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Little Bear Tube Phono Pre??

Yay! I got mine today! Now for my initial review:
1st off, mine came assembled since it was originally shipped to the wrong person. That person must have put it together, and they did a good job. The wires on the transformer should be braided better, but I'll do that myself.
2nd, that person must have added an EMI Filter from hifiss since that's on there.
3rd, my system is set up with an Audio Technica PL-120 Direct drive Turntable, Pioneer Elite VSX-50 receiver, and Paradigm Monitor 11 (Series 7) speakers.

Now for the guts of what I've found so far. Hum is awful. If I can't get rid of the hum for next to nothing, I'm done with this. Obviously I need to check voltages yet and do some examining, but out of the box my opinion is that this is worthless, and not money well spent.

Next: I've read in this thread about how you all love the high output of this pre amp. I don't. The "over" kept flashing on my receiver and the signal sounded heavily distorted (edit: yes I did switch off the internal pre amp).So once again, I'm just not seeing the value of this thing so far. It looks cool, but that's about it.

I'll do a few tests on it and also try it out with my B&O 1602 to see if that TT works better with it, but I have my doubts.
 
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What version number is on your board? Is it a V2.5? Did you buy the T10 pro from them?
I'm not sure if there is a difference between the non-pro and pro boards. If so why do you need the extra filter? V2.5 has that filter on board and not an extra PCB sitting on the main PCB.

In regard to the high gain, the V2.5 has a switch for running on lower gain. Depending on that setting I get less hum in low gain but need to crank my power amp for same signal. In general the hum is very low and I nearly got it removed by cutting the transformer wires short and don't have any wires going under the PCB board or around the transformer. This seems to do the trick for me.
Also my tube shield sitting on V1 reduces hum even without the rerouting of wires so these two steps made this little bear a good performer.

Axel
 
That explains the issues. From what I have seen in other forums the older versions are not as good as v2.5. V2.2 also does not support the switching between 6N2 and 12AX7 tubes.
The little filter board that they sell as extra to install by owner looks like the parts that are integrated now on the v2.5 board so that should be the same but maybe the difference is in having it sitting extra on the main PCB or implemented on the board itself. That also means you don't have low/high gain option? I have heard any below v2.5 has only high gain which might be prone to hum.
 
I have the 2.2 and it has the switches for 12ax7/6n2p. It doesn't have a gain switch nor some kind of filter you're talking about. The 2.2 hum is bad and there are some distortion problems. But since I had some time last week, I looked a bit at my LB and i noticed that my 0.1uf caps were MKP and 0.47uf should be all MKS (according to what someone here mentioned) one of my 0.47uf cap was actually MKP and the other three were MKS. So I desoldered those caps, checked their capacity and they weren't matched at all.
So now I'm waiting for my k42 PIO caps, wating for new noval sockets along with shields. Also gonna do the diodes mod but only for the 15v cause i got smth over 16v there.
But after all I must say that for the money, it is a proper value. Now I plugged in my Cambridge Azur 540p that I used before (desoldered caps in LB) and the sound is sooo flat !
Oh and one thing. Since you say that 2.5v gain switch helps a little with the hum. Can someone post a photo of a PCB layout? Mabye we, previous versions owners, can figure it out and mod ours to lower the gain/lower the hum ?
 
I guess the reason I'm upset is because I ordered this NEW on January 6th of this year (2015). I was assuming I'd get the newest version with the gain switch. However, since it didn't ship directly to me, I'm not sure weather the other guy in CA messed with this, swapped out the one he didn't want, ect.
 
I have the 2.5v which I ordered in January 2015 and when I first connected it I thought it was very quite and a bit muddy compared to my internal phono on the Rega Brio R. I then switched it to high gain and the sound was massive with far better than the Rega phono stage. I am using the 12AX7 tubes and my TT is a Thorens TD 166 modified with a Linn LP12 motor and an external power supply. My stylus is a AT440MLa on a Rega RB300 arm. I have had no hum at all even on higher volumes. Not checked the voltages yet but the tubes are fairly low glow so looks like they are not being overdriven.I have to say I am more than happy with the Little Bear. I will try and get a picture of the board up for all to see later
 
Beitie said:
I guess the reason I'm upset is because I ordered this NEW on January 6th of this year (2015). I was assuming I'd get the newest version with the gain switch. However, since it didn't ship directly to me, I'm not sure weather the other guy in CA messed with this, swapped out the one he didn't want, ect.
Click to expand...

The guy on Ebay has two different products running. One is the T10 with just the top and bottom plexi cap which is according to him the older V2.2 for $115. This one does not have the filter and also not the gain switch. He mentions in his auction text the hum filter board which you can order and install extra with instructions where to connect the little extra board.
He has in parallel the T10 Pro version for $155 with a full plexi housing which is fitted with the hum filter on board and gain switch.
Luckily I saw the difference and messaged back and forth with the seller about the differences of the two versions.

All this is not easily clear by just looking at one of his auctions, you need to find both and figure out the differences.

Axel
 
That's the same package that I have. V2.5 with him filter and all switches.
Just in case, I would shorten the wires from the trans to board a little bit.
 
darg said:
The guy on Ebay has two different products running. One is the T10 with just the top and bottom plexi cap which is according to him the older V2.2 for $115. This one does not have the filter and also not the gain switch. He mentions in his auction text the hum filter board which you can order and install extra with instructions where to connect the little extra board.
He has in parallel the T10 Pro version for $155 with a full plexi housing which is fitted with the hum filter on board and gain switch.
Luckily I saw the difference and messaged back and forth with the seller about the differences of the two versions.

All this is not easily clear by just looking at one of his auctions, you need to find both and figure out the differences.

Axel
Click to expand...

Except that I bought this off of Amazon for the $130 price.
 
Got the shields today & put them on....they were anodized so i needed to dremel them down first for electrical flow.
The shields WORKED cos i tested them with/without the earth connention.There was not an amazing difference in hum but noitcable enough to warrant increasing the tube hole sizes.While i was there i also increased the opening for the power on/off switch and drilled a hole to access the High/Low Gain switch externally.
Now all i'm waiting for is my Long Plate Tubes.
http://www.ebay.com.au/itm/290677695329?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
 

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I think the Chinese are preparing for New Years and some won't be available for at least a week. We have that all the time with our work facility in Malaysia, even they observe Chinese New Year.
Not sure when it exactly is but it's somewhere beginning of February as far as I know. They will be back after that.
 
Little Bear Gain switch

So anyway, instead of complaining about it, I wanna be able to get this pre amp working in a manor that makes all the money I've spent so far worth while.

The creator sent me this schematic on how to add the gain switch.
t10-mod_zpsr4daqwji.jpg

My question to you all out there, who has done this mod? Any pictures? Where is a good place to source the parts?

Also, I can read a schematic, but I know very little about these diodes, resistors, ect, so please help me out here, what parts would I need to buy?
*edit, kind of* I know I'll need a switch, two 4.7k(somethings, I don't know if this means resistor, diode, no idea.) and two 1.5k (again, no idea weather it's a resistor, diode... this is where I need help)
 
Hotrodster said:
What I would like to know is what is the smallest 12V transformer I can use for bucking.
Seeing how it's a 110V transformer I'd like to drop line voltage form 124V to 110V.
Running with a variac at 110V all secondary voltages correct and transformer cooler.
Have mine in a case and would like to add an internal bucking transformer.
Case too small for the 3A and 1.5A I have.
Will a 12V 450ma be big enough? or will I burn down the house?
Click to expand...

I wish I could answer you. I purchased mine at Rat Shack and have it mounted outside a standard electrical box. 110V to the Little Bear & 117v to my ST70.
I wired in a switch and a pilot light.
 
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