MICRO IDSD BLACK LABEL'S BIG BROTHER
iFi's Micro iDSD Black Label (shortened to the MiDSD BL for the rest of the review) is perhaps iFi's most popular product. It's a portable combo DAC/amp unit that packs a comprehensive feature set, along with a ridiculous amount of power, at a price ($600 USD) that doesn't break the bank. What's very notable is its analog tweak features, XBass and 3D+. I own the MiDSD BL, and used it as my everyday desktop DAC/amp, but there were a few things I found frustrating about it. It didn't provide enough power on eco (lowest) gain for my headphones. If I raised it to normal gain, there would be hissing. And using the IEMatch feature to eliminate the hissing resulted in a less airy sound.
The only upgraded model from iFi that has the analog tweak features, and has more power, is the Pro iCAN, but it's triple the price. As I loved the 3D+ tweak on the MiDSD BL, upgrading to the Pro iCAN for me was a no-brainer. Those who aren't as enthralled with the analog tweak features may wonder if the Pro iCAN is worth it for them.
The unit itself is a very nice size, as it's reasonably compact compared to the rackmount widths of beefier amps. It's as wide as the 8.5" length of a letter-size paper sheet. The front panel looks very symmetrical in its design. The iFi logo on the top left will change color depending on its current status. There's no way to disable this LED, but it's small enough to not be too obtrusive.
This is a Class A amp, which means it runs hot. It won't burn your hand when you immediately touch it, but it's very warm, and you wouldn't want to put your palm on the chassis for more than half a minute. If you're coming from the MiDSD BL like I did, this might be a bit of a shock to you.
INPUTS AND OUTPUTS (4 IN, 5 HEADPHONE OUT, 2 PREAMP OUT)
For inputs, there's a dual XLR3 in for the left and right channels, as well as 3 RCA ins. This is a bit of overkill, as for my purposes, I've never needed more than two inputs at the same time. But it's nice that the option is there. For this review, I mainly used the XLR3 input fed from a Topping D90 DAC, which at the time of this review was Topping's flagship DAC ($700 USD) using the AKM AK4499 chip. Other reviews have used iFi's own Pro iDSD ($2500 USD). I think $2500 for a DAC is a colossal waste of money, especially when the DAC has superfluous parts such as its own headphone amp and tubes. The Pro iDSD also uses the same DAC chip (TI PCM1793) as the MiDSD BL, and doesn't have the analog tweaks that the MiDSD BL has, so I couldn't justify it at all. Headphone amps affect the sound far more than the DAC, so by going with the Topping D90, I saved a lot of money.
As for outputs, there's an XLR4 headphone out, dual XLR3 headphone outs that double as 6.35mm outs, a single-ended 3.5mm out, and a balanced 3.5mm out. The Pro iCAN's vintage is 2016, so no balanced 2.5mm or 4.4mm outs. But you could plug up to a whopping 5 headphones into this unit. At the back is a dual XLR3 out and 1 RCA out, in which the iCAN may act as a preamp. Plugging headphones in at the front doesn't disable the rear outputs.
For this review, I mainly used the XLR4 headphone out with the Grado GS3000e, which has 40 ohm impedance and 97dB/mW sensitivity. (Grado's marketing states 32 ohm and 99.8dB/mW but measurements at RAA state otherwise.) At the time of this review, it was Grado's flagship wooden headphone ($1800 USD). Using XLR4 out over 6.35mm out provides a considerable advantage in that it doubles the power output without affecting the noise floor. This is very important as we'll see later.
The 3.5mm outs are disappointing. They automatically have iFi's IEMatch feature applied to them. Unlike the MiDSD BL, in which you had to determine the IEMatch strength yourself, the Pro iCAN detects the headphone's impedance and applies the appropriate IEMatch level. I don't like IEMatch and think it's a flawed solution to a problem that shouldn't exist in the first place. Users have reported that while it does remove hissing, it also reduces the overall volume, decreases the dynamic range, and makes things sound less airy. I agreed with these findings, and always had IEMatch off on the MiDSD BL, even though without it, I could hear a very faint amount of hissing. Instead of using IEMatch, it's better to just design an amp for ultra-sensitive headphones and IEMs that works. For moderately sensitive 3.5mm headphones, a 6.35mm adapter should be used in order to avoid IEMatch.
GAIN (0dB, 9dB, 18dB)
0dB gain mode was fantastic. Using the XLR4 out, 0dB gain mode outputs as much power as the MiDSD BL on normal gain, but without all the noise and distortion! It was plenty loud with my GS3000e at just 10 o'clock on the dial. ASR measurements state that 0dB gain mode is very clean, and excels with low to moderate impedance headphones. Most importantly, my GS3000e was finally dead silent when there's no output, even with the volume knob turned all the way to the maximum 5 o'clock position.
9dB gain mode introduced a very small amount of floor hiss on my GS3000e, about as much as I got on the MiDSD BL on normal power. Some users have reported that 9dB gain mode sounds more neutral than 0dB gain mode, but with no way to really do a fast comparison, I couldn't determine whether what I heard was placebo. Going to my Grado SR225i, 9dB was ideal for it, as it was a less efficient headphone (32 ohm, 93.5dB/mW) than the GS3000e (40 ohm, 97dB/mW), and was using the 6.35mm out, which provides half the power compared to XLR4.
18dB gain mode wasn't tested. I didn't have any headphones that required that much power. Attempting to use it on the GS3000e resulted in very audible hissing. ASR measurements state that distortion and noise are considerably higher, so if you have headphones that actually need this, you really should look at another amp.
AMPLIFICATION MODES (SOLID STATE, TUBE, TUBE+)
Unique to the Pro iCAN is its three different amplification modes. The solid state and tube modes run on separate circuits, so this isn't some halfhearted hybrid design. It's literally two amplifiers in one. Note that the temperature of the unit stays hot regardless of whether you use solid state or tube mode.
Solid state mode is what I use most of the time. It provides the best clarity and dynamics, and I use a software EQ to remove the harshness from my GS3000e anyway.
The tube modes are more of a gimmick, and I wouldn't really miss them if they were gone from the next iteration of this unit. Tubes have a limited lifespan, and the tubes in the Pro iCAN aren't easily replaceable. Some day, I'd like to resell this unit, so I'd rather minimize my tube usage if possible. Tube mode doesn't sound too much different than solid state mode on most recordings. Maybe it removes a bit of harshness, but I couldn't barely tell a difference, if at all. I wouldn't recommend using tube mode over solid state mode.
Tube+ mode, on the other hand, noticeably changes the sound signature, as the increased harmonic distortion really takes the edge out of any harsh treble. This means there's some detail and dynamics loss, but if you're not feeling analytical and want a more relaxing sound, this mode will work for you.
ANALOG TWEAKS (XBASS, 3D)
Here we go. This is what I consider to be the primary selling point of the Pro iCAN: getting the "best" version of iFi's analog tweaks.
XBass comes in 3 flavors: 10hz/20hz/40hz. Note that these are poorly named. "10hz" starts with a +9.5dB boost @ 10hz and slopes down towards 0 @ 200hz. "20hz" has a +10.5dB boost @ 20hz and slopes down towards 0 @ 500hz. "40hz" has a +10.5dB boost @ 40hz and slopes down towards 0 @ 1khz. The "20hz" boost is about the same as the XBass+ boost on the MiDSD BL, though I typically never used it when I had the MiDSD BL because I thought there was too much lower-mids bleed. "40hz" was even worse, and I switched out of it after about 30 seconds of listening. However, there was a plus: the "10hz" boost is much more subtle, and I greatly enjoyed this on my GS3000e.
The 3D mode is interesting. For those who haven't used iFi's 3D, I need to debunk a misconception. It is not just crossfeed. Simple crossfeed reduces the soundstage width. What iFi's 3D does is mess around with the phase at various frequencies, sending some sound from one channel to the other, but this is done in such a way that it increases the soundstage width, not reduce it. It also preserves the bass, unlike a simple "out of phase" filter. Therefore, iFi's 3D tweak is superior than simple crossfeed, and it's something that I have turned on all the time for increased immersion. Different headphones will vary in the amount of benefit that iFi's 3D provides, but it really shines on my GS3000e.
Note that the Pro iCAN was launched before the MiDSD BL, about 8 months earlier, in the first half of 2016, while the MiDSD BL was launched in the beginning of 2017. The MiDSD has an updated 3D mode that's called "3D+". 3D on the Pro iCAN comes in 3 flavors: 30°, 60°, and 90°. 30° and 60° provide a lesser effect than the MiDSD BL, and so they're not worth using if you've been used to the MiDSD BL.
90° provides about as much width as 3D+. However, 3D+ introduced some extra airiness and brightness by increasing the amount of perceived treble. This is all done with phase voodoo, as measurements have shown that the frequency response doesn't change. 90° on the Pro iCAN doesn't do this. Some may feel the MiDSD BL might exhibit a "stronger" effect due to the treble lift. When I used the MiDSD BL, I had to reduce the treble via software EQ to offset this. With the Pro iCAN, I adjusted my software EQ so that it was back to having the appropriate amount of brightness. Overall, I'd give a slight edge to the Pro iCAN because it keeps the heft of the mids, but I could totally see someone preferring the 3D+ of the MiDSD BL.
So to compare, for the MiDSD BL, I had XBass+ off and 3D+ on. On the Pro iCAN, I have XBass at "10hz" and 3D at 90°. I feel this is a slight improvement over the MiDSD BL's tweaked sound.
CONCLUSION
The Pro iCAN is a considerable upgrade, especially if you already enjoy the MiDSD BL and frequently use the XBass and 3D analog tweaks. It measures significantly better, provides more clean power, and is definitely worth triple the asking price ($1800 USD vs. $600 USD) if you can take advantage of its strengths. However, it's not a universal recommendation, as I feel it's best used specifically with balanced headphones with moderate sensitivity and impedance.
Those with sensitive IEMs should look elsewhere, as the forced IEMatch is a letdown. The marketing states that there's a monster amount of power on tap, and there is, but it's not clean. Those with low-sensitivity headphones have cleaner amp options at this price range, as moving to 9dB or 18dB gain results in worse performance. And finally, if you're a purist and think the XBass and 3D knobs are sacrilege, and won't take advantage of the preamp function, then don't get this amp. There are cheaper amps that will provide what you need.
iFi's Micro iDSD Black Label (shortened to the MiDSD BL for the rest of the review) is perhaps iFi's most popular product. It's a portable combo DAC/amp unit that packs a comprehensive feature set, along with a ridiculous amount of power, at a price ($600 USD) that doesn't break the bank. What's very notable is its analog tweak features, XBass and 3D+. I own the MiDSD BL, and used it as my everyday desktop DAC/amp, but there were a few things I found frustrating about it. It didn't provide enough power on eco (lowest) gain for my headphones. If I raised it to normal gain, there would be hissing. And using the IEMatch feature to eliminate the hissing resulted in a less airy sound.
The only upgraded model from iFi that has the analog tweak features, and has more power, is the Pro iCAN, but it's triple the price. As I loved the 3D+ tweak on the MiDSD BL, upgrading to the Pro iCAN for me was a no-brainer. Those who aren't as enthralled with the analog tweak features may wonder if the Pro iCAN is worth it for them.
The unit itself is a very nice size, as it's reasonably compact compared to the rackmount widths of beefier amps. It's as wide as the 8.5" length of a letter-size paper sheet. The front panel looks very symmetrical in its design. The iFi logo on the top left will change color depending on its current status. There's no way to disable this LED, but it's small enough to not be too obtrusive.
This is a Class A amp, which means it runs hot. It won't burn your hand when you immediately touch it, but it's very warm, and you wouldn't want to put your palm on the chassis for more than half a minute. If you're coming from the MiDSD BL like I did, this might be a bit of a shock to you.
INPUTS AND OUTPUTS (4 IN, 5 HEADPHONE OUT, 2 PREAMP OUT)
For inputs, there's a dual XLR3 in for the left and right channels, as well as 3 RCA ins. This is a bit of overkill, as for my purposes, I've never needed more than two inputs at the same time. But it's nice that the option is there. For this review, I mainly used the XLR3 input fed from a Topping D90 DAC, which at the time of this review was Topping's flagship DAC ($700 USD) using the AKM AK4499 chip. Other reviews have used iFi's own Pro iDSD ($2500 USD). I think $2500 for a DAC is a colossal waste of money, especially when the DAC has superfluous parts such as its own headphone amp and tubes. The Pro iDSD also uses the same DAC chip (TI PCM1793) as the MiDSD BL, and doesn't have the analog tweaks that the MiDSD BL has, so I couldn't justify it at all. Headphone amps affect the sound far more than the DAC, so by going with the Topping D90, I saved a lot of money.
As for outputs, there's an XLR4 headphone out, dual XLR3 headphone outs that double as 6.35mm outs, a single-ended 3.5mm out, and a balanced 3.5mm out. The Pro iCAN's vintage is 2016, so no balanced 2.5mm or 4.4mm outs. But you could plug up to a whopping 5 headphones into this unit. At the back is a dual XLR3 out and 1 RCA out, in which the iCAN may act as a preamp. Plugging headphones in at the front doesn't disable the rear outputs.
For this review, I mainly used the XLR4 headphone out with the Grado GS3000e, which has 40 ohm impedance and 97dB/mW sensitivity. (Grado's marketing states 32 ohm and 99.8dB/mW but measurements at RAA state otherwise.) At the time of this review, it was Grado's flagship wooden headphone ($1800 USD). Using XLR4 out over 6.35mm out provides a considerable advantage in that it doubles the power output without affecting the noise floor. This is very important as we'll see later.
The 3.5mm outs are disappointing. They automatically have iFi's IEMatch feature applied to them. Unlike the MiDSD BL, in which you had to determine the IEMatch strength yourself, the Pro iCAN detects the headphone's impedance and applies the appropriate IEMatch level. I don't like IEMatch and think it's a flawed solution to a problem that shouldn't exist in the first place. Users have reported that while it does remove hissing, it also reduces the overall volume, decreases the dynamic range, and makes things sound less airy. I agreed with these findings, and always had IEMatch off on the MiDSD BL, even though without it, I could hear a very faint amount of hissing. Instead of using IEMatch, it's better to just design an amp for ultra-sensitive headphones and IEMs that works. For moderately sensitive 3.5mm headphones, a 6.35mm adapter should be used in order to avoid IEMatch.
GAIN (0dB, 9dB, 18dB)
0dB gain mode was fantastic. Using the XLR4 out, 0dB gain mode outputs as much power as the MiDSD BL on normal gain, but without all the noise and distortion! It was plenty loud with my GS3000e at just 10 o'clock on the dial. ASR measurements state that 0dB gain mode is very clean, and excels with low to moderate impedance headphones. Most importantly, my GS3000e was finally dead silent when there's no output, even with the volume knob turned all the way to the maximum 5 o'clock position.
9dB gain mode introduced a very small amount of floor hiss on my GS3000e, about as much as I got on the MiDSD BL on normal power. Some users have reported that 9dB gain mode sounds more neutral than 0dB gain mode, but with no way to really do a fast comparison, I couldn't determine whether what I heard was placebo. Going to my Grado SR225i, 9dB was ideal for it, as it was a less efficient headphone (32 ohm, 93.5dB/mW) than the GS3000e (40 ohm, 97dB/mW), and was using the 6.35mm out, which provides half the power compared to XLR4.
18dB gain mode wasn't tested. I didn't have any headphones that required that much power. Attempting to use it on the GS3000e resulted in very audible hissing. ASR measurements state that distortion and noise are considerably higher, so if you have headphones that actually need this, you really should look at another amp.
AMPLIFICATION MODES (SOLID STATE, TUBE, TUBE+)
Unique to the Pro iCAN is its three different amplification modes. The solid state and tube modes run on separate circuits, so this isn't some halfhearted hybrid design. It's literally two amplifiers in one. Note that the temperature of the unit stays hot regardless of whether you use solid state or tube mode.
Solid state mode is what I use most of the time. It provides the best clarity and dynamics, and I use a software EQ to remove the harshness from my GS3000e anyway.
The tube modes are more of a gimmick, and I wouldn't really miss them if they were gone from the next iteration of this unit. Tubes have a limited lifespan, and the tubes in the Pro iCAN aren't easily replaceable. Some day, I'd like to resell this unit, so I'd rather minimize my tube usage if possible. Tube mode doesn't sound too much different than solid state mode on most recordings. Maybe it removes a bit of harshness, but I couldn't barely tell a difference, if at all. I wouldn't recommend using tube mode over solid state mode.
Tube+ mode, on the other hand, noticeably changes the sound signature, as the increased harmonic distortion really takes the edge out of any harsh treble. This means there's some detail and dynamics loss, but if you're not feeling analytical and want a more relaxing sound, this mode will work for you.
ANALOG TWEAKS (XBASS, 3D)
Here we go. This is what I consider to be the primary selling point of the Pro iCAN: getting the "best" version of iFi's analog tweaks.
XBass comes in 3 flavors: 10hz/20hz/40hz. Note that these are poorly named. "10hz" starts with a +9.5dB boost @ 10hz and slopes down towards 0 @ 200hz. "20hz" has a +10.5dB boost @ 20hz and slopes down towards 0 @ 500hz. "40hz" has a +10.5dB boost @ 40hz and slopes down towards 0 @ 1khz. The "20hz" boost is about the same as the XBass+ boost on the MiDSD BL, though I typically never used it when I had the MiDSD BL because I thought there was too much lower-mids bleed. "40hz" was even worse, and I switched out of it after about 30 seconds of listening. However, there was a plus: the "10hz" boost is much more subtle, and I greatly enjoyed this on my GS3000e.
The 3D mode is interesting. For those who haven't used iFi's 3D, I need to debunk a misconception. It is not just crossfeed. Simple crossfeed reduces the soundstage width. What iFi's 3D does is mess around with the phase at various frequencies, sending some sound from one channel to the other, but this is done in such a way that it increases the soundstage width, not reduce it. It also preserves the bass, unlike a simple "out of phase" filter. Therefore, iFi's 3D tweak is superior than simple crossfeed, and it's something that I have turned on all the time for increased immersion. Different headphones will vary in the amount of benefit that iFi's 3D provides, but it really shines on my GS3000e.
Note that the Pro iCAN was launched before the MiDSD BL, about 8 months earlier, in the first half of 2016, while the MiDSD BL was launched in the beginning of 2017. The MiDSD has an updated 3D mode that's called "3D+". 3D on the Pro iCAN comes in 3 flavors: 30°, 60°, and 90°. 30° and 60° provide a lesser effect than the MiDSD BL, and so they're not worth using if you've been used to the MiDSD BL.
90° provides about as much width as 3D+. However, 3D+ introduced some extra airiness and brightness by increasing the amount of perceived treble. This is all done with phase voodoo, as measurements have shown that the frequency response doesn't change. 90° on the Pro iCAN doesn't do this. Some may feel the MiDSD BL might exhibit a "stronger" effect due to the treble lift. When I used the MiDSD BL, I had to reduce the treble via software EQ to offset this. With the Pro iCAN, I adjusted my software EQ so that it was back to having the appropriate amount of brightness. Overall, I'd give a slight edge to the Pro iCAN because it keeps the heft of the mids, but I could totally see someone preferring the 3D+ of the MiDSD BL.
So to compare, for the MiDSD BL, I had XBass+ off and 3D+ on. On the Pro iCAN, I have XBass at "10hz" and 3D at 90°. I feel this is a slight improvement over the MiDSD BL's tweaked sound.
CONCLUSION
The Pro iCAN is a considerable upgrade, especially if you already enjoy the MiDSD BL and frequently use the XBass and 3D analog tweaks. It measures significantly better, provides more clean power, and is definitely worth triple the asking price ($1800 USD vs. $600 USD) if you can take advantage of its strengths. However, it's not a universal recommendation, as I feel it's best used specifically with balanced headphones with moderate sensitivity and impedance.
Those with sensitive IEMs should look elsewhere, as the forced IEMatch is a letdown. The marketing states that there's a monster amount of power on tap, and there is, but it's not clean. Those with low-sensitivity headphones have cleaner amp options at this price range, as moving to 9dB or 18dB gain results in worse performance. And finally, if you're a purist and think the XBass and 3D knobs are sacrilege, and won't take advantage of the preamp function, then don't get this amp. There are cheaper amps that will provide what you need.