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Old 19th December 2013, 02:16 PM   #1
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Default Boozhound JFET Phono Pre Build

A couple of my friends are kind of on the fence about DIY'ing a phono preamp so I'm walking them through one I just happen to be building. I thought I'd share the process here, too. It's a Boozhound Labs JFET. It arrived quickly and everything is pretty high quality. Jason/Boozhound even threw in some nice hook-up wire (Teflon, maybe?).

Phono kit arrived yesterday and I simply couldn't resist getting to work on it (though I'm still waiting on power supply parts and a chassis).

All this in a single beer (though not the first of my night).

Separated all the components and laid out the values (less than 50 parts overall):
Click the image to open in full size.

Started with resistors. I bend the legs out slightly so that they stay flush with the board when I flip it to solder. I like to solder from the bottom with boards like this (holes are through-plated). Solder first, then clip the excess component legs. You see the corner of the schematic on the right; it took me a minute to realize that there are two R1's, R2's, etc on the board (the schematic is one channel or half the board). Same steps and approximately same layout each channel.
Click the image to open in full size.

Here's all the resistors installed and a couple of the first NOS Russian Paper-in-Oil capacitors (the big guys). I do touch up any soldering on the top if it hasn't flowed through board well or looks goopy (technical term). I like to see the pads on the top as well as the bottom with some solder on them.
Click the image to open in full size.

Here's all those totally sweet vintage capacitors installed. They have some beefy legs, so they may need a judicious application of heat to get the solder flowing well.
Click the image to open in full size.

And the electrolytics. The board does not have + and - marked on these holes (and it needs to be installed in the right orientation), but the square pad should be + (with board-in-hand, you can see that the other pad just connects to the ground plane on the back of the board). Also nice caps (Nichicon Muse).
Click the image to open in full size.

And the pièce de résistance. Flat side of the transistors goes towards the flat side of the silk-screened symbol (away from us in this picture). These were the trickiest thing to solder, just because the pads are small and close together. Patience and a little gymnastics with the transistor legs to get it to sit still works wonders, though.
Click the image to open in full size.

I did find a 12VDC wall wart power supply in my box of junk, but I don't have the correct jack and I don't want to cut the end just to test this board. I'll need some odds and ends when my power supply parts arrive anyways, so I'll probably pick up the right jack for my wall wart this weekend to hear the difference between 12V (wall wart) and 18V (what I'm building) on this board.

I bought an 18V PSU from Glass Labs because I've always drooled over John's Aikido kits. I don't really *need* a preamp so at least I'll buy something from him and get to see the boards/parts/service. Should be here soon.

Last edited by Sodacose; 19th December 2013 at 02:31 PM. Reason: I may be slightly hung over. Appropriate.
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Old 19th December 2013, 04:36 PM   #2
jsn is offline jsn  United States
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Hi Sodacose,

Looks great so far. Nice writeup (and nice choice - those Ranger IPAs are tasty).

One other trick I would like to add is that you can install the 1/2" standoffs upside-down (screws on the bottom of the board) so that the board has a nice steady base to sit on while you are soldering.

The entire bottom layer is a ground plane, which is great for noise, but can absorb a lot of heat, so be sure to use a relatively high power soldering iron and make sure the grounded pads flow nicely.

Good point about the polarity of the electrolytics. The input and output connections can also be confusing. Be sure to look at the traces to see which one is signal and which one is ground.

The wire I include is untinned copper with teflon insulation. Pretty good stuff.

And one last tip: I am offering free shipping in the US on boozhoundloabs.com to encourage folks to use my site.

I'll sub to this thread if anyone has any questions.

Thanks,
Jason
boozhoundlabs.com

Last edited by jsn; 19th December 2013 at 05:00 PM.
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Old 19th December 2013, 06:07 PM   #3
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Jason-

Cool, thanks for the tips! I did notice the I/O connections, but it was clear what was grounded and what was signal. I'll be sure to mention that when I'm casing this bad boy up.

That Ranger IPA was the cool down after a Rampant IIPA (8.5% ABV!). If I can successfully build this after that, it should be easy enough for my buddies to tackle.
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Old 21st December 2013, 12:30 AM   #4
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Progress!

My power supply bits haven't arrived yet so I, being the impatient DIY'er that I am, have forged ahead with junk bin stuff to get this kit working.

I found a 12VDC wall wart among my equipment, which only left a handful of RCA's and a power jack to at least get the board working. I'll save you the gory details of my cannabalistic spree through old unused projects, suffice to say I got what I needed.

First step, to get this board working at least temporarily, was stripping an old cheap RCA cable for the output and soldering it into the appropriate spots on the board. The shield went to ground, whose location is obvious when you flip the board over and see which hole is connected to the big ground plane on the back:
Click the image to open in full size.

And the back (ground on the left pad):
Click the image to open in full size.

Next up: a power jack for my 12VDC wall wart. If you think it looks blurry in the pic, you should see it in real life after a couple of beers (not pictured):
Click the image to open in full size.

Finally, here's the very nice Teflon-coated hook-up wire that's included in the kit. It may be a PITA to strip, but it's good stuff. Input pads are similar to the output pads; just check to see which connects to the ground plane on the back of the board:
Click the image to open in full size.

And we're ready to rock (cheapo scavenged RCAs shown here):
Click the image to open in full size.

I plugged it in. And...PANIC! HUMMMMMM!

Oh wait, I forgot it's held together with bubble-gum (for the moment). A repositioning of the power jack and all is silent again.

Until the needle hit the vinyl...

Last edited by Sodacose; 21st December 2013 at 12:35 AM.
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Old 21st December 2013, 03:42 PM   #5
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I spun several vinyls last night, testing the Boozhound with my temporary 12V setup. I also own a Hagtech Bugle (Gen 1), so I've got an appropriate DIY point of comparison in both size and price. The Bugle is opamp based and one of the reasons I built the Boozhound (other than for fun) was to hear what JFETs do. Here's initial impressions at 12V on the Boozhound:

Setup: Ortofon 2m Blue>Rega Planar 3 (motor upgrade)>Bugle/Boozhound>Tubelab SSE ("Winged C" EL34s and Edcor OPTs)>Klipsch Heresy IIs (titanium tweeters and rebuilt crossovers)

Noise/hum: after futzing with the power jack a bit, I got a very silent background out of the Boozhound. My speakers at the moment are Klipsch Heresy IIs, so they're quite sensitive. Because of the temporary nature of the Boozhound at the present, I didn't go all out to find noise; but noise didn't seem to be finding me, either. Too early to call, but I don't find anything inherently noisy about the Boozhound. My Bugle is very quiet, though not completely silent (I will revisit this later).

Bass: The Bugle has nice, solid bass. I found that the Boozhound has perhaps less 'slam' but better texture. The instrument --be it upright bass, synth bass, electric bass, organ, etc-- is more easily identified with the Boozhound. Higher voltage may bring the Boozhound's impact closer to the Bugle (which has a bipolar +-15V PSU).

Mids: Again, textures seem to shine through a bit better on the Boozhound and instruments seem a bit better separated. The Bugle gives more weight to vocals, at the expense of airiness and detail. What one prefers is, at this point, a matter of personal opinion.

Highs: Here's something I always found slightly lacking with my Bugle, and the Boozhound goes a long way to giving me my fix. Acoustic guitar, cymbals, misc percussion all sound more lively with the Boozhound.

Soundstage: Tough call. The Bugle's solidity of presentation puts the music right there in front of you. The Boozhound, on the other hand, paints a more delicate picture with additional reverb/room information. While this is still a somewhat premature comparison, I think each phono preamp will have its preferred genre.

Gain: The Boozhound requires a few extra degrees of rotation out of my Tubelab SSE's volume knob at this point, but it wasn't a problem with my 5.5mV MM cartridge. I'm not sure how higher voltage will affect this.


I should mention that I built the Bugle quite a while ago and I did not go all out on components (other than swapping some opamps). The second generation Bugle has been getting some praise on the boards, but I don't believe the RIAA or gain portions have been appreciably changed (I think the revision was mainly to the power section). If it weren't for my curiosity about JFETs and PIO caps, I would have built a Bugle 2 in a heart beat. It has served me well.

Once I build the 18V power supply for the Boozhound and case it up, I'll revisit my Bugle and see what my subsequent years of DIY experience since building it have taught me. I'm sure there's some low-hanging improvements waiting for me.
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Last edited by Sodacose; 21st December 2013 at 03:51 PM.
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Old 21st December 2013, 05:27 PM   #6
Neville is offline Neville  United States
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Nice step by steps. I built mine several months back and have it running off rechargeable batteries. A very nice laidback preamp. Jason also sells a moving coil preamp kit which attaches to this board.
I built it but found it had too much gain for my Dynavector 12x5...but at least I know I have it if/when i go back to low mc.

Last edited by Neville; 21st December 2013 at 05:33 PM.
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Old 21st December 2013, 05:39 PM   #7
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Hi Neville,

Good to know about the Dynavector (I've looked at that cart in the past). I assume you mean you're no longer using the MC kit with it, but still using the regular Boozhound RIAA?

How many volts are you supplying?
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Old 22nd December 2013, 08:56 PM   #8
Neville is offline Neville  United States
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Correct, using the regular Boozhound. I am using 2 x 12v batteries.
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Old 24th December 2013, 04:00 PM   #9
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I received the Glass Wares H-PS-1 PSU a couple of days ago and, again, I'm very impressed with the quality of the board and components. If looks are any indication, this is going to provide rock solid power. I bought the kit configured for 18V.

First, I stuck all the diodes in the board, making sure to pay attention to the orientation. Check out the board thickness on this bad boy!
Click the image to open in full size.

And the flipside with rectifier bypass caps and resistors (which set the ratio on the LD1085). You can see that this board is configurable in several ways (note the extra pads for the capacitors). It can be setup as a voltage doubler, full-wave rectifier and for use with a center tap; this gives you quite a range of transformer options (and voltage options using the LD1085).
Click the image to open in full size.

Speaking of which, here she is. The kit comes with a bolt, nut and washer, but also an isolation nut and film so that the regulator is not touching the heatsink. Repeat, the regulator is not touching the heatsink!
Click the image to open in full size.

And the board, now with the electrolytics installed, ready for the regulator:
Click the image to open in full size.

Somehow, I managed to not take a picture of the finished product! You can imagine, I'm sure.

I'm still waiting on my chassis because I ordered something custom to match my tube amp. Once it's here, the next step is casing it all up.
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Old 12th January 2014, 04:19 PM   #10
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Boozhound JFET is now up and running on 18V and, so far, I like what I'm hearing. A lot.

Unfortunately, the custom chassis for it fell through. But this is DIY after all, isn't it? So I purchased a Hammond aluminum chassis of approximately the correct dimensions and cut a couple of walnut end panels. The result is as good as I could have realistically hoped for:

Click the image to open in full size.

That's the preamp under my Tubelab SSE (KT88s atm) and on top of my Rotel CD player. The CD player will likely go into the cabinet they're sitting on. The negotiation for this project hinged on cleaning up the stereo cabinet. In this regard, it's a success.

But how does it sound now that it's finished (for the moment, anyways)?

Noise/Hum: Record player spinning (without the needle dropped), volume knob on the SSE maxed, ear a couple inches from my 97db sensitive speakers, I hear a very, very faint hiss. This might be the tubes, or my record player or any number of things. For my intents and purposes, the Boozhound is silent. Of course, a masterful job of assembly and enclosure wiring didn't hurt.

The Boozhound, like the Hagtech Bugle I had in the system, also does a great job of minimizing snap, crackle, and pops from the records themselves. Motor sound from the Rega is minimal when the needle is dropped. All in all, noise being one of the big worries for many DIY'ers when building something new, I think this is an excellent design. If your Boozhound hums, I don't think it's the Boozhound's fault.

Bass: In terms of quantity, I find the bass to be well balanced here. One of the small faults I had found with the Bugle in my system was a tendency for it to sound heavy and ponderous, which I attributed to an overemphasized mid-bass. This worked for some types of music (classic rock), but was distracting with others (small jazz ensembles). The mid-bass hump with the Boozhound in my system is gone. "Slam" is down slightly, but it is still there when it's intended to be. Zeppelin II Side B still thumps you in the mid parts with the kick, but Ray Lamontagne Side B doesn't. I'm pretty sure that's how it is supposed to be.

No doubt owing to this balanced response, the quality of the bass with the Boozhound is also improved. The 'little things' that were before buried by the bass note fundamentals are showing up more consistently. There's more texture to piano's lower octaves and more mic-placement/room-acoustics with drums. As a musician, I like this. It seems to bring out just a bit more of what the artist intended.

Mids: More, more, more. Timbre, details, expressiveness. There are no more mysterious instruments with the Boozhound. Guitarists are all instinctively covetous of classic guitar tones and now I get it. This is ear-candy. Small percussion instruments are all distinct, strings can moan or sing. I can pick out the effects chain on a pedal board without trouble. The Boozhound is getting more life out of old worn vinyl than I thought was there to be got. I won't say more about the mids because every new record is a discovery of something else the Boozhound is doing right. Bravo.

Treble: I mentioned this when I tried the Boozhound at 12V and the same still holds true. Cymbals decay naturally, steel string guitar has more zip, Peterson and Milt Jackson are gods. A vibraphone doesn't ring, it tinkles and talks. This was one of the areas I always felt was lacking with my old Bugle (first generation) and so it's one of the improvements I'm most thrilled with.

Soundstage: The Bugle, with its solid bass and forward mids, threw a respectable stereo image, but it was limited to two dimensions. It was a front-row kind of performance. Loud, exciting, thick, unrelenting.

The Boozhound seats you a few rows further back, but now you're right next to the sound guy. Now you're getting the performance. The soundstage is as wide, but it has depth. This is one of those audiophile-isms that's hard to understand, especially with studio recordings. To me, it is the layering effect of multiple instruments recorded with different microphones in different spaces and how they come together in the mix-down and mastering process. This is what truly separates Alan Parsons or Bruce Swedien from so many other engineers and producers. Anyone can EQ; the construction of a soundstage is an art unto itself. Suddenly, with the Boozhound, this is something I can appreciate and wax poetic about on forums

Gain: At 18V I'm still turning a few extra degrees on my volume knob than I was with the Bugle. This might be the honeymoon, that I'm enjoying the tunes, or that it has lower gain. Intellectually, I understand that I'm probably burning up less gain with the volume knob this way and that's a good thing. But I've forgotten about the technicalities of it all and I don't care to ponder them too much. Higher praise to a piece of gear I cannot give.

For the price of dinner for two at a nice restaurant ($89), plus a clean 12V-24V of power (@ 50mA), the Boozhound JFET is an easy recommendation. Go build one.
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