DCAudioDIY.com

DC Area Audio DIYer's Community
It is currently March 28th, 2024, 6:13 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 5 posts ] 
Author Message
 Post subject: New Headphone System
PostPosted: May 26th, 2022, 9:42 pm 
Offline

Joined: February 28th, 2013, 1:19 pm
Posts: 914
With my wife occasionally working from home and the fact she is an early to bed/early to rise person, I have decided to be a good husband and cut back on my loud/late night listening and build up a nice little headphone system. I never was much of a headphone person in the past, but I recently picked up a pair of HiFiMan Sundara planar magnetic headphones that were clearly so much better than the Beyer DT880 Pro headphones I have had for years. These sounded great on the Chord DAVE DAC, and really got me thinking seriously about the potential of headphone listening. I wanted to not be tethered to my equipment rack though and be able to enjoy music in a more comfortable situation. So it led me to build up a high quality system that I can setup in another room (really any room in the house).

DIYAudio.com has a nice Wayne Colburn (PASS Labs) designed headphone amp kit (WHAMMY) for around $300 with case, board, and parts that I built that sounds pretty nice with the new headphones. https://www.diyaudio.com/community/threads/whammy-pass-diy-headphone-amp-guide.317803/
The HiFiMan Sundara have a low output impedance (35 ohms) that needs a good amount of drive, so this design with a complementary pair MOSFET output buffer provides plenty of current drive. It does use an opamp as the input device, and the output buffer is inside the feedback loop. I am currently trying out a pair of OPA627AU in a Browndog single to dual DIP adapter, but it really sounds good with an OPA2604 (dual) and similar eight legged bugs. The amp is a pretty easy build, I had it finished in a day. Sounds pretty nice, and being able to tailor the sound by switching opamps is a plus.

Using a RPi4 as a Roon endpoint (bridge) running RoPieee connected via USB to a Chord Qutest DAC. I am using the Roon DSP crossfeed implementation. BTW, having the RPI4 on an inexpensive LPS really makes a difference in sound quality.

I probably should look into building a transformer coupled tube headphone amp since the headphones have such a low impedance, but that is another project.

Anyway, nice sounding setup to keep the peace at home.


Top
 Profile  
 
 Post subject: Re: New Headphone System
PostPosted: May 27th, 2022, 3:46 am 
Offline

Joined: April 22nd, 2013, 12:58 pm
Posts: 285
David, I remember you had a couple of tube-based headphone amps a few years ago, one SE OTL, cap-coupled and one transformer-coupled. They're obviously much less portable, but I wonder if you still have them. BTW, I also have the Sundara headphones and I'm headed down the path to building my own headphone amp. Maybe two, as I have some hi-impedance Sennheisers, too.
As always, it's great to be able to learn from one another.


Top
 Profile  
 
 Post subject: Re: New Headphone System
PostPosted: May 27th, 2022, 8:16 am 
Offline

Joined: February 28th, 2013, 1:19 pm
Posts: 914
Yes, I still have them, but they may not be ideal.

1. Low Voltage Aikido (SE) OTL that runs with a 24V supply with 6GM8 tubes and a solid state buffer. Uses a cap output to block DC, an electrolytic bypassed by film. This would work, and I should drag it out and knock off the dust to see how it does. It may be a surprise, though I would prefer not to listen through large capacitors if I can help it.
2. A transformer output linestage using a 6C45P with 600 ohm outputs. Obviously, neither has the current nor impedance. Worked well for a pair of BeyerDynamics DT880 600 ohm headphones.
3. SRPP 6H30, cap output. High impedance only.

Designing a transformer coupled tube headphone amp for lower impedance headphones shouldn't be too difficult with the right output transformer. Almost there with a 16 ohm tap. Not much voltage gain is needed, so an easy to drive low wattage tube that does not require alot of swing would be key. An EL84 or 6BX7 probably would not need anything on the front end. Question is SE vs PP, and ensuring enough inductance on the primary (for SE) for full range

Now, the output stage of the WHAMMY (complimentary MOSFET output) could just as easily be combined with a tube front end, though excess gain would need to be managed. Still, it might be a place where a classic triode like a 76 or 6SN7 would work well in a hybrid arrangement. The challenge is having the drive to overcome the input capacitance of the MOSFETs, so may need a follower output (tube or FET), and use of global negative feedback to reduce gain if needed. No output caps necessary. It would be another interesting pathway to explore.

Lots of ideas!....

BTW, how do you like the Sundaras?

David


Top
 Profile  
 
 Post subject: Re: New Headphone System
PostPosted: May 27th, 2022, 4:39 pm 
Offline

Joined: April 22nd, 2013, 12:58 pm
Posts: 285
The old amps definitely sound like they are better suited to hi-impedance headphones.

My Sundaras had a lot of HF detail when I first got them, but they mellowed out after ~ 100 hours of break in. The opposite happened with my Sennheiser 6XX headphones. The midrange and lower treble opened up a bit after break in.

Now, the bass...... I was dumbfounded by the bass on the Sundaras. It's no wonder that planar magnetics are all the rage recently.


Top
 Profile  
 
 Post subject: Re: New Headphone System
PostPosted: May 27th, 2022, 5:34 pm 
Offline

Joined: February 28th, 2013, 1:19 pm
Posts: 914
Yes, the bass in the Sundaras is pretty amazing, I am surprised by how well they work on large scale orchestral music. Bass drums really have impact, and really tight (how DID they fit subwoofers in these cans?!). They are really involving as well...maybe also the product of the new amplifier, but still, it is really hard for me to tear myself away from listening. My wife has been on a work related Zoom session in the next room for the past two hours, and I have been listening through a Chandos Vaughn Williams symphony collection on Qobuz and not leaving my seat.

I have found that the OPA627au op amps have such a spacious sound, that using crossfeed really is not necessary, and actually detracts from the sound quality. This is using DSP crossfeed in ROON. I did not find that to be case with other opamps. At some point, I will have to try a Burson V6 Classic or Vivid, or better yet, the SparkosLabs SS2590 Pro Discrete OpAmps if I can make them fit. But REALLY liking the classic Burr Brown opamps right now.

David


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 38 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group