Little Dot I+ Headphone Amp Impressions

[33&athird]

Very cool, I really hope to get one of these in a week, if not...well, eventually.

I need to read through everything again, since I would love to upgrade mine when I get one...but from what i've read, if you change to a tube in a different "family" you have to set jumpers, is this correct for the little dot 1+, or just the higher, all-tube models (little dot II+). I assume the jumpers are for this...though for whatever reason, I kind of expected to see DIP switches:scratch2:.

As much as I would love a all-tube model, something about the layout on this one calls to me, the inside looks much more substantial for instance, plus I probably can't afford more than two tubes. Would love to try out different op-amps as well, since I haven't delved into those past a 741.

Definitly enjoying reading everything...a excellent write-up:yes:

Edit: Looks like I will wind up with one (looking forward for it). I was looking for the tubes you were mentioning (or equivilent families). A little luck...however, I really can't put down $50 on a couple of tubes. There are some EF91 Mullards on the bay for $13, which is somewhat reasonable, I assume...then there are some 70's VOSKHOD russian military tubes, which are much cheaper, and thusly more suspicious. Any thoughts on these? I read through the topic and the mullards seem like a good set, and really, it's all i'm finding :scratch2:. The op-amp is another matter, I can find TI versions of the 2107, but not burr-brown...I may look for other chips.

I assuming it sounded good stock, but better modified...I may do it over time. I love reading about the tubes though...those valvos look particuarly interesting.

Thanks in advance for any thoughts :yes:

 

[Mr. Lin]

Thanks 33&athird!

The original version of the I+ did in fact have DIP switches in it, but those are less reliable and just plain cheaper than using shunts, or "jumpers." Even my Sutherland Ph3D phono preamp uses shunts to change gain and loading settings rather than DIP switches. It's pretty easy to do.

Are the Mullards you're looking at the CV4010? I have those, but haven't given them much of a chance. It's a good idea to watch ebay once you have your I+, good ones come up in auctions fairly frequently, and these tubes aren't in extremely high demand so you can get a lot for little money.

I definitely recommend changing the op-amp first, since it's cheap and, at least to my ears, makes a big difference. Keep us updated, I'll do the same.

 

[33&athird]

Thanks 33&athird!

The original version of the I+ did in fact have DIP switches in it, but those are less reliable and just plain cheaper than using shunts, or "jumpers." Even my Sutherland Ph3D phono preamp uses shunts to change gain and loading settings rather than DIP switches. It's pretty easy to do.

Hmm, the one i'm looking at has only two small switches, and the rest are jumpers, but I will say those two small switches in it look like a failure waiting to happen. Did you replace them with shunts?

I assume the increase in gain makes it easier to drive low-impedance headphones, but with a trade-off of extra noise...

Are the Mullards you're looking at the CV4010? I have those, but haven't given them much of a chance. It's a good idea to watch ebay once you have your I+, good ones come up in auctions fairly frequently, and these tubes aren't in extremely high demand so you can get a lot for little money.

yes they are CV4010...the cheaper auction for the mullards is a little lacking (no pictures), supposedly from a NOS set...but honestly, I would have no way of telling. Somehow I suspect the tubes in the unit are probably better than 70's soviet tubes :scratch2:. I geuss I shouldn't knock the stock tube without hearing it...probably will sound good to me no matter what.

I definitely recommend changing the op-amp first, since it's cheap and, at least to my ears, makes a big difference. Keep us updated, I'll do the same.

We are talking cheap for performance I assume?...the TI 2107's I found were around $16, I think (I know) the Burr-Brown would be more expensive, however neither Digikey or Mouser has it:scratch2: I'll look into the other "models" you mentioned...is the 2107 still in it, or did you swap it out?

Edit: Read a mention of a LT1364, seems well liked...think i'll try it out :yes:

 

[john57]

The two small switches would not be possibility of a problem unless you are spending a lot of time molding with different types of tubes. On my new Little Dot 1+ being sold it is using jumpers with the version 2 board I have. I found a reliable cheap source for the BB 2107 op-amp that is in the delivery pipeline and I will give my impression once the chip gets here. Also getting some different 408A tubes as well. I decided to stay with the 408A family of tubes since I believe that will give me the best sound for my needs and has a unique special tube sound that I was not getting with the 6DJ8 on the Melos. Long time ago I wanted to get an Audio Research tube pre-amp as I considered it to be the cream of the crop at the time but could not afford it at the time and ended with the Melos SHA Gold. However I heard something very unique with my Little Dot that I have not heard in a long time which in my opinion puts it into a class of its own. Here is a post of an Audio Research product review against the Little Dot MkII .

http://www.head-fi.org/forums/6243897-post383.html

 

[33&athird]

The two small switches would not be possibility of a problem unless you are spending a lot of time molding with different types of tubes. On my new Little Dot 1+ being sold it is using jumpers with the version 2 board I have. I found a reliable cheap source for the BB 2107 op-amp that is in the delivery pipeline and I will give my impression once the chip gets here. Also getting some different 408A tubes as well. I decided to stay with the 408A family of tubes since I believe that will give me the best sound for my needs and has a unique special tube sound that I was not getting with the 6DJ8 on the Melos. Long time ago I wanted to get an Audio Research tube pre-amp as I considered it to be the cream of the crop at the time but could not afford it at the time and ended with the Melos SHA Gold. However I heard something very unique with my Little Dot that I have not heard in a long time which in my opinion puts it into a class of its own. Here is a post of an Audio Research product review against the Little Dot MkII .

http://www.head-fi.org/forums/6243897-post383.html

Good to know, thanks:thmbsp:

I determined why I couldn't find the Burr-Brown 2107. My dad actually pointed this out; TI bought Burr-Brown, so the TI chip is the same one:scratch2:...still a little pricy for my taste, so i'll start cheap, my best headphones at the moment are Pioneer se-305s, so it's not like I have audiophile quality phones...though I hope to get some grado sr60's or koss pro-4aa, maybe then it will matter what tubes I have.

 

[john57]

Do a search using; Burr-Brown OPA2107AP You should not have any issue in finding Burr-Brown branded 2107 chips with BB printed not TI. Burr-Brown has a partnership and merged with TI as per news release:


On June 21st a merger agreement between Burr-Brown and Texas Instruments was revealed. On August 24, 2000 the two companies officially joined, creating the industry's strongest portfolio of data converters, amplifiers, power management and interface products for high-performance and low-power applications.

The 2107 chip I am getting cost 6.80 plus 2.20 for shipping with a total of $9 which is cheaper that seeing the 3D movie of Avatar. Cheap as far I am concerned and I am not paying top dollar for tubes either.

 

[ehoove]

I get what I can from Digikey. If they don't have it I usually buy from samerpav on ebay. He's proven trustworthy and reliable over and over again.

Agreed, I've used him as well with no problems at all. Highly recommended!
Regards,
Jim

 

[Mr. Lin]

Some thoughts and a mini update:

Hmm, the one i'm looking at has only two small switches, and the rest are jumpers, but I will say those two small switches in it look like a failure waiting to happen. Did you replace them with shunts?

I assume the increase in gain makes it easier to drive low-impedance headphones, but with a trade-off of extra noise...



yes they are CV4010...the cheaper auction for the mullards is a little lacking (no pictures), supposedly from a NOS set...but honestly, I would have no way of telling. Somehow I suspect the tubes in the unit are probably better than 70's soviet tubes :scratch2:. I geuss I shouldn't knock the stock tube without hearing it...probably will sound good to me no matter what.



We are talking cheap for performance I assume?...the TI 2107's I found were around $16, I think (I know) the Burr-Brown would be more expensive, however neither Digikey or Mouser has it:scratch2: I'll look into the other "models" you mentioned...is the 2107 still in it, or did you swap it out?

Edit: Read a mention of a LT1364, seems well liked...think i'll try it out :yes:

With the gain set for use with 32 ohms I hear no noise whatsoever, unless there's no music playing and I turn the volume up much higher than listening levels (like 12 o'clock+), then there's a faint hum and some white noise. In other words, noise is not an issue for me.

Don't be so quick in assuming that old Russian tubes are no good - because that's what I almost did, but fortunately I tried the old Soviet-era tubes you can see on the previous page. Again, I was biased because I don't care for modern-production Russian tubes, but this NOS ones are quality.

Yes all the Burr Brown chips are technically TI, and sometimes it just says "BB," sometimes it says "BB" and there's the TI outline of Texas as well.

I currently have had a BB 4032 SOIC op-amp in my I+ for roughly a month. This was my first experiment putting a small, but good quality capacitor across the + and - of the op-amp. It wasn't a huge change from what I had in there before, still very good, but like I said, I hear only small differences if any between the best op-amps I try, so if you find a really good one there's no need to keep searching - unless you're a bit obsessive like I am.

Your post reminded me that I foolishly skipped over the LT1364, so tonight that's what I'm going to put in it.

The Mullard CV4010 tubes I bought had pictures in the auction. Is this seller you're looking at in the UK? Mine was, and they're not bad. If you could save up and spring for the Tung Sol 408, that's a really safe bet and you'd probably be happy to stop there.

My I+ has about five shunts I believe, and that's just how it came.

So take a look at these pictures. I had thought I'd put them up a while back when I put this thing together, but I guess I fought. This is what's currently inside my I+, it's the BB4032 on an adapter with a .1mf Mallory metal film capacitor. But take a look at the second picture. You can see four of the shunts in this one, toward the bottom right of the picture, and there are more than those, some not currently installed due to the type of tube I'm using.

 

[33&athird]

Don't be so quick in assuming that old Russian tubes are no good - because that's what I almost did, but fortunately I tried the old Soviet-era tubes you can see on the previous page. Again, I was biased because I don't care for modern-production Russian tubes, but this NOS ones are quality.

For the price, they would be worth a shot...i'd just never heard of Voskhod tubes .

The Mullard CV4010 tubes I bought had pictures in the auction. Is this seller you're looking at in the UK? Mine was, and they're not bad. If you could save up and spring for the Tung Sol 408, that's a really safe bet and you'd probably be happy to stop there.

I could swear I saw the auction the other day, but I can't find it now. When looking I did run across some mullard EF92 versions of the CV4010...they look like what you had, weird solid-looking shields, and taller...I'll be on the look-out for tung-sols, none around now, even if they were, I probably wouldn't want to see the price. I think i'll upgrade the op-amp when I get it, but watch out for tubes. Around $20 for 2 tubes really isn't insane, and I can study brands while I wait...there are some GE EF95s that look pretty neat (hate to say it, but half the appeal is visuals), the russian tubes look kind of cool, but the mullards are very appealing...I like the taller tube look:yes:.

Thanks for all the other information...i'll keep at it and see what I come up with.

 

[Mr. Lin]

For the price, they would be worth a shot...i'd just never heard of Voskhod tubes .



I could swear I saw the auction the other day, but I can't find it now. When looking I did run across some mullard EF92 versions of the CV4010...they look like what you had, weird solid-looking shields, and taller...I'll be on the look-out for tung-sols, none around now, even if they were, I probably wouldn't want to see the price. I think i'll upgrade the op-amp when I get it, but watch out for tubes. Around $20 for 2 tubes really isn't insane, and I can study brands while I wait...there are some GE EF95s that look pretty neat (hate to say it, but half the appeal is visuals), the russian tubes look kind of cool, but the mullards are very appealing...I like the taller tube look:yes:.

Thanks for all the other information...i'll keep at it and see what I come up with.

The Russian tubes I have aren't Voskhod, it says "Radio Lampe" in Cyrillic on the box. So I couldn't tell you if the ones you're looking at are any good.

The CV4010 Mullard tubes, is the price around $32? I have those, they seem ok, but haven't given them much time yet.

There's one seller on ebay who regularly offers the Tung Sol 408a for $50 a pair. Yeah, it's steep, but they're pretty good. Smooth and neutral.

And I agree, looks are a plus! I really like the Valvo boxes, and the Russian ones too.

 

[33&athird]

The Russian tubes I have aren't Voskhod, it says "Radio Lampe" in Cyrillic on the box. So I couldn't tell you if the ones you're looking at are any good.

The CV4010 Mullard tubes, is the price around $32? I have those, they seem ok, but haven't given them much time yet.

There's one seller on ebay who regularly offers the Tung Sol 408a for $50 a pair. Yeah, it's steep, but they're pretty good. Smooth and neutral.

And I agree, looks are a plus! I really like the Valvo boxes, and the Russian ones too.

man...$50? sad thing, i've seen alot of tube higher than that for a single tube...

The voskhod doesn't look as good as the "radio lampe"...and the military use probably implies there rugged, but not much about sound since as far as i've read, they were originally tv or radio tubes

the mullards are a matched pair for about $15 (to the door)...I may get them they are used and from 1966...it says they tested at 2.9 and 2.8mA/V...good? bad? I don't know...though the getter looks a little lean on one:scratch2:.

Edit: for comparison; the GE EF95 would be $20 and are NOS...the russian tubes would be $18. If the mullards are still good, then they seem to be the best of them, and oddly enough, cheapest, I wish I had converted the GBP over earlier.

Double Edit; those mullard CV4010 should be around 7mA/V...so they are at half capacity...i'm going to pass on them. On with the search I guess.

 

[john57]

I have a few of the 408A tubes came in which are 6028 TUNG SOL,
Sylvania Gold and a pair of GE408A with golden pins on its way. Some of the tubes came from amperex-us. Today the OPA2107 chip came in by audiosector and it was nicely packed with three layers and the chip in the tube as well. This is going to be fun. I will first try to find the best sounding tube and then switch the Op-amp and I may still be experimenting on Christmas day.

 

[Mr. Lin]

I have a few of the 408A tubes came in which are 6028 TUNG SOL,
Sylvania Gold and a pair of GE408A with golden pins on its way. Some of the tubes came from amperex-us. Today the OPA2107 chip came in by audiosector and it was nicely packed with three layers and the chip in the tube as well. This is going to be fun. I will first try to find the best sounding tube and then switch the Op-amp and I may still be experimenting on Christmas day.

Wow, sounds like you're going to be having fun! Definitely let us know how it turns out.

 

[Mr. Lin]

man...$50? sad thing, i've seen alot of tube higher than that for a single tube...

Another sad thing, I've paid a LOT more than $50 for single NOS tubes in the past.

Of course, those were 12AX7s.

 

[33&athird]

Another sad thing, I've paid a LOT more than $50 for single NOS tubes in the past.

Of course, those were 12AX7s.

Of course...the most common tube in the world

I found those 2107 op-amps on e-bay, 2 for $9 from the samerpav guy...I think i'll pick them up. Probably another project for the second one in the wings...

I think for now i'll keep the 6j1 stock tube, and update when I can, or see if anything comes up later. Usually, as soon as I stop looking everthing turns up:scratch2:...gather what to look for helped alot:yes:.

I have a few of the 408A tubes came in which are 6028 TUNG SOL,
Sylvania Gold and a pair of GE408A with golden pins on its way. Some of the tubes came from amperex-us. Today the OPA2107 chip came in by audiosector and it was nicely packed with three layers and the chip in the tube as well. This is going to be fun. I will first try to find the best sounding tube and then switch the Op-amp and I may still be experimenting on Christmas day.

I'd love to know too...sounds like alot of fun:thmbsp:

 

[Mr. Lin]

I hope you like the 2107. Let me know. I've been tempted to put mine back in, but haven't really had the time. Incidentally, I did finally get around to trying the LT1364 the other night. I've been listening exclusively to classical music the past couple weeks, much of it chamber music and solo harpsichord (especially the latter), and unfortunately this makes it more difficult to detect subtle improvements. Because again, among the better op-amps I don't hear huge differences. Anyway, I'll leave it in there for a while, let the Frybaby have at it for a few nights, then see if I hear anything different.

This is something I think many of us, myself included, might be missing by changing around the op-amps so quickly. They allegedly take quite some time to settle in and sound their best. I haven't had nearly enough time to come up with an opinion on that claim.

Finally, 33&athird, I think it's not a bad idea at all for you to just stick with the original 6J1 tube for a while and get used to it. Then you'll really appreciate the benefits of better tubes, IMO. So if you're not blown away by the 6J1s don't worry. From what I read in the headfi thread, most people didn't care much for them. You'll recall that I foolishly ordered mine with the WE 408a tubes, since I didn't know you can get them ridiculously cheap on ebay.

 

[charliexxx]

Love my LD MK III - still rollin' dem tubes and Mullards still top so far.

 

[Mr. Lin]

Love my LD MK III - still rollin' dem tubes and Mullards still top so far.

I am tempted to try the MKIII, and go all-tube, but it's probably not the most prudent thing to do right now, despite the low price. I have a lot invested in the I+ and I'm very happy with it. Although, the MKIII is compatible with many of the same tubes the I+ uses...

 

[john57]

I would get the MKIII if I needed the controlled RCA outputs. I am just about finished comparing the stock OP-amp with the 2107 chip. In the mean time I finished the review of my latest headphone with my Little Dot at the following site:

http://www.head-fi.org/forums/f4/se...-photos-inside-378999/index8.html#post6265743

I am tempted to try the MKIII, and go all-tube, but it's probably not the most prudent thing to do right now, despite the low price. I have a lot invested in the I+ and I'm very happy with it. Although, the MKIII is compatible with many of the same tubes the I+ uses...

 

[Mr. Lin]

I would get the MKIII if I needed the extra controlled RCA outputs. I am just about finished comparing the stock OP-amp with the 2107 chip. In the mean time I finished the review of my latest headphone with my Little Dot at the following site:

http://www.head-fi.org/forums/f4/se...-photos-inside-378999/index8.html#post6265743

I took a look at your review, it's interesting info. Definitely look forward to reading about your experience with the 2107.

Incidentally, if anyone is interested, I just finished writing a review of the Jolida 100A CD player, which is my source component with the I+. It's in the equipment reviews and opinions forum.