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Informal Comparison of Six Phono Preamps

By | November 23rd, 2011|Categories: DIY AUDIOFILE|Tags: , , |

This is a project that sort of evolved from an interest to see how good a particular phonograph preamplifier was. Not the one I designed, but one from a DIY kit. If I would have known how difficult and possibly inconclusive it would become, I might have not done it. As it was, the experience was valuable in several ways. First let it be clear in everyone’s mind that this comparison is largely subjective and based on what I hear or can measure.Read the full article

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Knock-Down Birch Speaker Cabinets

By | November 12th, 2011|Categories: DIY AUDIOFILE|Tags: |

Speaker building is a lot of fun and there are many who would love to try it out but can’t due to some common woodworking hurdles.  You may not have the space, tools or skills necessary to build a good loudspeaker enclosure.  For others sawdust or climate (winter) could be the problem.  Fortunately there are some great solutions that can eliminate much of the woodworking necessary to build a speaker box.  For a number of years Dayton Audio has been producing pre-made speaker enclosures like the Dayton pre-made curved speaker cabinets which make it real simple to put together a great looking finished speaker.  Perhaps the only downside to the great looking ready-made cabinets is that they eliminate too much DIY and they are bulky to ship.Read the full article

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Groovewatt Tube RIAA Phono Preamp

By | November 3rd, 2011|Categories: DIY AUDIOFILE|Tags: , , |

The latest project from Bruce’s workbench is the Groovewatt, a tube based RIAA phono preamplifier.  The Groovewatt is the result of over one year of work and several build iterations.  Bruce set some pretty high performance requirements for the tube preamp and he is very pleased with the results. 

Second Groovewatt Build 
The Groovewatt uses a symmetrical SRPP (12AX7) input stage which feeds a passive RIAA equalization network. The second gain stage is nearly identical to the input stage and is direct coupled to the third stage which is a cathode follower (12AT7).  Bruce used Gold Pin JJ ECC83S for the SRPP stages and half of a ECC81 for each side of the cathode follower.  The power supply is solid state and DC is used for the tube heaters.  Total gain of the RIAA phono preamp is about 45 dB which should be sufficient for use with a high output MC cartridge.Read the full article

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BK-12m Folded Horn Kit – Fostex FE126En

By | September 12th, 2011|Categories: DIY AUDIOFILE|Tags: , |

There is a new high-sensitivity folded horn speaker kit being offered by Madisound.  The new BK-12m is a single-driver folded horn speaker kit that follows in the lineage of the BK-16 and BK-20 designs.  The BK-12m uses the Fostex FE126En full-range speaker driver in a custom folded horn enclosure while the driver is run full range with no filters whatsoever.  The Fostex FE126En driver is 4.7″ (120 mm) in diameter with a rated sensitivity of 93dB/W(m).  This high-sensitivity means that the BK-12m speakers will be suitable for use with low powered amplifiers.Read the full article

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DIY 2-Way Tower Speakers – Ion

By | September 5th, 2011|Categories: DIY AUDIOFILE|Tags: |

Adam has put together a fantastic looking pair of tower loudspeakers and he has shared his design with us.  The speaker design uses a Tang Band 25-1372SC 1″ inverted titanium dome tweeter combined with a pair of Audax HM170CO 6″ woven carbon fiber mid-woofers and used in a TMM configuration.

DIY 2-Way Tower Speakers Audax HM170CO Tang Band 25-1372SC

The loudspeaker enclosures are constructed using 1.5″ thick MDF with solid oak side panels. The overall dimensions of the tower speakers are 37.5″ x 8.5″ x 11.5″ with each weighing about 60 pounds.  The MDF is painted with a textured graphite spray and the side oak panels are stained.Read the full article

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Boozhound Labs JFET RIAA Phono Preamp Kit Review

By | July 11th, 2011|Categories: DIY AUDIOFILE|Tags: , |

After building a few diy versions of the Boozhound Labs / Le Pacific JFET RIAA phono preamps,  Mark decided to try the actual $79US Boozhound Laboratories (BHL) JFET RIAA phono preamplifier kit. In Mark’s diy versions of the phono preamp he used polypropylene capacitors.

DIY JFET Phono Preamp on Stripboard
On the other hand, the BHL phono preamp kit comes with fabulous looking vintage new old stock (NOS) Russian military paper-in-oil (PIO) capacitors. PIO capacitors made in this fashion are quite respected and sought after for their sonic qualities.  The BHL phono preamp kit comes with a PCB, the circuit parts and detailed building instructions.Read the full article

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Fundamental Amplifier Techniques with Electron Tubes: Book Review

By | June 15th, 2011|Categories: DIY AUDIOFILE|Tags: , |

Late last year Elektor released their most recent publication on the increasingly popular subject of hi-fi tube audio, Fundamental Amplifier Techniques with Electron Tubes by Rudolf Moers.  The new book is actually the English translation of “Fundamentele versterkertechniek met elektronenbuizen” (ISBN 978-90-5381-226-6) authored earlier in Dutch by Rudolf Moers.  The thick hard bound book is 834 pages and seemingly covers what appears to be just about every topic on the subject of audio amplifier design with vacuum tubes.  I recently had an opportunity to read the book and here is my overview of the new electron tube book. 
Fundamental Amplifier Techniques with Electron Tubes – Rudolf Moers
The thick book is divided into ten chapters.Read the full article

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How to Solder – Comic Book Guide

By | April 13th, 2011|Categories: DIY AUDIOFILE|Tags: |

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.… Read the full article

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

By | April 8th, 2011|Categories: DIY AUDIOFILE|Tags: , , |

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.Read the full article

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