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Headamp Blue Hawaii Special Edition - Page 389

post #5821 of 8720
Batch #4 parts just arrived

HeadAmp Audio Electronics - home of the Pico and Gilmore amps.  Now with Audeze, Fostex, HiFiMAN, Sennheiser, and STAX.
Find us at www.HeadAmp.com

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post #5822 of 8720
Quote:
Originally Posted by justin w. View Post

Batch #4 parts just arrived
 

Sweet!!!  Hopefully no fakes in there...:blink:

post #5823 of 8720
Quote:
Originally Posted by justin w. View Post

i will be sending an email about that soon

Thanks Justin!
post #5824 of 8720
So Justin, is the next production run (batch #4) sold out???
post #5825 of 8720

Can someone shed some light on the ALPS RK50 used in the BHSE?  

 

Does the RK50 use a ladder of SMD resisters vs. a conventional pot that drags contacts across a wire/membrane surface?  If the RK50 uses a resister ladder, is the adjustment perceived to be fully linear?  I can't tell from the specs on ALPS' Web site.

 

Thanks 

post #5826 of 8720

... not a part specialist here but from what I can read in the specs, this looks like a traditional potentiometer

i.e. NOT a stepped attenuator with single resistors :

 

http://www.alps.com/prod/info/E/HTML/Potentiometer/RotaryPotentiometers/RK501/RK50112A0004.html

 

-Part number RK50112A0004

 

-Number of resistor elements Dual-unit

-Gang error -100dB to 0dB 3dB max.

post #5827 of 8720
Quote:
Originally Posted by caseyse View Post
 

Can someone shed some light on the ALPS RK50 used in the BHSE?  

 

Does the RK50 use a ladder of SMD resisters vs. a conventional pot that drags contacts across a wire/membrane surface?  If the RK50 uses a resister ladder, is the adjustment perceived to be fully linear?  I can't tell from the specs on ALPS' Web site.

 

Than

It is a traditional pot built to the highest tolerance.  I have it on my BHSE & DIY T2 and I'm extremely happy with it.  However, If you already own a DAC with an excellent digital volume attenuation, then the DAC-T should be select over the RK50 for economic reason without any expense of performance.  What the RK50 is great for is an infinite adjustment of volume/step, while you are limited to 24 volume positions on the DAC-T.  

post #5828 of 8720

Hello Kevin,

 

What is the output impedance of the BHSE (and also, to compare, that of the SRM 727) ?

 

For information, the internal resistance (output impedance) of the RKV-II would be of the order of 0.05 Ohm: 200 Ohm (load) / 3600 (damping factor at 200 Ohm)

 

See the link (RKV-II and Verto): specifications :

http://www.audiovalve.info/rkv/audiovalve%20rkv%20mark2.php  

and  http://www.audiovalve.info/to/verto.php 

 

and the commentary of the constructor:

 

" For a game changing product a simple idea is not enough, you have to find also a proper implementation. There are already promising approaches in the market combining transformers with headphone amps to drive STAX headphones. But RKV and VERTO are now exploiting the full potential of that approach. Inductance and capacitance of the transformer can harm the sound. The Pikatron output transformers we use have only very little stray inductances and capacitances. To avoid distortion we use only a low step up ratio of 1 to 5. But key is the fact that the output impedances of RKV II and III are extremely low, too low to cause any negative effect on the sound."

 

Eric

post #5829 of 8720
Quote:
Originally Posted by eric65 View Post

 

What is the output impedance of the BHSE (and also, to compare, that of the SRM 727) ?

 

Eric

 

Not insulting, but not far either...

post #5830 of 8720

Eric, I think all the answers you need are right here : http://headwize.com/?page_id=751

 

Ali

post #5831 of 8720
Quote:
Originally Posted by eric65 View Post
 

Hello Kevin,

 

What is the output impedance of the BHSE (and also, to compare, that of the SRM 727) ?

 

For information, the internal resistance (output impedance) of the RKV-II would be of the order of 0.05 Ohm: 200 Ohm (load) / 3600 (damping factor at 200 Ohm)

 

WOW, we are up to .05 ohms. Also a complete fabrication.

http://www.krellonline.com/downloads/Evolution_Brochure.pdf

so you are telling me that the rkv-ii has the same impedance as a krell 402.

Really, is that so. Not even for the first microwatt. What mighty tubes

a pair of pcl805 must be. way stronger than 6c33.

 

The output impedance of the BHSE is 5.1k ohms on each side. For safety purposes

so that the diaphrams don't get destroyed. Same as srm313,srm323,srm717,srm727,

sr006t,sr007t,srm-t1,srm-t2 etc. If the Verto does not have these safety

resistors, it will definitely damage the headphones.

 

The 2 minute or more charge time on the verto is also real bad. That means that

the headphones don't have any bias for 2 minutes while the music is playing.

Very bad for the charge layer on the diaphragm. Koss learned this 40 years ago

with the esp6.


Edited by kevin gilmore - 8/10/14 at 4:09am
post #5832 of 8720
Quote:
Originally Posted by kevin gilmore View Post
 

WOW, we are up to .05 ohms. Also a complete fabrication.

http://www.krellonline.com/downloads/Evolution_Brochure.pdf

so you are telling me that the rkv-ii has the same impedance as a krell 402.

Really, is that so. Not even for the first microwatt. What mighty tubes

a pair of pcl805 must be. way stronger than 6c33.

 

The output impedance of the BHSE is 5.1k ohms on each side. For safety purposes

so that the diaphrams don't get destroyed. Same as srm313,srm323,srm717,srm727,

sr006t,sr007t,srm-t1,srm-t2 etc. If the Verto does not have these safety

resistors, it will definitely damage the headphones.

 

The 2 minute or more charge time on the verto is also real bad. That means that

the headphones don't have any bias for 2 minutes while the music is playing.

Very bad for the charge layer on the diaphragm. Koss learned this 40 years ago

with the esp6.

 

Just wait 2 minutes, the potentiometer of the RKV to zero, before listening to music. 
Really, I do not see where is the problem.

 

You have still not answer me concerning the internal resistance of the BHSE and SRM 727, without the resistance of security.

post #5833 of 8720
Quote:
Originally Posted by eric65 View Post
 

 

Just wait 2 minutes, the potentiometer of the RKV to zero, before listening to music. 
Really, I do not see where is the problem.

 

 

If there is no music, then there is no AC voltage required to build the bias voltage.

post #5834 of 8720

I don't have a clue in electronics but I can't see how to get bias without input signal. Audiovalve's page : "To establish the charge an adequate volume is required."

Maybe a timer which blocks output signal except bias. No evidence of such a device on the page.

I also don't understand how this box does manage the bias value. Could the circuitry be fast enough to detect central pin and switch from 580 to 230 without any risk of arcing ?

Wrong thread anyway.


Ali


Edited by Ali-Pacha - 8/10/14 at 6:30am
post #5835 of 8720
Quote:
Originally Posted by kevin gilmore View Post
 

If there is no music, then there is no AC voltage required to build the bias voltage.

 

And well just send a weak signal (eg 1 volt) (potentiometer of the RKV early in the race (in no case at max)); This seems fairly intuitive.

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