I recently built this Bottlehead Stereomour 2A3 amplifier kit. Changes from stock are the elimination of the 431 shunt regulators, the addition of an Alps Blue Velvet potentiometer, Audyn Plus coupling/parafeed capacitors and the elimination of the input selector switch in the signal path.
My best friend asked me if I would convert his non-working 1939 Zenith Model 7-S-363 into a modern stereo that he and his children can enjoy with their iPhone and iPod sources. My pal and I met in Ann Arbor, Michigan for the weekend and he handed over his Zenith to spend a few weeks in the Fleawatt Factory. The old components were gutted and a 12 volt powered 3122 Class D stereo amplifier was installed in the old chassis, along with an extended shaft 100K volume pot and new 12 volt dial lamps. Two audiophile quality Wild Burro Betsy 8" full range drivers were installed on a new speaker baffle board, replacing the 10" Zenith field coil driver. A small toggle switch was installed on the right side of the console and a 6 foot mini plug equipped cable connects to sources. Scratches and scrapes were stained and the finish was given a cleaning. The dial glass gasket had completely dried out and crumbled. A new one was ordered and installed. We decided not to replace the broken selector buttons as that would have added major cost to the project with no functional value. How does it sound? Great! It puts out some serious sound and can fill a house with music.
I recently built this pair of 5 watt, pure class A mosfet output mono blocks designed by the master, Nelson Pass. The "Amp Camp" amp kit is available from the DIYAUDIO webstore. The enclosures are made in Italy and the parts quality is very good. Dale resistors, a solid circuit board, etc. The sound is typical low watt Class A Nelson Pass. Several users who own the First Watt F5 report these mono blocks sound very similar. I thought they sounded great, but preferred the sound of the TPA3116 amps.
The enclosure of this amplifier was made from solid walnut and baltic birch ply. A vintage new old stock Simpson DC panel meter indicates the direct current to the amplifier. An Alps blue velvet volume pot is combined with a vintage faux bakelite knob. This amplifier is rated at 10 watts per channel when using a 12 volt power supply. Nichicon fine gold output filter capacitors and Bourn's low loss toroidal 220mh output filter chokes due the output filtration. Panasonic FC are used for the power filter capacitors. High quality Dale resistors are used throughout the circuit.
These open backed speaker cabinets are mated with Telefunken branded Isophon 6"x 9"
full range drivers and Foster horn loaded tweeters. A 2 ohm Mills resistor and .22uf paper in oil Russian capacitor does the crossover duties. The cabinets are 1/2" Baltic Birch coated with General Finishes Brand gloss water based polyurethane. Stands are 24".
This amplifier uses a Texas Instruments TPA3122 IC mounted on a Jerry Electronics printed circuit board. The power supply capacitors are Nichicon Muse 1000uf. The output filter capacitors are Panasonic FC 470uf. Speaker connections and RCA inputs are mounted on the circuit board. A 10K volume pot is also board mounted for the ultimate in signal purity.
This battery powered amplifier uses a Philips TPA3122D2 Class D board. Output filter caps are Nichicon Fine Gold & the power supply capacitors are Nichicon Muse. The working panel meter indicates the power supply voltage. A nifty machined aluminum volume knob completes the package.
RCA input connections and speaker wire connections are made right at the circuit board. The purest signal path possible.
These were a Craigslist find from the Detroit area. I'm now a Saba "junkie", which is bad as Sabas were never imported to the United States. I couldn't find much information on the Internet regarding these particular speakers. If you know the model number or date of production, please e-mail me.
The "story" that goes along with these is they belonged to the seller's friend, who was stationed in the US Military base in Germany. He brought them back with him. The seller believes they date from approximately 1959. I crossed my fingers when powering them up that a voice coil hadn't been damaged. My fears were alleviated when they began singing like angels. Amazing sonics.
My wife Carrie, who supports my diy audio hobby 100%, has been seeing quite a few desktop stereos leave the factory lately. "When are you going to build me one?", she inquired. With her significant input and assistance in the design, this Fleawatt powered desktop stereo was born. The fabric color was chosen to match her office at work, where it will reside. This particular stereo is powered with a TPA3110 5 watt per channel Class D amplifier. The speakers are neodymium magnet equipped Tang Band, audiophile full range speakers. A 1/8" mini plug and dc connector are mounted on the rear panel. Thanks for supporting my hobby Carrie & Happy Valentines Day!
This 15 watt per channel Philips TPA3122D2 IC is a step forward from a Tripath based chip. Deeper and tighter bass, better imaging, black background and incredibly accurate musical timbre.
This particular board has direct speaker wire terminals and RCA connections at the printed circuit board! No binding posts, no signal wiring from the RCA inputs to the volume pot and from the volume pot to the board. All of that, which is susceptible to EMI and RFI interference, is eliminated! The most direct signal path possible and the pinnacle of design for those of us who want the purest sound possible. This amplifier can be powered by and 12 volt or 24 volt DC power supply. Sealed Lead Acid batteries are the preference among my fellow fleas. This particular amplifier has upgraded Elna Silmic II capacitors mounted under the board. There is a hole in the box lid under the circuit board to permit the mounting of the board.
This was a commissioned build for my friend & fellow audiophile, Kurt, who lives in Ft. Wayne, Indiana. The amplifier and speakers will be used with his laptop as a desktop system. The Class D TPA3110 amplifier is encased in a round wooden "box". The amplifier is powered by AA batteries under the chassis, on top of the cradle. Easily accessible. A DC input connector was placed on the back panel to allow the use of a AC to DC power pack should he decide to forego the battery power. The amplifier is equipped with a power switch, volume control and mini input to connect to a laptop, phone or iPod/iPhone. Gold plated, audiophile quality binding posts & solid walnut cradles complete the package. The speakers are 3" Tang Band, neodymium magnet, audiophile full range speakers. The speaker cabinets are also veneer thin tube boxes. They have absolutely gorgeous tone combined with the Tang Band speakers.
After the hardware has been mounted, it's time to string it all together. I use twisted Cat5e wire for the signals and twisted 18gauge solid core copper for the power supply wiring.
One input means no switches and an ultra pure signal path.
This phono preamplifier was built using a Boozehound Labs phono preamplifier kit.
The capacitors used in this kit are all Russian paper in oil caps. The preamp calls for a 24 volt power supply, so it can be run from two 12 volt SLA's in series.
I built this pair of Frugal Horn Sachikos around 2006. This was one of two pair that I built.
This pair was made from Birch ply are equipped with a Fostex Special Edition 206 driver. The magnet on these drivers is nearly the same dimension as the cone. Giant. They are rated at 98db.
This pair now resides in a friend's home and are still playing sweet music.