Amazing $50 3 Tube Preamp

Poultrygeist

Lunatic Member
I just finished placing this Chinese preamp from ebay in two glued together decorative boxes from Tuesday Morning. Tried it with a Lepai amp and some cheap speakers and the sound was beyond good. It almost looks store bought but every part except for amp/transformer I scrouged from the garage. I admit being a packrat for little boxes and parts that can be audio related and this puppy would make a nice cigar box preamp. My plans are to roll in some WE 396A tubes, try it with the Sure tripath and report back.

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Thanks guys,

I also used a switch plate cover on the rear. You can see from this view that the two boxes are glued together and having the tranny in it's own compartment wasn't totally by design. Could have crowded it all in the larger box but no need. Fun little project and although I added some touches it's plug and play. If one didn't want to fool with an on-off switch they could keep it on a fused power strip.

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If you're wondering about the top wooden cover where the tubes protrude it once provided ventilation for my PC hutch. The plastic latticework grills I found laying around and cut them down to fit. Thought about using plexi but it's a bitch to cut.
 
I don't have a Quickie but I have a Foreplay III which should sound better and an Aric Audio 3.7 which may or may not?

But for $50 this thing is way better than it has any right to be.
 
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Time for a side-by-side comparison with the $99 Quickie ?

http://www.bottlehead.com/store.php?crn=220&rn=438&action=show_detail


(Surprisingly hard to find a $99 quickie these days :D)

Quickie is not really $99. With the box, PJCSS, tax, and shipping - it is close to $230 (battery not included). I built one - sold it for $175 within couple months. I did not play with tube rolling but IMHO - it is overrated and sounds harsh. Big disappointment to me. I am sure however, there are others who disagree and love/enjoy it.
 
What are your sources for parts, Poultrygeist? I have a nice empty cigar box sitting right here, and Im in need of a preamp.

EDIT: Nevermind, found it :)
 
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Quickie is not really $99. With the box, PJCSS, tax, and shipping - it is close to $230 (battery not included). I built one - sold it for $175 within couple months. I did not play with tube rolling but IMHO - it is overrated and sounds harsh. Big disappointment to me. I am sure however, there are others who disagree and love/enjoy it.

Thanks for the feedback - it's important that we get both sides of the story. I did think $99 for a US-made tube pre-amp, even DiY, seemed a little too good to be true. Interested to hear from others who have built the kit though.
 
It's listed on ebay under this catch-it-all phase: " DIY Magic Sound Buffer 6N3 X 2 + 6Z4 Tube Preamp + 220v or 110v Transformer " and the seller is pokerelectronic

Other than a case the only extra part one might need would be a scavenged power cord or cut off extension cord. I elected to add a fuse and holder from RS and a toggle switch and metal switch plate from Lowes. The pre can be mounted to it's case using the included stand offs and fasteners. It comes with a nice plexi top which I wasn't able to use. I read that someone plugged their pre into a fused power strip and used that to turn it on and off but the fused at the switch off/on toggle works for me.

The only slight challenge was extending the RCAs to the rear of the case. I'm always swapping gear in and out so I didn't want to put constant pressure on the plastic board mounted RCAs. I used some left over IC ends and plugged them into the board mounted RCAs and soldered wires to the ground/hot center then back to the rear plate mounted inputs/outputs ( center and lug ).

An even easier solution would be using an existing RCA cable cut to fit with the ends soldered to the rear input/output plate. If you've made DIY IC's this is not much different.

Of course if you don't plan on plugging and unplugging then the board RCAs is all that's needed.

It took me awhile to figure out the connections for the 7 wires coming out of the transformer ( directions aren't included ) but I'll gladly share if anyone's interested. They aren't posted anywhere as the preamps like mine on ebay show connections for a 220 transformer.
 
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$50 Preamp vs $400 Preamp first impressions

This picture shows the $50 Preamp's competition, a $400 Aric 3.7 which is hand built and features two 12AU7. I've had the Aric for several years and consider it to be a pretty decent preamp and it's reviews support this opinion. Today I swapped it for the $50 Preamp and listened to Norah Jones with the Sure TK2050/Meanwell ( far right ) driving a pair of big Advents I recently refurbished. My immediate reaction was the edginess in Norah voice was smoothed out but without any loss of detail. Fingers sliding over guitar strings were less harsh and steely. An over all buttery smooth presentation that I could hang with for hours without fatigue. I have no complaints with the $50 Pre in this set up other than the limited range of the volume control. A slight turn will increase the level dramatically but I can live with that considering how inexpensive it is. Overall the $50 Pre is the more pleasant sounding of the two. The Aric has Amperex Orange Globes while I'm yet to replace the stock Chinese tubes in the $50 Pre. Maybe there's something to this Matisse circuit :D

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OK I lied. This $50 3 tube preamp actually cost $58.88 with free shipping. Still worth that and a lot more. For anyone buying this 3 tube model ( 2 6n3 and 1 6Z4 ) with the 110 transformer I decided to list which wires go where.

Looking down on the tranny with the two red wires on the left side and next to the preamp which is facing forward the tranny wires are connected to the screw downs in reverse order.

Last blue wire closest to rear of unit connects to first screw down closest to front of unit and so on. Following this order the one black wire will be connected to the screw down marked GND.

Some of the transformers may have different colored wires but this one has 2 red wires which are connected to the 110V source, 4 blue wires and 1 black wire. Just like vintage gear there is no ground provided with the power cord wires.
 
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