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Boozhound Labs Phono Preamp Kit

IMG_0426I know.  The grey box above ain’t much to look at in the abstract.  But, it’s what’s inside the box that we are concerned with today.  Jsn at Boozhound Labs (hf ‘BHL’) sent me one of his new “JFEt Phono Preamp Kits” to check out, and I’m glad I did.  It was a quick+ easy project that has greatly improved my LP listening situation in the living room mini-system.

IMG_0455Above you can see the BHL preamp right beneath a little stereo power amp (with A/B input select and a stereo volume pot).  The power amp is a design that I have built dozens of times for clients: a single 6SN7 is shared to provide one voltage-gain stage per channel, with each channel using a 6L6 (cathode biased) class-A to provide approx. 8 watts of power to each speaker.  Just so you know where I’m coming from, here’s the complete setup:  ADC QLM 30 mk III cartridge mounted on a Technics 1200 table, then into the BHL, then to the SE 8-watt power amp, and finally to JBL 18ti speakers.  Very circa-1980.  The other input of the power amp is connect to an Apple Airport Express so that I can stream music off the iPhone or the macbook.  Certainly not an audiophile setup, but I’ve never found it lacking.

IMG_0425The BHL kit ($89 direct) comprises the board that you see above, all the parts to stuff the board, instructions, and a bunch of good quality wire.  I supplied the Hammond steel chassis and bottom plate and the vintage-style lamp holder and big power switch, plus a $13 24v switching power supply from eBay, some El Cheapo-brand dual RCA jacks, a binding post, and a goofy old Amphenol connector to mate the power supply.

IMG_0427Note that since this thing is running at 24V, I had to try to find a 24v bayonet bulb for the vintage-type jeweled-lamp.  Don’t use a 6.3V bulb from yr parts drawer here!  It will not end well.  Luckily, MCM electronics had 28v bayonet-base bulbs (the closest value that I could find to 24v) for just a few cents.  Anyhow, I went through this trouble since I wanted the BHL preamp to match the appearance of the power amp perfectly, but you could easily build this board into whatever you want.  Here’s a dude on Instagram who went for more of an ultra-modern/brutalist look for his build.  Point is, you can do whatever you like as far as the visual aesthetic yr after.   I probably spent about $50 for the non-included components for my build.

The circuit is super-simple and it’s very very easy to assemble. The BHL site has a transcript of the directions that come with the kit if yr curious.   It took me less than an hour to solder all the parts together.  As Jsn explains on his site, “This is just about the simplest circuit possible that will accomplish what we need – reverse-RIAA equalization with gain. This is 2 JFET gain stages with a passive (no feedback) RIAA equalization network sandwiched between them.”  Simple as it is, the components included are of a very high quality.

Now, I was replacing a very cheap phono preamp with the BHL (I had been using a $50 Rolls VP29), so keep that in mind – but here were my initial impressions, which the past month of 4-hour-per day listening has proven to be (subjectively) correct:

*The sound is very good; the low end is a bit more even and less ‘rolled off’ versus the ROLLS preamp.  Vocal-area midrange is a bit more forward.  The high end seems to sound about the same, but the cartridge/LP is probably the limiting factor as far as treble.

*The biggest improvement is that the self-noise of the BHL is so much lower.  And there is less hum.  So overall there is really a huge difference in terms of background noise, which just brings out so much more detail in the music.  And honestly, I never even thought that my ROLLS preamp was noisy until I installed the BHL.

*Gain is a little lower than the ROLLS that it replaced (maybe 2 or 3 dbs).  Not ideal, but not a huge deal.

Full disclosure, and maybe this is unnecessary: Jsn provided the kit to me at-cost.  That being said, at the street price of $89 I do still think it is a very good value.  If yr thinking of testing the waters of Audio DIY (and you like listening to LPs…), I could not think of a better place to start.  Jsn is a great guy, and it was his old BHL blog that was one of my greatest inspirations in starting PS dot com; so if you dig this website, support the dude and get yrself some upgraded sound in the process.

Boozhound Labs

5 replies on “Boozhound Labs Phono Preamp Kit”

Very Nice.
I need something with a USB out.
My daughter is getting married…she wants me to record a bunch of “older music” for her. So I need to be able to get many of the songs that I have on vinyl, from the records and into my computer.
I suppose it will be best to buy a preamp for this application.?
Thank You

well,,, yr gonna need a phono pre and an audio interface. As far as phono pre, yes i highly recommend this one if you have the desire and skills to assemble it yrself. c.

Non so dire niente riguardo il mio vecchio pre mm, in merito alle sue caratteristiche tecniche, so che era artigianale e suonava molto meglio del modulo MM inserito nel mio amp nad 3020. Con il tempo, salita la mia competenza, aggiornai i componenti con apparecchi più performanti, intanto cresceva il numero delle mie testine MM. Oggi mi trovo tra le mani questo Boozhound, dopo averne studiato in profondità le caratteristiche e apportato le sogettive migliorie nel montaggio, devo riconoscere la bellezza del suo suono che riesce a restituire, dopo le mie attenzioni maniacali, un grande “piccolo”pre che mette in risalto particolari importanti nascosti nei solchi dei dischi neri, che non conoscevo, risultando piu silenzioso, meglio appagante e coinvolgente, del pur apprezzato “vecchio” pre, versatile con l’opzione del cambio carico, mi fa ascoltere tutte le mie 17 testine, nel miglior modo. Sono felice!

English translation via Google: “I can’t say anything about my old pre mm, regarding its technical features, I know it was artisanal and it sounded much better than the MM module inserted in my amp nad 3020. With time, my expertise rose, I updated the components with devices more performing, meanwhile the number of my MM heads grew. Today I find myself in the hands of this Boozhound, after having studied its characteristics in depth and made the mounting improvements in the editing, I must recognize the beauty of its sound that manages to give back, after my manic attention, a big “little” pre that puts highlighting important details hidden in the grooves of the black disks, which I did not know, resulting more silent, better satisfying and engaging, than the appreciated “old” pre, versatile with the option of load change, makes me listen to all my 17 heads, in the best way. I’m happy!”

I scratch-built this phono preamp from a circuit diagram at DIY Audio Projects. Even working with a perforated board, it wasn’t a difficult build. I went nuts with premium parts: Mills, PRP and Vishay S-102 resistors, mostly film and foil capacitors in the signal path, and solid silver, shielded, hook-up wire. For the power supply, I took an Antek toroid transformer rated at 50W (because over-size transformers sound better) and built the section with numerous inductor-capacitor stages and an LT1084 voltage regulator. Truly, I’m glad that I went to such effort, because the Boozhound really delivers. Subjectively, it has a ruler flat frequency response, very low noise floor, and oodles of detail. This is the first solid state component I have built, and the first one that I would place on the same level as tube components. In fact, it’s quieter and more detailed than my homemade tube phono preamp, based on a circuit from the RCA Tube Receiving Manual. Yes, the tube phono preamp has that certain je ne sais quoi – mainly harmonic richness, but it’s fair to state that it comes at the expense of ultimate detail. I swap between the Boozhound and tube preamp depending on my mood, and regard them as different, but equally good.
It should be mentioned that the voltage gain of the Boozhound is a little on the low side, measured at around 33 dB; whereas, most commercial moving magnet stages have a gain of 40 dB or more. My guess is that in 99 out of 100 cases, this is a non-issue, especially if there is an active line stage between the Boozhound and power amp.

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