AIMPIRE Little Dot I+ 6JI X2 Tube Standard Hybrid Headphone Headphone Amp Pre-Amp Tube Amplifier (LDI+)

First off, this amp is absolutely legendary when paired with Grado headphones, so if you own any in that lineup, make sure you read the reviews on head-fi.org and other sites. Secondly, this amp isn't amazing out of the box. The stock chinese 6JI tubes aren't bad actually, but replacing them should be the first order of business. Read the reviews to find out which tube family suits your taste in music, but this is a pretty versatile amp that can accommodate a wide range of tubes. Make sure you save the two jumpers that come bundled in with the cables. They are very small and easy to miss! This is a bargain and a fantastic sounding amp, but be careful about choosing the right tubes - Grados are revealing and sometimes, static is introduced with the wrong tubes. Lastly, the Opamp is replaceable as well! So you can tube and opamp roll with this amp. The synergy with Grados cannot be overemphasized enough. If you have Grados: SR-60, 80, 125, 225, 325, RS2, RS1 and beyond, these are magnificent and will really make your Grado's shine. The Little Dot 1+ is designed to drive current into low impedance headphones. In theory, that means any low impedance headphone would be great, but that's not the case. I have a pair of Audioquest Nighthawk Carbons that are 32 ohm cans, and they just don't sound right with the Little Dot 1+. My Grado SR-325 on the other hand, absolutely sings. Even in the stock configuration, this amp really makes the Grados come alive. The dynamics, the transients (listen to the Bangles "Hazy Shade of Winter" on a Grado and this amp and watch the drums come alive), female vocals, stringed instruments like acoustic guitar and violin, Blues (Anything Stevie Ray Vaughan sounds amazing), Metal, Rock. The only weak spot appears to be Hip Hop and Dance Music, but that's why I have the Audioquest Nighthawks and a Schitt Magni-Modi handy for those situations.

**Update with recommendations 9/20/19 at bottom** I'd like to start with all of the information that is relevant to this review. I have been into high-end audio for over a decade now, the entire time as an adult and I am above all other things, a music lover. Secondarily I am an audiophile and former musician of multiple instruments. Music, it's production and the listening experience are what I prize in my free time. My setup is as pictured: Tidal (HiFi) PC - Topping D30 DAC - Topping A30 Amp (using pass-through) - Little dot I+. I'll be frank, are there bad units out there from any manufacturer? Yes. Are the majority of issues with this amplifier setup related? Yes. You wont need to be an electrical engineer to set this up right but there are a few things that will go a long way to having a very satisfying purchase and end user experience. For starters if you use and external DAC (digital to analog converter) this will help. Preferably one that is not USB powered. Why does this matter you may ask and I'm happy to answer. Using your on-board PC sound card or phone or other battery powered device *MAY* create a ground loop. If so, you *MAY* hear humming or buzzing in your headphones when you use this. Just keep that in mind. An easy way to test is to have headphones plugged in to the amp, with the power on, and no RCA cable connected to the rear. If you do this and hear no hum/buzz/noise but when you connect RCA’s you do, then the issue is either a faulty cable or ground loop from a shared ground in your system. So now that we've addressed the most common issue people have had with this amp on with the review then. I have had zero issues with my LDI+ save the fact it's ridiculously loud. I don't listen at "I want to go deaf by 40" levels of sound but I don't play my music quietly either. Even with 300 ohm headphones on low gain I cannot get above 30 on the volume knob. So just accept you may be using very, very little of the volume knob. The good news is the channel imbalance fades out very fast and by about 8 both channels are the same volume. This is par for the course for a device at this price but the volume pot is not scratchy and makes no noise for me during any of my use. I have rolled the Op Amp and have purchased several more to find what I think is best. I also have purchased two additional pairs of matched tubes. Contrary to popular opinion the stock tubes are a lot less "garbage" than people would lead you to believe. If you run them in for about 20 hours you'll find the amp is actually setup pretty well out of the box. I started listening after having the amp on for about 30 minutes and immediately liked the sound of it. Setup is simple and the only thing it doesn't actually cover is how to open the housing of the amp. Google it as seeing it will be better than if I explain it but there are only 4 screws. It takes about 50 seconds or so to do. I have the Vokshod's, and the GE JAN tubes as well. I am currently running in both tubes to the 50 hour mark. The current Op Amp I am using is the Burr Brown/Texas Instrument OPA2134PA. I also have in the mail the AD8066, OPA2107 and OPA2228, all authentic and all purchased from reputable vendors. I will update once the my tubes are burned in and when the additional Op Amps arrive. *Update* As promised, here's the recommendations on pairings. I tried Burson, MUSES, Burr-Brown, and AD Op-Amps. I tried GE Jan tubes, Vokshods and Mullards. I'm going to try to save you money here. Best overall pairing: Burr Brown AD8066 Op-Amp (you'll need to buy one that is already ready to drop in DIP-8. If you search you will find for about $8). Use this with the Mullard M8100 CV4010 5654. You will not have to change jumpers to use this. Outstanding width, depth, bass and vocal. By far and away the best sound I achieved out of this amp. Best for bassier or warmer headphones. Closed backs or those who have more narrow music preferences. Burr Brown OPA2107 (I recommend a legit channel here, about $20). Pair this with the GE JAN 5654W tubes. You can find them on Amazon but I feel like the price is getting a bit outrageous. They were $25.79 when I bought hem and now they have skyrocketed to $35. IMHO these are by far the best two pairings. I'd recommend you try one and if you like it you'll know that the other pairing is also a great option for you. The Vokshods, while good tubes, didn't do anything better with any of the Op-Amps I tried it with vs the other tubes. Best of luck!

I had my eye on this amplifier for a very long time, and I finally purchased one, along with a set of Voshkod 6ZH1P-ev tubes and an LM4562 OP-amp. On arrival it is neatly packaged, the tubes are separately encased in foam and detached from the physical unit, it comes with a power cord and that is about it. Right out of the box, even with the supplied tubes, it sounded fantastic and the longer it ran, the better it sounded. I added the Voshkod tubes and the LM4562 and the sound came alive, incredible. This was using a set of ATH-m50x headphones. The unit does get very warm to touch but who cares because the tubes glow, and that trumps everything. I am using this unit as both a headphone amp, and a pre-amp for my solid-state amp which drives my speakers. As a pre-amp this unit is excellent and handles it like a champion while sounding fantastic. Pros: -Amazing sound, small package -Works great with my ATH-m50x's -Endless combinations of tubes and OP-amps to roll -Cheap for what you get Cons: -Gets pretty warm -Gain is not easily adjusted -OP-amp rolling involved disassembling the cover -Uses 2-channel OP-amps only, but can be converted to accept 2 1-channels I am not sure how this sounds with headphones other than a set of ATH-m50x's and AKG K240's, but with these two it sounds amazing, it makes sound come alive, its warm and filling in all ranges. I would recommend a DAC be used with this, I convert optical to analog via DAC. Get this amp.

update: After a few months the hissing is almost gone and it sounds much better. Took a while for the tube to get clean or something. Sounds bad if I output 24bit 192000hz so I have to use 24bit 96000hz. Maybe this fixed the hissing issues. ----------------------------- Good amp for the price. It also is nice looking with two capacitors and feels well built with a metal casing. Doesn't get too hot either. One major problem I have is the hum or hissing it produce when output from my laptop headphone jack. With nothing playing it is very noticeable. When I play an new music you can hear it and as the volume gets loader you don't notice it much. I almost consider returning it. I did a test and it has no hum or hissing if outputted from my cellphone or tablet jack. I will buy a USB DAC hoping it will be gone then I can update the score. Sounds, The tube do sound very bright on my AKG 702 which is brighter then most other headphone. I am using 24bit 192khz from my laptop. I also use my bass phone the Bowers & Wilkins P5 e=which doesn't need any amping and does sound worst with this. I was hoping this amp increase my bass on the AKG 702, it just made it a bit brighter, so I will get a different tube later. When I say bright I am referring to very clear to sharp high and mid. It gives ear fatigue after listening too long. I also get ear fatigue with too much bass.

It's been a month with this amazing little amp. I've since replaced the stock opamp with a MUSES02 and the stock tubes with many different ones, and have settled on the Voskhod 6ZH1P-EV. All I can say is WOW! The amp with the stock opamp and tubes sounded great. But with the upgrades, it's out of this world. Seriously. Below are my earlier reviews that I've made since the purchase. First night impressions: Pros -It's got that glow! Don't underestimate the glow. Probably biasing my impressions, but here goes anyway. -Clear and clean. Crisp highs and mid range is very smooth. Alison Krauss & Union Station Live sounds as good as I've heard. No hiss or distracting noises. Just crisp and clean sound. Voice sounds great. -3D imaging? Amber Rubarth "Hold On"; voice is front and center, first time hearing height in this track. Some instruments sound like they're floating above others. Not distracting at all, just a very neat effect. -Bass is present with stock tubes. KDrew "Bullseye" is a killer track if you like dub. Bass sounds thick, if a bit smeared sounding. I was afraid the stock tubes would be thin sounding, it isn't. But it leads to a con... Cons -Bass is a little smudgy or loose sounding. It's the first night with these stock tubes and I understand it takes 20 or so hours before tubes get comfy in their new homes and sing. -Piano sound isn't quite right. Smudgy bass makes the lower registers sound blurred. -BRIGHT LED. It's blue and it's bright. Should be a soothing green or white. Such a contrast to the glow. I should put tape over it. Two weeks later: Pros -Trying new tubes is fun! They glow and improve / alter the sound. -Bass is MUCH improved. Rolling tubes, I'm a believer. -Smooth smooth smooth! -Overall an EXCELLENT amp. Cons -BRIGHT LED. Still haven't put tape over it.

If you are looking for an amplifier to crank the music to your head phones this is a product for you. If you are looking for a rich and satisfying hi-fi music experience this is a product for you.I will take the rest of this review to describe the latter. I have always found it hard to describe a specific audio component itself as the total listening experience is going to be as good as the weakest component you have. So first... If you are looking for a true hi-fi experience playing music from your computer I would first recommend that you invest in an external DAC (Digital to Analog Converter). The DAC in your computer is not real good. There are three components you need to achieve quality Hi-Fi from your computer: 1) headphones; 2) an amplifier; 3) a DAC. My rig is: HRT Music Streamer II DAC, Audio-Technica ATH-M30 Headphones, and the Little Dot I+ Tube Amplifier. Before buying the Little Dot my musical experience was very, very good with my headphones and external dac. But, once you catch the Hi-Fi disease you realize the sound can even be better. Being the owner of a Fisher 500B tube receiver I began a search for a headphone tube amplifier so I could have the same warm sound that tubes deliver. After reading the reviews of others and researching competing products I settled on the Little Dot I+. I can say that this is is one of the best purchases I have ever made. First things first, if you buy this amplifier and use it with the tubes it comes with it is, frankly, little more than an amplifier. If you replace the tubes (referred to as rolling) with a nice set of tubes you will be blown away. Rolling the tubes involves plugging a new set of tubes into this amplifier. As you can see from the product picture the tubes are external so this is something anyone can do. If you google tube rolling and little dot you will get information on tube rolling. If you are not one to research everything in detail I will give you the cliff notes version and my experience. I have used GE JAN5654W (GE makes different versions of the 5654 tube so make sure you get this version!) and Tung-Sol 6AK5. Both are spectacular. The GE JAN5654W are the best value (I paid $18 for five). eBay has a number of stores that specialize in selling tubes. The Tung-Sol 6AK5 cost me $24. I have also read that the Voshkod 6ZH1P-EV, the Mullard M8100 CV4010, and the RCA 5654 Black Plate are also good tubes. The bass and treble are excellent using the GE JAN5654W or Tung-Sol 6AK5 tubes. The detail is also phenomenal on both. You will hear things in the music that you have never heard before. The soundstage is superb as well. For example, listening to Fleetwood Mac the Chain the drummer, Mic Fleetwood, sounds like he is directly behind you. The midrange is fantastic. Singers like Diana Krall and Adele are a joy to listen to. Both of these tubes provide a rich and warm musical experience that only tubes can provide. If I had to pick I would give a slight edge to the Tung-Sols. But listening is pretty subjective. One word of warning. Once you experience true hi-fi sound it is hard to go back to an MP3 player plugged into headphones or ear-buds. I let a co-worker listen to my setup and for the rest of the day he did not listen to his music. Even my wife who is not the music fanatic I am gets a smile on her face when she listens to her music though my setup. --- Added 1/28/2014 I have now tested the following tubes with this amplifier: -GE 5Star 5654 -Voshkod 6ZH1P-EV The 5Stars are very nice and a value at $16 (included shipping) for 5 through eBay. The Voshkod's from yen audio set me back $40 for the pair. They are spectacular. They are my new favorites.

I was not expecting it to sound this good, Being tube and solid state. The tubes are the preamp and do a great job at shaping the sound, I did upgrade them to the Riverstone Audio right out the box so i cant speak for the stock ones. Im running the gains on high and it has plenty of power to push low impedance cans my highest are 80 OHM and cant go over half volume. There is no noticeable distortion other then the tube sound, and if you are looking for something that fill tame bright headphones this is a great option. The only complaint i have is that the volume nob"potentiometer" is not that great, left channel comes on keep turning and then the right shows up for the party. Update Not even a week and i noticed buzzing, unplug the RCA from the back of the amp and it will go away. Tryd the cable it came with and the same thing. The volume output seams to be lower to now, 75% to achieve the same volume as 50%. There is no contacting the manufacturer I even had Amazon try.

Has that nice tube sound. Easy to roll tubes. Easy to swap out opamps. Unfortunately, the one I got had a slightly higher gain in the left channel. It sounds pretty good, but there are certainly much better amps out there for not much more money. Loved the sound of this amp with my Grado's, until I heard them with a slightly more expensive amp.