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Little Bear Tube Phono Survey.

sled108

sled108

Super Member
Little Bear Tube Phono Survey

Well then, it's been Long Enough to get an Opinion on the L.B...And, after You've done all the Mods on It...What do you Guys Think?...I say, as I've always have, It's a Hellava Deal with a Bit of DIY...It is Fun and Easy to Mod, and when you Do It...It Sounds Great!..What do you Guys Think?
 
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So far...so good. I like the extra gain especially with my homc. Later this week I will be trying out a Nova I picked up on BT. Wanted to see what the fuss is about and want the settings. But so far I tend to keep going back to the LB due to the warmth and gain. Fortunately, so far it works with the carts I have.

Mine worked fine out of the box but making the basic mods and upgrading the tubes definitely improved it.
 
Off topic a bit, but I'm impressed with the LB 6J1 right out of the box. Its been a couple of months and I use them every day, they sound crisp and clean with great all around sound. I run Marantz SR8001> Little Bear>ADCOM 5002 Bridged One I paid $15.00 for and the other was $40.00 both won on E=bay. I recently won a LB 6N3, going to use on my patio system, can't wait. Expanded the sound stage, smoother vocals, clean bass, seriously, lots of grit to these little units.
 
Not sure yet

Well Sled … I'm still awaiting the Russian Tubes and the 0.1 PIO's from "the federation". Once I get those installed maybe I'll have a useful opinion. As it is, now that the voltages are adjusted and shielding is done, its an interesting piece of gear. I guess for the money its pretty neat, but the lack of detail and the mid-high frequency glare (in its present state) makes it pretty much of no use to me. The phono stage in my 80's vintage NAD receiver is substantially better in all aspects except for soundstage (where they are close to the same). I only use the NAD as a phono stage and to drive my high frequency drivers (active bi-amp system), but the phono stage seems way better than it should be. I've owned some of the finest phono tube stages out there, and I had high hopes for the LB - maybe it will come through with some additional modification. No, I don't expect it to be a BAT or CAT or AI, but I thought it might outpace the NAD receiver, and maybe it will once it has better tubes and maybe some better caps. I'll keep you posted if your interested.
 
Russians to the rescue!

The Russian tubes finally arrived today. To say that they sound better is the understatement of the century! Everything snapped into focus in a way that I simply did not expect. Noise went down, detail improved while also sounding warmer and more palpable. I'm not sure that it delivers "high-end" sound yet, but it is definitely getting close. Soundstage is definitely "deeper" than before and it now extends beyond the edges of my speakers - which was not the case with the chinese tubes.

I have not installed the 0.1 PIO's yet, but can't wait to do so. If those improve things just a little, that will be exciting.

A quick question: I've not grounded the open ground on the signal tubes yet. Did you find this to be highly important in the mods that you did? I assume that you simply run a small wire from that pin (#9?) to the ground on each of the signal tubes? I know this was covered in an earlier post, but if you have the knowledge handy and can help .. thank you!
 
OK, so I installed the Russian PIO 0.1's last night. While I had the darn thing apart, I also added some sorbothane to the underside of the xfrmr. I can now say that the LB tube phono is approaching "high-end" sound. I guess the sorbothane helped as the noise floor dropped several more dB, and I'd actually say the LB is now pretty quiet for a tube phono stage. The PIO's made a big difference. The soundstage deepened substantially, the detail increased significantly and the timbre became much more "fleshed out" and natural sounding. The Wima's were somewhat "digital" sounding - harsh and unpleasant, but the PIO's sound much more natural with more of a "you are there" quality about them. I'm really wondering what would happen if I change out the 0.47 caps. If there is any improvement to be had, I really want to give it a go, because this thing is starting to sound like a "real" tube phono stage :-) Any recommendations out there on what 0.47's to put in?
 
I know what you mean jaymanaa, but some tube gear just seems to have a bit of background noise/hum whatever one would call it. …. Anyway, my LB has taken another couple of steps toward "high-end" sound. I have now replaced the Wima 0.47's with Sonicap Gen I's (tight fit) and I replaced the input loading resistors with some high grade 47K's - as my cartridge really likes a 47K load. The "shouting" character of the sound is now gone, and this phono pre is beginning to be VERY listenable - way beyond the cost would indicate is possible. The caps need to break in more, but I'm not getting the "quality" at the frequency extremes that I would really like to get. I'm thinking of changing the PIO 0.1's to something with better "extension". Have any of you tried K2 or K3 russian teflon caps in place of the PIO 0.1s? Or has anyone gone so far as to use V-Caps or Mundorf silver oil or silver/gold oil caps? Has anyone tried dynamicaps in this phono pre? I'm probably "overdoing" it by considering such high dollar caps (although the russian teflons are inexpensive - and very good from what I hear), but …. this project is pretty darned interesting!
 
My little bear is still in pieces, I haven't put it together yet. Can you adjust resistors and run MC, that's all I got anymore.
 
I'm running a high output MC … NOS Blue Point Special with roughly 2.5mv output. That cartridge seems to like a 47K load. But … I would think that you could replace those loading resistors (R16 and R17 I believe) with just about any value that you want to, but I'm no tech, so I don't know for sure. Sled108 might know. I doubt that you want to use an MC with less than about 1.0mv with this pre- as it is not the quietest thing on the planet. Even with all of the mods - there is a bit of residual noise that is OK with a 2.5mv cartridge … but I'm not sure what will happen when you drop the cartridge output … it might get to be a bit too much noise vs. signal? With the HO MC the noise is low enough that I can hear tape hiss on some of my albums - which indicates to me that the phono preamp noise is lower than that of the surface noise and even the analog tape noise on the master tape - so its not "distracting" in any way. If you try it, with a lower output MC, let us all know how it works out!
 
Hey Guys...Lets not forget that This is a $120 Tube Phono Pre, with shipping from China...That alone, can't be Beat...
And, I like the Sound of Wima MKP10's for the .47uFs...They just seem to sound 'Right'..
 
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Agreed … (with the mods) its quite the machine for the purchase price. I guess I should have tried the Wima MKP10's before I spent higher $ on caps, but I'm liking the Sonicap Gen I's … they provide lots of "air" with good detail … and are very smooth sounding. Maybe the fact that I'm considering Mundorf's or dynamicaps or K3/K2 teflons for the 0.1's speaks to how good this darn thing is starting to sound! I may have to try the 6DJ8's too … you say they are a "whole bother story" … so I'm assuming that it gets a bit better (but with less gain)? My experience with the 6DJ8's in pre-amps is that they soundstage even better, have a bit more detail while still being silky smooth … is that kind of what you got when you used them in the LB?
 
Ooops … typo … I meant to type "whole other story" in the previous post. Darn auto correct on my mac …. ughhh!
 
I have moved the LB to my office system (vintage tube) and it's just grand.

I just put the new LB headphone amp in my home system. Has a nice warmth to it. Unfortunately its more expensive the the phono pre and no power cord supplied. Still s cool little component.
 
At this point, I have to say that to me the LB is pretty good, but also a bit of a disappointment. I've done all of the mods, and it is now very quiet - a good thing. I've put in high quality film coupling capacitors throughout and have installed the russian 0.1 PIO's. I've even switched to the russian military tubes and changed over to high quality 47K loading resistors. Does it sound better that the stock LB … yes, very much so, but overall I don't like the way that it sounds. Strange for tubes, but there is not much liquidity in the midrange. The soundstage is nice, but the darn thing just has this small underlying "shouting" characteristic or "glare" to the sound that reminds me of mid-fi range SS gear. Each mod has lessened this characteristic somewhat ,but it remains. Whatever is causing this anomaly obscures detail and imparts a thickness to the sound that is not (to me) pleasant. It does not have the tube like "ease and liquidity" that I was expecting. OK, it is a $119 piece of gear (if you place no value on the expensive parts and my labor doing the mods). So, I guess I shouldn't expect too much, but my high hopes for "tube" musicality have not been realized. Does it sound "good"? Yes, but it seems flawed in a way that just doesn't work for me. Have any of you tried going point to point with the signal path wiring? Is the sound being impaired by the quality of the board? Maybe the power supply is a weak link? Does using 6DJ8's remove the hardness in the midrange? Or, am I just too picky and expecting too much from an inexpensive piece of gear?
 
Refresh an old thread!

I've had my L.B. V2.2 for a few months now.. Out of the box, its really sweet! The first tube for sure is your interference probe! That can be fixed, etc...
For some reason, I don't like the 6z4, so, like most stuff, I love to mod! And I did here too!
I built my own outboard 6ca4! Using a spare 120v -> 6.3v I had laying around... all is perfect! The 6ca4 is overkill for the L.B. but I don't care, lol.. I just wanted something different, and better quality then the China 6z4.. Well, ok.. I wanted a bigger rectifier tube since the 6n2's where larger! :p
I ran the power from from the pins of the 6ca4, into one side of the 200-0-200 spot on the board.. Then I jumper'ed the old 6z4 socket to 'bypass' as it were so I could revert if I felt the need to down the road.

Still a 'slight' hum when you crank the volume on your source, headphone, etc.. BUT!!! not bad at all, and I haven't done anything else to help fix that.. aside from twisting the power wires, etc.. I'll build a shield on the first tube soon..
I also have a double sided copper PCB (as big as the LB board) below the main board to to help with noise, etc... My record player doesn't have a ground, so I've got the earth ground, and the board grounded to the copper plate PCB.. That really killed the hum I had when I first did a dry run..
I have a Music Hall USB-1 with an Ortofon 2M Red and I found that 47k input helped a lot, and it seems to be the common opinion on the net.
Tube pre MOD 01.JPG Tube pre MOD 02.JPG
 
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