Little Bear P3 Preamp?

[btol]

Just bought one of these based on the couple pretty active "cheap tube preamp" threads kicking around. Most of the discussion, though, are on the red cheap tube preamps...not the P3 specifically. I have to admit this isn't exactly something I need since I just unloaded all my excess audio stuff to make room for our first baby. But, hey, I've loved the ss pre/tube amp combination so I wanted to take a foray into seeing how things sound if I were to flip flop and go tube pre/ss power amp. Plus it's pretty dang small, so space won't be an issue...yea...that's what I'll keep telling myself.

So, here's what I got. Comes w/ GE 5670's.

http://www.ebay.com/itm/Little-bear...t=US_Pro_Audio_Amplifiers&hash=item43d0f990b9

Anyone have experience with the P3? Anyone mounted it in a case, or done any mods they're really happy with? Would love to hear from you. One thing I've come across doing my research is an issue of too much gain. Looks like people swapped out a couple resistors next to the volume pot to fix this. Not sure exactly which resistors those are and what their values are, though.

 

[vinylkid58]

One thing I've come across doing my research is an issue of too much gain. Looks like people swapped out a couple resistors next to the volume pot to fix this. Not sure exactly which resistors those are and what their values are, though.

For a digital source like a CD player, gain isn't really needed. All you need is a volume control with a buffer stage, or just a passive preamp.

Without a schematic, it's impossible to know how much gain this preamp has.

jeff

 

[btol]

Hmmm...interesting...in general, I have noticed that my CD player (through a Schiit Bifrost Uber) doesn't need the preamp volume turned up as much as my phono-pre or my laptop (going through the same Bifrost). So you may be right. I do want to see how my sources sound with P3 tube preamp, though, so I will be going:

Source 1 (Phono Pre) & 2 (Bifrost) --> Schiit Sys (so I can switch btw. sources) --> Little Bear P3 --> Sansui AU-717 as a power amp

I'll also try things w/o the Sys in the chain to see if I like that sound better.

I guess as far as gain is concerned, I'll need to wait for the P3 to arrive so I can take some measurements and then ask around AK re possible resistors to remove/replace.

 

[fsdaron]

The volume control on those things suck. I have one, not happy with it.

 

[btol]

Yea, the Sys's volume pot is a bit on the dinky side but I'm happy for the money spent. I thought about doing a diy "passive" but I'm a no go on projects for the near future. In the setup I mention above, I'd just have the volume wide open and only use it for source switching.

 

[datafone]

Yeah, those pots are quiet, but sound very shut in/closed in.
If building it into a real/normal case, the Cosmos carbon pots are a big step up for around $10 off that auction site (they are better than the Alps Blue).

 

[ferninando]

yeah if you can find the rite value.
not a very good value spread.
No duals I could see.
mostly more than 10

 

[mrwood200]

I recently built the P3 & have been playing around with it.
Mine is the earlier version w/6N3 tubes & no power switch. I think it sounds pretty good! I have it paired with an Audiolab 8000 ss amp, and get a nice sound.

It does have too much gain for me, too early in the travel of the pot. I have tried different sources, and the volume level is difficult to control. I did find this on the net:
- The two output resistors (260K) next to the volume pot should be changed for 3.9Meg ohm, this reduces the gain to a usable level. There maybe a better way to reduce the gain,but without a schematic it’s hard to see what’s what as it’s a double sided PCB.

If I can get better control of the gain, I may look at the 5670's and other mods (e.g, case, IEC)

It does only have one input; you may want to pair this with an input switcher.

 

[btol]

Super helpful, mrwood200!

Looks like I there are two resistors on each side of the volume pot. Just need to figure out which two are the 260K's. Never worked on a double-sided PCB before so I'm a little worried about that. At least things look like they're through-hole for the most part and no surface mount. I can deal with that. Just not sure how I'll navigate the double-sided aspect.

 

[mrwood200]

Looks like I there are two resistors on each side of the volume pot. Just need to figure out which two are the 260K's.

When looking straight at the volume knob, these resistors are the ones on the right (between the volume pot & preamp RCA outputs)

Never worked on a double-sided PCB before so I'm a little worried about that.

Me too! If/when I do this, it will probably won't look as nice as it does now. But the low cost of this unit should make it a nice platform for some mods.

Apparently others have tried a different pot (100K?), but it did not reduce the gain enough. I put a larger knob on mine; this offered better ergonomics & control, but not enough to manage the gain.

 

[nj pheonix]

There's a thread on 3116 based chip amps on here. This pre is the choice of the masses when paired with this. I'll go as far as to say you won't get more bang for your buck with this pairing.

 

[choyb]

As I am now semi- retired, I don't anymore have the extra cash to splurge on equipment. So this Little Bear P3 was very attractive at $75 w/ free shipping. Installed it on my humble TT set up and was surprised with the sound it initially delivered, at least for my old ears ha ha. I agree, has much gain, so adjusted a bit setting on the phonomena ii, it improved a bit. Replaced the stock 6n3 J tubes with the GE 5670, but too early to tell as I have less than 10 hours on them. But don't get me wrong the stock 6n3j sounded OK too, so you might want to give them a few more hours before spending for the 5670 " upgrade."
HTH & good luck!

 

[PR Audio]

There is a model called the T10 (not T10-PRO) that looks promising at slightly more than the P3...What do you guys think? I am in the process of ordering parts to make a tube pre, but with the price on a T10 it maybe better to just order one of these and later modify. Don't want to post the link as to not break any forum rules, but if you do a search you'll find it at around $115.00. These is the specs they posted:

Focus:

1,It's a pure valve phono preamplifier.sound warm and classics,more clear and ture sound restore.

2,using 25VA customization E model transformer,with metal cover,low noise.

3,coupling capacitor all using HiFi WIMA audio capacitor,best model.very low noise and clear sound output.

4, 3x 6N2 tube(low noise tube) +1x 6Z4 tube.


RIAA phono stereo

the transformer with 110V and 220V both version. i will sent correct version to you by your address.
RIAA freq response 20hz-20kHz +/- 0.5dB, S/N ratio >92dB
THD <0.05%, input sensitivity 3.0mV, gain 50dB

Nominal / max output 300mV / 1.8V

Output impedance 200 ohms, input 47k ohm / 220 pF

gold-plated jacks
ground interace; click HERE to see why this feature is a MUST HAVE!

Package included:


1 x PHONO preamp
3 x 6N2 TUBE
1 x 6Z4 tube
2 x panel
1x transformer(110v or 220v)
1x power cable
5x screws

Edit: Sorry, seems like I hijacked...If you prefer, PM if you have one or have any thoughts.