Little Dot I+ Headphone Amp Impressions

[onepixel]

It's amazing that itty bitty thing makes such a big difference.

[Mr. Lin]

Originally Posted by onepixel

It's amazing that itty bitty thing makes such a big difference.

I should say that it's not a huge difference, but very noticeable, and there seems to be more "liveliness" to the music now, which makes it worth the effort.

[ehoove]

Originally Posted by Mr. Lin

Tonight I soldered the AD8620 to a Brown Dog adapter. This is a dual SOIC 8 op-amp. I've been listening for about 20 minutes and I'm pleased with it. Everything seems to have been brought up front a bit, and there's a lot more detail, as well as dynamic impact. Snare drums sound snappier, even keyboard sounds have more texture and presence in the music. I'm listening to the remastered version of XTC's Mummer album, btw.

Pictures of the process below. It wasn't as hard as I thought it was going to be, especially after watching a tutorial on the internet about soldering this exact type of op-amp onto a circuit board. This particular adapter fits perfectly in the I+, but the wider ones for two single circuit DIP 8 op-amps will require me to bend the two small green capacitors over just a bit.

Dave,
It certainly is a tight fit! Your assesment of the Tung Sols is close, although I prefer the warm detail of their midrange over the lushness of the Mullards. Once again using the LT1364 with the AKG 701's.
Regards,
Jim

[Mr. Lin]

Originally Posted by ehoove

Dave,
It certainly is a tight fit! Your assesment of the Tung Sols is close, although I prefer the warm detail of their midrange over the lushness of the Mullards. Once again using the LT1364 with the AKG 701's.
Regards,
Jim

Hi Jim,
It (the Brown Dog adapter) looks a little worse than it actually is. The PCB is not much larger than a normal 8 DIP op-amp, just a bit wider. Things are going to be much tighter when I try to fit one of the single-to-dual 8 DIP adapters in there, which I'll be doing just as soon as my newest Digikey order arrives. But I've checked it out and I'm confident it will work.

Which Mullards have you tried Jim? The Mullards I've recently tried are the CV4010 version offered by a UK seller on ebay for relatively little money. Most people on Headfi seem to talk about "large shield" Mullards. I believe that's what arrived at my doorstep this afternoon, a 1950s version with a big shield on it. The Sylvania gold pin 6028 also arrived in that package. No time to test them tonight since it's late, but I will tomorrow.

I've yet to try the infamous LT1364.

[ehoove]

Dave,
Keep rolling and keep us posted. My Mullards are the same as yours.
Regards,
Jim

[Mr. Lin]

Originally Posted by ehoove

Dave,
Keep rolling and keep us posted. My Mullards are the same as yours.
Regards,
Jim

Which one, the CV4010 or the 6AK5 with the larger shield on it?

[Mr. Lin]

I put this together last night, as well as a pair of single AD843 op-amps on the adapter that are not pictured. The one in the pictures is the AD744, again two separate single op-amps. In case you're wondering, I was using the diode to hold the adapter in place on a foam block while I soldered. I listened to both with a couple CDs. Both sound excellent, I don't feel I had enough time to completely hear the differences between them.

Today I put two single OPA827 SOIC op-amps on an adapter, and I'm listening to that right now with the Sylvania gold pin 6028.

[Mr. Lin]

At this point I've added so many little "tweaks" to my I+ that I feel the need to reiterate my previous disclaimer.

While reading my thoughts on its sound, consider the fact that I've done the following things to it, and some new ones to my source, the Jolida 100 CD player. This is how I have it set up currently and I have to say it sounds quite good, meaning better than it did before:

-Cardas Golden power cord

-Sylvania Gold Pin 6028 tubes

-Herbie's Blackberry tube dampers

-Two Burr-Brown 827 SOIC op-amps (on adapter)

-HiFi Tuning Silver Star fuse

-Homemade all-silver from tip to tip interconnects (pictured earlier)

-Herbie's Iso-Cup footers with African ebony balls (go ahead and laugh)

-Mapleshade Audio Silclear contact enhancer on pc plugs, fuse, and tube
pins.

I think that's it. I also dabbed some of the Silclear contact enhancer on the tube pins inside the Jolida, and all the fuses in it as well. The Grover power cord went back to the Jolida.

Among the power cords, to my surprise, the I+ seems to work best with the Cardas Golden. I hear more micro-detail with this pc, after comparing it directly with the Grover pc and a Shunyata Diamondback, playing the same song, "Misty," from Tsuyoshi Yamamoto's Autumn in Seattle XRCD, which was superbly recorded and mastered. For example, I thought there was strange, loud noise coming from the TV playing fairly closely by, then I thought something was wrong with the CD, and finally I realized I was hearing the cymbals of the hi-hat rattling quietly in between strikes from the drum stick, which I hadn't hear before. Subtle, but there it was.

Right now the I+ sounds strong and dynamic, with instruments having lots of impact. It doesn't get cluttered or confused sounding in louder, more complex passages of classical music. An example of this is my very favorite classical CD (and XRCD for that matter), Stravinsky Le Sacre Du Printemps (JVC). Those familiar with this piece will recall that it goes from very quiet to very loud and involved. With everything set up the way it is now, even in the loudest passages I can hear all the separate instruments. There's no distortion that I'm able to hear, and the I+ does reasonable justice to the dynamic range of this recording, as it goes from soft to quite loud, and everything in between during other moments. Good stuff, for sure.

Additionally, the sound is three-dimensional to a decent degree. Soundstage is wide enough to sometimes create the illusion that instruments are outside of where the headphones are physically located, and imaging is very good, with lots of space between various instruments.

There is a good amount of bass as well. Whether this comes from the tubes, or the op-amps, I'm not sure, as both are new. One would intuitively think that the tubes are adding warmth, but comparing the Sylvania Gold Pins to the previous Mullard 6AK5 I had installed, the former is slightly thinner in the midrange, with more emphasis on the higher frequencies. Or perhaps it's just that the Mullards are rolled off on top, thereby giving the illusion of more upper-frequency extension and detail with the Sylvanias. In any case, this combination works well.

Overall I can say the I+ has really impressed me, though I wonder if I would be so impressed without all the little things I've done to give it a kick in the tail, because it did not sound this good out of the box. I should also point out that the myriad things I've used to enhance its performance were by and large things I already had sitting around, with the exceptions of the tubes, tube dampers, and various op-amps.

It has the musicality factor, which is the most important thing of all.

No, I'm not done yet, stay tuned.

[onepixel]

Originally Posted by Mr. Lin

...As for interconnects, I'm using one of the best of my own designs, tri-braided with all solid-core silver conductors, and silver Eichmann Bullets.

Hey Mr. Lin, not to wander off, but when you have the chance, maybe in another thread could you give us a run down on your interconnect design.

Thanks!

[thefragger]

Mr. Lin, excellent work! I'm curious about where you sourced the Brown Dog adapters from-- they look top-rate!

[Mr. Lin]

Originally Posted by onepixel

Hey Mr. Lin, not to wander off, but when you have the chance, maybe in another thread could you give us a run down on your interconnect design.

Thanks!

Well it's sort of a work in progress. The pair pictured is fairly simple, just three solid silver conductors. The positive is OCC silver with a cotton dielectric. Everything is covered in Teflon. Connectors are the Eichmann Silver Bullet. This was sort of a one time thing since it was so expensive to make, I just wanted to try this design out and use nothing but silver throughout, since usually at least the RCA connectors are a brass alloy, sometimes copper. I'm working on something similar now that's more cost effective, but it's definitely nice to have a pair of this caliber lying around, and to buy something equivalent from a major manufacturer would probably cost a fortune.

Originally Posted by thefragger

Mr. Lin, excellent work! I'm curious about where you sourced the Brown Dog adapters from-- they look top-rate!

Go to the Cimarron Technology website - I guess that's the company behind Brown Dog. They also offer pre-assembled components, so the op-amp is already mounted in case you have really shaky hands or something. Actually, I admit I don't have the steadiest hands in the world, but I made my life easier by watching the tutorial they link to at the bottom of the home page. The Surface Mount Soldering Techniques lesson demonstrates how to solder a little SOIC chip to a board. If you know how to solder, much of it won't be new to you, but he has a few tips that really did help.

[ehoove]

Originally Posted by Mr. Lin

Which one, the CV4010 or the 6AK5 with the larger shield on it?

The CV4010
Regards,
Jim

[Mr. Lin]

Originally Posted by ehoove

The CV4010
Regards,
Jim

Ever tried anything from the EF91/EF92 family yet Jim? I'm curious about these because it seems to be a very different tube. I have a set of Valvo EF91s coming from Bulgaria, but I'm confused about the directions for placing the shunts inside so the I+ works with this tube family. It says to place jumper caps onto J1 and J2, but where do those caps come from? I guess I'll have to e-mail David again.

[TerryS]

Originally Posted by Mr. Lin

Ever tried anything from the EF91/EF92 family yet Jim? I'm curious about these because it seems to be a very different tube. I have a set of Valvo EF91s coming from Bulgaria, but I'm confused about the directions for placing the shunts inside so the I+ works with this tube family. It says to place jumper caps onto J1 and J2, but where do those caps come from? I guess I'll have to e-mail David again.

Spare jumpers came in the bag with the headphone adapter cable with my LD-1+.
Terry

[Mr. Lin]

Originally Posted by TerryS

Spare jumpers came in the bag with the headphone adapter cable with my LD-1+.
Terry

Found them, thanks! I'm not going to use the cables that came with the I+, so I just put them away. The bag the cables are in looks like something you'd buy at Radioshack, that's why I didn't expect there to be anything else in it. Kind of strange that they were in there.