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SOHA II and AKG K1000 ?

post #1 of 15
5/23/10 at 1:46pm
Thread Starter 

I just won an auction on ebay for an AKG K-1000 headphone.

 

I currently use a SOHA II amp (with AKG-701).

 

Do you think that the SOHA II could power the K1000 (power, impedance...) ?

 

Regards ?

 

JMF

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post #2 of 15
5/24/10 at 7:17am

Sure looks like it can.

At least 'Ferrari' have reported good results with a SOHA II and K1000 combo.

 

Quote:
Originally Posted by Ferrari View Post

On a side note, I’m listening to my balanced SOHA II via AKG K1000 while typing this, it sounds damn good.
I can confirm that a well-constructed balanced SOHA II can drive AKG K1000 at a very loud level (the wife starts complain) without any sign of distortion or other shortage.
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post #3 of 15
5/24/10 at 10:21am
Thread Starter 

Hey, Good news !

 

I have a plain vanilla SOHA II (Glass Jar Audio Kit ; I use a pair of telefunken 12AU7).

 

I should have the K-1000 next week, will solder a cable to plug it in the SOHA II.

 

I do not know if it is easy to modify standard SOHA II to go to balanced, and found nothing on internet.

 

Regards,

 

JMF

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post #4 of 15
5/24/10 at 6:28pm

Ferrari has also done this. Check the builders thread.

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post #5 of 15
5/24/10 at 7:29pm

To do Balanced with a SOHA II, you'll need to add a second one..  since you need 4 channels to drive the right + and - and the left + and -..  Just like all other balanced amps.
 

Quote:
Originally Posted by jmf View Post


I do not know if it is easy to modify standard SOHA II to go to balanced, and found nothing on internet.

 

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post #6 of 15
5/24/10 at 10:08pm
Thread Starter 

Thank's !

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post #7 of 15
6/2/10 at 12:06pm
Thread Starter 

Hi all,

 

The K-1000 is at home. An "old" one (serial 2478).

 

I quickly tried it with my 3 amps :

- tweaked Philips CD722  + Cyrus one : works

- tweaked Philips CD722  + Charlize2 : works better

- USB Monica + NOT balanced SOHAII : the best (but DAC is important difference), but volume pot is 3/4. Power could become an issue in this conf...

 

I'm happy. I will have to try USB Monica+Charlize2+K1000 but more difficult as amp and DAC are harwired.

 

Regards.

 

JM

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post #8 of 15
6/2/10 at 3:30pm

If you need more gain, just use different tubes.

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post #9 of 15
6/4/10 at 8:17am


Current from the buffer stage may be a limiting factor not voltage gain.
 

Quote:
Originally Posted by FallenAngel View Post

If you need more gain, just use different tubes.

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post #10 of 15
6/4/10 at 10:49am

With a BD139 running off a BD139 CSS at 100mA, I can't imagine 120R headphones using much more current than provided within Class-A.
 

Quote:
Originally Posted by regal View Post


Current from the buffer stage may be a limiting factor not voltage gain.
 


 
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post #11 of 15
6/4/10 at 11:09pm

Why then is the AKG1000 considered to require a big expensive amp?  Not arguing just curious,  is it low sensitivity?

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post #12 of 15
6/5/10 at 12:17am
Quote:
Originally Posted by regal View Post

Why then is the AKG1000 considered to require a big expensive amp?  Not arguing just curious,  is it low sensitivity?

 

Yes, very low sensitivity.  Some 20dB lower than other popular cans at a given power level.  This is why they work best with amps with lots of voltage swing capability.
 

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post #13 of 15
6/5/10 at 12:37am

Got it,  but I am afraid if one goes to too much higher gain tube there may be issues with the buffer since it only has +-15 V rails,  so its still probably the limiting factor?

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post #14 of 15
6/5/10 at 9:02am
Quote:
Originally Posted by amb View Post



 

Yes, very low sensitivity.  Some 20dB lower than other popular cans at a given power level.  This is why they work best with amps with lots of voltage swing capability.
 



 

That’s exactly the point when I decided to go balanced with my SOHA II for the AKG K1000.

For the most popular headphones on the market, the benefits of twice the voltage swing and four times the total power (in balanced mode) may not be really necessary, but for the K1000... I would say yes.

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post #15 of 15
6/22/10 at 1:39pm
Thread Starter 

Hi Guys,

 

I now use my AKG K-1000 for some weeks... I've had no time to do some extensive testing. They finally found their way to the SOHAII plug, plain vanilla SOHAII...

 

And it works not bad at all ! Sure you have to push the volume, but no distortion or other problem on what I listen too. More flesh with SOHAII than with a CharlizeII Tripath amp (I have to try Charlize with 8 R resistors in parallel to the headphone).

 

I'm happy (and think that the K701 will be sold) ! Balanced SOHAII must be even better, but simple one is quite OK.

 

Cheers.

 

JMF

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