I currently do not have access to a camera, hence I don't have pictures of the amp and the equipment that I am using to make this review. Hope that I get as many replies as to their thoughts about this amp.
Just like with the Little Dot MKI, the MKI+ features a familar case design. When the two amps are side by side, the look and feel is 95% identical. Still a fingerprint magnet of sorts, the MKI+ features two subtitle differences that sets it apart from the MKI. First the lettering and the rear panel (1, 2, and 4X gain and the 3.7V x 2 battery lettering).
The internals of the amp are a different story. Little-Tube completely redesigned the internal components of the MKI+ to the point where amp rolling is no longer possible. From what I can understand based on my opening up the amplifier to place the jumper caps for higher current output, the circuit features two discrete op-amps and buffers with the caps and transistors in place to delivery a much more airy and open sound-stage. Not that I am saying the original LDMKI isn't open (before the op-amp upgrade), the redesigned version delivers more dynamic characteristics than the one it replaces while further expanding the sound-stage. In comparisons to the LDMKI with the LT1364 op-amp upgrade, the improvement is rather significant. Linear response, clarity, and open sound-stage is apparent with the Little Dot MKI, however once the MKI+ is auditioned, low-frequency punch and mid-range frequencies are further enhanced with a tonal quality that of actually being there.
Here is the description from Little-Dot's website and the link to their site for the LDMKI+ - www.little-tube.com/forum
The successor to the Little Dot MK I, the new Little Dot MK I+ takes advantage of American National Semiconductor’s newest offerings in ultra-low distortion circuit components: LME49710HA high fidelity operational amplifier and the LME40600TS high performance current buffer. The new power supply consists of two 3.7V 700mA/h Lithium-Ion battery to provide up to 30 hours of high current, ultra-low distortion power to your headphones. Circuit stability and reliability over the previous Little Dot MK I has been markedly improved as well. The Little Dot MK I+ also has exceptional compatibility with a wide variety of IEMs, earphones, and full-sized headphones due to its user-selectable three gain settings, as well as output current control via internal jumpers. When jumper caps are set in place, output current increases by 80%, dramatically improving dynamics, impact, and low frequency response with the trade-off of lower battery life.
Little Dot MK I+ Technical Specifications:
* Line Input: 3.5mm (1/8 inch) mini-stereo
* Headphone Output: 3.5mm (1/8 inch) mini-stereo
* Frequency Response: 5 Hz (-0.6dB) to 200KHz (-0.3db)
* THD+N: 0.0010% (1V @ 1000 Hz)
* Suitable Headphone Impedance: 8 - 300 ohms
* Power Output: 200mW (32 ohms)
* Gain Factor: 1, 2, 4x (User Selectable)
* Battery Life: up to 30 hours per charge
* Battery Overcharge Protection
* Universal Voltage AC Charger/Adapter included (Type B plug)
* Metric: 95 mm (length) by 70 mm (width) by 24 mm (height)
* English: 3.74 inches (length) by 2.75 inches (width) by 0.94 inches (height)
* Weight: 192 g (includes internal battery)
* 1 Year Little Dot Warranty
The interesting thing is the battery life. The Little Dot MKI featured four 3.7VDC lithium-ion batteries to deliver 14.8VDC. The average battery life is about 18-hours with the gain switch set to 8X gain. In the case with the Little Dot MKI+, two 3.7VDC set in a split rail method tested and will deliver about 30-hours give or take 3-hours with the jumper caps set to open. Once the current jumper caps are set to closed, then the battery is significantly cut short. In fact the average battery life is about 10-hours +/- 2-hrs, however that is to be expected especially when I use the dynamic passages of Igor Stravinsky's Rite of Spring part 1. The only nuisance with this amp is when I need to switch between high and low current output mode. Now I pretty much leave the jumper caps open so that I can maximize battery life with excellent pairings with my other headphones.
For this review I use two headphones because I have grown accustomed to sound signature reproduced. Plus they fit rather well.
Headphones used: (2002) Sennheiser HD280-Pro purchased during a trip to Hamburg, Deutschland, and (recently purchased 2008) AKG K701 standard cable.
The latter headphone has more than 1200-hours so the drivers are very well settled. The interconnect used is Moon Audio's Blue Dragon version-1 (uses 26-gauge silver conductor) 12-inch with straight Neutrik 3.5-mm stereo mini-jack.
Now on with the Test
Actually I use the HD280 more than the K701 only because it is a closed headphone with fully settled drivers.
Telarc's 2002 release of Tchaikovsky's 1812 overture serves as the first in four test samples to see how the Little Dot MKI+ handles smooth overtones while reaching a powerful crescendo toward the end of the passage. Upon the first opening I can tell that this amp has the reserve capacity to deliver what was promised from Little-Tube's website. Now mind all of those who think the Sennheiser HD280-pro is an efficient headphone. Unfortunately it isn't and in fact it can be rather current hungry because if this were to be plugged into a portable device, the sound produced will be there, however there won't be any body to the music being played. Once an amp is used, the sound-quality is enhanced to a significant degree even though this headphone is rated at 64-ohms.
After the first few minutes (the headphone amp is fully run-in - 120-hours+) I fully understand the difference between the MKI and MKI+. The lush overtones of the MKI are further solidified with the MKI+. The warmth, balance, and sound-stage are further reinforced to deliver a more life like representation. I am now truly impressed with this amp. Bass tones are much tighter with the LDMKI+ than with the LDMKI. More so with the last three-minutes of the 1812 overture. And with closed headphones, the open and expansive sound-stage is even more apparent as I reach for another musical number.
The Drums of Jiangzhou
I am using the first track, which since I can't really Chinese, I am just going to give you impressions. For one thing, this piece will test any headphone and amp to the limit. This piece consists of several large drums, little drums, and other percussion instruments hence the Drums of Jiangzhou. The Little Dot MKI+ does not disappoint. Where as the Little Dot MKI was excellent, the MKI+ is supremely better in just about every aspect. Bass tones are further reinforced with better extension while the mid-range and high-tones are brought out with distinction. The sound-stage of this musical number is reproduced as though the listener is actually there, watching the drummers work.
Many of the subtitle tones and mid-frequency overtones are reproduced in exact detail. Having been to one of these concerts, I know of this group's musical pieces. While many believe that the Sennheiser HD280 is a dark sounding headphone, I tend to think that given enough time, any headphone should just about settle down to a degree where the darkness as it were should be not so apparent. Anyway, using a rather dynamic passage to test whether or not the LDMKI+ can perform has been proven. This amp has surpassed the LDMKI in just about every aspect (dynamically speaking that is). The sonic character of this headphone amp is not as linear or warm as the Little-Dot MKI (with the LT1364 op-amp upgrade).
Jennifer Warnes - Famous Blue Raincoat
This recording is rather old however it was Stereophile's recommendation many years ago as a good album for overall listening and testing purposes. Track-3 Famous Blue Raincoat was used in the album for this next test. Warnes vocal representation along with the overtones of the piano and double-bass presents as a live concert. The reverberations can be heard much more clearly than with the MKI. In fact after reading the little booklet, this track was recorded in a concert hall environment. Her vocal presence and nasal tones are heard ever so clearly. The instrument placement in space is presented with precision and clarity with a slight bit of harshness (very slight since I am using the Sennheiser HD280). The tonal quality of the recording is excellent and reproduced in every detail. The LDMKI+ reproduces every tone with excellent representation as though the listener is actually sitting front row.
The price tag of $175 USD is still a good number for a high-class amplifier. Some may not agree with me, but this is a forum with many people looking for a good review (opinion) of equipment before actually putting down the money for an amp/headphone. After a very careful A/B comparison between the Little Dot MKI and MKI+, I can say with certainty that there is a significant improvement in High, Mid, Low-Frequency response, tonal quality, and sound-stage representation. A little bit of warmth is (very little yet still noticeable) is sacrificed however the advantages are more than disadvantages. I may not be a rated as a Headphone Supremeus, however it is not the rating that counts, but it is the knowledge and experience that will prevail so to speak.
The Little Dot MK+ is thumbs up in my opinion for those looking to have a good amp in their system without having to pay heavy money. Sure there are the CMOY amps out there, however I find most of them (I have actually listened to many including the Shellbrook, MINT, etc) to have very rich and sonically transparent (not sonically precise) sound reproduction. Not quite my tastes, however I actually did own the Shellbrook Mini Moy about five years ago when I became rather serious with headphones. Both the MKI and MKI+ are more than several steps higher than both the DIY and traditional CMOY amps. Everybody has different tastes and I respect everybody's opinion so feel free to ask questions and I will be more than happy to answer them.
Oh and just for clarification, the LDMKI+ doesn't quite drive 600-ohm headphones since it does run out of steam about 300 +/- 50-ohms. So if you have headphones higher than 300-ohms, I suggest finding a LDMKI or look for other amps reviewed by other members of the forum. And when paired with the AKG K701, I find that this amp really brings out the sonic qualities of this headphone though I find the MKI to bring out the tonal qualities of K701 since bass is not the AKG K701's strong suit. A warmer sounding amp will help the K701 in this department.
Until next time. Have a great New Year 2009.