New Little Bear Pro v2.5 breakdown

[StylinLP]

Ihaveread - Im not an EE or remember what I read about cases. But I know you can do a search for that kind of advice. I would just buy a case designed for such use from one of the vendors.

ScaleAutoArt - Thats great! I don't remember what ive read on that subject but I now suspect that 5751 tubes are a drop in replacement for 12ax7 tubes. Awesome. I know im happy with my Telefunken 12ax7 tubes as well.

 

[ScaleAutoArt]

The advantage, I think, to the 5751 is you can run it on the high gain setting and let the lower gain of the tubes work for you. I notice a tad less distortion and lower noise floor in my case

 

[StylinLP]

Im a little confused about choosing Electrolytic or Film capacitors. On the Little Bear how can you tell which is what? The list below are the caps I am planning on swapping out. Most are in the signal path. I put questions in bold. Unfortunately the height clearance from circuit board to the top of the plastic case is only 17mm.

I found Amtrans AMCO Series Metalized Polyester (PET) Capacitors which looks to be the same drop in replacement size for the WIMA MKS4 caps. Any recomendations on Amtrans?
The .1uF cap is 25 x 16 x 6.5 mm
The .47 cap is 30 x 24.5 x 13.5 mm (this is too big for the space.)

x4 WIMA MKS4 0.47uF 400v 26mm wide x 15mm tall - axial - Film cap?
x2 WIMA MKS4 0.1uF 400v 18mm wide x 15mm tall - axial - Film cap?

x2 Labeled 301 = 100pf? - small little tantalum "pearl" style cap (there is no + sign on the cap so this makes it a film cap?)
. I am still very confused by these two caps. They are labeled 301 with no other markings. What value does that stand for? 300pF?
I see that Parts Connexion sells these ceramic caps: Miconics: Silver Mica. Are these better than what I have now in the little Bear? Are they recommended quality or is there better.
x2 220uF 50v 100mm wide x 15mm tall - radial - Electrolytic cap

 

[StylinLP]

Well, after further research I submitted my order. It seemed to be the best choice for the price. 2 of the 0.47uF caps cannot be replaced because they are way to close together. Only a 3mm gap on the circuit board between two of them. Also, there is only 17mm clearance from board to top of the case.

Quantity Image Name
2 Silver Mica Capacitors_54421 300pf / 500V
2 Amtrans AMCO Metalized Polyester (PET)_0.1uF / 630V
2 Mundorf Film Cap 0.47uF / 450V, Mcap EVO Oil
7 KIMBER TCSS 19 awg RED
7 KIMBER TCSS 19 awg YELLOW
2 Amtrans AMCH Polypropylene Film Cap_100pf / 100VDC, gold-plated OFHC Leads
2 Caddock Resistor 3M3 / 0.75 (3/4) Watt, MK-132
2 Caddock Resistor 910R / 0.75 (3/4) Watt, MK-132
2 Caddock Resistor 220R / 0.75 (3/4) Watt MK-132
4 Caddock Resistor 330R / 2.25 (to 30*) Watts MP-930

 

[Ihaveread]

The advantage, I think, to the 5751 is you can run it on the high gain setting and let the lower gain of the tubes work for you. I notice a tad less distortion and lower noise floor in my case

Which brand of 5751s and what cartridge do you use?
No matter what I try the unit will go heavily distorted if I switch to high gain setting.
I am running a Shure V15 type 3.

 

[derekva]

Which brand of 5751s and what cartridge do you use?
No matter what I try the unit will go heavily distorted if I switch to high gain setting.
I am running a Shure V15 type 3.

That's because the high gain setting is probably for low-output cartridges, whereas the Shure is (as cartridges go) high-output. It's distorting because you are overdriving the signal.

-D

 

[Sir Bakerman]

StylinLP,

I am following this quite closely. I am deciding between a Yaqin and the Little Bear. Am I correct in assuming your greatest improvements stem from tube rolling?

Reason I ask is I am not good with a soldering iron so I am steering clear of anything requiring a great amount of parts replacement,( think MS-23B). Tube rolling and cleaning the circuit board I can do.

My biggest question is: How does it sound with what you have done? Are your up coming changes due to your desire to make it the very best or do you find it lacking in some degree?

Thank you for your informative thread.

SB

 

[StylinLP]

Sir Bakerman, I have not yet upgraded the capacitors or resistors as of yet. Been very busy lately. But, in regards to the tubes, tube dampers, feet and power cable I can make few comments.

The tube dampers did make a big difference damping the microphonic stock Chinese tubes. They actually sound very good. Much more than I would have expected. They are balanced, detailed and full sounding. The tube dampers tamed and smoothed the highs. There wasn't as much of an improvement damping the excellent euphoric Telefunken tubes. The telefunkens has a much larger sound stage with greater air between the instruments giving a more ethereal sound. Very smooth with unlimited detail and depth.

The Russian tube gave me a tad more dynamic sound. I visited my buddy in Boulder CO. Last weekend bringing him I need of the Russian rectifier tubes for his list bear t10 v2.5 phono preamp. We both agree on the little improvement. Also, I put the stock Chinese and the Russian tube behind my back and randomly let him take them to feel the weight and size. He immediately picked out the Russian tube without looking. Little larger and heavier. The inner plates are a darker pure black.

I'm not sure how much improvement the Pangea feet and power cable had on the little bear. But mine was much quieter than my friends with his stock cable and no feet.

Hope that helps!

 

[Sir Bakerman]

Yes it does! I am interested in this phono. I am curious as to connecting to my SS pre amp. I have a B&K Pro10 that is very nice,but I want to try tubes. My question is this: If I connect through the tape in on my B&K will that "color" the sound. The reason I want to do this is simple. The B&K Pro10 has a mono switch that enables me to listen to my mono LP'S (namely the Beatles and Hendrix). Plus it has a headphone jack for quiet listening.

 

[T68]

Hi guys!
Bumping this thread with a question regarding the different versions of the little bear t10.
Right now there's an opportunity to buy the 2.5 version at a substantially lower price than the 2.6 or the newer t11.
Would that make the 2.5 an interesting buy vs the tradeoffs in features . and performance?
Thanks for any input!

 

[Nixxuz]

If they are real then WIMAs (especially the MKP10's) are very capable caps already, no less good than regular Mundorf M-Cap. I'd say in this class of preamp, there's probably limited gain to be had from replacing already good components by slightly better ones. The tubes are another matter though

Whoops, didn't see how old the thread was!