Friday, March 8, 2024

OJAS 529B Horn



During my visit to the OJAS listening room late last year, Devon asked me to evaluate a pair of horns OJAS developed in collaboration with Lycan R&R. The OJAS 529B is a 500 Hz horn rescaled from the large format Altec 329A for use with 1" format Altec/GPA compression drivers.


  This horn was designed with a throat inspired by the Western Electric 32 horn to avoid the harshness and distortion I (as well as others ๐Ÿ˜‰) associate with the Altec 811 and 511 horns
For more details about this horn's evolution and construction, please click here.

Thursday, February 22, 2024

SE171A Amp Remastered

My dad would've turned 97 today. To celebrate his birthday, the video clip above features a recording of his favorite violinist, Nathan Milstein, playing Presto from Bach's Sonata No. 1 in G minor for unaccompanied violin. While he was doing post-graduate studies at The Juilliard School in the mid 50s, he was fortunate to have attended concerts of the great violin virtuosos of that era - Jascha Heifetz, David Oistrakh, Nathan Milstein, etc.

He would later recount that Nathan Milstein's performance of the Glazunov violin concerto was the most unforgettable! Even if he never got a chance to add this violin concerto to his repertoire, he conducted the Manila Chamber Orchestra with me playing the Glazunov violin concerto in 1987. The music of the slide clip above is the middle movement from our performance.

Before I bore everyone reminiscing about my dad and our life as musicians, let's get on with the subject at hand. The amp featured in this upload uses a directly heated triode power tube that was introduced around the time my dad was born.

Thursday, February 8, 2024

Line Transformers for Digital Audio

Altec 15356 + UTC A20

While browsing at Books Kinokuniya in NYC in the 90's, this Noguchi ad from the November 1994 MJ Audio Technology issue inspired me to experiment with line transformers as digital sound enhancers. Since I was living on a post-grad assistantship budget back then, importing this pair from Japan was out of the question.

Monday, January 22, 2024

Minimalist Twin-Armed Thorens TD124

Ever since I left this twin-tonearm compatible TD124 plinth in the attic, I've been trying to find the simplest way to use two tonearms on this turntable.

Monday, January 8, 2024

JE Labs Man Cave 2024


This is the side of the man cave where I spend a lot of time listening and evaluating new projects.

In the coming months, I will be talking about phono preamps, autoformer volume control, revisit the transformer coupled line stage topology, SE amps, etc. I will also continue my classic Japanese idler-driven turntable series, feature a couple of SE-DHT amp-friendly drivers + more.

Most of the audio components listed below are hyperlinked if you mouse over the text. Those that are not will be linked once the article is uploaded.

I like to taste new sonic flavors that are within the DIY realm๐Ÿ˜Š

JEL man cave tour


Sunday, December 17, 2023

3D printed WP12024 horn from Lycan R&R

In late September, I received a message from Trieu of Lycan R&R, asking if I'd be interested in evaluating his 3D-printed prototype pair of multi-cell horns.

Before proceeding further, this blog entry contains a lot of hyperlinked texts to either previous entries or other sites pertinent to the article (e.g. "Lycan R&R" above). Mousing over and clicking those texts will open the link on another page. Thanks!

Design notes from Trieu: "These horns are slightly wider. The original KS12024 has a rather narrow 50° horizontal dispersion. When updated to the 1" driver opening, the wider initial diameter of the of the 1" driver would not allow for the throat geometries to work correctly. I felt the slim vertical profile of the original KS12024 is important sonically.

The best way to maintain it is to increase the horizontal width via a wider angle. So I increased the horizontal dispersion to 62.5° allowing for the proper expansion and geometries of the throat piece. BTW, I used carbon fiber infused PLA filaments."