, this HE-6 owner removed the two Mills 10 ohm resistors connected in parallel to the 8 ohm speaker taps of the auto-biasing BAT VK-55SE. There was absolutely no improvement whatsoever.
 
In fact, the opposite was the case. At least one tube in the left channel went microphonic and the center image "wandered". These traits became apparent almost immediately and lasted over the entire 7 minutes the amp was subjected to this impedance mismatch.
 
Needless to say, the Mills have been reinstalled and apparently no permanent damage was done. Once again enjoying the synergy of these cans with the BAT and the Calypso linestage.

 


In my amp driving the HE-6 I can definitely hear the change in sound with the resistors in now that I have my Wadia transport back working in a semi state (trying to find a new unobtainium laser).
 
Listening to Holy Cole- I can see clearly now- with the resistor the bass is stronger (I like the more solid thwack of the kick drum -Ben Webster at the REnaissance- Georgia on my mind and other cuts- Analogue Productions)  and the sound stage is slightly collapsed, everything is a bit rounder and there is more sibilance and it is clearly evident  in the first two lines. So without the resistors  the sound is more transparent, almost no sibilance and the piano has more decay time and the most important more air around the instruments. Tho I must admit on some (CD's)  recordings the resistors do take the edge off more so when listening to Flac files off my computer. So a real quagmire to decide.
 
And I am surprised that the BAT had problems without the resistors- tho the 6C33B tubes tend to be very finicky.

 

[essencez]

Hi, I have recently purchased an Hifiman HE-6 mostly due to the praises from David's Battle of the Flagships piece. During the audition I've found its sound signature much to my liking.
 
I was originally planned to drive it with Woo Audio's WA2 (after Skylab's comment about the combination) but found the results to be unsatisfactory especially with the distortion at higher volume levels. I am currently using the WA2 as a preamp and using my speaker amp, Cambridge Topaz AM10 to drive them and so far very happy with the performance.
 
Currently looking at an aftermarket cable upgrade, I had connection issues with the stock cable but was too lazy to send it back for a replacement and just took the loose, right side connection jack apart and resoldered the connection, although now it looks kinda ragtag. I've been swaying towards toxic cables, any recommendations will be appreciated.
 

 

[preproman]

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

 

 

[Dr. Roberts]

Quote:

 
Which tube became microphonic? And did it go away after you re-installed the resistors?

 
When listening to how the amp behaved without the resistors, I concluded the wiser course of action was to stop subjecting it to the impedance mismatch sooner as opposed to later. Therefore, did not make the effort to determine which tube(s) had gone microphonic.
 
With the resistors re-installed, the SQ returned to what I have become accustomed to with this amplifier, no tube noise and a stable center image.
 
 

 
The amp is equipped with 4 taps per channel which allows for three separate configurations for speakers ranging from 3 to 8 ohms of resistance. Obviously, the amp proved to be incompatible with a 50 ohm load.
 
For those more knowledgeable than myself, if an integrated amp is rated at 32 watts into 8 ohms from the taps, using the headphone output, would said integrated deliver approximately 5 watts into a 50 ohm load or does the wattage depend on the specific amplifier and/or how the headphone output is configured? In this case I am referring to the Leben CS-600.

 

[Happy Camper]

Approx. values are to half the wattage when doubling the impedance (orthos loads). So I'd say your in the ballpark. So that BAT is keeping your gratification sated?

 

[preproman]

For the Headphone out as well?

 

[gurus]

Quote:

 
When listening to how the amp behaved without the resistors, I concluded the wiser course of action was to stop subjecting it to the impedance mismatch sooner as opposed to later. Therefore, did not make the effort to determine which tube(s) had gone microphonic.
 
With the resistors re-installed, the SQ returned to what I have become accustomed to with this amplifier, no tube noise and a stable center image.
 
 

 
The amp is equipped with 4 taps per channel which allows for three separate configurations for speakers ranging from 3 to 8 ohms of resistance. Obviously, the amp proved to be incompatible with a 50 ohm load.
 
For those more knowledgeable than myself, if an integrated amp is rated at 32 watts into 8 ohms from the taps, using the headphone output, would said integrated deliver approximately 5 watts into a 50 ohm load or does the wattage depend on the specific amplifier and/or how the headphone output is configured? In this case I am referring to the Leben CS-600.

 Almost all regular amps have a lower output at the HP jack even if they are using the regular amp circuit to drive the phones. It is generally accomplished by adding a resistor (150 ohm+) to the amp circuit to drop the wattage. Very likely this is what should be in the Leben CS-600. The power output at the HP jack is quite low to be able to drive only regular headphones and therefore the small current draw by the headphones does not put a strain on the the transformer/tubes at different impedances.

 

[conquerator2]

Quote:

 Almost all regular amps have a lower output at the HP jack even if they are using the regular amp circuit to drive the phones. It is generally accomplished by adding a resistor (150 ohm+) to the amp circuit to drop the wattage. Very likely this is what should be in the Leben CS-600. The power output at the HP jack is quite low to be able to drive only regular headphones and therefore the small current draw by the headphones does not put a strain on the the transformer/tubes at different impedances.

 
My experience as well... I tried the HE-6 with a Yamaha receiver but had to use the 1/4 HP out and the results were very underwhelming... Not nearly enough volume and the soundstage was very dark and meh + started to distort heavily very early at relatively low volumes...
So wouldnt recommend the HP outs on receivers (most atleast) Not nearly as good as those on the HP amps...

 

[Dr. Roberts]

Quote:

 Almost all regular amps have a lower output at the HP jack even if they are using the regular amp circuit to drive the phones. It is generally accomplished by adding a resistor (150 ohm+) to the amp circuit to drop the wattage. Very likely this is what should be in the Leben CS-600. The power output at the HP jack is quite low to be able to drive only regular headphones and therefore the small current draw by the headphones does not put a strain on the the transformer/tubes at different impedances.

 
I was concerned that would be the reality. In other words, the Leben does not have sufficient power from the headphone output to properly drive the HE-6. However, these cans do sound sound engaging when amplified in this manner by the Leben regardless of the inherent compromises. Thanks for the info.
 
Makes me wonder how much the addition of the 10 ohm Mills resistors installed in parallel to the 8 ohm taps of the 55 watts into 8 ohms BAT amp lowers the output.
 
Quote:

 So that BAT is keeping your gratification sated?

 
Yeah....for now. Thinking about "going all the way" though with a pair of 009's and a BHSE. Am getting to the stage in life where I would basically prefer to forget about the gear and just "listen". Have read Tyll's comparison of the TOTL phones, and then his article on the various TOTL amps with the Stax cans which has convinced me the aforementioned combo would allow me to achieve my Head-Fi goal.
 
Realistically, this would need to be done in stages. The BAT would help out nicely in this regard when paired with a Woo Wee. I would prefer to keep my marriage intact!

 

[wuwhere]

Quote:

Originally Posted by Dr. Roberts /img/forum/go_quote.gif
 
Makes me wonder how much the addition of the 10 ohm Mills resistors installed in parallel to the 8 ohm taps of the 55 watts into 8 ohms BAT amp lowers the output.
 

 
The resistor is absorbing most of the power, but remember you are not using most of that 55 watts.

 

[gurus]

Quote:

 
I was concerned that would be the reality. In other words, the Leben does not have sufficient power from the headphone output to properly drive the HE-6. However, these cans do sound sound engaging when amplified in this manner by the Leben regardless of the inherent compromises. Thanks for the info.
 
Makes me wonder how much the addition of the 10 ohm Mills resistors installed in parallel to the 8 ohm taps of the 55 watts into 8 ohms BAT amp lowers the output.
 
 
Yeah....for now. Thinking about "going all the way" though with a pair of 009's and a BHSE. Am getting to the stage in life where I would basically prefer to forget about the gear and just "listen". Have read Tyll's comparison of the TOTL phones, and then his article on the various TOTL amps with the Stax cans which has convinced me the aforementioned combo would allow me to achieve my Head-Fi goal.
 
Realistically, this would need to be done in stages. The BAT would help out nicely in this regard when paired with a Woo Wee. I would prefer to keep my marriage intact!

Ok First of all I was partially wrong. Looks like the Leben CS300, at least has separate output taps from the transformer to achieve lower output power and impedance matching for the Headphone jack. So I would suspect the Leben 600 is configured the same way. It is the better way (right way)  to power the HP jack than to have a resistor across for a tube amp.
 
The BAT would give you 9.16 watts into a 50 ohm load and the balance of the 45+ watts would be sucked up by the 10 ohm resistor.

 

[grokit]

Quote:

Quote:

Originally Posted by Dr. Roberts /img/forum/go_quote.gif
 
Makes me wonder how much the addition of the 10 ohm Mills resistors installed in parallel to the 8 ohm taps of the 55 watts into 8 ohms BAT amp lowers the output.

 
The resistor is absorbing most of the power, but remember you are not using most of that 55 watts.

 
I thought the resistor has to be connected in series to lower the output level, in parallel only equalizes the impedance

 

[wuwhere]

Quote:

 
I thought the resistor has to be connected in series to lower the output level, in parallel only equalizes the impedance

 
It has to be in parallel. In parallel the voltage is the same between the resistor and the HE-6, in series the current is the same between them.

 

[gurus]

Quote:

 
I thought the resistor has to be connected in series to lower the output level, in parallel only equalizes the impedance

 
In series the resistor adds impedance so 50 ohms (HE-6) + 10 Ohms (resistor) =60 ohms impedance as seen by the amp, making it a more difficult load to drive for the amp; just what you were trying to avoid.

 

[Dr. Roberts]

Quote:

Ok First of all I was partially wrong. Looks like the Leben CS300, at least has separate output taps from the transformer to achieve lower output power and impedance matching for the Headphone jack. So I would suspect the Leben 600 is configured the same way. It is the better way (right way)  to power the HP jack than to have a resistor across for a tube amp.
 
The BAT would give you 9.16 watts into a 50 ohm load and the balance of the 45+ watts would be sucked up by the 10 ohm resistor.

 
Thanks gurus, from this one can conclude that wuwhere has been absolutely correct from the very beginning that a well designed tube-amplifier capable of delivering 55 watts into an 8 ohm load will properly drive the HE-6.
 
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.
 
Nice to hear that Leben configures the HP output properly although it is somewhat frustrating that it is next to impossible to find out just how much power is generated into a 50 ohm load. The dealer as well as the importer have not been of much assistance when it comes to the headphone capabilities of the CS-600 and the manual is devoid of any info regarding the HP output. A pity really since it is such a unique and lovely sounding integrated.