DIY Audio Projects Photo Gallery

Phono Preamp Ki.

Thu, 21 Aug 2008 00:03:31 GMT

The cct. brd was assemble and the ABS plastic case drilled ready for assemble. ABS is a very hard plastic to drill. Before assembly the lid, base and sides were lined with heavy tar and foil stick-on shielding. This helps with case dampening also. All gold RCA connections were kept to the rear (see other photos). The chips are the LM833s but the Burr-Brown OPA2134 high performance chip can be directly substituted. The on-board +/- 12V regulated PS is shielded from the rest of the sensitive cct. Additional snubbing was added to the line caps to remove PS noise and chip RF decoupling. Though three different compensation can be selected from the cct. brd by moving two jumpers the lid must be removed to do this. A double pole rotating three position switch could be added to provide this facility externally. The cct. includes a gain control which is accessed from the front and allows easy and silent level adjustment. The sound is natural with no hiss or hum. Easy to build.
6 views
Aug 20, 2008

DIY Phono Preamplifier Kit

Wed, 20 Aug 2008 23:47:32 GMT

The finished kit (see other photos) can be assembled in an afternoon. I used insulated gold plated RCAs but on an ABS plastic case like this insulated RCAs are not required. Keeping all connections on the rear makes for a simple front panel with gain control and recessed red led. I used thick silicon stick-on feet to ensure vibration into the unit is kept to a minimum. Stick down computer stand-off hold the cct. brd. to the bottom of the case and also help with vibration control. The case is lined with heavy sticky tar and foil. Base, sides and lid and are lined but not earth. This helps with shielding the low voltage levels and case dampening also. Shielded wiring is used internally and silver solder used throughout.
4 views
Aug 20, 2008

Phono Preamp Kit with RIAA Equalization

Wed, 20 Aug 2008 23:36:18 GMT

After resurrecting the Rega TT and RB300 tone arm with a Grado Sonata wood body cartridge I went on the hunt for a phono preamp. The Pro-Ject PhonoBox SE preamp was a value for money purchase, a neat and good sounding unit. This phono premp kit cost under $AU100 to build (including AC adapter) and challenges the Pro-Ject on a the sonic level. I can find no fault musically with the kit which has no hiss or hum and a natural sound quality. It is available from Jaycar Australia. Better than the Pro-Ject by provide the facility to have three different selectable compensations including RIAA and early DECCA (ffrr) and a host of others to select from. And to go one step better again there is a gain control to balance between CD and phono input levels. The case is ABS plastic and tar and foil lined. Gold RCAs used (see other photos). A +/- 12V regulated PS is include on the one peace cct. brd. The PS is shielded. Distortion is rated at .014% and RIAA accuracy is better than 1db. Signal to noise is -84dB.
2 views
Aug 20, 2008

Jordan JX92S Transmission Line Loudspeakers

Wed, 20 Aug 2008 05:44:34 GMT

The Jordan JX92S fullrange drivers in solid oak MLTL cabinets. These sound great. See my site for more details.
10 views
Aug 20, 2008

Jordan JX92S Transmission Line Speakers

Wed, 20 Aug 2008 05:42:37 GMT

Pair of Jordan JX92S fullrange drivers in a solid oak loudspeaker enclosure. The enclosure is the MLTL 48 transmission line design with a slightly smaller cross-sectional area. More details and pictures are available at my site.
11 views
Aug 20, 2008

Capacitance Multiplier Power Supply For Class-A Amp

Tue, 19 Aug 2008 04:23:05 GMT

Using Rod Elliot's Capacitance Multiplier Power Supply with Mark's DIY Class-A 2SK1058 MOSFET Amplifier.

This is a big improvement in heat dissipation, but I still may make more improvements to make it run cooler though.

I'm considering adding some kind of impedance matching to the passive preamp I'm using for it. Nelson Pass has one at his website I might try.
16 views
Aug 19, 2008

Fonken Speaker Enclosure for Fostex FE127E

Sun, 17 Aug 2008 16:37:48 GMT

A pair of Fonken speaker cabinets for the Fostex FE127 fullrange driver. So far they sound very nice.
38 views
Aug 17, 2008

OPA2134 Opamp Preamp - Big Brass Knob

Thu, 07 Aug 2008 03:25:18 GMT

My third Burr-Brown OPA2134 based preamp sees a sleek red die-cast aluminum case of two coats of epoxy paint and a sexy 4 oz brass knob. This build is based around the 1uf Jupiter Bees Wax and Paper caps. See other photos for more info. The first thing I notice when playing this preamp through my valve monoblocks was a dramatic increase in bass. The other obvious audio advantage is an increase in stereo focus. Not only is bass deeper (and louder) but there appears to be more layers to it. Voice sounds earthier and more immediate. A 26V 3.5A computer PS powers the unit but each channel has its own and separate virtual PS. Five 220uF low ESR caps store power directly on the cct. brds. A suspended wooden floor in the case provides a base to suspend the cct. brds on. Silver wire and silver solder is used throughout with an Alps blue velvet attenuator. Very impressive sound. The very best one I have made to date.
69 views
Aug 06, 2008

OPA2134 Opamp Preamp - Bees Wax Paper Capacitor

Thu, 07 Aug 2008 03:10:26 GMT

This is the third of these diy opamp preamplifiers I have made using the Burr-Brown OPA2134 chip. In this build as with my last (which was sold to an audio buff in Denver) I included two switchable inputs. I used 1uF Bees Wax and Paper Jupiter caps (see other photos) which have increased the bass depth a lot. A lot of resonance dampening has been employed. This is a smart looking and very smart sounding preamp. The stereo focus has increased dramatically.
58 views
Aug 06, 2008

Jupiter Bees Wax and Paper Capacitors - OPA2134 Opamp Preamplifier

Thu, 07 Aug 2008 03:01:32 GMT

When you get bored with high voltage valve amplifiers you start to look to other things to get your audio gear junky fix. I have always like the weird combos of materials in coupling/audio caps. I started with Jupiter Bees Wax and Paper caps and built a preamplifier around them. They are the dynamite sticks you can see. These are hand made and have silver connecting wire. Pure silver wire was used throughout and silver solder. Alps blue velvet attenuator and gold plated RCA add to a rich mix of components. The active bit is the Burr-Brown OPA2134 in milled sockets. Two sets of inputs are switchable and each channel has its own virtual power. This unit runs from a 26V 3.5A computer power pack. A timber suspended, tar and heavy Al foil dampened floor provides the base for the cct. brds. which sit on standoffs and are rubber grommet dampened. The lid and base of the thick die-cast aluminum case are also tar and foil lined.
86 views
Aug 06, 2008

Fostex FE127E Sealed Bipole Loudspeaker

Wed, 06 Aug 2008 02:28:02 GMT

My version of the DIY Fostex FE127E Sealed Bipole Speaker build.
85 views
Aug 05, 2008

DIY RCA Interconnect Cables

Wed, 06 Aug 2008 02:25:37 GMT

24ga shielded silver plated OFC copper twisted pair with teflon dielectric. Machined RCAs and hardware are from surplus auto interconnects. Including TechFlex and heat shrink, these cost under five bucks.
47 views
Aug 05, 2008

YAHA Headphone Amplifier

Wed, 06 Aug 2008 02:23:11 GMT

Here is on of my YAHA builds, I have never been a fan of Altoid tins. Later I used the Yaha voltage gain stage in my 12AU7 Tube / IRF612 MOSFET Hybrid Headphone Amplifier project.
35 views
Aug 05, 2008

6T9 Tube Amp with Edcor Output Transformers

Mon, 28 Jul 2008 06:10:22 GMT

The addition of the Edcor OPTs (XSE15-8-5K) has allowed this little amp to perform to its full potential. -3dB points are 30Hz and 20kHz and though the 1kHz square wave is a little wobbly, the amp plays well with good bass and lots of treble. See the 6T9 Tube Amp Project page for full details.
46 views
Jul 28, 2008

DIY Tower Loudspeakers

Tue, 22 Jul 2008 18:17:00 GMT

The empty front panel close-up !
107 views
Jul 22, 2008

DIY Folded Horn Tower Speaker

Tue, 22 Jul 2008 18:16:24 GMT

Here is a front close-up of the tower speakers !
101 views
Jul 22, 2008

DIY Towers Speakers

Tue, 22 Jul 2008 18:16:00 GMT

This is the DIY folded horn tower speaker that I did recently !
114 views
Jul 22, 2008

DIY Speaker Cable

Mon, 21 Jul 2008 13:45:46 GMT

The cable in the beginning of the project.
67 views
Jul 21, 2008

DIY Speaker Cable

Mon, 21 Jul 2008 13:45:22 GMT

This is DIY Speaker Cable that I made for a friend.
This is the regular twisted pair design with the double shielding. I've used the regular heat shrink tube for the primary shield and nylon braided sleeve for the secondary shield.

The ends are terminated via plastic banana pins.
64 views
Jul 21, 2008

DIY Speaker Cable - Twisted Pair Design

Mon, 21 Jul 2008 13:44:22 GMT

12AX7 Valve Preamp in Twinings Tea box

Wed, 16 Jul 2008 00:21:45 GMT

This is the fourth 12AX7 tube based preamplifier kit I have built. A Twinings presentation tea box was used as the case (similar to my Gwado CMoy / Grado RA1 Headphone Amp) with a remote PS. Cardas caps were used, all pure silver wire, silver solder, Alps blue velvet attenuator and 4 oz brass knob. The rear has a terminal strip for all the connections and the case is lined with a tar and aluminum film. The power supply has speaker absorbing vinyl lining it to ensure the switch mode tranni remains quiet.
76 views
Jul 15, 2008

Wooden boxed 12AX7 Tube Preamplifier

Sun, 13 Jul 2008 10:09:31 GMT

This is my fourth of these 12AX7 valve preamp kits in which I built it in a wooden tea box and used Cardas Capacitors. The connections to the timber box are made by a 3mm think aluminum strip.The remote power supply is hard wired to the preamp via a short cord. This preamp has brought an element of focus to my 6T9 Tube Amplifier, Fostex speakers and from early listening, greater detail across the board.
66 views
Jul 13, 2008

TQWT for the Fostex FE103E

Wed, 09 Jul 2008 17:09:24 GMT

A nicely finished Tapered Quarter Wavelength Tube (TQWT) Loudspeaker from Japan. The enclosure is for the Fostex FE103E Fullrange Speaker driver.
190 views
Jul 09, 2008

Bookshelf Sized Spiral Horn with Fostex FE103E Driver

Wed, 09 Jul 2008 17:03:04 GMT

A nicely sized bookshelf single driver speaker system from Japan. This loudspekaer uses a spiral horn enclosure for the Fostex FE103E Fullrange Speaker.
197 views
Jul 09, 2008

Single Ended 50EH5 Tube Amplifier

Wed, 09 Jul 2008 16:58:03 GMT

A DIY SE Tube amp from Japan using 50EH5 vacuum tubes. Similar in design to this DIY 50EH5 Single Ended Tube Amplifier project. Editors Note: I've seen these used before in Japan without an isolation transformer, but for safety reasons, please use a power transformer.
76 views
Jul 09, 2008

OPA2134 Inside the Chip amp preamp II

Tue, 08 Jul 2008 07:48:44 GMT

You can see how compact the boards are. The yellow caps are MPX 0.47uF and 220uF low ESR electrolytics store power from the voltage divider network (virtual ground). Computer stand-off keep the brds. off the case and are fitted with rubber grommets to control cct. resonance and vibration. More details are available at the DIY OPA2134PA Preamplifier Project page.
93 views
Jul 08, 2008

OPA2134 Preamp II with selectable inputs

Tue, 08 Jul 2008 07:39:25 GMT

OP amp based preamp, that provides two pairs of selectable inputs, volume and balance control and 6dB of gain. A compact cct. with the only links on the cct. brd. being silver earth links, packs a lot of performance into a solid cast aluminum case. With distortion figures as low as .00008%, solid pure silver wire throughout, WBT silver solder and each of the the two circuit boards having their own virtual +/- power supply plus additional tar and aluminum damping/shielding internally this preamp can deliver. I hope the new owner enjoys listen through it as much as I have enjoyed building it. See the DIY OPA2134 Preamplifier page for more build details.
81 views
Jul 08, 2008

Burr-Brown OpAmp Preamp II

Tue, 08 Jul 2008 07:17:55 GMT

This is the second of my preamps based on the high performance Burr-Brown OPA2134PA. This one has been custom built for a fellow in the US. This build has additional and switchable inputs-as you can see. The bottom and center row of inputs are selectable by the switch, the top row of connections is the output. See the DIY OP Amp Based Preamplifier page for more details.
82 views
Jul 08, 2008

DIY EL84 Push-Pull (PP) Tube Amplifier

Tue, 08 Jul 2008 02:51:32 GMT

EL84 Push-Pull Tube Amplifier constructed following Bruce's DIY EL84 Push-Pull Tube Amplifier Project documentation.
71 views
Jul 07, 2008

6BQ5 / EL84 Push-Pull (PP) Tube Amp

Mon, 07 Jul 2008 04:16:20 GMT

Tube amplifier built on the basis of the Schematic from 6BQ5 / EL84 Push-Pull (PP) Tube Amp.
70 views
Jul 07, 2008