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Mods to "Little Bear" phono-preamp

A viewer sent me this made in China "Little bear" phono stage to look at, and out of the box it was nothing special. But with some simple mods, it really sounds quite good.

The main issues IMHO were the coupling caps were the wrong sizes: stage 1-2 was a 0.1uf which is fine, stage 2-3 was a .47uf which only needs to be a 0.1uf, and the output cap was a .47uf which needs to be a 1.0uf. The output cap change in particular resolves the low bass output this pre-amp had. I used Mundorf Alum/oil but if you are on a budget, other types could be used. I have a feeling the supplied "Wima" film caps are fakes and I would replace even the correct size 0.1uf first stage cap while I was in there.

The China 12AX7 tubes it came with were noisy and lifeless. Some new production Mullard 12AX7 gave it some life but were still noisy. Ended up with some EH7025 tubes, which massively reduced the noise yet kept the spunky sound of the Mullard 12AX7 tubes.

They also have 62K resistors for the cart loading/input caps which should be 47K for the vast majority of MM phono carts out there. And finally I swapped the ceramic caps in the feedback loop for high precision mica caps, which made a very audible difference! I also did a bit of lead dress while I had it open.

At the end, this is a nice sounding little pre-amp for a small amount of work. I still think my EAR834 clone sounds better, but if you already own one of these, it's worth doing these upgrades to it.

Here some videos on this phono pre:



Little Bear Mods.png Little-bear-BOM.png
 
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