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Temporary Hi Fi 2018

Set-up in the living room until I finish renovating the man cave

Recent posts

Altec 2-way XO Redux

This is an update on crossovers I use for the Altec 2-way speakers.

The above crossover circuit, as discussed in this previous post, was optimized for my cherished pair of green Hammertone Altec 802Ds fitted with the original aluminum 20275 diaphragm, which has an aluminum wound voice coil. To my ears, this diaphragm has a more prominent midrange response which necessitates rolling off the upper midrange/lower high frequencies of the 414A woofer for flatter response.

For the Altec 802 driver equipped with the 34852 (16 ohm) or 34647 (8 ohm) diaphragms, which have copper wound voice coils, I recommend the 6dB/octave crossover circuit below which is hinged at around 2500 Hz + high frequency EQ boost. This aluminum diaphragm has less energy in the upper midrange giving a tonal balance that sounds more extended in the high frequencies compared to its 20275 predecessor. In this implementation the Altec 414A woofer is connected as a full-range driver inspired by Joe Roberts. 

I've also…

Happy Holidays and a Great New Year to All!

JEL Loctal Preamp

Motivated by Ding's octal version of the 834P, I quickly got my hands dirty punching out and painting a chassis. 

Loctal tubes

The concept of this project was to build a full function stereo preamp utilizing loctal tubes based on the schematics below.

Preamp circuit
Power Supply

Tube rectified CLC power supply

Line Stage

Zero feedback single gain stage direct coupled to a cathode follower line stage topology featuring the two medium-mu triodes below


The stock EAR 834P circuit (above) used all high-mu 12AX7s with the second stage capacitor coupled to the cathode follower stage. While preparing this blog entry, I remembered that my dearly departed friend, mono aficionado BrianmonofantasticoClark, grafted his own interpretation of an EAR 834P phono stage to his SE 801 mono integrated amplifier. He was an active participant in this discussion of 834P modifications initiated by Thorsten Loesch.

Line Transformers Redux + Art Dudley + AQ Dragonfly Black

My boring digital life

Probably the most significant digital audio gear I ever owned was the Tascam DA-P1 DAT recorder. This machine recorded my recitals, chamber music performances and served as a back-up and playback deck for my CD projects from the mid 90s until the early 2000s. It was rendered obsolete when HD based recording became the industry standard.

I never invested in a high-end CD player. The most I ever did for CD playback was get an Audio Alchemy DAC in the Box fed by the digital output of a consumer grade Philips CD player. When the Philips CD player conked out in the early 2000s, it was replaced by a Sony DVD/SACD player.
Line transformers as Digital Sound Processors

Ever since I inserted a pair of Tamura 600:600 line transformers as a digital sound processor (DSP) between the CD player/DAC and my preamp line inputs, I didn't see the necessity of upgrading the Audio Alchemy DitB. I don't know if this holds water but my empirical rational for this is, magnetic …

November Hifi Show 2017

I actively participated in this annual event for nine consecutive years with my Harana/Tono/Setup buddies but will break the tradition this year. 😞 This is a must see for every audio/video enthusiast based in Manila. 👍👍👍 
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Grace G707 + Denon DP1250 = road less travelled

The 70s through the early 80s was the era of great development in direct drive turntable technology. It was only stifled by the introduction of the CD player in 1982 and to a minor degree by the revived interest in the classic suspended sub-chassis belt-drive system within the audiophile community.

Although I was exposed to some of the great direct drive turntables from the 70s, like the Luxman PD444 and the Technics SP10 MkII in a Mitch Cotter base in the home system of my late DIY audio mentor Tom Cadawas, I never had a direct drive turntable in my audio system till now.

This was probably due to the almost cult-like indoctrination inculcated by early 1980s Haymarket publications like Popular Hi-Fi and Hi-Fi Answers exalting the virtues of the 3-point suspended belt-drive from the land of kilts vs. the evils of cogging and servo hunting direct drive turntables from the land of the rising sun.

Even though the late Harry Pearson of TAS used a direct drive Goldmund Studio in his refere…