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Initial impressions - Little Dot I+ hybrid tube/transistor headphone amplifier

post #1 of 20
Thread Starter 

The Little Dot I+ hybrid tube/transistor headphone amplifier is made in China.
I ordered one through eBay for $109.
Shipping cost $34.
Total cost to my door $143.
For a headphone amplifier with convenience of an integrated power supply and comes preassembled, $143 sounds like an extremely reasonable price.
Preliminary COST: Very resonable

I ordered and paid for the Little Dot I+ on Monday 11/10/2008 at noon.
Communication was constant, receiving updates and timely responses.
I received polite emails including one that contained a postal tracking number.
Shipping was top notch and incredibly fast.
The Little Dot I+ arrived to my door (Saturday 11/15/2008) in just under five days!
Packaging consisted of two molded foam inserts that held the amplifier and tubes safe and secure.
SERVICE: Professional

Unpacking and setting up
After unpacking the headphone amplifier, I quickly read through the instruction manual.
It suggested to first remove oxidation from the vacuum tube pins with Caig DeoxIT.
Upon inspection of the tube pins, oxidation indeed had set in.
I sprayed some DeoxIT on the pins and then onto a cotton swab.
Cleaning took about ten minutes.

The instruction manual also suggested burning in the amplifier at 8-hour intervals.
An hour of cool-down time between each session was recommended.
I plugged in the stock 6JI vacuum tubes.
It played on through the night for a total of ten hours.

post #2 of 20
Thread Starter 
Initial listening impressions

I briefly played an assortment of music through a variety of headphones.
I have not yet formed exhaustive conclusions but I can share some notable first impressions using the stock 6JI vacuum tubes.

Many have had favorable results pairing the Grado SR225 headphone with the Little Dot I+ amplifier.
I tried it and I did not like it.
I did hear detailed and open sound, but this combination produces an aggravating piercing characteristic.
I don’t think that my opinion will change after I have listened more.
Time will tell.

With the Koss PortaPro2 headphone I actually preferred my CD players headphone output. (Denon DCD-1500) I preferred the dullness and darkness of the non-amplified sound. Koss headphones often seem to break all of the rules. Koss headphones are engineered to already sound incredible without sophisticated amplification.

The next headphone to try was the Sennheiser HD-280PRO. The ensuing sound was reminiscent of pairing the Sennheiser HD-280 with a meta42 headphone amplifier. This pairing worked. It produced controlled and detailed sound. You could really feel the power of the Little Dot I+ amplifier. It has some real bad boy raw power. This might be a good combination for a gaming system. I may use this for some FPS games. (If I ever have time for gaming again.)

Lastly, I tried the Little Dot I+ amplifier with my Sony MDR-CD780. Incredible! The Sony headphone sang beautifully. The Sony headphones characteristic for boomy bass was recessed. However, bass was finally under some control. Perhaps this is the Little Dot I+ amplifier flexing its muscles again. I see some potential with this combination.
I had not yet bothered to listen to Beyerdynamic DT-880 with the Little Dot I+ headphone amplifier since others have not had good results. I did not try any other headphones yet since I currently am under too many time constraints.

I did make some side-by-side listening comparisons of the Little Dot I+ headphone amplifier to a Ray Samuels XP-7 headphone amplifier ($700 retail /with power supply). This particular XP-7 had been upgraded with AD797 opamps giving it a rich dark full sound. The XP-7 easily plays well with any headphone. Clearly, this was no contest no matter what headphone was used. As expected, the XP-7 could not be beat. Ray Samuels can engineer like no other.

Initially what had sparked my interest about the Little Dot I+ headphone amplifier was the hope that it would produce magic with the Grado SR225 headphone. To my ears that combination proved too piercing. One thing that the Little Dot I+ headphone amplifier does have is potential. My hope is that someone discovers an alternate vacuum tube/opamp combination that can produce a rich dark full sound with the Grado SR-225.

The Little Dot I+ hybrid tube/transistor headphone amplifier is inexpensive. You might pay more for a similar amp that requires assembly. If your budget is around the $100 mark then this amplifier might work for you. The company is professional and the product appears well made.
post #3 of 20
Thread Starter 
100-hour burn-in mark

The Little Dot I+ headphone amplifier has completed more acceptable amount of burn in time. The Little Dot I+ has had over 100 hours burn in. Giving the amplifier a one-hour break between every ten-hour burn in session has made the burn in process take much longer than I would have liked.
Now that the amp had been properly burned in, this time around I listened to the Little Dot I+ more objectively. I put away all of my more expensive gear. I wanted to dispense with direct unfair comparisons to any much more expensive equipment. By this time, I have also shed preconceived hopes that the Little Dot I+ might be a giant killer.

I connected a non-Beresford TC-7510 DAC to the Little Dot I+ using Canare silver soldered interconnects. The TC-7510 DAC had well over 100 hours burn-in and possesses much better qualities than the others of my inexpensive quality digital sources. Like the Little Dot I+, the TC-7510 DAC is a respectable choice for the budget minded Head-fier.

General listening impressions
I switched out various headphones and just listened to what the Little Dot I+ with stock tubes had to offer compared to the headphone output of the TC-7510 DAC. Amplified output exhibited recessed bass with some headphones and with others it controlled and tightened up the bass. Sound stage opened up. Sound was clear, dynamic and controlled. The Little Dot I+ overall character is bright, clear, open, and powerful.


Meat and potatoes


Determining whether the Little Dot I+ sounds good or not depends on which headphone is being used. The source from which the music comes from is the most important element of a system. However the synergy between headphone and headphone amplifier is what makes or breaks the listening experience. If a Little Dot I+ headphone system does not have this synergy, then it may sound better leaving the headphone amplifier out entirely.
Headphones used: Beyerdynamic DT-880 (2003 version), Grado SR225, Koss KSC75, Koss PortaPro, Realistic LV-20 (Koss TD/80 with vents), Sennheiser HD-280, Sennheiser PX-100, Sony MDR-CD780, Shure E2C
Beyerdynamic DT-880 (2003 version)
The Beyerdynamic DT-880 can sound extremely sweet with the right amplification. As reported by many head-fiers, I can confirm that the Little Dot 1+ does not sound good at all with the Beyerdynamic DT-880. This combo was dead with no bottom end.
Verdict: NO

Grado SR225
The Little Dot 1+ made the Grado SR225 sound punchy and clear. I was hoping that after burn in that sound might improve. However, it is upsetting that I must report that it is still too piercing to my ears.
Verdict: NO
Koss KSC75
Koss PortaPro

The Koss KSC75 and Koss PortaPro sound was similar enough to reflect the same benefits of amplification. With the Koss KSC75 and Koss PortaPro headphones I was completely stunned! Like some of the other modern Koss headphones, these inexpensive little wonders already sound incredibly good without dedicated headphone amplification. However, without an amplifier bass tends to be overly heavy, loose and without definition. With the Little Dot I+ amplifier the loose Koss bass was fully controlled and brought to an ideal level. I am simply floored at the high-end sound that is coming from such cheap headphones. To have a DAC, headphone, and headphone amp system that work this well for around a price tag of $300 is phenomenal. This combination is the poor man’s door to high-end audio.
Verdict: OMG shout it from rooftops YES!
Realistic LV-20 (Koss TD/80 with vents)
At one time the Koss TD/80 was a very popular Koss headphone. Radio Shack carried their own version re-branded as the LV-20. Both share the same specs but the LV-20 has a vented rear chamber. The Little Dot I+ sang beautify with another Koss headphone. I was very impressed once again. This was the only headphone of the bunch that bass actually increased with amplification. Everything had improved with amplification. Not as radical as the KSC75 and PortaPro, but still to a substantial degree.
Verdict: YES
Sennheiser HD-280PRO
Sound stage has always been missing from the Sennheiser HD-280PRO. The Little Dot I+ brought the analytical Sennheiser HD-280PRO to life. It was odd yielding a very musical outcome with these paired together. This was a very pleasing combination except for one caveat. The bass was jut a little too recessed for my ears. I tried to be forgiving but I just couldn’t bring myself to accept the missing bass. Perhaps it would work if there were a “bass boost” setting somewhere in the system?
Verdict: NO

Sony MDR-CD780
The Sony MDR-CD780 ear cushions are often referred to as “pillows.” And, this headphone is the most comfortable headphone I know of. The Sony MDR-CD780 has the signature boomy bass characteristic of Sony’s better headphones. With the Little Dot I+ I was extremely happy to hear these headphones sound the best that I have ever heard them. Just as in the case of the Koss KSC75, bass was controlled and the Sony boomy bass was gone! The sound stage opened up just a little more, and female voices took on a three dimensional sweetness.
Verdict: YES

Sennheiser PX-100
The Sennheiser PX-100 is a convenient portable headphone that sounds pretty good. When combined with the Little Dot I+ music came alive. Bass was punchy and not recessed. Instruments and voices became ultra clear and separate. Acoustic guitars reverberated from all around. This was a very musical experience.
Verdict: YES
Shure E2C (orange spongy tips)
You may be asking yourself why there is an in ear monitor in this roundup? The Shure E2C has always had a problem when used un-amplified. With the grey soft rubber tips the sound is acceptable except for the recessed bass unless your player initiates a “bass boost” setting. With large orange spongy tips the bass sounds good but everything else becomes a little muffled. The hope is that the Little Dot I+ would remove the muffled sound when using the orange spongy tips while preserving the bass. With the Little Dot 1+ the bass was still there. Vocals had improved clarity. Sound stage opened up slightly. Overall there was improvement but not an extreme one.
Verdict: YES

The Little Dot I+ headphone amplifier with stock tubes (6JI) is an interesting amplifier. The way it works with headphones was completely different than any other solid-state amplifier I have listened to. Perhaps this is due to the solid-state/tube hybrid design. The build quality appears high quality and solid. Customer support is first-rate and professional.

If you can find a headphone combination with the Little Dot I+ that pleases your ears, then you have a winner. At $143 shipped to your door (USA), I would consider this amplifier quite a bargain.
post #4 of 20

Try some CBS Hytron 6AK5s or EF92s to tame those highs. Right now I'm listening to some GE408As with my SR225s and although I love the sound of these tubes for other phones, they are still a bit bright for Grados.

You have many possibilities with that little amp (EF91, 92, 95, 6AK5, 5654, 408A, 6096, 403A,B.....)

post #5 of 20
Thread Starter 
Passed the 100-hour mark

<post moved up top>

I added my post together up top in the thread with the rest.
It didn't quite make sense having my posts separated.

post #6 of 20
Very nice and compact review.
I am just about to order the LDI+ myself. I will be listening thru my pair of AKG 701s. Should be an interesting journey!!
post #7 of 20
Very good and long review hottyson. I wish i had the brain to write all this about my experience.

Asl. I have not a good experience with the dot and my aks 271. it dont have the juice that my nad have to bring out the bass.i guess the k701 issnt easier to drive than the 271 Its grado only on my dot now. and i have to say that my nad is exceptional with the grados too. it tames the hights with the dark sound but their in the dot most of the time
post #8 of 20
Thread Starter 
Thank you for your kind words. I had lots of fun! I just put the Little Dot I+ and the TC-7510 DAC for sale together as a set in the "Amplification for-sale" section.

I just received some more audio gear including two more amplifiers that I will try and listen to over the holiday break. I will try and post some impressions on those too if I get some spare time again.

My wife (who is expecting) almost killed me when she found on our bank statement that I had ordered more headphone amplifiers again. "Why do you need so many? !!!" She just doesn't understand.

post #9 of 20
How much of an increase in clarity and punchiness (percentage wise) would you say the sr225 gained when using the Little Dot?
post #10 of 20
Thread Starter 
Originally Posted by Brighten View Post
How much of an increase in clarity and punchiness (percentage wise) would you say the sr225 gained when using the Little Dot?
I don't think that I possess abilities to quantify the increase with a percentage, but I do recall an improved clarity of the music and an impression of an authoritative and powerful amplifier. The piercing quality of the stock Little Dot I+ with the Grado SR225 was just too uncomfortable for my taste to try to form in depth positive characteristics let alone analyze and quantify them.

Sorry. Perhaps someone who has used warmer tubes with the Little Dot I+ with the Grado SR225 could provide a more useful answer?

post #11 of 20
Thread Starter 

Just a quick update

Originally Posted by Brighten View Post
How much of an increase in clarity and punchiness (percentage wise) would you say the sr225 gained when using the Little Dot?
After having listened for around two months since asking your question, I felt an update might be appropriate. One thing that I can say is that I don't plan on ever going back to stock op-amp and stock tubes. You can find plenty of posts from me and a few others that gush about the Grado SR225 / Little Dot I+ / LT1364 op-amp / Sylvania Gold Brand 408A. It's the cats meow, and it will very likely become a semi-permanent home for my Grado SR225 after I have completed my tube-rolling impressions thread.

I have been tube rolling like mad to the point that I feel almost numb and zombie like. So, I decided on a short break from my tube-rolling thread for sanity sake and to also take in some enjoyment of the beautiful music I now can hear. I did something more fun. I listening to the Little Dot I+ / LT1364 op-amp / Sylvania Gold Brand 408A with a few of my headphones. Here is a quick and dirty update for anyone interested or curious.

Well, pretty much all of the original "YES" verdicts remain "YES," and the "NO" verdicts remain "NO" except for the Grado SR225. Both Koss headphones lost a little bit of magic with this combo. The Realistic LV-20 I no longer own. I borrowed Shure SCL4 Sound Isolating Earphones (IEM). It sounded very good with this combo. I did not yet retry Sennheiser PX-100 with this combo yet.

One interesting revelation that I am happy to announce is that both the Grado SR225, and Shure SCL4
sound better with this Little Dot I+ / LT1364 op-amp / Sylvania Gold Brand 408A combo than my Ray Samuels Audio Emmeline XP-7 (AD797). This is quite shocking considering difference in price.

Sorry to go off topic here but:
In defense of the Ray Samuels Emmeline XP-7, it is still king with ALL of my other headphones and still does a respectable job with the Grado SR225 and the Shure SCL4. I am still in love with the XP-7, especially when paired with Beyerdynamic DT-880. I plan on keeping that combo together unless a tube amp someday works a magical spell with the Beyerdynamic too. Not to mention that the XP-7 is family heirloom quality. Built with such high standards, it may likely outlive me.

post #12 of 20
I have found a fair number of 408A tubes for sale, but none are Sylvania Gold Brand. Where does one get those?
post #13 of 20
How do you think it would pair with some HD580s?
post #14 of 20
Thread Starter 
Originally Posted by intoart View Post
I have found a fair number of 408A tubes for sale, but none are Sylvania Gold Brand. Where does one get those?
The Sylvania Gold Brand are drying up and getting rare and harder to find (for a decent price). I bought all the best ones that I could from a dealer to distribute to Head-fi since they may soon be very hard to find and prices are ridiculously skyrocketing from what is left.

I have shipped all but one pair of the best ones that tested "excellent" (where GM measures > 71) out to Head-fiers. This has been on a first-come / highest-quality basis through the FS forum section. I still have a few that tested "good" where GM measures <71. Highest quality ones will continue to go out on a first come basis until they are gone. After that we will have to pay eBay prices. I almost hate to post this information because eBay tube sellers are likely reading these threads and might increase prices even more.

Originally Posted by Bleuburd View Post
How do you think it would pair with some HD580s?
My two headphones that sound good with this combination are both low-impedance headphones. Your Sennheiser HD-580 is a high-impedance headphone. So I would take a guess that it might not work very well. Mind you that I am only making an educated guess and you will have to seek out and ask others who actually own it.

I think you might want to read some threads on how the Sennheiser HD-580 synergize with other headphone amplifiers from Darkvoice or perhaps a Little Dot IV SE if you are seeking tube amplification with that high-impedance headphone.

post #15 of 20
The LD I+ does have high gain so that could help but not sure how much.

And your comment about the ebay sellers and the 408A's...they are already on there with Buy It Now prices at 80+ a pair.
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