Happy Birthday Daddy!

Daddy was born 94 years ago.

Family Picture, ca. '91

Dad on his 89th birthday with Mom and grandkids!

Daddy and Mommy were soulmates for 58 blissful years in this world. Now they're reunited! 

We love you and miss you both dearly!

Happy Birthday Mommy!

Picture of me and my Mom taken by my Dad

My beloved Mom would've turned 87 today.

She was a very loving, dedicated and supportive wife, mom, and grandmother!

Mommy with her youngest grandchild

Mommy completed a Bachelor of Science Degree in Education, major in Math.  

She also loved music and played the piano.

While teaching high school mathematics, Mom took music courses that would lead towards an Associate's Degree in Music Education. Meanwhile, Dad had just returned to Manila from post-graduate studies at The Juilliard School and got appointed as a faculty member at the same music school where my mom enrolled.

That was the beginning of their beautiful and idyllic love story! 

That's me, the first of four brats!

Our Family, early 80s

Dad and Mom's 25th Anniversary
December 1983

90s Family Pic

Mom and Dad's 50th
wedding anniversary, 2008

Mom and Dad, Feb. 8, 2014
Mom's 80th birthday

Dad and Mom's 56th

wedding anniversary, 2014

Mom
May 2015

Mom and Dad's 58th
wedding anniversary, 2016

Christmas 2016 was the last time the family was together.
Tish and I flew back to the USA on January 23, 2017.

Sadly, Daddy left us on May 23, 2017. 

Mommy joined Daddy on January 23, 2021.

We sorely miss you, Daddy and Mommy, but we're very happy you're together again! 

6C8-G

I've always found tubes with grid caps fascinating. 😉

I've been evaluating a project using this tube.

Stay tuned!

 

Looking Back to the Past for a Better-Sounding Future

'80s Nostalgia

 

Early to mid '90s

I was based in the DC metro area in the early to mid 90s. 

When I wasn't playing gigs or teaching, I serviced classic audio equipment and Audio Note, UK Kits for Angela instruments.

Mid-late 90s

Sound Practices 17 Homebrewer Article

2000-2008

Main Listening Room

Monaural Hi-Fi

Home Theatre with SET amps

The Attic 2008-2016

2017

2018

Man Cave 2020

Near-field

Monaural HiFi

Stereo

🎆 Welcome 2021! 🎆

nos TDA1541 tube DAC

I've become cynical of the latest is best mentality because in my 30 years of searching for sound that pleases my ears, I've always gone back to move forward. From this experience, I've learned to use planned obsolescence to my advantage by investing in old school components that have achieved classic status.

 There is a common denominator between the Philips TDA1541 DAC chip and the Western Electric 300B directly heated output triode vacuum tube. The former brought digital sound to everyone’s homes in the '80s, while the latter amplified talking pictures in movie theaters in the '30s. Both have also been rediscovered for their distinguished musical abilities.

This tubed TDA1541 sans oversampling multi-bit DAC evolved from my frustration with its bitstream and delta-sigma successors, revisiting and studying multi-bit CD players and DACs, performing Magnavox CDP + DAC mods, and other digital audio experiments.

Home Brewer: Silbatone 755 Cabinet DIYers Club

Left = JE Labs clone (by John Piro)
Right = J-Rob's Silbatone original 

"The cabinets were designed by genius Silbatone engineer Dr. Stefano Bae as a group project for the Silbatone-sponsored DIY/Western Electric forum in South Korea. 100 pairs were quickly sold out, immediately driving up the world price for 755As. The original uses Silbatone's custom silver litz wire, which is said to be an essential ingredient of the original recipe, and top shelf WBT connectors.

Over the years Silbatone designed and made literally dozens of experimental boxes, including back horns for up to four (755A) drivers per side. This was probably the most successful, although rather modest.

My analysis of this untuned little cabinet is that it falls under the 'small box with a hole in it' design paradigm."

Joe Roberts 

May 17, 2019

John Linsley-Hood Class A Headphone Amp

Having been a happy user of a John Linsley-Hood (JLH) 1969 Class A amp cloned by Nobsound, I was intrigued by the JLH Class A headphone amp boards featuring discrete circuitry (no ICs or op-amps) advertised on eBay. In the midst of the 2020 lockdown, I ordered this $25 pre-assembled board, which arrived in a padded pouch within 10 days. I also got a surplus 24 VCT @ 2A power transformer for another $15.

!!!WARNING!!! 
The voltages in this project are potentially lethal! Proceed at your own risk!

Typical of Chinese kits, this board didn't come with instructions or any type of documentation. But the board is marked for an experienced DIYer to decipher and set up in no time. Unlike the original JLH 1969 design, which needed DC blocking capacitors at the output due to the single rail supply, this headphone amp module was updated to work with a dual rail (+/-) supply so the output capacitors can be omitted.

 

Unfortunately, I couldn't get stable zero DC offset at the output terminals. Trimming for zero volts after 30-45 minutes of warm up was not a guarantee that in another 30 minutes it'll still be zero - I've measured as much as 0.3V.😞

Since I didn't want to risk frying my headphones and classic speakers, I installed 2500uf @ 16V electrolytic blocking capacitors at each channel’s output. Then, I bypassed the electrolytic caps with hermetically sealed 4uf paper caps just like I did to the Nobsound NS02g.  

Top trace = audio generator
Bottom trace = amp output

In spite of the DC blocking caps at the output, the square waves still show excellent bandwidth, transient response with no trace of ringing. 

Before clipping, I measured 250mW/channel @ 4 ohms, 500mW/channel @ 8 ohms and 950mW/channel @ 16 ohms, 1.2W/channel @ 32 ohms,  395mW/channel @ 150 ohms, 190mW/channel @ 330 ohms and 115mW/channel @ 560ohms. I pretty much exhausted the resistor values from my parts bin to emulate the nominal impedance of typical headphones. 

The 115mW output into a 560 ohm load shouldn't worry headphone enthusiasts since this amp drove my Austrian AKG K240/600 ohm Monitor cleanly beyond SPLs my ears could tolerate. It also had no issues driving less efficient ortho-dynamic headphones like the Fostex T50RP MKII below, courtesy of my friend Nate. Thanks, buddy!

This amp definitely outclassed the Rat Shack mini amps I'm fond of. Its class A design's purity and transparency puts it on another league. Unfortunately, Class A amp designs require a more substantial power supply, which is incompatible with portability. 

The character of this amp is exactly like that of its bigger brother, a fatigue-free solid state amp that almost (but not quite) succeeds in sounding like a good tube amp!

BTW, did I mention that it can also drive my Altec 755As in Silbatone cabinets?