Sometimes upgrading parts can change the flavor of the sound or presentation, but not necessarily "improve" the sound. Well, changing the standard, small wire inductors to these large Bourns low loss, high current output filter inductors made a nice improvement in the clarity department. These will definitely go on every Class D amplifier I build from here on out.
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".
I've fallen in love with the sound of vintage German alnico magnet full range speaker drivers. Vintage German drivers have exceptionally lightweight & rigid paper cones along with alnico magnets. The sound is the best I've heard from any full range driver. Hauntingly real midrange, smooth, yet delicate highs, and tuneful bass. In addition, absent are the annoying frequency peaks in the upper midrange that seem to plague so many modern full range drivers.
I recently acquired a pair of oval Telefunken branded alnico magnet full range drivers. My research indicates they were likely manufactured by Isophon for Telefunken. These drivers originated from a Telefunken console stereo and have a Telefunken decal on the Dortmund magnet. Having been impressed by the open back Saba bookshelf speakers (previous post), I designed an open back speaker box for the oval Telefunken drivers. I used 1/2" Baltic Birch as opposed to 3/4". I think this is important in achieving a warm, rich, natural timbre from the speaker system. The cabinets are made to be stand mounted, or placed on the floor and angled up.
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 circuit board was populated with Nichicon Muse power supply capacitors and Nichicon Fine Gold output filter capacitors. Gold plated RCA connectors were added. The meter is calibrated for use with a 12 volt power supply. (included) This amplifier is on display in the cafe' and is for sale for $135 shipped to anywhere in the U.S.
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.
This is a recently acquired WWII Western Electric panel meter. I'll use this in an upcoming amplifier build. It's very rare to find these in the original boxes, with the date and intended use. This meter, which has the U.S. Navy stamp on the back and a date of March 8, 1945, would have been used with a U.S. Naval Doppler Radar system during WWII.
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.
Bag-o-parts about to be turned into a living circuit.
My favorite solder for audiophile projects.
When my daughter was around the age of four, I let her play with my helping hands. She thought it looked like a robot, so she added a face. I've left him this way and every time I use it, I think of her at that age.
This Fleawatt amplifier was commissioned by Robbie, who is a member of the diy audio forum community. I left the hardware options up to him. Robbie decided to go with a Class D, Philips TPA3122D2 Jerry Electronics amplifier board, Elna Silmic II power supply capacitors, Elna Silmic II output filter caps, Neutrik RCA connectors, Dayton Audio gold plated 5 way binding posts, a blue LED digital DC voltmeter and a 12volt 7a/h sealed lead acid battery for power delivery. He is also requesting a dc connector and power switch. A cigar box is going to be utilized as they are attractive and cost $2. It's a fantastic enclosure when one is on a budget.
Parts are sourced from Parts Express, Jerry's Electronics and Parts Connexion.
Because a cigar box has thick sides, the wood thickness where the panel mount hardware is attached must be thinned down. I use either a chisel or a Dremel with a wood carving bit.
This is a TPA3122 with the power supply capacitors and output filter capacitors mounted on the bottom of the printed circuit board. There is a two inch diameter hole cut into the top of the cigar box. This allows for easier access to the volume control when using larger bodied capacitors. The DC input is on the back (shown) and a heavy duty toggle switch is on the side. Speakers are connected directly to the terminal blocks on the board, eliminating any sonic impact binding posts and wire terminations may cause. RCA inputs are also board mounted, eliminating any low voltage signal wire that is susceptible to RF or EMI. Nichicon Muse power and filter caps were installed on this board. This has become my very good friend Michael's reference amplifier. He has it paired with Frugal Horn Sachiko speakers (Fostex 206ESR) and a Garrard 501 with a tube phono preamp.
"So many differences between audio gear has to do with voicing, i.e. is about how the designer hears things and how his vision interacts with your system. You can’t simply buy a bunch of well-reviewed products and expect magic. There’s no better or worse. You simply like what the designer is doing or you don’t. Does his vision gel with yours?"
Jerry Electronics TPA3112 Amplifier kit modified with Elna Silmic II power and output filter capacitors.
Chassis made by God in Ohio. Solid Ash construction.