JE Labs: Homebrewer

Showing posts with label Homebrewer. Show all posts

Tuesday, December 1, 2020

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 Piro, Craftsman Extraordinaire!

When John emailed me a picture of his WE753C clone cabinets, I had to have a pair!

JP in the man cave with my freshly minted Altec 753C boxes

JP's System (in constant flux)
Thorens TD124, Marantz 7T, Garrard 301
DIY Stuff
Marantz 8B, REL Precendent
DIY amps
Wharfedale SFB3

Garrard 301 + Karmadon Viscous Damped Tonearm

WIP - Gray Research HF-500 Turntable

Hey JP, are you prepping this for a Schröder BA tonearm? 😎

JP repurposed a WE chassis for his preamp

JP's preamp is based on JE Labs Circuit

JP's Simple 45 amp using James 6113HS OPTs

JP's Stereo SE300B with James 6123HS OPTs visited the man cave,
it's based on the JE Labs circuit

JP's Vintage RCA Collection

RCA Theatre Amps

RCA Compression Drivers

RCA Horns

Altec 614 cabinet
by JP

Open Baffle by JP

JP's handcrafted multi-cell horn made from wood,

based on the Western Electric WE26A

REL Precedent 646B with a DIY front faceplate by JP

JP's take on the Dr. Bae/Silbatone 755A cabinet

Unlike my friends in Manila who have reported good things using the Altec 755C in this box, JP prefers the Lafayette SK98/Pioneer PIM8L

If you want to contact John for a commission, please leave a comment with your email address. Your comment will not be published, instead, I will reply with his contact info.

Coming Soon
JP757A

Thursday, January 9, 2020

TBT '96-'97: JE Labs Project Pics

I'll start the new decade with scanned negatives of my DIY Audio projects from the mid to late 90s. Most of these pictures were taken either with my Pentax K1000 or Leica M3 + Rigid 50mm Summicron, loaded with either Agfa Vista or Kodak Plus X, processed by a local lab. I didn't know how to develop film yet back then. 😉

ca. '96

My last Dyna PAS hack

This Dyna PAS 2 chassis sports an RCA phono circuit with Ni-Cad batteries for cathode bias. Check out those wonderful (then) anti-high-end paper in oil caps from Jensen, Facon and Icar. Too bad they get leaky after a couple of years.

Yup, that's an octal socket in the line stage for the mighty 6SN7!

Under the hood of the outboard power supply is a choke for the B+ for better filtration. Connection to the main preamp is via an octal plug/socket.

By this time I was already a firm believer in tube rectification. I retained the original PAS transformer for B+ supply duty only and relegated DC filament duty to another power transformer.

JE Labs Stereo "Classic" SE300B with Audio Note UK 2.5K OPTs

A Thorens TD124 + a (then) newly-acquired ($60!) Grace G540L tonearm + Grado 8MZ on my very first laminated plywood plinth project. All these components are still in service.

The original Simple 45

ca. '97

JE Labs Stereo SE2A3 with Tango U808 OPTs

JE Labs Classic SE300B mono-block with Audio Note UK 3K OPT

I briefly owned a pair of AES/Soliloquy 5.2 TQWT speakers. Coming from Spendor LS3/5As, these sounded lean and weren't more efficient either - probably in the high 80s rather than the claimed low 90s.😏

Fortunately, I snagged a pair of Altec 755Cs at a hamfest and quickly whipped out a pair of small open baffles. I was hooked!

The Altec 755Cs in open baffles based on dimensions published by Stereo Sound "Tube Kingdom" Issue No. 3/1996. And yes, I added a Garrard 301 to my system!

I got my Garrard 301 in the early summer of '97 along with the Altec 755Cs.

This was the block diagram of my system before the end of the millennium as a featured "Home-brewer" in Sound Practices. I can't believe 20 years went by so quickly!

Monday, August 15, 2016

Octal EAR 834P phono preamp

During my visit to NYC earlier this summer, my buddy Ding loaned me his home-brewed octal version of the EAR 834P phono preamp using 3 x 6SL7 octal tubes. Powering the preamp is a General Radio 1201-B tube regulated power supply.

Ding is not into boutique parts. Instead, he used carbon film resistors, mylar coupling capacitors and electrolytic caps gathered from Hamfests and surplus stores. Proper grounding and parts placement ensured a very quiet phono stage.

Traditional tube phono stages like the classic Dyna PAS 3 and Marantz 7 employed active RIAA EQ networks inserted in the negative feedback loop from the final stage to the input stage. In the 834P, Tim de Paravicini used active RIAA EQ with a clever twist - the EQ network is fed from the cathode follower output back to the second stage only. IMO, the benefits of this topology are: a 1st stage unimpeded by negative feedback, low noise and low output impedance.

I've been enjoying this phono stage so much that I'm inspired to build my own version. Good job, Ding!