DIY Audio Projects - Hi-Fi Blog for DIY Audiophiles: April 2011

12 April 2011

How to Solder - Comic Book Guide

There are a number of great soldering tutorials already available via the internet in the form of videos and webpages and today I came across another great soldering guide - this one packaged in a comic book format (see below for PDF download link).

The great new seven page comic book guide about how to solder has been put together by Mitch Altman (Cornfield Electronics) , Andie Nordgren and Jeff Keyzer (Mighty Ohm). The comic book guide is based on the popular one-page soldering guide below that Andie and Mitch made last year. (Click image to enlarge)

The Soldering Is Easy comic book guide is easy to follow and informative. The guide is published under a Creative Commons License and the link to the PDF version of the soldering guide is below.

Soldering Is Easy - Here's How To Do It

Soldering Is Easy - Comic Book Guide [PDF - 812kB]

07 April 2011

Feastrex NF-5 and NF-5ex Drivers at SSI 2011

We are big fans of single full-range driver loud speakers so we were excited to check out the Feastrex drivers. Michael Tang of Mike Tang Audio is importing the Japanese Feastrex NF-5 and NF-5EX drivers into Canada and had them on display at the show.

The 5" Feastrex NF-5 ($2000CDN, shown above) uses a large Alnico magnet. The handmade cones are made from Japanese Washi paper (a higher density fibrous paper) which is impressed in a spiral pattern with embossed ridges. The drivers surround is made from lamb skin.

The 5" Feastrex NF-5ex ($3000CDN, shown above) uses the same Washi paper cone and a lambskin surround, but with a motor that uses a field-coil magnet (electromagnet). The field-coil magnet can be operated between 10 and 17V dc. Changing the voltage allows you to change the damping of the driver. Michael uses a 12V car battery for the field-coil magnet. 16 ohms, 95 dB, 35 to 25,000 Hz (+/- 3dB).

A Mastersound Compact 845 SET powered the 5" Feastrex NF-5 drivers which were housed in a bass reflex enclosure (enclosure plans from Feastrex, shown below), no passive filters were used. The speakers sounded excellent, wide soundstage and impressive depth. The single drivers delivered superb clarity with vocals to die for.

Michael indicated that he is working on a transmission line enclosure design for use with the Feastrex NF-5 and NF-5ex drivers which he plans to have ready for the TAVES (Toronto Audio and Video Entertainment Show) this fall.

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Voxativ Ampeggio Horn Speakers at SSI 2011

There were a number of ultra high-end Hi-Fi systems at the Montreal show and like last year, my favorite Hi-Fi systems at the show was once again a low powered single-ended tube amp matched with high sensitivity fullrange drivers. My favorite this year were the new German made Voxativ Ampeggio single-driver rear-loaded horn speakers. The hand built rear-loaded horn enclosures are built in a collaboration between Voxativ and the famous German piano factory Schimmel Pianos. The cabinet surface is finished with a minimum of 13 applications of hand polished lacquer covered in real piano lacquer. The finish on the loudspeakers was simply amazing.

The product literature lists the following specifications for the Ampeggio:

Frequency Response: 38 - 20,000 Hz
Sensitivity: 101 dB / 1w / 1m
Impedance: 10 ohms
Dimensions (W x H x D): 16" x 43" x 14" (40 x 110 x 35 cm)
Weight: 121 lbs (55 kg)
Cost: $29,750US

The lone transducer used in the Ampeggio is the Voxativ AC-3X, which is their largest neodymium driver and unavailable for purchase. The drivers suspension is made from goat leather. The loudspeaker systems does not use any crossover components.

A Don Garber Fi WE421A ($3275) single-ended triode amplifier (a single dual triode), putting out just 5 watts per channel was used to drive the Ampeggio speakers. With a sensitivity of 101dB it was plenty loud. The high sensitivity and easy 10 ohm loads means these speakers will mate very well with low power SET amplifiers. The Ampeggio speakers sounded every bit as wonderful as they looked. Open, dynamic, excellent clarity and plenty of detail.

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05 April 2011

The AuDIYo.com room at SSI 2011

Like last year, the AuDIYo.com room was displaying a number of high-end audio accessories, cables, audio connectors, tweaks and DIY parts from Furutech, Mundorf, DACT, TentLabs, 1877Phono and others.

The AuDIYo show setup was focused around the recently introduced Furutech GT40 USB DAC with phono stage - $495. The Furutech GT40 USB DAC with phono stage was previously used with a computer to make vinyl rips into 24bits/96kHz lossless digital files. The digital files were then played back through the DAC which fed a vintage Dynaco ST-70 tube amplifier, which in turn drove a pair of Klaro speakers. The quality of the vinyl rips was excellent and if you were not paying attention you would think that you are listening to a record as the recording preserved all the surface noise, pops and clicks one would expect from vinyl. The Furutech GT40 USB DAC also features a very good headphone amplifier and a pair of Sennheiser HD598 headphones were on hand to audition the head amp section.

The vintage Dynaco ST-70 tube amplifier on had been upgraded with Mundorf high voltage filter capacitors and M-Caps were used upgrade the signal and coupling caps. Simon Au of AuDIYo indicated that they are working on printed circuit boards and customizable kits that can be used to upgrade ST70 amplifiers. We will post an update when we get word that the upgrade kits are available.

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04 April 2011

Solen.ca DIY Speaker Kit - SSI 2011

On display on the Solen.ca room was a new DIY bookshelf speaker kit that is currently being developed and should be available soon.

The DIY speaker kit will use a pre-finished curved Dayton Audio 0.38 ft^3 speaker enclosure. The drivers are from Airborne, a 120 mm wood cone driver with a 25 mm voice coil (HR124B8-10L) and the high-end is covered by a Air Motion Ribbon Tweeter (RT-20021). The kit will use a 2-way passive crossover which has yet to be finalized. No word on when exactly the DIY speaker kit will be available but Solen indicated that that the price of the kit will be about $550. As more details come available about the kit we will post an update.

Also on display were a number of drivers, amplifiers, connectors and feet for you DIY speakr projects.

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02 April 2011

Little Horn Speakers - SSI 2011

The unique looking "Little Horn Speakers" caught my eye and I was particularly excited to see they use a familiar transducer, the Fostex FE108E Sigma. While their size is far from what most would describe as a little speaker, they are little for a horn. [Click on the images to enlarge]

The custom handcrafted speakers are produced by Specimen Products from Chicago. The enclosure (base) is made using Baltic birch plywood and this acts as the compression chamber. The horn is cast using a heavy-duty resin and both the base and horn are finished with lacquer.

The overall height is 36" (915 mm) and the bell of the horn is 14" (355 mm) across. The base is an 8" (200 mm) cube. The impedance is noted as 8 ohms with a sensitivity of 90 dB. The frequency response is listed as 77Hz to 23kHz. The speakers are well suited for use with low power tube amplifiers.

The Little Horn Speakers delivered a surprising large soundstage and you get the single-driver finesse and detail that FE108E Sigma is known to deliver. The speakers retail for $2400 / pair are available in a number of colors. More information and photographs are available from Specimen Products website.

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01 April 2011

Orangutan O/96 High Sensitivity Speakers - SSI 2011

We have arrived at the Salon Son & Image 2011 show and have taken a quick look at the various exhibits. Since we cannot cover the entire show, we have decided that our coverage will be focused primarily around our favorite topics, DIY audio, high sensitivity speaker systems, headphones and vacuum tube gear. To get the show coverage started, here are the Orangutan O/96 Oscar loudspeakers (click image to enlarge).

The DeVore Fidelity Orangutan O/96 is a 2-way design that uses a custom SEAS 10" (254 mm) paper cone woofer with a phase plug. The tweeter is a 1" (25 mm) silk-dome tweeter that uses a double-magnet motor system and is gently loaded by a waveguide. The speakers are individually hand built in New York City and are listed at about $12,000US.

The sensitivity is noted at 96 dB and the nominal impedance is 9 ohms. The in-room representative indicated that the impedance does not drop below 7.8 ohms - so these speakers will be an easy load to drive. The frequency bandwidth is noted as 30 Hz to 31 kHz. The overall dimensions are 12" d x 18" w x 28.5" h (305 x 457 x 723 mm).

The speakers had a very nice coherent sound with holographic imaging. With the high sensitivity and easy to drive load, this speaker mates well with lower powered single-ended tube amplifiers.

More Salon Son & Image 2011 Coverage