Speaker amps for headphones
Aug 28, 2013 at 6:40 PM Post #871 of 3,871
In addition to being a good guy, I really think Jan is having some fun with all of the headphone stuff.  It offers him new challenges and a new market to explore.  He is still feeling his way ahead in finding the best approaches for matching his amp to headphones, and he is very open-minded to ideas from this community, just like he has been open to ideas on powering the amp, most of which have come from the speaker people on Audio Circle.  That's the right way to do business, even though there are many designers of audio products who think they are so much smarter than their customers that they don't need to listen to the anybody's inputs.  While I am sure that some of them are true geniuses, they might discover that if they ignore their customers they won't make a living despite their brilliance.
 
Mike's suggestion of hard-wiring the box on the amp side vs. using binding posts might have both sonic and cost merit -- there are fewer connections and less hardware, and those are usually good things for both improving sound and saving costs.  But there's really only one way to find out for sure... just do it (sorry for violating any trademarks).  And if Mike's idea does work well, then Jan can make it the standard approach and the community benefits -- and he sells more amps and boxes.  What a concept!
 
Aug 28, 2013 at 10:59 PM Post #872 of 3,871
Quote:
... snip ...
 
Mike's suggestion of hard-wiring the box on the amp side vs. using binding posts might have both sonic and cost merit -- there are fewer connections and less hardware, and those are usually good things for both improving sound and saving costs.  But there's really only one way to find out for sure... just do it (sorry for violating any trademarks).  And if Mike's idea does work well, then Jan can make it the standard approach and the community benefits -- and he sells more amps and boxes.  What a concept!

And while you're at it, have Jan do a 4 pin XLR on the output side.  I'm really liking my 4 pin XLR output resistor box :)
 
Aug 28, 2013 at 11:07 PM Post #873 of 3,871
Quote:
And while you're at it, have Jan do a 4 pin XLR on the output side.  I'm really liking my 4 pin XLR output resistor box :)


+1, that would be nice.
 
Or he could put either an XLR jack or a TRS jack right in the Millenia (Call them the MG 4 and MG1...).  I actually talked to him a bit about adding a headphone jack tapping directly from the amp, and he indicated that it was not a simple thing to do, particularly if he wanted to keep the amp's price reasonable and the size small.  Plus let's face it, we Head-Fiers are still not exactly a huge market, so he needs to keep his eye on the larger pool of potential customers -- folks with speakers.  But I'm guessing that we've all got him thinking about all sorts of ideas he hadn't considered before, so who knows.
 
Aug 29, 2013 at 12:51 AM Post #874 of 3,871
Yes, I'm sure there is no room in the existing package for either a TRS or XLR output.  BUT if the market would support it, Increasing the package height would give plenty of room for a resistor network and either a TRS or XLR jack.  I'd pay a couple hundred extra for the built in option.
But now we're getting into Marketing Madness... Only Jan can make the call whether it would be worthwhile or not.  Gotta balance units sold/profit and extra hassle of at least 3 configurations...  Meah... I guess a separate box isn't so bad.
 
Aug 30, 2013 at 4:53 PM Post #875 of 3,871
Quick update:
 
After Jan received my HD800 & resistor box and hooked it up to his Millenia(s), he mentioned only heard a slight amount of hiss when the pot was fully open (which is a non-issue since only insane people would listen at this volume level.. or if a sane person is using a pre-amp).  So, I figured it might be something to do with my Millenia and/or SMPS.  I sent the entire package back to him.  Once he received my Millenia, he concluded that he did hear some (omnipresent) hiss in the right channel.  So, he's replacing my Millenia.
 
Per my request, he's also adjusting my resistor box.  The current resistor box is quite good in terms of being able to listen at low volume levels & have a degree of fine control w/o channel imbalance.. but I wanted a little more.  So, Jan's adjusting it so my normal listening range (which currently sits slightly below 9 o'clock on the pot) will be near 12 o'clock.
 
Gotta say it again, Jan's willingness to assist us really goes above and beyond what I've experienced.
 
Aug 30, 2013 at 7:34 PM Post #876 of 3,871
Hey FlySweep,
 
No kidding!   I wish Jan the all the best at establishing some benchmarks for various headphones and streamlining the process for more business downstream.  It sounds as if he's doing R&D for us.  Unreal dedication.  
 
I suppose I'll be next when he finishes yours, but it will be a lot easier to just give me what Gary has, given that my LCD-2 have about the same impedance as his LCD-3.  
 
Meanwhile, I'm having tons of fun with my MG3 and SM45 monitors.  You may recall that early on, I had heard some hiss into those 8-Ohm speakers only when using supply voltages higher than 15V.  Remarkably, that has faded away to almost nothing with break-in of the MG3. I have to put my ear right against the speaker grill to hear it now, with 24V power.  I know the speakers already had at least 50 hours on them before I received the MG3, nine days ago, but maybe they were in need of additional break-in, too.  
 
But early on, independent of that fairly low level of hiss at 24V, that's now all but gone, I had also concluded that I preferred the sound quality had at or below 15V, to that had near 24V.  That's no longer the case, either!  I'm really liking what I hear now on 25.2V power, using a 3600 mAh six-cell LiPo battery (that produces 25.2V when fully charged, down to 18.0V when fully discharged.)
 
 

 
http://www.amazon.com/gp/product/B0027G87MI
 
 
I had also previously discussed my use of this voltage monitoring alarm:
 
 

http://www.amazon.com/Integy-C23212-Voltage-Checker-Warning
 
This thing sounds like a smoke detector when it goes off.  It comes factory preset to alarm when any cell in the LiPo pack falls to 3.3V.  (Anything less than 3.0V can cause damage - a phase change - to LiPo cells.)  3.3V allows time for RC enthusiasts to get their aircraft (or boats) back on the ground (or back to shore).  I had reset mine to alarm at 3.0V instead of 3.3, for extended playing time, until I found this graph the other day on a pretty good page that covers the basics of using LiPo batteries:
 
 

 
http://revolution-robotics.com/articles/lithium_polymer_lipo_battery_guide
 
As stated in the annotated graphic, I'm now discharging to 3.4V per cell (20.4V total), instead of to 3.0V per cell (18.0V total) - just to keep the MG3's output from dropping precipitously in the last 9% of available play time.
 
Joy!
 
Mike
 
Aug 30, 2013 at 11:43 PM Post #877 of 3,871
I dub thee Zilch0md "Lord of LiPo"
tongue_smile.gif

Quote:
Hey FlySweep,
 
No kidding!   I wish Jan the all the best at establishing some benchmarks for various headphones and streamlining the process for more business downstream.  It sounds as if he's doing R&D for us.  Unreal dedication.  
 
I suppose I'll be next when he finishes yours, but it will be a lot easier to just give me what Gary has, given that my LCD-2 have about the same impedance as his LCD-3.  
 
Meanwhile, I'm having tons of fun with my MG3 and SM45 monitors.  You may recall that early on, I had heard some hiss into those 8-Ohm speakers only when using supply voltages higher than 15V.  Remarkably, that has faded away to almost nothing with break-in of the MG3. I have to put my ear right against the speaker grill to hear it now, with 24V power.  I know the speakers already had at least 50 hours on them before I received the MG3, nine days ago, but maybe they were in need of additional break-in, too.  
 
But early on, independent of that fairly low level of hiss at 24V, that's now all but gone, I had also concluded that I preferred the sound quality had at or below 15V, to that had near 24V.  That's no longer the case, either!  I'm really liking what I hear now on 25.2V power, using a 3600 mAh six-cell LiPo battery (that produces 25.2V when fully charged, down to 18.0V when fully discharged.)
 
 
 

 
http://www.amazon.com/gp/product/B0027G87MI
 
 
I had also previously discussed my use of this voltage monitoring alarm:
 
 

http://www.amazon.com/Integy-C23212-Voltage-Checker-Warning
 
This thing sounds like a smoke detector when it goes off.  It comes factory preset to alarm when any cell in the LiPo pack falls to 3.3V.  (Anything less than 3.0V can cause damage - a phase change - to LiPo cells.)  3.3V allows time for RC enthusiasts to get their aircraft (or boats) back on the ground (or back to shore).  I had reset mine to alarm at 3.0V instead of 3.3, for extended playing time, until I found this graph the other day on a pretty good page that covers the basics of using LiPo batteries:
 
 

 
http://revolution-robotics.com/articles/lithium_polymer_lipo_battery_guide
 
As stated in the annotated graphic, I'm now discharging to 3.4V per cell (20.4V total), instead of to 3.0V per cell (18.0V total) - just to keep the MG3's output from dropping precipitously in the last 9% of available play time.
 
Joy!
 
Mike
 
 

 
Aug 31, 2013 at 12:43 AM Post #879 of 3,871
Hey Stew!
 
Quote:
I realize this is a headphone site, but just gotta say that this past weekend I was listening over my speaker system to a cd I just purchased - Laurence Juber plays The Beatles, Volume 2 (both volume 1 and 2 are highly recommended).

 
I received the Laurence Juber CD today - Vol. 1.  This is an excellent demo for the MG3.  Other acoustic music I've heard has been great, no doubt,but acoustic guitar doesn't get much better than this.  I'm listening to it now.
 
 It's a wee bit more laid-back than what I would normally listen to, but I am undeniably hooked.  I love it when the quality of a recording, the musicanship, and the gear are all high enough to take me outside my "comfort zone" in terms of genre - only to discover there's a lot to enjoy there.  
 
 

 
http://www.amazon.com/gp/product/B00004TFCO
 
Thank you for the recommendation,
 
Mike
 
Aug 31, 2013 at 1:53 AM Post #880 of 3,871
Hey Zilch, check out what I'll be building hopefully next weekend. Ever heard of the Lightspeed Attenuator? It's a Stereophile Class "B" component. Anyways, there's a recently released DIY version from Tortuga Audio, called the LDR3X. It's still on it's promo sale. You can currently do 1in/1out RCA or XLR with matching slave board. It even comes with a remote, and next to no soldering needed! Total cost for the board, chassis, jacks, wall wart etc. came out to $250 shipped. Incredible. In the future, Tortuga Audio will also be releasing add-on cards for additional I/O, rotary encoders, and discrete buttons if you desire.
 
Anyways, the reason i bring it to your attention is that what would be a good battery solution that is small as possible. It can accept either 5VDC (trigger-out disabled)or 12VDC. I suppose going with 5VDC (regulated) would be more practical. The black steel case I bought for it has dimensions of 7"(178mm) L x 5"(127mm) W x 2"(51mm) H. The LDR3X has dimensions o2.5 inches wide by 4.7 inches long, so it will be a pretty tight fit. I just think it would be awesome if i could have this transportable since it's so small. I'll start a thread on it once i get the parts in the DIY section.
 

 
 
 
You enjoy a challenge right? 
tongue.gif

 
Aug 31, 2013 at 2:32 AM Post #881 of 3,871
So.......... I received my Millenia MG3 amp from Jan today.
 
First thing I did was hook up my vintage Yamaha HP-1 headphones... Initial impression with female vocals (SHEL) VERY positive.  The HP-1 in stock form tend to be dark, or at least lean toward the dark side (Luke...  Oh, never mind).  These are my go-to headphone despite the fact that they are not the BEST headphone I own.  The HiFiMan HE-6 hold that honor.  
 
I listened to a couple of tracks and found myself continually dialing down the volume.  Too loud!  Turn it down!  So, what does it sound like against a couple of other amps on the shelf?
I went about the task of measuring and setting a set SPL level between the Millenia and an old-school Parasound HCA-1000A amplifier (John Curl design, you know!).
Pink noise has been my go-to for setting SPL level between amps, headphones, and such... Right off I discovered a dramatic difference in the perceived "loudness" with identical SPL levels between the MG3 and the Parasound (C weighted).  If I set the Parasound output to a decent listening level, swap to the MG3 and set identical SPL, the same track is much too loud!  Repeat, repeat repeat... yeah, same result....
 
OK, time to break out the Scientist in me.  Launch REW (RoomEquilizer) and take some measurements.  Sure enough, no matter what I do to ensure the set up is as close to identical as possible between the Millenia and the Parasound, from 2 kHz and above the Millenia measures between 3 and >10 dB higher than the Parasound.
 
I think to myself, Self, maybe the problem is with them old Yammis!  Try those fancy HE-6's!  To my dismay, dern near same result.  Much enhanced 2k+ frequency range on the Millenia over the Parasound.  OK, maybe the Parasound is the problem!  Squelching the high frequencies!  Lets compare to the First Watt F1!  OK... Same problem.  Frequency response measurements of the Parasound HCA-1000A and the First Watt F1 with the HE-6's very nearly overlap (within experimental error).
 
Being bothered by the inequity of perceived loudness and SPL measurements, I investigated other noise forms.  Violet, blue, blah, blah, blah.... gray... there it is... Gray Noise.  If I set SPL equivalent between MG3 and other amps, PERCEIVED loudness is much closer to "the same"....   Boy is this an inexact science!  Gray noise seems to help, though.
 
Progress...
 
Need to go back and do some A/B listening with the Gray Noise technique.
 
Next, I went to some favorite test tracks that especially emphasize bass response: The Dead Weather: 60 Feet Tall and Hang You From The Heavens.  Holy CRAP!  What is that I hear!?!?!?  Bass clipping!?!?!?  Quick comparo to F1... Yup... F1 sounds like it should... Bass clipping in the MG3....  Need sleep and further investigation...
 
Back to SHEL, HP-1, MG3.... Heaven...  (SHEL is amazing, by the way, if you are not familiar with them).
 
Config notes:  Signal path is flac played via Foobar2k->Schiit Gungnir->MG3 on 24 VDC wall plug (no battery or capacitor bank operation yet, sorry)
or 
 flac played via Foobar2k->Schiit Gungnir-> First Watt B1 preamp -> Parasound HCA-1000A or First Watt F1.
SPL measurement duties: Radio Shack SPL meter.
Bass clipping observations through my resistor box driving HE-6's.  Bass clipping not observed with Yamaha HP-1's and resistor box.
 
I plan to run the HE-6's direct to the MG3 to see if the resistor box is forcing the drive level too high, causing the clipping behavior.
 
MG3 Hiss... Its there, but pretty minimal with both the HE-6 and HP-1's.  Apparent enough that the resistor box was definitely helpful.  It may be that tuning the resistor values will allow the elimination of hiss and not induce clipping.  Time and experimentation will tell.
 
Edit to add I've noticed clipping on The Dead Weather, 3 Birds with the MG3... Gotta look at the resistor box and see what I need to do to reduce the resistor divider.  Bass extension is not nearly as good on this track with the MG3 as it is with the B1/F1 combo... Expecting too much?  Gary set my expectations very high... I blame it on him!  (j/k Gary :) )
-michael
 
Aug 31, 2013 at 6:10 AM Post #882 of 3,871
Congrats on your MG3. Hopefully you'll end up solving your problem soon and it wont be so bittersweet. 
Quote:
So.......... I received my Millenia MG3 amp from Jan today.
 
 
First thing I did was hook up my vintage Yamaha HP-1 headphones... Initial impression with female vocals (SHEL) VERY positive.  The HP-1 in stock form tend to be dark, or at least lean toward the dark side (Luke...  Oh, never mind).  These are my go-to headphone despite the fact that they are not the BEST headphone I own.  The HiFiMan HE-6 hold that honor.  
 
I listened to a couple of tracks and found myself continually dialing down the volume.  Too loud!  Turn it down!  So, what does it sound like against a couple of other amps on the shelf?
I went about the task of measuring and setting a set SPL level between the Millenia and an old-school Parasound HCA-1000A amplifier (John Curl design, you know!).
Pink noise has been my go-to for setting SPL level between amps, headphones, and such... Right off I discovered a dramatic difference in the perceived "loudness" with identical SPL levels between the MG3 and the Parasound (C weighted).  If I set the Parasound output to a decent listening level, swap to the MG3 and set identical SPL, the same track is much too loud!  Repeat, repeat repeat... yeah, same result....
 
OK, time to break out the Scientist in me.  Launch REW (RoomEquilizer) and take some measurements.  Sure enough, no matter what I do to ensure the set up is as close to identical as possible between the Millenia and the Parasound, from 2 kHz and above the Millenia measures between 3 and >10 dB higher than the Parasound.
 
I think to myself, Self, maybe the problem is with them old Yammis!  Try those fancy HE-6's!  To my dismay, dern near same result.  Much enhanced 2k+ frequency range on the Millenia over the Parasound.  OK, maybe the Parasound is the problem!  Squelching the high frequencies!  Lets compare to the First Watt F1!  OK... Same problem.  Frequency response measurements of the Parasound HCA-1000A and the First Watt F1 with the HE-6's very nearly overlap (within experimental error).
 
Being bothered by the inequity of perceived loudness and SPL measurements, I investigated other noise forms.  Violet, blue, blah, blah, blah.... gray... there it is... Gray Noise.  If I set SPL equivalent between MG3 and other amps, PERCEIVED loudness is much closer to "the same"....   Boy is this an inexact science!  Gray noise seems to help, though.
 
Progress...
 
Need to go back and do some A/B listening with the Gray Noise technique.
 
Next, I went to some favorite test tracks that especially emphasize bass response: The Dead Weather: 60 Feet Tall and Hang You From The Heavens.  Holy CRAP!  What is that I hear!?!?!?  Bass clipping!?!?!?  Quick comparo to F1... Yup... F1 sounds like it should... Bass clipping in the MG3....  Need sleep and further investigation...
 
Back to SHEL, HP-1, MG3.... Heaven...  (SHEL is amazing, by the way, if you are not familiar with them).
 
Config notes:  Signal path is flac played via Foobar2k->Schiit Gungnir->MG3 on 24 VDC wall plug (no battery or capacitor bank operation yet, sorry)
or 
 flac played via Foobar2k->Schiit Gungnir-> First Watt B1 preamp -> Parasound HCA-1000A or First Watt F1.
SPL measurement duties: Radio Shack SPL meter.
Bass clipping observations through my resistor box driving HE-6's.  Bass clipping not observed with Yamaha HP-1's and resistor box.
 
I plan to run the HE-6's direct to the MG3 to see if the resistor box is forcing the drive level too high, causing the clipping behavior.
 
MG3 Hiss... Its there, but pretty minimal with both the HE-6 and HP-1's.  Apparent enough that the resistor box was definitely helpful.  It may be that tuning the resistor values will allow the elimination of hiss and not induce clipping.  Time and experimentation will tell.
 
Edit to add I've noticed clipping on The Dead Weather, 3 Birds with the MG3... Gotta look at the resistor box and see what I need to do to reduce the resistor divider.  Bass extension is not nearly as good on this track with the MG3 as it is with the B1/F1 combo... Expecting too much?  Gary set my expectations very high... I blame it on him!  (j/k Gary :) )
 
 

 
Aug 31, 2013 at 7:44 AM Post #883 of 3,871
Quote:
Hey Zilch, check out what I'll be building hopefully next weekend. Ever heard of the Lightspeed Attenuator? It's a Stereophile Class "B" component. Anyways, there's a recently released DIY version from Tortuga Audio, called the LDR3X. It's still on it's promo sale. You can currently do 1in/1out RCA or XLR with matching slave board. It even comes with a remote, and next to no soldering needed! Total cost for the board, chassis, jacks, wall wart etc. came out to $250 shipped. Incredible. In the future, Tortuga Audio will also be releasing add-on cards for additional I/O, rotary encoders, and discrete buttons if you desire.
 
Anyways, the reason i bring it to your attention is that what would be a good battery solution that is small as possible. It can accept either 5VDC (trigger-out disabled)or 12VDC. I suppose going with 5VDC (regulated) would be more practical. The black steel case I bought for it has dimensions of 7"(178mm) L x 5"(127mm) W x 2"(51mm) H. The LDR3X has dimensions o2.5 inches wide by 4.7 inches long, so it will be a pretty tight fit. I just think it would be awesome if i could have this transportable since it's so small. I'll start a thread on it once i get the parts in the DIY section.
 
 
You enjoy a challenge right? 
tongue.gif

The Tortuga is quite overpriced imo, so are most other commercial LDR stuffs.
 
If you're going with DIY, 2 pairs of matched LDRs cost 35 bucks - the rest of the component is cheap. Especially when you want battery instead of a toroidal transformer. 
 
Why do you need one anyway - replacing the pot of the Crack? I see no power amp in your profile 
blink.gif

 
Aug 31, 2013 at 8:36 AM Post #885 of 3,871
Quote:
Hey Stew!
 
 
I received the Laurence Juber CD today - Vol. 1.  This is an excellent demo for the MG3.  Other acoustic music I've heard has been great, no doubt,but acoustic guitar doesn't get much better than this.  I'm listening to it now.
 
 It's a wee bit more laid-back than what I would normally listen to, but I am undeniably hooked.  I love it when the quality of a recording, the musicanship, and the gear are all high enough to take me outside my "comfort zone" in terms of genre - only to discover there's a lot to enjoy there.  
 
 

 
http://www.amazon.com/gp/product/B00004TFCO
 
Thank you for the recommendation,
 
Mike

Glad you are enjoying the cd. Can't go wrong with the Beatles! Anyhow, I feel volume two is an even better recording......more lifelike guitar sound. But both cds are an awesome display of acoustic guitar work, with lovely arrangements which manage to remain true to the originals.  
 
http://www.amazon.com/LJ-Plays-Beatles-Vol-2/dp/B003U8O2OY/ref=sr_1_2?s=music&ie=UTF8&qid=1377951917&sr=1-2&keywords=laurence+juber
 
I listened to Dire Straits the other day, Brothers In Arms. I agree, some fabulous sounding stuff on there with the Millenia and my Clue speakers. I was never that taken by that recording, I think it was one of the early all digital recordings. But it sounds very smooth, very atmospheric, and the vocals are lifelike. Awesome bass. With my speakers I am experiencing some of the best bass response with this little amp than I have heard over multiple systems and equipment over the years that I have used. I hope Potterma gets his issues sorted out. Once again, a call to Jan might help to sort it all out. Headphones are not what the amp was designed for, so it's taking some experimenting, etc. I tell you, with the resistor box I have for my Paradox headphones, those Audeze LCD2 headphones I had on loan last week sounded sublime. Absolutely quiet background (no hiss), instruments and voices sounded real, no treble hashy artifacts that appear to be on many recordings (how do those headphones filter that stuff out!) Anyhow, still on the fence about ordering a pair, mostly due to commitment that would be necessary to sort out the comfort issues.
 

Users who are viewing this thread

Back
Top