[thoughtcriminal]

Hi guys, what do you think of the Crown D75A powering the HE-6?  It's a studio power amplifier, and it has a headphone jack that apparently has no extra resistors to what the speakers would get. 
  
http://www.crownaudio.com/media/pdf/amps/125243.pdf  
  
Some notes from the manual:

WARNING: HEADPHONE JACK

SUPPLIES FULL OUTPUT POWER AND

MAY DAMAGE HEADPHONES OR

CAUSE HEARING DAMAGE.

1 kHz with 0.1% THD
4 ohms         55W
8 ohms         40W

16 ohms       25W     
  
Signal to Noise Ratio (below rated power, 20 Hz to 20 kHz) 106 dB unweighted
Damping Factor: DC to 400 Hz > 400
Total Harmonic Distortion (THD) at 1 watt, from 20 Hz to 20 kHz < 0.05%  
  
  
I don't know anything about electricity but from fiddling with numbers at http://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.htm I think the D75A would put somewhere between 4.4 and 8 watts into a 50 ohm load?   
  
Reason I ask is I have one with a damaged volume pot or something like that, that I left at my dad's house a while back. It might be worth professionally fixing it up and trying it out with a cool headphone.   
  
My only experience is with it as a power amplifier for speakers, and I thought it had a very clean, pure, flavorless tone to it. Studio stuff all seems that way, and that's cool for some, not for others I guess. 

Hmmm I have a crown d75 just sitting. Once I have the right preamp I'll be using it to power a set of yahama studio monitors. I may have to try that...

 

[Pooger]

I used a d75a for my 560s for the past few months. I know the he-6 is considerably harder to drive, but I'm sure the crown will do fine. Through inefficient headphones it is very quiet (there is audible noise with more sensitive headphones). Sound was certainly controlled, but the mids are slightly thick, and the highs have a very slight glare to them. The was a stock amp. So a few parts upgrades could probably fix a lot of both these issues. I've since switched to "the wire" which is just better in every regard (except raw power)--but again, this is with my 560s, not he-6es.

 

[Timestretch]

  "I've heard the HE-6 from a Schiit Lyr for a while in the past, and thought it was alright. " with what DAC and what source material using what cables and with or without power conditioning...etc...etc.. lots of links in the audio chain other than the cans and the amp ?

PC, generic optical cable, Benchmark DAC1, generic RCA cables, Schiit Lyr with stock tubes, Hifiman HE-6.  Lyr and DAC1 were plugged into a tripp lite hospital grade isolation transformer. It was a setup I owned in 2011 for about half a year. 
  
From my own experience, I don't personally hear a difference between cables or DACs. Others may be able to detect differences; more power to them.   
  
 

  "It seems really attractive based on specs" BIG mistake.

 
Unless it doesn't actually do the advertised 5.5W into 50ohms? I mean from specs on power output alone you can rule out 90% of headphone amplifiers as useless for the power-hungry HE-6, right? Most amps I see don't even do 1W per channel at 50ohm. 
 

  " and doesn't use tubes ".... a bad thing for many 

 
Tubes look great, are interesting, and can sound different, and I see why many people adore them. For me I'd prefer not to worry about replacing tubes or giving them time to warmup before use, so I choose solid state when possible. 

 

[Xenophon]

  PC, generic optical cable, Benchmark DAC1, generic RCA cables, Schiit Lyr with stock tubes, Hifiman HE-6.  Lyr and DAC1 were plugged into a tripp lite hospital grade isolation transformer. It was a setup I owned in 2011 for about half a year. 
  
From my own experience, I don't personally hear a difference between cables or DACs. Others may be able to detect differences; more power to them.   
  
 
 
Unless it doesn't actually do the advertised 5.5W into 50ohms? I mean from specs on power output alone you can rule out 90% of headphone amplifiers as useless for the power-hungry HE-6, right? Most amps I see don't even do 1W per channel at 50ohm. 
 

 
Tubes look great, are interesting, and can sound different, and I see why many people adore them. For me I'd prefer not to worry about replacing tubes or giving them time to warmup before use, so I choose solid state when possible. 

I'm not into cables either and to me a good DAC is transparent and -if the same filters are used- any differences should be beyond hearing.  If you can hear a clear difference and demonstrate it with objective means then something's not right.   But I never liked the Lyr, which I got the chance to try for a month (not easy to find in the EU).  I didn't like it with my HE-6, I didn't like it with my HD-800.  To me it sounded harsh, especially with the HD-800, with which it wasn't dead quiet either.  Some people might disagree but that's my experience.  I only got to try one unit though (which had been circulated a number of times) so I guess I can't exclude 100% that something might have been off.
 
The biggest issue with power amps to drive the HE-6 is usually the background that's not quiet.  You can have all the watts in the world but as my favourite amp builder says 'Who cares about the last 99 Watts if the first one sounds like crap?'.  What I would recommend if you're a bit handy and know how to solder is to just visit diyaudio.com, pick your poison and start building.  You can get absolute top grade stuff at comparatively low prices with some designs.

 

[shayson1357]

wattage isn't everything you know....
there are a lot of 4 figure 50w amplifiers out there which trample 100w 500$ speaker amps, so take that for what you will

 
"Unless it doesn't actually do the advertised 5.5W into 50ohms?" you never want to get close to clipping the amp and the he-6 requires 6-8 watts at 50r so the amp's supply would run out of gas fairly quickly( power supply design is much more complex than that though, and I'm in no position to give you a reliable explanation).....

tubes are high voltage,high impedance devices..... electrostatic speakers and headphones are ultra-high impedance and high voltage devices so these two are an engineering match made in heaven(no need for an output transformer to shape the output impedance and the ability of direct-coupling the panel with the cathode 

 )

transistors are low impedance,high current devices..... coil transducers are low impedance(4/8/16 ohm) and current oriented devices.... with transistors you need a transformer for every ESL you have but not so for other drivers like coil and planar ones.

for the he-6 I personally recommend going with the solid state route simply from a technical view point(if you want 70 class A1 watts from tubes you're going to have a hard time doing that, not to mention a skinny pocket)

if you want an amp for the he-6 don't get a headphone amp, since the he-6's power requirements aren't in the league of headphones in the first place and it can handle a lot more noise than headphones, so get a speaker amp...or at least audition a few(no shortage of speaker amps around the world) and make up your mind then.

 

[Justin_Time]

   
The slight drop in bass response is the missing 1%.
 
Rather than me try and paraphrase the opinions of others, best thing is to read them for yourself - link to a post a little earlier in this thread:
 
Link.
 
EDIT - I come away from that email exchange with someone with experience of driving the HE6 from the WA5, and also from thumping speaker amps, is that you gain a small bass improvement from the extra megawatts. Other than that, the 8W of the WA5 does the job nicely, and you get the tube magic of the WA5 (great musicality). I'll take that trade anyday.
 
I have thought about hooking up the HE6 to the speaker taps on my 20W TRV845SE amp, but the WA5 does such a great job driving the HE6 that I struggle to find the motivation to do it.

 
Like you, I prefer to stick with the Woo WA5 with only occasional lapse into some high-quality "speaker amps."
 
Like many owners of HE-6, I became obsessed for a while with feeding more power to the monster.  But my experience with "speaker amps" was somewhat different for that of many folks here. With many mass-produced speaker amps, I did gain an improvement (1% as you said) in the bass--mostly bass impact, not always bass pitch--but I did not get anywhere close to the overall superb sound I get (especially in the midrange and treble) from lower-power but superb tube amps like the Woo WA5 (K1K output) and the EAR-HP4, or great SS amps like the HeadAmp GS-X Mk2 and the Bakoon HPA-21. It was a negative trade-off.  
 
These result should not be surprising with hindsight.  In order to achieve the high power required to drive speakers, many mass-produced speaker amps operate in class AB using excessive negative feedback, a large number of low-quality part in the signal path and typically a puny power supply to keep the cost down. Consequently, the sound quality was sacrificed for the sake of quantity.  Such sacrifice is not necessary with low-power amps (say less than 25 watts into 8 ohms) where they can adopt simple designs using a small number of high quality parts, minimal negative feedback and small number of gain devices operating in their most linear region (class A or SET).
 
But for those of you who are still not satisfied with excellent but modestly-powered headphone amps such as the Woo WA5, by all means seek higher-powered speaker amps, but please make sure that they are high-quality amps that do not compromise the HE-6 sound in other areas besides the bass. More than just power rating, a massive power supply seems to play a big role in satisfying the power demands of the HE-6 
 
I had great results with modestly-powered but outstanding speaker amps such the First Watt (SS; 25 watts x 2; Class A) and some vintage tube amps such as the Conrad-Johnson MV75 (Tube, 75 watts x 2) and BAT VK75SE (tube; 75 watts x 2) all loaded down to 8 ohms across the speaker binding posts to protect the HE-6.  With high-powered SS speaker amps, I got great sound out of  the venerable Pass Aleph 2 (SS; 100 watt monoblocks; Class A) and Threshold Stasis S300 (150 watts x 2, class A/AB sliding bias).  
 
So, unlike many on this Forum, I had disappointing experience with most mass-produced speaker amps. What I gained in volume and bass impact could not make up for what I lost in sound quality overall compared to that of the excellent headphone amps like the Woo WA5.   In a nutshell, the quality of the amp is just as important as its power. It is best to have both for the HE-6 but for that you need outstanding amps, and they ain't cheap. The irony of using a $5,000 amp to drive a $1,000 pair of headphones was not lost on me. It is a good thing these amps are already parts of my stereo system.
 
 
  

 

[preproman]

   
Like you, I prefer to stick with the Woo WA5 with only occasional lapse into some high-quality "speaker amps."
 
Like many owners of HE-6, I became obsessed for a while with feeding more power to the monster.  But my experience with "speaker amps" was somewhat different for that of many folks here. With many mass-produced speaker amps, I did gain an improvement (1% as you said) in the bass--mostly bass impact, not always bass pitch--but I did not get anywhere close to the overall superb sound I get (especially in the midrange and treble) from lower-power but superb tube amps like the Woo WA5 (K1K output) and the EAR-HP4, or great SS amps like the HeadAmp GS-X Mk2 and the Bakoon HPA-21. It was a negative trade-off.  
 
These result should not be surprising with hindsight.  In order to achieve the high power required to drive speakers, many mass-produced speaker amps operate in class AB using excessive negative feedback, a large number of low-quality part in the signal path and typically a puny power supply to keep the cost down. Consequently, the sound quality was sacrificed for the sake of quantity.  Such sacrifice is not necessary with low-power amps (say less than 25 watts into 8 ohms) where they can adopt simple designs using a small number of high quality parts, minimal negative feedback and small number of gain devices operating in their most linear region (class A or SET).
 
But for those of you who are still not satisfied with excellent but modestly-powered headphone amps such as the Woo WA5, by all means seek higher-powered speaker amps, but please make sure that they are high-quality amps that do not compromise the HE-6 sound in other areas besides the bass. More than just power rating, a massive power supply seems to play a big role in satisfying the power demands of the HE-6
 
I had great results with modestly-powered but outstanding speaker amps such the First Watt (SS; 25 watts x 2; Class A) and some vintage tube amps such as the Conrad-Johnson MV75 (Tube, 75 watts x 2) and BAT VK75SE (tube; 75 watts x 2) all loaded down to 8 ohms across the speaker binding posts to protect the HE-6.  With high-powered SS speaker amps, I got great sound out of  the venerable Pass Aleph 2 (SS; 100 watt monoblocks; Class A) and Threshold Stasis S300 (150 watts x 2, class A/AB sliding bias).
 
So, unlike many on this Forum, I had disappointing experience with most mass-produced speaker amps. What I gained in volume and bass impact could not make up for what I lost in sound quality overall compared to that of the excellent headphone amps like the Woo WA5.   In a nutshell, the quality of the amp is just as important as its power. It is best to have both for the HE-6 but for that you need outstanding amps, and they ain't cheap. The irony of using a $5,000 amp to drive a $1,000 pair of headphones was not lost on me. It is a good thing these amps are already parts of my stereo system.
 
 
  

 
What are some examples of these mass-produced speaker amps (names)?

 

[TonyNewman]

  From my own experience, I don't personally hear a difference between cables or DACs. Others may be able to detect differences; more power to them.   
 

 
I have never been able to detect an audible difference between any cables and interconnects - I have tried expensive cables and interconnects - they didn't do anything at all for me in A/B testing in my system - so I now use solid but basic and modestly priced cabling and interconnects. I can't hear a damn thing between a $5/m cable and a $300/m cable. To each their own.
 
I disagree on the DAC front, however. I can detect an audible difference when A/B testing between my Simaudio Moon 100D and Auralic Vega. Detail & soundstage are two areas that change markedly between these 2 devices, but it is more than that - the music is rendered more faithfully in the Vega - I get a lot more of the 'you are there' experience from the better DAC.  Not sure how this can be measured - but to me it can be heard.
 
The audio industry has created some rather absurd hype to help sell products (my personal favorites are "cable burn-in" and "cable directionality" - those make me smile ever time), but saying that DACs can't be differentiated is perhaps taking the skepticism a step too far.
 
(Apologies for going a little OT. Last thing I want is another thread derailment with a cable debate. My reply is more about better DACs and my suggestion that they do make an audible difference.)

 

[Justin_Time]

   
What are some examples of these mass-produced speaker amps (names)?

The vast majority of mid-fi amplifiers/receivers from the 80s and 90s selling for under $1000 in those days are class AB amps. The compromise to get high power while at the same time reducing size/weight/cost and ensuring long life and ease of operation (cool-running) for the average consumers took a toll on the sound quality.  The vintage High-End amps (tube or transistor) were selling well above $1,000 even in those days. 
 
I saw little to gain in mentioning the names of these mass-market amps in a negative light. They were made to drive mass-produced, low-cost speakers, not state-of-the-art transducers like the HE-6.  They are what they are.  If we misuse them, the fault is ours.  Besides, they could be someone's favorite amps...So I deliberately omitted their names and will continue to do so. 
 
But if you are looking for vintage mass-produced amps that performed admirably with the HE-6, I will mention the Harman Kardon HK 775 (135 w monoblocks) , HK 770 (65 w x 2 stereo amp) and HK750 (65 w x 2 integrated amp) using the superb design of Dr. Matti Otala (the Japanese guru of T.I.M. and I.I.M. distorsions).  Despite the crappy components inside, these HK 7 series amps have the outstanding mid-range and smooth treble to match the HE-6 high resolution and plenty of power.  They can be bought for $100-$200 on ebay. Unfortunately, they are over a quarter of a century old so a full restoration is in order--the bias with these amps tend to notoriously drift.  The whole restoration/repair/upgrade should cost you about $300 and you have then a superb HE-6's headphone amp that will last another 15 years.
 
 I do not know if the HK 6-series or 8-series amps that came before and after the 7 series respectively were any good.  More than likely not.  But the 7 series HK are truly dynamite. You can actually have them strapped two per channel in mono (two amps per side).  I did and they produce nearly 500 watts per channel of pure sweet sound into my Maggies 3.7 (4 -ohm)--these amazing amps are stable down to two ohms!  You can melt the HE-6 with that much power so some common sense is in order here.  
 
. 

 

[ohhgourami]

  PC, generic optical cable, Benchmark DAC1, generic RCA cables, Schiit Lyr with stock tubes, Hifiman HE-6.  Lyr and DAC1 were plugged into a tripp lite hospital grade isolation transformer. It was a setup I owned in 2011 for about half a year. 
  
From my own experience, I don't personally hear a difference between cables or DACs. Others may be able to detect differences; more power to them.   
  
Unless it doesn't actually do the advertised 5.5W into 50ohms? I mean from specs on power output alone you can rule out 90% of headphone amplifiers as useless for the power-hungry HE-6, right? Most amps I see don't even do 1W per channel at 50ohm. 
 

Tubes look great, are interesting, and can sound different, and I see why many people adore them. For me I'd prefer not to worry about replacing tubes or giving them time to warmup before use, so I choose solid state when possible. 

 
Lyr is not enough for HE-6. I had a chance to demo it when it barely came out and it was disappointing to say the least when hypetrain was going at full speed. I don't know how many times I have to repeat this until people get it in their heads; it's not about the output power but the power reserve/transformer that makes the HE-6 shine.
 
My 300wpc Krell cranks out ~45wpc @50ohms, but I can chop that down to 0.1wpc with resistors and it would sound the same (better than any amp I've heard). The Lyr is putting out 50x the power at that point but how come it still sounds bad? It's not the output!
 
DACs are pretty damn easy to differentiate. I should probably leave it at that.

 

[hifimanrookie]

Lyr is not enough for HE-6. I had a chance to demo it when it barely came out and it was disappointing to say the least when hypetrain was going at full speed. I don't know how many times I have to repeat this until people get it in their heads; it's not about the output power but the power reserve/transformer that makes the HE-6 shine.

My 300wpc Krell cranks out ~45wpc @50ohms, but I can chop that down to 0.1wpc with resistors and it would sound the same (better than any amp I've heard). The Lyr is putting out 50x the power at that point but how come it still sounds bad? It's not the output!

DACs are pretty damn easy to differentiate. I should probably leave it at that.

I agree..its the reserve (huge condensators) and huge transformer that is important....and keyword here: quality power..

.look at my amp...only 5,23w at 50ohm...but with humungous reserves 650.000 it sounds powerful and very very good, never clips or gets muddy...and recently gilbert finished a sister of my amp (called ctag) for a fellow headfi'er's he6...and that one has only 5w into 50ohm but with 850.000 in reserves....if u check the insides of both, although different in built, u only see high quality parts...( yep u get pics of insides from these people so u see what u get inside) .everywhere...even the bolts are not standard..its all wellthought...maybe somebody else should try a BC for his he6.. I understand the CTAG was completely in the pricerange in which many of you guys shop....he posted in my review thread..so check it out

Ps..i always loved krell amps....had one once...sounded wonderful.

 

[Xenophon]

I agree..its the reserve (huge condensators) and huge transformer that is important....and keyword here: quality power..

.look at my amp...only 5,23w at 50ohm...but with humungous reserves 650.000 it sounds powerful and very very good, never clips or gets muddy...and recently gilbert finished a sister of my amp (called ctag) for a fellow headfi'er's he6...and that one has only 5w into 50ohm but with 850.000 in reserves....if u check the insides of both, although different in built, u only see high quality parts...( yep u get pics of insides from these people so u see what u get inside) .everywhere...even the bolts are not standard..its all wellthought...maybe somebody else should try a BC for his he6.. I understand the CTAG was completely in the pricerange in which many of you guys shop....he posted in my review thread..so check it out

Ps..i always loved krell amps....had one once...sounded wonderful.

850000 microF......I'd like to see the soft start module on that beast.  Probably the lights in the neighbourhood dim when you switch it on and it runs for 5 minutes after switching it off.  I'd like to hear why he goes for SO MUCH capacitance.  Power reserve...ok, low ripple...obvious check, but I still wonder.  Would you happen to know what kind of transfo's in there?

 

[wuwhere]

Its those monster electrolytic caps. They're like instant source of energy when those kick bass drum come in. Caps technology has evolved so newer caps are better in terms of charging and discharging faster than the older caps in vintage amps. Big capacitors are not cheap and they occupy a lot of pcb board real estate. Even my vintage ARC tube amp will have better bass with newer caps.

 

[shayson1357]

 
850000 microF......I'd like to see the soft start module on that beast.  Probably the lights in the neighbourhood dim when you switch it on and it runs for 5 minutes after switching it off.  I'd like to hear why he goes for SO MUCH capacitance.  Power reserve...ok, low ripple...obvious check, but I still wonder.  Would you happen to know what kind of transfo's in there?

I just tried to simulate filling that much capacitance but my bridged rectifiers(super heavy duty) got fried, pretty sure the amp can't work without a soft start module and the transformer would be HUGE and the inrush currents would cause a lot of damage, but I'm sure gilbert put a tight enough leash on the amp so it doesn't trip your house's circuit breaker(or your building's main fuze 

)

 

[gjc11028]

My blue circle dac has 880000 uf. It does not even have an on/off switch -- it just stays on. the preamp has an even bigger power supply. I am sure Gilbert would respond to n email or question on the blue circle forum.