[acantor]

I just wanted to add my opinion to what has been said about the FW F3 and the HE6.  I recently purchased an F3 from Mark at Reno HiFi and read with disappointment reviews on this thread.
I was thinking about returning the amp.  Mark was incredibly gracious when I called him, and was willing to take the amp back for a full refund.  However, I now have my rig set up, with an EMM DAC2X feeding an AR Ref 5 preamp into a Placette passive preamp and finally the F3.  All these preamps in the chain were necessary to get the proper 10K ohm input impedence for the F3.
I am using a q cable with spades attached to the speaker posts of the amp.  In any case, I am very pleased with the results. I intend to keep the F3.  The set up is in many ways as satisfying as my reference which is Stax 009 with EC Electra.

 

[Xenophon]

Happy for you, Ididn't want to take the risk as the amp would be shipped to Europe and sending it back would have cost a fortune + reclaiming the duties and taxes a major hassle. Went with a diy F5 that has an option to easily exchange the boards so if it srrikes my fancy and the F3 boards come out I can always swap them out and give the F3 sound a spin. Enjoy!

 

[twizzleraddict]

  However, I now have my rig set up, with an EMM DAC2X feeding an AR Ref 5 preamp into a Placette passive preamp and finally the F3.  All these preamps in the chain were necessary to get the proper 10K ohm input impedence for the F3.
I am using a q cable with spades attached to the speaker posts of the amp.  In any case, I am very pleased with the results. I intend to keep the F3.  The set up is in many ways as satisfying as my reference which is Stax 009 with EC Electra.

 
Guess I'm going to have to find a preamp that matches well with an F1J in order to get the full effect and potential of the headphone!

 

[Xenophon]

Why does impedance matter provided the output impedance of the dac preamp section is at least 10 times lower than the input impedance of the power amp (which itwill be I imagine) and that output gain matches what the power amp expects?

 

[gjc11028]

Why does impedance matter provided the output impedance of the dac preamp section is at least 10 times lower than the input impedance of the power amp (which itwill be I imagine) and that output gain matches what the power amp expects?

from the first watt website discussion of the F1J (discussion differences from F1)
 
You may notice that the F1J also has approximately 1.5 dB more gain. This is because the Jfets have a higher transconductance figure that the original Mosfets.
There is another factor as well, which is that the F1J has a lower input impedance than the F1- approximately 30 Kohm balanced and 15 Kohm single-ended. The modifications that help achieve this bandwidth take advantage of lower impedances, so the F1J is recommended for use with preamps with ordinary to low output resistance – tube preamps without cathode followers will work but will not reap as much benefit at high frequencies.

 

[musicinmymind]

  I just wanted to add my opinion to what has been said about the FW F3 and the HE6.  I recently purchased an F3 from Mark at Reno HiFi and read with disappointment reviews on this thread.
I was thinking about returning the amp.  Mark was incredibly gracious when I called him, and was willing to take the amp back for a full refund.  However, I now have my rig set up, with an EMM DAC2X feeding an AR Ref 5 preamp into a Placette passive preamp and finally the F3.  All these preamps in the chain were necessary to get the proper 10K ohm input impedence for the F3.
I am using a q cable with spades attached to the speaker posts of the amp.  In any case, I am very pleased with the results. I intend to keep the F3.  The set up is in many ways as satisfying as my reference which is Stax 009 with EC Electra.

 
You should be having hard time to set the vol to your preferred level, as you have more than one vol knobs in the chain. Curious to know why are you using two preamps

 

[acantor]

The passive preamp is set at maximum output and the volume is regulated on the AR ref 5.
However, I am not sure I need the passive preamp in the loop and I am going to try omitting it from the setup.
I thought I needed it because the AR ref 5 has a minimum output impedence of 20K and the F3 has an input impedence of 10K.
To be honest, all this electricity theory is beyond me.  I only understand V=IR.

 

[ALRAINBOW]

There is recommend ratio of output to input. And someone else here can post it. But a good rule is less devices in the loop and volume controls is paramount to be removed as they rob you of details and dynamics.
Last you ears are the best judge in all of this . But you must be decerning it your listening. Also try removing anything that you can . My feelings with the F3 were it was lean and not tonally correct . However it was very reviewing at the same time. So in the end of you like it that's fine Nd no one including me can tell you what you like.

Al

 

[brunk]

The general rule of thumb is that if your amps input impedance is 47kOhms or higher and interconnects are less than a meter in length, your system is passive compliant and a passive pre should be used. If any of those requirements can't be met, then an active preamp should be used.

 

[gjc11028]

  The passive preamp is set at maximum output and the volume is regulated on the AR ref 5.
However, I am not sure I need the passive preamp in the loop and I am going to try omitting it from the setup.
I thought I needed it because the AR ref 5 has a minimum output impedence of 20K and the F3 has an input impedence of 10K.
To be honest, all this electricity theory is beyond me.  I only understand V=IR.

 
from the AR site.  looks like they are suggesting an amp with at least a 20k ohm input impedance
 
OUTPUT IMPEDANCE: 600 ohms Balanced, 300 ohms SE main (2), 20K ohms minimum load and 2000pF maximum capacitance. Outputs (3): 2 main, 1 tape (XLR and RCA connectors).

 

[acantor]

The same information I gleaned.  I spoke with Calvin at Audio Research and the fact that the preamp has a recommended minimum output impedence of 20K and the F3 has an input impedence of 10K means I might lose some sound quality, particularly dynamics, and rolled off high end.  I will listen tonight and see how it sounds!

 

[barza]

First post after lurking here for quite a while - this place can be really intimidating, so please go easy on me if any of what follows belies laughable ignorance. But I need some good advice.
 
I am planning to add a pair of a HE6s to my collection of headphones for use in my man cave when the kids are asleep (oh, the joys of fatherhood!). And I have been ploughing through this thread and others, agonising about what to do about driving these headphones (I have an IFI ICan for less demanding cans, and that works for me). I have been thinking about all the relatively low budget options for driving the HE6 (Topping TP60, Alesis RA-150, for example) as interim solutions before committing any more serious money to amplification for the HE6. I also have a couple of other amps lying around (Marantz PM66SE K I Sig, Arcam A85, Pioneer VS-AX5i) I could press into service for a while. But then I had a lightbulb moment.
 
I have a Musical Fidelity A1008 Integrated Amp in the room in question. I love it, and its as about as audiophile as I am prepared to get for now. My main speakers are wired to that amp. But what if I could also connect the HIFIMAN HE adaptor to that amp, and then use it to drive my HE-6s. With the amp able to push 250w RMS into 8 ohms, I am assuming the adaptor would ensure I don't blow the HE6s up provided I am careful with the amp volume control.
 
I don't want to have to get into pulling the speaker bananas out and putting in the set connected to the Hifiman adaptor. And the A1008 only has one set of speaker outputs. So I need some kind of switch between the two outputs, bearing in mind that I would never have cause to be using the speakers and the HE adaptor at the same time. A bit of research throws up this...
 
http://www.qed.co.uk/switching_units/switching_and_control_units/ss21_2_way_audiophile_parallel_speaker_switch.html
 
...which at first glance looks good to me, even though it allows simultaneous use of two sets of "speakers" which I certainly do not need. But this raises several questions:
 
1. Would the switch in conjunction with the HE adaptor create risks of damaging my amp if you accidentally selected both outputs to be operative at once?
2. Would the switch degrade the audio performance of the outputs?
3. If the answer to either of the above is yes, is there another solution beyond physically swapping banana plugs at the back of the A1008?
 
And finally
 
4. Anyone have any views on how good the A1008----->HE adaptor----->HE6 combo would sound?
 
Thanks for any responses, and for the endurance required to reading this long post!!

 

[ohhgourami]

  First post after lurking here for quite a while - this place can be really intimidating, so please go easy on me if any of what follows belies laughable ignorance. But I need some good advice.
 
I am planning to add a pair of a HE6s to my collection of headphones for use in my man cave when the kids are asleep (oh, the joys of fatherhood!). And I have been ploughing through this thread and others, agonising about what to do about driving these headphones (I have an IFI ICan for less demanding cans, and that works for me). I have been thinking about all the relatively low budget options for driving the HE6 (Topping TP60, Alesis RA-150, for example) as interim solutions before committing any more serious money to amplification for the HE6. I also have a couple of other amps lying around (Marantz PM66SE K I Sig, Arcam A85, Pioneer VS-AX5i) I could press into service for a while. But then I had a lightbulb moment.
 
I have a Musical Fidelity A1008 Integrated Amp in the room in question. I love it, and its as about as audiophile as I am prepared to get for now. My main speakers are wired to that amp. But what if I could also connect the HIFIMAN HE adaptor to that amp, and then use it to drive my HE-6s. With the amp able to push 250w RMS into 8 ohms, I am assuming the adaptor would ensure I don't blow the HE6s up provided I am careful with the amp volume control.
 
I don't want to have to get into pulling the speaker bananas out and putting in the set connected to the Hifiman adaptor. And the A1008 only has one set of speaker outputs. So I need some kind of switch between the two outputs, bearing in mind that I would never have cause to be using the speakers and the HE adaptor at the same time. A bit of research throws up this...
 
http://www.qed.co.uk/switching_units/switching_and_control_units/ss21_2_way_audiophile_parallel_speaker_switch.html
 
...which at first glance looks good to me, even though it allows simultaneous use of two sets of "speakers" which I certainly do not need. But this raises several questions:
 
1. Would the switch in conjunction with the HE adaptor create risks of damaging my amp if you accidentally selected both outputs to be operative at once?
2. Would the switch degrade the audio performance of the outputs?
3. If the answer to either of the above is yes, is there another solution beyond physically swapping banana plugs at the back of the A1008?
 
And finally
 
4. Anyone have any views on how good the A1008----->HE adaptor----->HE6 combo would sound?
 
Thanks for any responses, and for the endurance required to reading this long post!!

Switch would probably not degrade sound, but the HE-adaptor would. I would just get a pair of wirewound resistors for your situation.
 
The main issue you would have is volume when switching between outputs when using the switch. That said, your speakers sound be far less efficient so you'll need to use the right resistor values to give you the right attenuation to match volume levels.

 

[barza]

Ohhgourami - thanks very much for your reply. The fact the switch would not cause issues per se is very helpful to know.

I have been puzzling about this issue of whether the HE adaptor would degrade the sound. I don't understand enough electrical theory to answer that question for myself, even after ploughing through most of this thread. I certainly see some people reporting using the adaptor happily, and others like you crafting solutions with resistors of their own. But the fact that adaptor is made by HE had always inclined me towards using it.

Could someone point me toward a resource that would help me understand the basics of this stuff better? Or if someone could sketch out a "resistors 101" here that would be great.

I have a pair of B and W 605s2 as my main speakers attached to the A1008 amp. Volume on the amp has never been above 12 o'clock, at 10 o'clock it is already very loud. I am used to working with the volume in that range, and ideally would want the usable range on the HE6 to be more or less the same.

Any views on how this combo may sound?

 

[ohhgourami]

Ohhgourami - thanks very much for your reply. The fact the switch would not cause issues per se is very helpful to know.

I have been puzzling about this issue of whether the HE adaptor would degrade the sound. I don't understand enough electrical theory to answer that question for myself, even after ploughing through most of this thread. I certainly see some people reporting using the adaptor happily, and others like you crafting solutions with resistors of their own. But the fact that adaptor is made by HE had always inclined me towards using it.

Could someone point me toward a resource that would help me understand the basics of this stuff better? Or if someone could sketch out a "resistors 101" here that would be great.

I have a pair of B and W 605s2 as my main speakers attached to the A1008 amp. Volume on the amp has never been above 12 o'clock, at 10 o'clock it is already very loud. I am used to working with the volume in that range, and ideally would want the usable range on the HE6 to be more or less the same.

Any views on how this combo may sound?

It's the type of resistors that are in the HE-adaptor. Others that have been using wirewound resistors have also reported no change in SQ. Here is some reading: http://www.eetimes.com/document.asp?doc_id=1256482
 
I'm no good with the math to match the volumes. I hope someone else could step in. I'm going to guess you'll need similar attenuation to what I'm using 100ohm and 30hm for -32dB, probably not as much.