Little Bear T11 Tube Phono Pre-amp Upgrade Final
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- čas přidán 24. 06. 2023
- This is a short series on upgrading the popular "Little Bear" RIAA Phono pre-amp. This is basically a pretty decent little phono stage, that we are correcting a few faults to see if we can take this to the next level.
www.skunkiedesigns.com/little...
These are the little Hako flush cutters I use:
amzn.to/3qVghwj
And this is the Hako FX888D soldering iron I love:
amzn.to/3XhW6F5
You can send me links and messaged at:
www.skunkiedesigns.com/contact
Here is my Patreon, as well as the donation page at my site, if you feel so inclined to help fund some of the future projects for the channel
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Always a good watch with my coffee in the AM. You make it look so easy. I would be ashamed to show my soldering skills to the general public. Kudos and have a great day.
HOLY CRAP!! I just finished the upgrades and it's so FREAKIN' quiet compared to before the mods! I'm only listening to my first album and it's just AWESOME! Boston's debut LP is sounding so good!
Good to hear!
That PCB looks very similar to the one you used for the CJ preamp (zero zone, maybe?) clone as well as PCB’s that are in Musical Paradise components. I wouldn’t be surprised if they were made in the same factory by the same co. Beautiful work as usual, Stephe. It’s always a pleasure and very inspiring to see you improve upon or build gear. Looking forward to how you feel this pre sounds. 🔊😊🎶
I used to use desoldering braid, i'd flux the braid though... never used a spring loaded or bulb-type solder sucker, i went straight to a cheap chinese desoldering iron with the vacuum pump, MUCH quicker, fewer burned fingers, and less mess.
The key there is to add solder to the joints....
I just bought one on eBay that I should have in by next week. I'm going to test it out and do a few test recordings before doing your mods. I still plan on building your EL34 clone preamp sometime in the future, but I want to start off with this. I can't wait to start the FUN! 🎸🎸
I got my T11 in early today and I'm making an unboxing and setup video using your name in vain for inspiring me to plunge into the tube world! 🤣🤣 It was easy to set up and I'm finishing up my first LP and yes it does sound really good! There is no hum like some people have complained about. The odd thing is that I had to turn the Volume on the front all the way up and then turn up my Schiit SYS most of the way up to get it to play at the normal volume when I used my Schiit Mani preamps. 🤔🤔 I did some reading online about the tubes that come with it and like you said it needs better ones. I'll play this for a bit and then order the upgrade parts and the tubes you recommended. I don't monetize my channel so I'm gonna upload some before and after upgrades music samples that I'll record through my USB interface.
Hi, working on PCB's scared the shit out of me, but you showed us how to do it in a very instructive and calm way. Using the flux worked like a charm. I even used the big toroidal transformer from my LB T10 Pro project (in an external case). Fitting in some very nice 47k resistors and the Mundorf EVO aluminium oil, works! The sound I get from the modified unit is on so much levels better than stock, it's freakin' amazing. Thank you so much! 🙂
Glad this helped you get this little pre-amp sounding good!
My Little Bear T11's plastic RCA housing turned brittle and I ended up replacing the RCA connectors with Neutrik. Highly recommended to change those RCAs. Nice video, thank you!
Great tip!
Hi and thanks, can't wait to see the next video !
Coming soon!
Ditto on laundry noise, but I’m a retired HS band director. 🤷🏻♂️Longer screwdriver definite called for at 17:57. 😅 Love the video, thanks!
I know right? It was the closest one :)
I'm in the middle of placing the caps on the PCB and discovered the BOM you listed has the wrong quantity listed for the Mundorf caps. You have 4 needed for the 1uf Alum/oil film cap MUNDORF-76428, but only 2 are needed. You have 2 listed for the 0.10uf Alum/oil film cap MUNDORF-76422, but 4 are needed. I just ordered 2 more of the smaller 0.10uf caps. All is okay as I just wanted to let others know of the type-O when ordering the caps. I now have two (2) extra of the bigger 1uf caps that I can't use right now. The desoldering braid works like a charm! I'll finish up the rest of the upgrades and wait for my two other caps. This is a fun project so far! 😜😜
This is why I hate doing BOM's, I suck at things like this and ALWAYS get them wrong... Like every single time after spending hours creating them. So them I spend more time correcting and uploading new ones.. sigh
Just looked at the BOM I posted, it looks right to me?
www.skunkiedesigns.com/littlebear?pgid=ljf3wo5m-98a06ae7-e388-451d-92df-347da6ae2646
@@SkunkieDesignsElectronics like I said all is okay. I appreciate what you do 😁
Oh I see I got the part numbers backwards...
Hi Stephe.. If those ceramic caps are part of the RIAA EQ, try to replace them with polystyrene and/or silver mica…
That's likely a good call!
@@SkunkieDesignsElectronics If you prefer polypropylene, try Panasonic ECQP types (gold plated copper leads), but they are hard to find NOS ‘cos they were discontinued some years ago.. Alternatively, Orange Drop 716P’s are also good if you prefer polyprop over styrene or mica…
@@matthewtaylor7355 charcroft
I replaced them with some mica caps and it made a huge improvement! Thanks for reminding me to replace those!!
@@SkunkieDesignsElectronics You’re welcome👍🏼, Stephe…
Hi, great video. I have done these mods to a T10 V2.6(same) and sounds great. I also put it in my own hammond plastic case. I didn’t like the acrylic casing. Wish I had tools to make an aluminium case. Although I shielded the Toroid with a metal cover. And added Beyer SUT internally for MC… I added 2x input, 1x output connectors. all the switches for MM/MC select, SUT 1:15/1:30 select, and farday sheild lift switch for mc sut. Sounds great with my Denon 103R at 1:15 ratio.
I have a question. The high/low gain. If the high gain is 50dB what is the low gain? 25dB?
I also wonder about R4. seen people change these to 220K. And R29 to 750k.Any advantage to doing this ?
Thx
Hello! Im interested in this unit, i have tube amps, why would this unit be a good choice with my set up? Can the tubes be coverd? Thankyou..
Hi, I had a question about the 1uF output caps. You mention the direction is different than the other caps for those. Is the foil side going towards the tube or the output ? Thx
I believe I was talking about the physical direction on the board.
hi, ok i thought u meant the foil direction. So for the 1uF the writing on the cap is still going in the direction of the signal flow right ?thx
Yes
I want to share my latest fix on this T11 that some may encounter with the front INPUT and OUTPUT RCA connectors as they are so cheap. If you swap cables around from different turntables or USB interfaces like I do then you will hear the connectors snap and break away from the PCB inside. They are weak and they break away at the ground solder connection on the PCB. I made a permanent fix by installing RCA jacks in the front face plate and hard wired them to the PCB with solid copper wire. Here's my video showing my fix: czcams.com/video/lfVh-bu6dhQ/video.html
Good stuff! Thanks for sharing.
Great info on this , got a t11 on the way. Also got your pdf of the parts , how awesome. Couldnt find the schematic though , just the parts list? those Mundorfs are pricey. Got the parts with the mundorfs ordered.
www.skunkiedesigns.com/littlebear Hope this helps.
@@SkunkieDesignsElectronics awesome i got it. I think i watched your vids on this 5 times, 😆
@@SkunkieDesignsElectronics I seen where the 47 resisters go, and the munfords but not sure i seen in your videos where the other 4 items on the parts list go. Dont recall seeing you remove those?
email me if you get lost.
@@SkunkieDesignsElectronics will do, the 110pf mica caps1 % and the same in 330pf mica caps 1% ,2 each is what im not clear on. The 47k resistors and the munfords im good on.
Curious how that volume pot affects the output response.
That's a good question!
@@SkunkieDesignsElectronics my ear 834 clone has a 1uf and a 220k on output. It has a lot of gain so limiting this could be nice. I assume the pot is on output and might affect frequency response
Laundry? I spent 6 years in the field artillery, i can't hear anything, lol...
Actually heard the "sparkles" with my chinese amp and my R-51Ms, it scared me...
BAD sockets ............chinese crap but they look nice !
Some MM cartridges sound better with capacitance loading. The 100 or 200 pF mica caps would go in series with the 47K resistors.
Most cables are going to provide the needed capacitance.
In //.....with the load......
Always try first with no extra capacitor ...............and MC does not them
@@SkunkieDesignsElectronics Indeed ;
Some vintage Stanton and Shure cartridges have recommended 300 pF for the flattest response. As you've said the cable will provide about 100 pF which is enough for almost any currently produced MM. MI's and MC's aren't nearly as sensitive to load capacitance.
Where can you purchase preamp?
Let me review it after mods. Not sure if it's a "recommended" yet.
Your vids are always interesting to me. But as much as I like tubes I wonder how You came to pre-amping the phono signal with tubes, since they got a high signal to noise ratio. Long ago I owned a hybrid pre amp from a small local company that finished after an arson. The pre-amp was very stylish with thick anodized aluminium walls and a smoked glass platter on top with 2x ECC88 in the phono stage. It ended up with I liked the look more than how it sounded. A friend took it and then I had to exchange a capacitor. What a shame! Luckily for me a cheap Philips piece. But since then I came to the conclusion, the phono stage has to be done by transistors because of all the microphonies tubes come along with.
Done right, they work fine and IMHO sound better than most SS phono-stages.
62K Ohms input impedence is a TRICK -- I will explain.
A little known fact is A FEW modern moving magnet cartridges have excessive rolloff and/or spikes at 8khz - 13khz or after 16khz.
One way to get NEAR LINEAR response from these cartridges is to "load them up or down" while also getting the lowest capacitence interconnect [Blue Jeans LC1 or Audio Envy Prestige] you can to run from the turntable/tonearm output to the input of the phono stage (read: BRING BACK THE SHURE V15 !!)
.....to summerize, 62K Ohms means this preamp was optimized for a Shure M97xe :)
...if it was a 38k Ohms resistor, it would have told me it was optinized for an Audio Technica 760SLC
...if it was a 33k Ohms resistor, it would have told me it was optinized for an Ortofon 2M Black
....I MAY have done this in the past and can CONFIRM it makes the cartridge sing......ESPECIALLY with a Vishay Dale CMF55 1/4 watt pair of mil-spec resistors that have 100 hours of PINK NOISE burn-in.......OH MY !!
That sounds like nonsense, especially "burning in" for 100 hours with pink noise.
I just completed the video on my Little Bear T11 tube phono preamp. It was a fun project and I'm just loving it! Here's my video for anyone interested and thank you very much Skunkie for the inspiration! czcams.com/video/r5_5I1HtZls/video.html