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Little Dot I+

100% Positive Reviews
Rated #17 in Desktop Amps


Pros: Price, Construction, Sound-tailoring Options

Cons: Power, Chassis Design (sort of)

The I+ from Little Dot is an excellent tube hybrid that offers much more than its sub-$150 price tag would suggest.


This is the first piece of head-fi equipment that I've owned twice. Bought one from a fellow Alabamian head-fier a couple months ago and had it for a little more than a month before deciding to sell as my "best" pair of cans weren't benefitting as much from amping. Within a week of the sale, I missed the LD too much and pulled the trigger on a new one! (Oh well, you live and you learn).


I purchased the I+ after reading up on how well it pairs with Grados, my flavor of choice. And let me tell you, it certainly performs brilliantly!


1st: Price: Inexpensive. These can be purchased from Little Dot's webstore for ~$140 shipped to North America and currently from Amazon for ~$120 with Prime shipping. For a hybrid tube amp with tube/opamp roll-ability, excellent sound and sturdy construction, why keep looking? This is it!


2nd: Design: Simple. 1/4" plug, volume pot, RCA inputs, and power supply. That's what you get. All sturdily built and thoughtfully implemented. While we're on the topic, the thick aluminum frame of the I+ feels great and hasn't shown any signs of component failure or weakness. The board is assembled very well and when I open it up to change the opamp, I don't feel afraid to touch the I+'s innards. Ain't nothin' goin' nowhere. The volume pot also turns very smoothly, the tube sockets are of sound quality, and the included power supply doesn't make me feel like LD tried to cut corners.


3rd: Sound: Natural. Since the I+ is a hybrid, the syrupy smoothness a.k.a. "tubeyness" is tempered with the detail and resolution of solid state technology. IMHO the LD is the amp equivalent of the Colorfly C3's sound: organic, musical, and neither so flat that it sounds boring nor so fun as to seem artificial. The best is yet to come however - you can roll tubes. AND opamps. 


Options for tailoring your sound are virtually endless. Thanks to its interchangeable jumper capabilities, the I+ accepts tubes from the EF91, EF92, and EF95 families (not to mention others that may have to be adapted). That's plenty of tubes! From the punchy detail of the Voskhod 6ZH1P-EV to the buttery smoothness of the Tung Sol 6AK5, sound signatures are easily changed just by swapping tubes. The circuitry within also makes the I+ very quiet (as in noise floor) and it will warm tubes rather quickly. Opamps are also swappable, any DIP8 will fit (along with any that will fit onto a dual-to-mono adapter), so yet again, sound-tailoring is easy and abundant. So whether you're a vinyl junkie yearning for the super smooth tube sound of yesteryear or a digital wizard who likes the ultra modern edge of solid state, you can modify the SQ of this little amp quickly and easily to your taste. 


As far as cons go, there aren't any real issues, just a few shortcomings that I may as well mention. 1. This is not the most powerful amp in the world. It will power all but the most hungry cans so, if you have THE MOST HUNGRY CANS, you may want to keep looking. 2. Opening the chassis to swap jumpers or opamps is a little inconvenient. Just to swap one or two pieces of plastic, I have to remove all 8 screws. Not hard to do, but the screws that hold the base to the upper half are tiny and sometimes hard to re-screw. Not to mention they are a part of the ground circuit, so if you lose one, you may open your amp up to noise. EDIT: Don't know why this didn't dawn on me, but I could just loosen the lower 2 screws on each side to open the amp up... Whoops!


So overall, the LD I+ is an excellent choice for those looking to get tube capability with plenty of variety available for tube/opamp rolling. The sub-$150 price tag makes this amp very affordable and the quality design makes operation very easy. I certainly recommend!


P.S. It plays wonderfully well with Grados. Enjoying Kind of Blue with my 325is as I finish this review!


Pros: Amazing value, good sound, it looks nice (IMHO), good for Grado, Denon, and other efficient headphones, great build quality

Cons: Only one input, not the most powerful amp ever created, needs an upgrade from stock tubes

For $140 (Shipping included), this is probably one of the best amps out there. The Little Dot I+ is a great inexpensive chi-fi amp and with a small tube upgrade (I upgraded to Mullard M8161 tubes) it is a great budget solution. I know I didn't really want to spend a lot on an amp as I am still in high school and living on a strict (sorta) budget. I am using this in conjunction with an iStreamer from HRT and Denon AH-D5000 headphones and it really shines (for the price of course) with this system. Build and design are very good (Again, IMHO). I think that it is the simplicity of one analogue input that can keep the price down and really just make a straight foreword beginner amp. Another great value product from Little Dot!   


Pros: Solid build & clarity of sound; affordable

Cons: Power and maybe aesthetics

The Little Dot line of headphone amps represent what is possible when a Chinese production amp doesn't cut corners on build quality and engineering. This amp has my vote as the best desktop hybrid amp in the price range.




The build quality is very solid; the housing is all metal with a very smooth and clean-looking volume knob. The amp is also quite heavy. The design is very plain however, which is fine, but a little boring. 


What really stands out in the design department is the choice of tube socket/settings (WE408A, EF92, and EF95). Both WE408A's and EF95's are very affordable and effective replacements for the unimpressive stock 6JI's. The 6ZH1P-EV Voshkhods for example are available through eBay from Russia or Ukraine for less than 15USD per NOS pair. Another favorite of mine is the GE JAN5654, which I found for 3USD for a NOS pair! If you want to splurge, EF92 Mullards (M8161) are also a great option. But to play devil's advocate, a user on AudioKarma ran some tests on the circuit and concluded that tubes contribute next to nothing to the circuit. 


Along the same lines, the op-amp can also be rolled since the LDI+ has a no-solder DIP-8 slot installed rather than a surface mounted or through-hole soldered op-amp. Personally, I think op-amp rolling is a waste of time when comparing op-amps above the 1USD mark. For example, an OPA2134 (~4USD) is hard to distinguished from an OPA2107 (~15USD) or MUSE02 (~30-70USD) but is probably better than the stock, which is worth less than a dollar.


Sound Quality


The sound you get is somewhat dictated by the tube you roll since this hybrid amp does rely on the tubes for color (whereas most of the amplification is done by the solid state components). Whatever tubes you roll however, the sound is very clear and balanced, which is what you want out of an amp barring any coloration you desire from the tubes. Detail is also great on this amp, especially with a good pair of open or semi-open cans like the DT880. Higher impedance headphones also benefit since the output impedance is said to be around 30 Ohms. A quick overview of tube impressions and reviews are available here: http://www.head-fi.org/t/364043/little-dot-i-tube-rolling


The only demerit for this amp is the relatively low power compared to other amps in the price range. For my 250 Ohm DT880's, it takes about 70-80% on the volume knob to get good volume for modern mainstream recordings and full volume to enjoy classical recordings (which tend to be much lower volume recordings). The gain can apparently be changed internally, but this is annoying if you switch between different headphones of different impedances.


Overall, I love this amp and powers my home headphone setup. A great option for all except the most frugal shoppers of HiFi devices.


Pros: Amazing for the price

Cons: Gain has to be changed internally

Amazing headphone amp for the price.  Used with my 325is, Pro900s and Q701s.  Great value, drives most headphones incredibly well, even powered my Q701s on the high gain setting with no signs of distortion.   It's a really nice looking headphone amp for the money also, very study with a neat, clean build.  For the price this absolutely can't be beat.

Little Dot I+

The Little Dot I+ is a hybrid transistor-vacuum tube headphone amplifier, which combines the smooth, musical sound of tubes with the high output current of transistors. The vacuum tube stage is run in Class-A, the MC33078 operational amplifier (socketed) provides voltage amplification, and BD139/BD140 transistors serve as output buffers. The Little Dot I+ is specifically designed and optimized for driving low impedance headphones that require high current to perform to their full potential. Depending on how the switches are configured, three different families of vacuum tubes can be used (EF95, EF92, and 408A). With two gain settings and DIP switches for vacuum tube rolling, the Little Dot I+ offers versatility in a tiny footprint!

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