[Happy Camper]

Gotta love monoblocks.

 

[shayson1357]

we need a beefed up F1J version for the he-6, the original claims 10w at 8r , double that figure would be more than welcome(more than double the price of course 

 )

 

[preproman]

  we need a beefed up F1J version for the he-6, the original claims 10w at 8r , double that figure would be more than welcome(more than double the price of course 

 )

 
Why?  The F1J is fine just the way it is.  

 

[preproman]

  the first watt ive used so far are the J2 and the F1J . its was not even close - the F1J brings out every bit of sounds - its sounds just right .

 
I had the F1J and the GS-X mk2, EF-6 and 4 Channel B22 at the same time.  The F1J outplayed them all.  I sold everything kept the F1J.

 

[Silent One]

Gotta love monoblocks.

Gotta love tube monoblocks. 

 

[shayson1357]

   
Why?  The F1J is fine just the way it is.  

if we accepted "fine just the way it is" we wouldn't be talking here about he-6s and F1Js would we 

 

[preproman]

But we are, and the F1J will not be changed or upgraded anymore.  So yes -"it's fine just the way it is"

 

[Xenophon]

  But we are, and the F1J will not be changed or upgraded anymore.  So yes -"it's fine just the way it is"

To be honest, I don't think the F1J would improve with more power, it's got more than enough but the raw figures are misleading due to its design.  Besides, the Silicon carbide power JFETS it (the J version) uses are almost unobtainium now due to the producer going out of business and you really require a closely matched pair or will run into problems that are not easily resolved.   It doesn't help that most of 'em that you see on the net are chinese counterfeit.  So if you want one and it pops up for sale, grab it quick.  There is (or was) one for sale on the forums for I believe 1800 USD.  If you want to build a clone and can source the parts and know what you're doing, you're looking at about 1 k USD minimum to build (except if you can build a case yourself, which I wouldn't want to try).
 
That said, it may not be for everyone, the amp is called 'the truth machine' and that's what it is.  Imo most people don't appreciate a brutally honest, clean sound, even if they claim beforehand that that's the holy grail.

 

[Justin_Time]

I need help from the EEs out there on using speaker amps with the HE-6 and other headphones.
 
 
I have been experimenting a bit lately and got outstanding results from the HE-6 using several amps with a wide range of power rating and designs--some of the recent successful amps are the First Watt M2, Threshold S300, Nakamichi PA-5 II, Mark Levinson KAV 400xi, Conrad-Johnson MV75, BAT VK75SE and, unexpectedly, the Harman Kardon HK775, 770 and 870. 
 
With more efficient headphones such as the HD800, TH900 and PS1000, however, I typically get a constant background noise (low hum, buzz or hiss depending on the headphones and amps) when everything is connected even with zero volume from the direct source (Oppo 105 or PS Audio PerfectWave Mk II) or from the preamp when one is used (Krell KAV 400xi or Jeff Roland Consummate).  It sounded like the noise is from the amps themselves and is louder with more efficient headphones.  This happened with or without 8-ohm arrays used at the speaker outputs.
 
Is this normal and is there any way to reduce or eliminate that noise?
 
Sorry to be off topic but I thought that folks using this thread may be the most knowledgeable about this problem--and hopefully solutions. Help me, Obi-wan Kenobi... 

 

[kevin gilmore]

if you short the input to the amplifiers, and if there is still noise (likely)
then that is all you can do. Speaker amplifiers driving high impedance
headphones are designed for different purposes.

 

[Timestretch]

  I need help from the EEs out there on using speaker amps with the HE-6 and other headphones.
 
 
I have been experimenting a bit lately and got outstanding results from the HE-6 using several amps with a wide range of power rating and designs--some of the recent successful amps are the First Watt M2, Threshold S300, Nakamichi PA-5 II, Mark Levinson KAV 400xi, Conrad-Johnson MV75, BAT VK75SE and, unexpectedly, the Harman Kardon HK775, 770 and 870. 
 
With more efficient headphones such as the HD800, TH900 and PS1000, however, I typically get a constant background noise (low hum, buzz or hiss depending on the headphones and amps) when everything is connected even with zero volume from the direct source (Oppo 105 or PS Audio PerfectWave Mk II) or from the preamp when one is used (Krell KAV 400xi or Jeff Roland Consummate).  It sounded like the noise is from the amps themselves and is louder with more efficient headphones.  This happened with or without 8-ohm arrays used at the speaker outputs.
 
Is this normal and is there any way to reduce or eliminate that noise?
 
Sorry to be off topic but I thought that folks using this thread may be the most knowledgeable about this problem--and hopefully solutions. Help me, Obi-wan Kenobi... 

  
  
I am also interested in this.  
  
I have both my DAC and amplifier plugged into an isolation transformer. This is something I started doing years ago, and I test it fairly regularly and continue to find that plugging power into an isolation transformer will audibly reduce the noise floor as compared to plugging devices into the wall or normal surge protector.  If there is a ground loop hum, however quiet, this sort of configuration 100% removes that. 
  
However, since getting the old used D75A, I find that this amp seems to introduce a little bit of new noise -- not a noise floor, but more like an occasional quick, irregular crackle that will pop up audibly every now and then in either channel. It's quiet and will never be heard over loud music, but can sometimes be heard during soft musical passages or silence. I wonder if this is an effect due to an old amplifier's aging internal parts? I wonder if I could replace capacitors and such in the D75A to make it perfectly fully silent, or if I should consider something like a Schiit Mjolnir which is brand new and shouldn't have any issues.   
  
TO be clear here, it is not a noise that is enough to really affect enjoyment of the music. You have to really be listening for it, and it appears seldomly. If I didn't replay parts of tracks consistently when I do hear it, I'd think it was just a minor flaw in the source recording. 

 

[Justin_Time]

    
  
I am also interested in this.  
  
I have both my DAC and amplifier plugged into an isolation transformer. This is something I started doing years ago, and I test it fairly regularly and continue to find that plugging power into an isolation transformer will audibly reduce the noise floor as compared to plugging devices into the wall or normal surge protector.  If there is a ground loop hum, however quiet, this sort of configuration 100% removes that. 
  
However, since getting the old used D75A, I find that this amp seems to introduce a little bit of new noise -- not a noise floor, but more like an occasional quick, irregular crackle that will pop up audibly every now and then in either channel. It's quiet and will never be heard over loud music, but can sometimes be heard during soft musical passages or silence. I wonder if this is an effect due to an old amplifier's aging internal parts? I wonder if I could replace capacitors and such in the D75A to make it perfectly fully silent, or if I should consider something like a Schiit Mjolnir which is brand new and shouldn't have any issues.   
  
TO be clear here, it is not a noise that is enough to really affect enjoyment of the music. You have to really be listening for it, and it appears seldomly. If I didn't replay parts of tracks consistently when I do hear it, I'd think it was just a minor flaw in the source recording. 

Ground loop would not explain the hissing noise...

 

[Anda]

Probably too much gain for those headphones. You could use resistors in series similar to what manufacturers used to do on vintage amplifiers OR use an L-pad resistor network OR get an amp with lower gain.
Have a look at Rob's homepage:
 
http://robrobinette.com/RobinetteBox.htm
http://robrobinette.com/HeadphoneResistorNetworkCalculator.htm
 
I don't know which effect the output impedances of the first two solutions will have on headphones with dynamic drivers.

 

[Timestretch]

The D75A does have 30-step gain knobs for each channel. I currently have these at max, but I could always set them to half and see if I still ever hear that crackle. 

 

[Anda]

Sorry, it was a response to the 'hissing issues'. Don't know about the crackle though