Patents & Awards
"Bugle" Phono ($29 kit/2) Order now!
The Bugle is a low cost solid-state phono preamplifier. It utilizes a split, passive
RC-type equalization network that offers excellent flexibility for customization.
The circuit is not the typical "feedback" type commonly used, but rather uses the opamps as
pure frequency-independent gain stages. Two of these gain stages drive the equalization networks
followed by a third gain/buffer stage to provide a low output impedance. The overall gain is
thus optimally split between the three stages.
The Bugle is only available as a half-kit -
a blank circuit board and plans, you'll need to buy the rest of the parts yourself
from DigiKey. For a fully assembled phonostage, see the new Bugle2.
Read Michael Fremer's review in Stereophile. Or this
Audio Asylum post.
PowerSupply kit now available! Read some actual
|Input Impedance||47k ohm plus 14pF|
|Output Impedance||330 ohms|
|RIAA Response||+/-0.5dB from 30Hz to 60kHz|
|Bandwidth (-3dB)||15Hz to 150kHz|
|SNR||74dB ref 5mV A-weighted|
|Battery Life||16 hours|
"Over time we were so pleased with the Hagerman that it became the benchmark for the others ... The clear
winner from this assortment was the Hagerman preamplifier ... Its performance was consistent across all recordings."
- John & Sandra Schubel
Using stock parts, the RIAA equalization response was checked using a 1kHz square wave.
Here's a bode plot of frequency response (+40dB gain) using the OPA2134 opamps. The -3dB points were 13Hz and
"PowerSupply" ($29 kit/2) Order now!
The PowerSupply is a regulated supply designed especially for the Bugle phono stage. It can be configured
for either 115Vac or 230Vac inputs. The circuit design uses both series and parallel snubber networks for
clean rectification and hash-free operation. Internal loading provides class-A operation for improved regulation.
The compact circuit board matches the Bugle in size for easy stacking.
Available as a "half-kit", this easy to build product can be applied to other applications requiring
clean regulated +/-15V supplies. Output current is up to 100mA on each tap.
|Output Voltage||+/-15V +/-5%|
|Output Current||0mA to 100mA|
|Size||3" x 5"|
- Just wanted you to know, I gave the Bugle another go this morning ... and it works wonderfully! I'm reallzy amazed
how much better it sounds than my old Carver preamp/tuner. Much fuller bodied with deeper bass and more inner detail.
You're really onto something with the Bugle. Quite a buy!
- I just wanted to tell you that I think that this is a very good product - it is easy to build, hard to screw
up, and it sounds great.
- Wow, now that's a quality lookin' board. Solid.
- I bought a Bugle from you the other day and it is great! In comparison to my control amp, a Bedini 66SPA, the Bugle
orders orchestral music better, has more detail and tighter bass, sounds "faster", and most importantly somehow puts the
"song" in music, perhaps with peppier rythm from better dynamic range. Thanks so much for making this phono preamp!
- Congratulations on putting together something that is so easy to build, even for a novice, it went together
easily and worked first time, it is also unbelievably quiet.
- Thought I would write to you and commend you on the excellent Bugle Power Supply kit. I built the unit this evening
and let it soak at full load current (300 ohm between outputs) for 1/2 hour to stabilize, and then took some data ...
Output noise [positive] 500uV and [negative] 650uV ... This is excellent performance and shows when competently designed,
the much maligned 78 series regulators are capable of outstanding results. The noise performance is particularly impressive
and shows you have reduced ripple to negligible levels. As an electrical engineer myself, I appreciate the fine quality
of the double-sided, plated through hole FR4 PCB, the neat layout, comprehensive documentation, and a parts list that can
be ordered in minutes from DigiKey. This is how all kits should be presented, and I have built a few in over 30 years of
- It sounds great - more of a difference than I thought, and honestly, I was expecting a lot.
- I then switched to shellacs. Wow! What a difference it makes listening to an old shellac with the
proper equalization! ... The Bugle Pro allowed me to hear the records as they were recorded. This is exactly what
I wanted the Bugle Pro for: to be able to listen to the 100 or so shellacs I have inherited from my Grandpa.
- I was really floored at how good this thing sounds!
- The quality of the circuit board is remarkable, and the layout of the resistors makes the assembly basically
idiot-proof. Your passion for electronics design shows through in the visual simplicity of the board itself and
in the sound the circuit produces. Well done!
- Well, I've learned a lot about electronics and vinyl through building the Bugle. That you make items like these
available at such low cost is awesome. The Bugle sounds great.
- Quality of layout and PCB is good! Round corners of the tracks is excellent way to do audio signal tracks! I like
the ground screw, too. Nice move!
- Just wanted to pass on that I've built my Bugle and am very impressed with your design. The Bugle is the first kit
I've ever built that has ZERO hum. As this is a phono pre, that's really saying something! THe sound is fantastic -
very neutral and 'organic'.
- It's great. It's better than great, it's amazing. It seems so transparent. I see people write about a
black background, but it seems like there's no background at all. A lot of detail, too. And the bass is
tight and controlled. I'm really pleased--this is a terrific phono stage!
- I received my Bugle last week and so far I am stunned. Wow. I didn't imagine it would sound this good.
Clearly the best upgrade I've ever made. LPs that I thought should beat their CD counterparts - but didn't
with my old equipment - are now clearly superior. More wows.
- You cannot imagine how happy I am with the inexpensive [Bugle] amp you designed and for which you
provided plans, boards, and front and rear panels. My girlfriend (a complete nontechie) and I (a total
techie) bought and built the preamp and have connected it to an Audiotechnica turntable that I bought for
$1 at a garage sale cause it didn't work (I fixed that), and an expensive cartridge. I have since blown the
socks off of everyone who has entered my home. I put a record on the table and show people a range not
equalled by any cd player in history. Joe Walsh, Styx, Stones, Zepellin, and Floyd have never sounded so
good and I want to thank you (and I am sure they would if they could hear this also). You are a god among
techs and I can't thank you enough.
- I finished the bugle, tried it and WOW!! Not only it works as the sound is beautiful so clear and spacious,
I’m really happy! Congratulations you created a great amp for the music lovers.
- I have experimented with the unit [bugle pro] for several hours this evening and am pleased with the
results. I ran an RIAA test record to check the accuracy of the RIAA curve and found it comparable with that
of the other RIAA preamps that I have been using. Similarly, the noise level appears to be right down where
it ought to be.
- It sounds great – it was fun to build, and I really enjoy the bang for the buck. Thank you for
engineering such a great product.
- My Bugle arrived, safely, at my home yesterday, very quick service and shipping! Better still, this little
pre-amp delivers a fabulous sound! I am running it into a refurbed Sansui 771 receiver AUX input, and there is no
comparison to what I was hearing from the 771's phono section. Very nice product, at this price point, staggeringly
good. Thanks again!
- I wanted to let you know I finished the Bugle Pro kit and it works great and sounds gorgeous. I made some
transfers from vinyl to digital at 192k/24 bits and the tracks sound wonderful. It's exactly what I was looking for.
- I just finished your Bugle and populated it with LM4562's. I've owned a number of decent quality preamps
over the years that included phono sections (Tandberg, Adcom, Advent, Halfer, Dynaco) . The Bugle bests them
all. It offers noticeable improvements in subtle details and sharpness with a full and tight bass to boot.
And all of this while being very musical, smooth and unfatiguing. I'm tickled. Well done!
- I finally got round to building the Bugle kit, but in the end used a +/-15v supply as suggested,
and wanted to let you know that it sounds excellent. Previously I had rated listening to my CDs and
records as similarly satisfying for different reasons - CDs for detail and dynamics vs. records for
warmth and coherence. However, I am getting far more subtlety, silkiness and coherence from the
records than I have experienced before, and suddenly my record collection is a bit special compared
with my CDs, offering a real sense of the presence of the performers. I am very impressed, particularly
for an item that cost so little and was so easy to build.