Hello,
I know everything can be run from battery, it is just a question of the size of the battery
So, with a reasonable battery, what amp would you recommend? With this, I would use my smaller, portable cans and plan to get some good Grado. Maybe I would use sometime with 300 Ohm cans, but it is not the most important.
Also, it may be important that I less care about the base, much more about wide and deep stage. I do not prefer ICs, but may try. Opamps I do not like at all however (maybe DC servo). I made with TPA6130 and it was not bad. Very detailed sound, but less the amp what I would listen to for hours.
Thanks a lot!
JG
I know everything can be run from battery, it is just a question of the size of the battery
So, with a reasonable battery, what amp would you recommend? With this, I would use my smaller, portable cans and plan to get some good Grado. Maybe I would use sometime with 300 Ohm cans, but it is not the most important.
Also, it may be important that I less care about the base, much more about wide and deep stage. I do not prefer ICs, but may try. Opamps I do not like at all however (maybe DC servo). I made with TPA6130 and it was not bad. Very detailed sound, but less the amp what I would listen to for hours.
Thanks a lot!
JG
If you are looking for non-opamp based, discrete, single ended Class A, my Pocket Class A (PCA) is tough to beat. It was picked as best sounding (vs several other pocket and desktop amps) in a blind virtual audition here on DIYA:
Blind Virtual Audition of Several Headamps
With a pair of 600mAhr 9v lithium ion rechargeable batteries you can get about 4.5hrs of use. But the batteries can be swapped out for longer run time.
Blind Virtual Audition of Several Headamps
With a pair of 600mAhr 9v lithium ion rechargeable batteries you can get about 4.5hrs of use. But the batteries can be swapped out for longer run time.
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Can you help to find the circuit diagram please?
I find it strange that you tested with mp3. I think the comparison is still interesting, but I do not understand why you guys used this as source. I also have a Focusrite, a different one, a scarlett 2i2. Good for recording, but for listening it is a strong compromise I think. For headphone I use an xmos usb to I2S, a conversion pcb and AD1865 DAC. In a few seconds you would hear how much the stage is better, more air in the sound, I really suggest to forget the Focusrite for music listening. ... Maybe the solo is better.
Thanks a lot!
JG
I find it strange that you tested with mp3. I think the comparison is still interesting, but I do not understand why you guys used this as source. I also have a Focusrite, a different one, a scarlett 2i2. Good for recording, but for listening it is a strong compromise I think. For headphone I use an xmos usb to I2S, a conversion pcb and AD1865 DAC. In a few seconds you would hear how much the stage is better, more air in the sound, I really suggest to forget the Focusrite for music listening. ... Maybe the solo is better.
Thanks a lot!
JG
MP3 was just to record the sound for blind listening. There was a 1.7MB max duke size limit for posting files on DIYA. The source playing during the test was higher resolution CD quality 44kHz 16bit wav I think. I think since then DIYA has relaxed the file limit and larger files are now allowed.
The schematic for the winning amp is here:
xrk971 Pocket Class A Headamp GB
Since both BF862 and ZVN4306 are EOL, the latest version uses 2SK209GR and ZXMN10A08GTA.
The schematic for the winning amp is here:
xrk971 Pocket Class A Headamp GB
Since both BF862 and ZVN4306 are EOL, the latest version uses 2SK209GR and ZXMN10A08GTA.
Or just avoid class A entirely, which is the logical thing to do for battery power.
Couple of opamps, 8mA drain, plus a bit for the load, 50+ hours from that same power source seems plausible...
But the Super CMOY 1688 lost to the PCA in the blind virtual headphone amp shootout linked in post 3 above. It’s a great amp, don’t get me wrong, but not as good in perceived sound quality and enjoyment as a SE Class A. If one carries a set of spare rechargeables, 9hrs is achievable. That’s good enough for a full day of listening for most needs.
You can see it here in the red tin next to the blue tin which is the PCA.
And that test was made with the “Ur-PCA prototype” hand etched using a Sharpie marker as acid resist and undersized output caps. The production “NHB” spec version with 2000uF OSCON output cap will sound superior.
You can see it here in the red tin next to the blue tin which is the PCA.
And that test was made with the “Ur-PCA prototype” hand etched using a Sharpie marker as acid resist and undersized output caps. The production “NHB” spec version with 2000uF OSCON output cap will sound superior.
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I appreciate your enthusiasm but you'll excuse me if I think that this shoot out is fundamentally flawed and not quite the gospel: not enough participants (especially with undefined playing gear), too many comparative points to have a serious result (listening fatigue, short term auditive memory) and a recording chain not clearly better than the amps being recorded. So 4 votes vs 2... hardly significant and I wouldn't draw any conclusion as drastic as saying that the super cmoy "lost" to the PCA.
As for SE class A. Been there, done that. I've literally half a dozen "nice" sounding headphones amps sleeping on my shelves (SS and tubes based). But my daily drivers are opamps based.
4.5h of music and swapping batteries would have been acceptable in the early 2000's. Today it's a bit difficult to swallow when top notch bluetooth cans have 30h+ of autonomy. I see few situations where I'd still keep the hassle of a portable amp tbh.
As for SE class A. Been there, done that. I've literally half a dozen "nice" sounding headphones amps sleeping on my shelves (SS and tubes based). But my daily drivers are opamps based.
4.5h of music and swapping batteries would have been acceptable in the early 2000's. Today it's a bit difficult to swallow when top notch bluetooth cans have 30h+ of autonomy. I see few situations where I'd still keep the hassle of a portable amp tbh.
At the very least check out a MAX97220 based inexpensive off-the-shelf portable amp as a baseline. Doesn't take much for 20-30 hours.
I'd have to agree that I'd find a 4.5 hour runtime for a portable amp much too annoying... the ca. 10 hours of my Clip+' (180 mAh pouch cell!) can get a bit tight as-is, but at least I want to scrobble those every once in a while anyway.
I'd have to agree that I'd find a 4.5 hour runtime for a portable amp much too annoying... the ca. 10 hours of my Clip+' (180 mAh pouch cell!) can get a bit tight as-is, but at least I want to scrobble those every once in a while anyway.
I'm getting the parts for the class A amp. But, I was reading now that the Sennheiser HDV 820 (which is told to pair well with the HD800S headphone) is ended with 2 TPA6120A2. That really surprised me. I thought there is some kind of class A amp under that heatsink. Do you guys know what settings are used for the TPA6120? What supply voltage, etc. ?
I made a (not bad) amp with one TPA6120 and it did not create much heat. That heatsink is probably needed for a more class A bias somehow. I guess.
?
Thanks!
JG
I made a (not bad) amp with one TPA6120 and it did not create much heat. That heatsink is probably needed for a more class A bias somehow. I guess.
?
Thanks!
JG
$2400 for a TPA6120 chip amp? It has a very nice analog/digital input and balanced or SE input options. Box looks very nice too. It’s not Class A and not sure what heatsink you are referring too. They do use two of them per channel for balanced drive though. There is probably another opamp stage to provide the voltage gain (you can see the gain knob in the back) and use the 6120 as a 0dB buffer (I am speculating).
I bought one of these 6120 with a built in linear PSU for $7 and it sounds quite nice. 0dB gain though so needs a preamp. I hear that the 820 has SMPS vs linear.
HIFI TPA6120A2 Enthusiast Headphones Board Amplifier Accessories TPA6120 Amp Board|MP3 Players & Amplifier Accessories| - AliExpress
Which Class A?
I bought one of these 6120 with a built in linear PSU for $7 and it sounds quite nice. 0dB gain though so needs a preamp. I hear that the 820 has SMPS vs linear.
HIFI TPA6120A2 Enthusiast Headphones Board Amplifier Accessories TPA6120 Amp Board|MP3 Players & Amplifier Accessories| - AliExpress
Which Class A?
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If you look at the internal pictures like this : https://www.av-online.hu/pictures/g...20_2018-01-17/Sennheiser-HDV-820-inside-4.jpg , there is an alu heatsink. On other pictures you can see two TPA, when the heatsink is removed.
It would be interesting to know what supply voltage levels are used.
I was playing with one TPA before, I was very depending on the PSU. Very strange, but just like a CK2III, it was good with my old rack psu (HP6624A) and when I switched 2 SLA battery, I preferred the rack psu. Also tried with LM317/337 psu with quality caps and another psu what was proven with preamps, but these were all less performing.
I also found that as with other chip amps, to put the fb resistor as close to the package as possible with the shortest wires does help.
JG
It would be interesting to know what supply voltage levels are used.
I was playing with one TPA before, I was very depending on the PSU. Very strange, but just like a CK2III, it was good with my old rack psu (HP6624A) and when I switched 2 SLA battery, I preferred the rack psu. Also tried with LM317/337 psu with quality caps and another psu what was proven with preamps, but these were all less performing.
I also found that as with other chip amps, to put the fb resistor as close to the package as possible with the shortest wires does help.
JG
This very thorough review of it is not so flattering. -115dB SNR is not appropriate for a $2400 class amp. You will hear self-hiss with IEM’s at this kind of performance on noise.
Sennheiser HDV-820 USB DAC & Headphone Amp Review | Audio Science Review (ASR) Forum
But we are off topic as this is not a battery powered amp. It can put out 0.44w so those heatsinks need to dissipate maybe a watt or so and that looks like an appropriate 2w heatsink.
Sennheiser HDV-820 USB DAC & Headphone Amp Review | Audio Science Review (ASR) Forum
But we are off topic as this is not a battery powered amp. It can put out 0.44w so those heatsinks need to dissipate maybe a watt or so and that looks like an appropriate 2w heatsink.
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The 6120 is not off topic at all, that would be one of the smallest and least power hungry option. But, JPS64 has a valid question too, because even my 14kg 190W eating amp can be battery operated, but for sure I'm not looking for that. I'm using a cheap headphone with a secondary Sony mobile phone for listening to music on the go. On the other hand, often I take the main headphone for example to vacations we go with car. For sure I do not take the monster amp, and also it is difficult to find mains on the terrace etc., so a small battery operated amp is my target, but it does not have to be pocket size. If it is, even better, but does not have to be. On the other hand, I would avoid 3.5mm jacks and use cinch on the input, 1/4" on the output.
Thanks for all replies!
JG
Thanks for all replies!
JG
Hmm. Maybe an O2 in a custom (slightly larger) case? The standard version uses 3.5 mm jacks but can be battery powered, while in the desktop version the RCAs seem to be taking up some of the space otherwise occupied by the batteries. You rarely find all 3 in one amplifier. You could buy the board, parts and take the jacks from the desktop kit, only another enclosure would have to be found.
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