chillysalsa
Headphoneus Supremus
- Joined
- Sep 26, 2002
- Posts
- 1,989
- Likes
- 187
Preamble:
After being content for several years with HD800’s through my Xduoo TA-03, getting a pair of LCD-X’s required an amp that was more stable at lower impedances, and I stumbled upon this after searching “headphone amplifier class a” on aliexpress. With an intriguing description, impressive but potentially bogus measurements in the product description, and decent build quality photos, I took the bait. I won’t go through all the power specifications or the screen shots of distortion and cross-talk measurements they posted in the listing, but for the record they claim 9.7W at 32 ohm, and 1W at 300 ohm.
Initial impression:
The box arrived similarly to many how many other Chinese amps from aliexpress ship, a generic box and packed with seemingly hand cut styrofoam blocks about 1 to 2” thick on each side, and no power chord. Picking it up, I could already hear and issue, something rattling around. Unboxing and taking the plastic wrap off, flipping it over I can hear it very clear: sounds like a screw. Opening the top panel, I immediately find 2 screws inside, thank goodness I didn’t just power it up and possibly short something out. The output jacks are both single ended, one standard ¼” and other is the xlr + ¼ combo plug, also wired from the same point on the board. There are some listings of this amp that show a 4-pin XLR, which I thought might be balanced, but when I looked again at those internals – they are also wired the 4-pin plug from the same point, so it wouldn’t be true balanced any away, but just to allow you to use the 4 pin plug. At the back you have a fused standard power plug, and nice L, R gold plated RCA input plugs.
Everything otherwise looks fine, nothing loose and required fasteners everywhere they should be, so the screws were just extras left behind. So, not even a basic quality check by turn the unit over at the end of building? I am not hopeful this thing is even biased right or has acceptably low DC offset setup.
While I’m inside, a brief tour:
Power input section: Good size 100VA R-core transformer and rectifier diodes, two big boi 4700uF Nichicon Super Through caps, some small 78L15 regulators. To the bottom left the control circuit for the VU meters, where there are two blue 103 trim pots to adjust their sensitivity on L, R channels.
Regulator section: several BC transistors, some more Nichicon caps, K2381 and J407 Chopper regulators for DC-DC that are heatsinked to the case, now this is getting interesting. Seems like a beefy power input actually.
Main amplifier section key components: 2SK1058 and 2SJ162 output mosfets heatsinked to the enclosure, 2SC3421 and 2SA1358 bipolar transistors on vertical heatsinks, filtering inductors, an Omron relay near the wires to the jacks (perhaps for output protection?), ALPS pot (which looks possibly fake compared to real one I bought before, notice the indent in the middle of the label), and two silver RIFA caps, pretty nice!
I cautiously hook it up to power, no headphones plugged in yet, to check the DC output. SUCCESS: it lights up and there’s no smoke! Voltmeter shows 2.5 and 0.6 mV at the output, quite acceptable. The 102 and 101 trim pots on the main amplifier section are likely to adjust the bias and DC offset, but without the schematic I have no plan or need with these since the offset is ok. I don’t know where to measure the bias or what it should be. Offset drifts a little lower after slightly warming up – let’s have a listen!
Initial impressions:
Before to comparisons, first thing: WOW this is punchy! The amplifier has a lot of gain! Something that immediately catches my attention is the way control over bass. It’s like a vice grip clamping on the drivers that go to new lows of depth without flab. The instrument separation through the midrange is also very articulate, as you often see with Class A solid state amps. The high end is extended and free of noticeable grain.
The HD800 is treated to this helping of bass with fantastic results! I have never heard these go so low, and it confirms what many others claim about the anemic bass being improved with more power. Granted, this headphone is pretty linear and neutral in the bass, so if it’s not there in the source it will not fill it in. The high end has an enhanced sense of 3D quality. Though the HD800 always cast a wide stage, but this amp gives it height and separation. The midrange is very refined and textured. Though at higher listening levels it tends to get a little shouty, but not to the point that it’s unlistenable. I think the main problem is fatigue begins to creep in as you crave to listen at higher levels, and this amp really inspires you to do that.
The LCD-X is already pretty sensitive, but do they ever benefit from extra power! The degree of bass slam is impressive. The extension is so linear and effortless, things get very fun with electronic music in particular. Moving to the midrange there is a huge helping of texture that again comes through. There is a benefit from the surplus power in being able to maintain the dynamics of the low end, all while there are louder elements in the midrange poking through. The extension up through the top end is kind of subtle and unremarkable, which is perhaps a good thing. What you notice more is the sound stage has a lot of height and not particularly over-emphasized in width, but just in proportion. Yes, it still projects ‘outside of your head’ nicely though.
One issue is at the very lowest point, volume starts in the right channel first, and then things are balanced past the first 2% of rotation. I’ve noticed this on both fake and authentic ALPS pots, if not almost every pot I’ve tried in a few amps I’ve built. Given the enormous gain, you may need to turn down the source output if you plan to listen to very low levels. But, even at the lowest levels would listened to, it’s already balanced out.
Another issue is the VU meters are barely moving until you get to ear shredding levels on either the HD800 or LCD-X. Adjusting the 103 trim pots (up in the first two pictures), by rotating counter clockwise about a dozen turns gets them moving at normal levels, and I balanced L/R meters using a reference tone. Bouncy needle visuals - check!
Quick comparison:
Compared to the Xduoo TA-03 (which is an OTL or output transfermerless tube amp), the DCP is far more appropriate to drive the LCD-X. The Xduoo is actually only recommended for 60-600 ohms in the specifications, and that was the main reason for looking at the DCP, and the huge power and stability with the 20 ohm LCD-X is a huge benefit. Yes, the Xduoo can drive the LCD-X and to more than loud enough levels, but it does run out of breath in the bass department. The lack of control and flabbiness become noticeable at moderate volumes, and the Xduoo even gets a little hotter than usual. The overall midrange seems a little recessed compared to the DCP. My main impression is the DCP is a brute in comparison, and drives the LCD-X effortlessly. When driving the HD800 with the Xduoo I was happy for many years with the liquid and snappy response. This pairing is great synergy, and the Xduoo can be driven to really high levels, with the upper frequencies being so slightly tamed by the Xduoo. I feel the DCP is more of a side step, there is a very different experience, with a more visceral and organic midrange coming through. The DCP also has a far more extended bottom end, there is actually fair bit of slam that is hitting with the HD800, which you would never expect.
Compared to my self-built Dynahi, you have a more similar design to the DCP, both being solid state Class A amps with several watts of power on tap. I would say that the main difference being that the Dynahi has a more neutral presentation, the mid range is a little more restrained. They both go to really low frequencies without breaking a sweat of course. The upper frequencies are perhaps a little more refined with the Dynahi, but it is splitting hairs, you really need to focus on the soundstage to note more differences. The sound stage of the DCP is just slightly narrower, but taller compared to the Dynahi. The only other difference I noticed is the Dynahi has lower self-noise, with less hiss and hum when you crank the dial all the way to full, but of course neither is audible at normal listening levels.
Anyway, I would recommend this amp if you’re looking for something powerful. Though, as I experienced, be prepared for some surprises!
After being content for several years with HD800’s through my Xduoo TA-03, getting a pair of LCD-X’s required an amp that was more stable at lower impedances, and I stumbled upon this after searching “headphone amplifier class a” on aliexpress. With an intriguing description, impressive but potentially bogus measurements in the product description, and decent build quality photos, I took the bait. I won’t go through all the power specifications or the screen shots of distortion and cross-talk measurements they posted in the listing, but for the record they claim 9.7W at 32 ohm, and 1W at 300 ohm.
Initial impression:
The box arrived similarly to many how many other Chinese amps from aliexpress ship, a generic box and packed with seemingly hand cut styrofoam blocks about 1 to 2” thick on each side, and no power chord. Picking it up, I could already hear and issue, something rattling around. Unboxing and taking the plastic wrap off, flipping it over I can hear it very clear: sounds like a screw. Opening the top panel, I immediately find 2 screws inside, thank goodness I didn’t just power it up and possibly short something out. The output jacks are both single ended, one standard ¼” and other is the xlr + ¼ combo plug, also wired from the same point on the board. There are some listings of this amp that show a 4-pin XLR, which I thought might be balanced, but when I looked again at those internals – they are also wired the 4-pin plug from the same point, so it wouldn’t be true balanced any away, but just to allow you to use the 4 pin plug. At the back you have a fused standard power plug, and nice L, R gold plated RCA input plugs.
Everything otherwise looks fine, nothing loose and required fasteners everywhere they should be, so the screws were just extras left behind. So, not even a basic quality check by turn the unit over at the end of building? I am not hopeful this thing is even biased right or has acceptably low DC offset setup.
While I’m inside, a brief tour:
Power input section: Good size 100VA R-core transformer and rectifier diodes, two big boi 4700uF Nichicon Super Through caps, some small 78L15 regulators. To the bottom left the control circuit for the VU meters, where there are two blue 103 trim pots to adjust their sensitivity on L, R channels.
Regulator section: several BC transistors, some more Nichicon caps, K2381 and J407 Chopper regulators for DC-DC that are heatsinked to the case, now this is getting interesting. Seems like a beefy power input actually.
Main amplifier section key components: 2SK1058 and 2SJ162 output mosfets heatsinked to the enclosure, 2SC3421 and 2SA1358 bipolar transistors on vertical heatsinks, filtering inductors, an Omron relay near the wires to the jacks (perhaps for output protection?), ALPS pot (which looks possibly fake compared to real one I bought before, notice the indent in the middle of the label), and two silver RIFA caps, pretty nice!
I cautiously hook it up to power, no headphones plugged in yet, to check the DC output. SUCCESS: it lights up and there’s no smoke! Voltmeter shows 2.5 and 0.6 mV at the output, quite acceptable. The 102 and 101 trim pots on the main amplifier section are likely to adjust the bias and DC offset, but without the schematic I have no plan or need with these since the offset is ok. I don’t know where to measure the bias or what it should be. Offset drifts a little lower after slightly warming up – let’s have a listen!
Initial impressions:
Before to comparisons, first thing: WOW this is punchy! The amplifier has a lot of gain! Something that immediately catches my attention is the way control over bass. It’s like a vice grip clamping on the drivers that go to new lows of depth without flab. The instrument separation through the midrange is also very articulate, as you often see with Class A solid state amps. The high end is extended and free of noticeable grain.
The HD800 is treated to this helping of bass with fantastic results! I have never heard these go so low, and it confirms what many others claim about the anemic bass being improved with more power. Granted, this headphone is pretty linear and neutral in the bass, so if it’s not there in the source it will not fill it in. The high end has an enhanced sense of 3D quality. Though the HD800 always cast a wide stage, but this amp gives it height and separation. The midrange is very refined and textured. Though at higher listening levels it tends to get a little shouty, but not to the point that it’s unlistenable. I think the main problem is fatigue begins to creep in as you crave to listen at higher levels, and this amp really inspires you to do that.
The LCD-X is already pretty sensitive, but do they ever benefit from extra power! The degree of bass slam is impressive. The extension is so linear and effortless, things get very fun with electronic music in particular. Moving to the midrange there is a huge helping of texture that again comes through. There is a benefit from the surplus power in being able to maintain the dynamics of the low end, all while there are louder elements in the midrange poking through. The extension up through the top end is kind of subtle and unremarkable, which is perhaps a good thing. What you notice more is the sound stage has a lot of height and not particularly over-emphasized in width, but just in proportion. Yes, it still projects ‘outside of your head’ nicely though.
One issue is at the very lowest point, volume starts in the right channel first, and then things are balanced past the first 2% of rotation. I’ve noticed this on both fake and authentic ALPS pots, if not almost every pot I’ve tried in a few amps I’ve built. Given the enormous gain, you may need to turn down the source output if you plan to listen to very low levels. But, even at the lowest levels would listened to, it’s already balanced out.
Another issue is the VU meters are barely moving until you get to ear shredding levels on either the HD800 or LCD-X. Adjusting the 103 trim pots (up in the first two pictures), by rotating counter clockwise about a dozen turns gets them moving at normal levels, and I balanced L/R meters using a reference tone. Bouncy needle visuals - check!
Quick comparison:
Compared to the Xduoo TA-03 (which is an OTL or output transfermerless tube amp), the DCP is far more appropriate to drive the LCD-X. The Xduoo is actually only recommended for 60-600 ohms in the specifications, and that was the main reason for looking at the DCP, and the huge power and stability with the 20 ohm LCD-X is a huge benefit. Yes, the Xduoo can drive the LCD-X and to more than loud enough levels, but it does run out of breath in the bass department. The lack of control and flabbiness become noticeable at moderate volumes, and the Xduoo even gets a little hotter than usual. The overall midrange seems a little recessed compared to the DCP. My main impression is the DCP is a brute in comparison, and drives the LCD-X effortlessly. When driving the HD800 with the Xduoo I was happy for many years with the liquid and snappy response. This pairing is great synergy, and the Xduoo can be driven to really high levels, with the upper frequencies being so slightly tamed by the Xduoo. I feel the DCP is more of a side step, there is a very different experience, with a more visceral and organic midrange coming through. The DCP also has a far more extended bottom end, there is actually fair bit of slam that is hitting with the HD800, which you would never expect.
Compared to my self-built Dynahi, you have a more similar design to the DCP, both being solid state Class A amps with several watts of power on tap. I would say that the main difference being that the Dynahi has a more neutral presentation, the mid range is a little more restrained. They both go to really low frequencies without breaking a sweat of course. The upper frequencies are perhaps a little more refined with the Dynahi, but it is splitting hairs, you really need to focus on the soundstage to note more differences. The sound stage of the DCP is just slightly narrower, but taller compared to the Dynahi. The only other difference I noticed is the Dynahi has lower self-noise, with less hiss and hum when you crank the dial all the way to full, but of course neither is audible at normal listening levels.
Anyway, I would recommend this amp if you’re looking for something powerful. Though, as I experienced, be prepared for some surprises!
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