• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Synrgy87

Member
Joined
Apr 7, 2021
Messages
23
Likes
14
This fell into the "Cheap enough, worth a pop" category so decided to get one to play around with.

It arrived this morning, no power supply just a USB A to Barrel jack cable and the unit itself, thing is tiny. Got it hooked up to a Topping E50 via XLR and powered at the min with a cheap generic 5V USB charger that might just be 1amp can't make out the ratings anymore.

Tested it out (just listening) with my Sennheiser HD565(fitted with 300ohm drivers) via balanced cable both 4.4 and 4 pin XLR via adapter, seems OK so far it can get very loud 11-12 o'clock on the volume knob is just about too loud. If you're after a small footprint balanced headphone amp this may well be a decent budget option, have seen people also feed it unbalanced signal but may pair well with a D10S balanced or something similar.

Price wise I got mine via amazon for £49 but can be sourced from aliexpress / others for cheaper, didn't want to wait on the shipping.

Modifications:

Nothing crazy, all of the 4 8 pin op amps are socketed with the nicer rounded pin sockets, I left them alone for now though need to order some in maybe OPA2134, was going to use NE5532s but ti don't have enough this thing takes 5v in and feeds the op amps 24v (checked with multimeter) the stock op amps are JRC 4850D but i don't know if they are legit or remarked fakes like LM358s or something. OPA2134 seems better spec'd though with lower THD so opinions and options here welcome.

The thing has a bright blue LED, not the most offensive blue LED but still, that had to go, couldn't find my smaller LEDs(didn't look for them tbh) so threw in a 5mm red lighty uppy boi which just about fit and is visible through the hole in the front panel, will tidy later with something that fits better.

Capacitors: there's 4x 100uf 16v 105c electrolytic caps from JWco and 1x 1000uf 10v 105c Chongx branded electrolytic which people don't seem to be too fond of. so they were all replaced with what i had at hand that fit, which were 4 x Panasonic 100uf 25v 105c and 1x 1500uf 16v(might have actually been a 10v too had both out on my desk thinking about it now the 16v might have been a bit too tall) 105c also from Panasonic.

Was there any improvement? I dunno maybe more punch? Probably not makes me feel better with nicer components there though, more listening to do. Pictures:

 

DVDdoug

Major Contributor
Joined
May 27, 2021
Messages
2,916
Likes
3,831
there's 4x 100uf 16v 105c electrolytic caps from JWco and 1x 1000uf 10v 105c Chongx branded electrolytic
1000uF would probably be power supply filter capacitors so they are not in the signal path and swapping them won't make any difference unless they are defective or unreliable.

Capacitors in the signal path rarely make a difference unless they are part of a high-pass or low-pass filter, etc., or it's simply a bad design and the caps are too-low in value.

Swapping the op-amps usually won't make any difference either unless the originals are noisy. Distortion is rarely an issue because of the negative feedback (AKA "corrective feedback") used in op-amp circuits reduces distortion (and it tends to reduce noise and flatten frequency response). But if the op-amps are directly driving headphones most are not designed to drive low impedance loads (some can put-out more current than others) so you could get distortion or limited output with the "wrong" op-amp.
 
OP
S

Synrgy87

Member
Joined
Apr 7, 2021
Messages
23
Likes
14
1000uF would probably be power supply filter capacitors so they are not in the signal path and swapping them won't make any difference unless they are defective or unreliable.

Capacitors in the signal path rarely make a difference unless they are part of a high-pass or low-pass filter, etc., or it's simply a bad design and the caps are too-low in value.

Swapping the op-amps usually won't make any difference either unless the originals are noisy. Distortion is rarely an issue because of the negative feedback (AKA "corrective feedback") used in op-amp circuits reduces distortion (and it tends to reduce noise and flatten frequency response). But if the op-amps are directly driving headphones most are not designed to drive low impedance loads (some can put-out more current than others) so you could get distortion or limited output with the "wrong" op-amp.
They were changed for the sake of putting better quality components in first and foremost rather than for any meaningful difference in audio quality, the "more punchy" sounds likely just my brain or the volume level which isn't easy to keep the same as it's also the on/off switch. The capacitors I already had in stock so no additional cost there(their normal purpose is re-capping old computer motherboards, arcade boards, game consoles etc)

I've had nice results in swapping out op amps in these cheaper Chinese products (Aiyima A07, FX-Audio DAC-X6, SUCA Audio Tube-T1) the dac-x6 made the most difference along with the A07, in the DAC-X6 especially although that's probably because they were fake junk or defective to begin with as this was not in any way a subtle change. Will it make any positive difference here? It's the same level of device and at the very least I'll feel better about it with some nicer components in there appropriately sourced. Need to get some more XLR cables to A-B it with the Topping A30pro but that's not really a fair comparison.
 

Berwhale

Major Contributor
Forum Donor
Joined
Aug 29, 2019
Messages
3,933
Likes
4,922
Location
UK
OP
S

Synrgy87

Member
Joined
Apr 7, 2021
Messages
23
Likes
14
Nice, I wonder how it's bigger brother, the U8 measures...

Built in ESS DAC and single ended output front and back too but no analogue input.

It does though apparently have... A special big knob:
 

Attachments

  • specialbig.jpg
    specialbig.jpg
    95.5 KB · Views: 119

Badunn

Member
Joined
Nov 11, 2022
Messages
25
Likes
46
@amirm … this little box of trickery up for a test any time soon? Seems too cheap to be true.
I‘m still confused if balanced headphone outputs are mere myth or true legend.
 

mackiemesser

New Member
Joined
Sep 17, 2022
Messages
4
Likes
0
Hello Synrgy87 and others,
I just have a quick question regarding the outputs of U5:
Do you think it is possible to mod the U5 to have also a 'single-ended' output?

How do the other manufacturers build their HP-Amps that offer both kinds of outputs?

An easy adapter-solution wouldn't work I think, because shortening (or bridging) the negative Outputs of the amps is risky.

My idea would be to get rid of the 4.4mm Output and build in a 6,3mm (or 3,5mm)3-Pin Headphone-jack.
But I am unsure about the internal connection or wiring.

Any help is appreciated!
Best regards.
mackiemesser

PS: I bought this amp mainly for its balanced inputs, combined with its small and transportable size.
I have a 650 and balanced cables, but also several "single-enders", and sometimes a colleague would like to hear something through his cans.

I also often need a distinct headphone-out in different recording-studios or broadcast-vans, so would like to carry this small beast with me, that even works with USB-power.
 
OP
S

Synrgy87

Member
Joined
Apr 7, 2021
Messages
23
Likes
14
Hello Synrgy87 and others,
I just have a quick question regarding the outputs of U5:
Do you think it is possible to mod the U5 to have also a 'single-ended' output?

How do the other manufacturers build their HP-Amps that offer both kinds of outputs?

An easy adapter-solution wouldn't work I think, because shortening (or bridging) the negative Outputs of the amps is risky.

My idea would be to get rid of the 4.4mm Output and build in a 6,3mm (or 3,5mm)3-Pin Headphone-jack.
But I am unsure about the internal connection or wiring.

Any help is appreciated!
Best regards.
mackiemesser

PS: I bought this amp mainly for its balanced inputs, combined with its small and transportable size.
I have a 650 and balanced cables, but also several "single-enders", and sometimes a colleague would like to hear something through his cans.

I also often need a distinct headphone-out in different recording-studios or broadcast-vans, so would like to carry this small beast with me, that even works with USB-power.

As cool as that would be I'm not sure how practical it would be or if you could fit what's needed in the limited space. Not sure if there's any mini modules designed for that purpose out there somewhere.
 

mackiemesser

New Member
Joined
Sep 17, 2022
Messages
4
Likes
0
Thanks for your reply,
I was thinking about other HP-amps that offer both: a balanced and single ended output.

Question would be:
Where do the single-ended outs get their signals from?
I'm not sure if those amps really have a distinct second audio-(amplification)-path for those outs. I would guess they pick up the signal somewhere behind the op-amps.

As in the U5 the amplification seems to be a push-pull-concept, I was wondering if just using the "+R" and "+L" in combination with the internal GND would make sense for an unbalanced connection.

If the housing would fit another jack is another question, but even if I had to let a cable hang out of the box, it would be okay for me.

So my question is more regarding the signal pickup for "unbalanced-mode".

Maybe anyone else has an idea?

Thanks in advance and best regards
mackiemesser
 
OP
S

Synrgy87

Member
Joined
Apr 7, 2021
Messages
23
Likes
14
As in the U5 the amplification seems to be a push-pull-concept, I was wondering if just using the "+R" and "+L" in combination with the internal GND would make sense for an unbalanced connection.
I thought about that, taking a ground and then pulling L and R signal from the op amps but not sure if the grounding would become a problem or the voltage levels of the signals. otherwise may need a transformer based solution. Something to experiment with maybe if you have them the op amp data sheets are available online for pinouts.
 

mackiemesser

New Member
Joined
Sep 17, 2022
Messages
4
Likes
0
I'll check for that.
And actually I'll have to behind the volume-pot...
We'll seems to be a kind of bigger project. Yeah, and you're right, maybe it's impossible without another trafo.

Thanks mate!
BR
mackiemesser
 

Dunring

Major Contributor
Forum Donor
Joined
Feb 7, 2021
Messages
1,212
Likes
1,277
Location
Florida
Old thread, but I just got one for $20 used on Amazon. Couldn't resist at that price and tossed a 2 amp phone charger on it. This has a lot more power than I expected, but the channel balance under 30 percent is really bad. Over that it's good though. I just needed something to test cables for functionality with the XLR plug the DL200 doesn't have. The Hifiman HE5xx was ridiculous volume at 50 percent, and had to turn the DAC down to 50 percent volume just to get it up over 30 percent for channel matching. It sounds pretty good too, no obvious problems, but doesn't sound nearly as clean as the DL200 by itself, which is my daily driver these days.

PXL_20231217_002927637.jpg
 

mackiemesser

New Member
Joined
Sep 17, 2022
Messages
4
Likes
0
Dear 'U5' - community,
wanted to check here first, before I get in touch with Douk-Audio:
My U5 was sitting around unused for a month or two. I now needed it again, plugged in two XLR-lines and immediately had a pretty loud noise on the HP-Output.
Noise sounds like white-noise. When XLRs are not connected, the noise is gone.
Does anyone have an idea where this could come from? Can this be the ICs? Bad capacitor(s)?

The device worked flawless before, so it'd be too bad to give up on it.

Thanks in advance
BR
mackiemesser
 

6Channel

New Member
Joined
Mar 9, 2024
Messages
1
Likes
0
Old thread, but I just got one for $20 used on Amazon. Couldn't resist at that price and tossed a 2 amp phone charger on it. This has a lot more power than I expected, but the channel balance under 30 percent is really bad. Over that it's good though. I just needed something to test cables for functionality with the XLR plug the DL200 doesn't have. The Hifiman HE5xx was ridiculous volume at 50 percent, and had to turn the DAC down to 50 percent volume just to get it up over 30 percent for channel matching. It sounds pretty good too, no obvious problems, but doesn't sound nearly as clean as the DL200 by itself, which is my daily driver these days.

View attachment 334813
I just registered because a U5 has become a little project for me. Ya, the first one I got mistracked so badly I just shoved it aside - horrible imbalance until ~1:00 on the dial. But the audio was enough to encourage me, so I wrote it off & purchased another. Bingo! Perfect tracking. Swapped in 4 NJM5532DD's for the lazy-sounding stock 4580's and rounded up a 5A 5V power supply. It sounds very, very good right now. It's a killer "bedside" balanced solution for me. Ya need to tie it down with zips to the surface it's on (or screw it through the chassis bottom), because it flits around like a leaf with any cords attached. Marked response to the new chips - I'm into the "etched" audio, but you might fare better plugging in your fave bipolars.
 
Top Bottom