Friday, July 28, 2017

Noguchi Finemet: FM-3WS-H + FM-6WS output transformers


This was the last extensive testing and listening session I did in the attic before the stereo and mono systems were rescaled. I misplaced some data and just recovered them recently. So as promised in a previous blog entry, here's the write-up on the two entry-level SE Finemet OPTs from Noguchi.

WARNING

These are bonsai-sized output transformers. If thumping bass frequencies is your idea of high-fidelity you should stop here right now. Otherwise, please proceed with caution ;)

Noguchi FM-3WS-H

Noguchi FM-3WS-H + Tamura F7004

David vs. Goliath - indeed, the FM-3WS-H is tiny. I had to mount it on a perf board so that it wouldn't fall from the square mounting hole left by the Tamura F7004 ;)

JPY 13,910 or US $124

Noguchi FM-3WS-H
100Hz (top left), 1kHz (top right)
 and 10kHz (bottom right)

Technical and listening tests were done with the output transformer mounted in the SE10/VT25 amp, which resides in the attic mono system.

Noguchi FM-6WS

Noguchi FM-6WS + Tango U808

The FM-6WS is not that much bigger either.

JPY 16,000 or US $142

Noguchi FM-6WS
100Hz (top left), 1kHz (top right)
and 10kHz (bottom right)

Technical and listening tests were done with the output transformer mounted in the Radiotron SE2A3 stereo amp in place of a pair of Tango U808 OPTs.

Color Chart in Kanji
for wiring
transformer leads

Subjective evaluation of both OPTs


I have to admit that given the Lilliputian dimensions of these OPTs, I was predisposed to expect poor bass performance in spite of the claims from their respective spec sheets. The 100Hz square waves verified the manufacturers' claims and the quality of bass I hear more than compensates for the lack of ultimate extension which, in my experience, can only be had from OPTs the size of a Tango XE60/NY15s or Tamura F2000/F7000 series. In fact, when I invited my seasoned DIY Audio buddies for a listening session, none of them noticed significant bass deficiency.

Back in the 90s, there were two types of exotic transformer core material vying for the best - Permalloy and Amorphous. I learned then that the virtue of exotic core material shone through the mid-range, rather than at the frequency extremes. I never quite made the leap to Amorphous because I was already satisfied with the life-like mid-range abilities of Permalloy. I heard the Amorphous Tamura F5002 in a familiar circuit and system context, and thought that in spite of its edge in resolving detail, it sounded clinical compared to Permalloy. Finemet is supposed to have evolved from Amorphous. However, the mid-range performance from these two entry-level Noguchi Finemet OPTs have the warmth and lucidity of Permalloy without the antiseptic quality of Amorphous.

With such fine midrange performance I didn't expect any high frequency aberrations and the two 10kHz square wave oscillograms above confirm the smooth falling response beyond 20kHz (no ringing or phase shift), as shown in their respective spec sheets.

If I didn't already have Tamura and Tango Permalloy OPTs the bigger Finemet offerings from Noguchi are very tempting! 

Wednesday, July 19, 2017

Harrisburg Hamfest

After playing the first concert for the July 4th Summer Series with Harrisburg Symphony, I received a text message from a friend that there was a Hamfest in town on July 1st. 


The venue was only 10 minutes away from our hotel.


Pick of the day!


Friday, June 30, 2017

Spring 2017 Camera, Hamfests and Radio Shows

 Kutztown Radio Meet

May 12-13, 2017
Kutztown, PA


I used to frequent this radio show until I left in '08. It used to be a relatively small event but has evolved to the biggest radio show in the east coast.

Contax II + Helios 103
Foma 100 in Rodinal

A pair of MC60s + a Dyna PAS 3 preamp


RCA preamp/mixer + 2 x Rek O Kut B12s


My friend Larry's booth featuring handcrafted and modified tube preamps and amps

Contax II + Helios 103
Foma 100 in Rodinal

Mike used to sell vintage audio but has shifted to classic/vintage film cameras. An avid music lover, he still listens to a hifi system using carefully chosen classic equipment.

Got an EV MC12, loktal triodes, 6C6 pentodes, a 10Y and a Ciro-Flex C TLR

Classic cars in the field





Photorama USA

June 3, 2017
Centreville Moose Lodge
Fairfax, VA

Fuji X-E1 + Voigtlander Heliar 15mm f4.5

Twenty some years ago I frequented Photorama shows in the Washington, DC/Baltimore area.

Fuji X-E1 + Voigtlander Heliar 15mm f4.5

This was a good place to source classic cameras, lenses and accessories during pre-eBay days. Since I've been in the market for a Sonnar 50mm f2 or f1.5 for my Contax II, I thought I'd try my luck at this event...

Fuji X-E1 + Voigtlander Heliar 15mm f4.5

Even if the show was only a fraction of what it was 20 years ago, I did find a nice Opton Sonnar 50/2 with a dead Contax III (good for parts) rear lens cap for less than the going rate on eBay.

Icing on the cake: Tewe Zoom finder, Paterson Tank, a book and freebie expired TX400s

Radioactivity 2017

June 15-17, 2017
College Park, MD


From the early 90s until '08 I attended this event regularly. Many of the tubes, transformers and chokes I am still using in my hifi system came from this radio show.

Leica M6 + Canon 35mm f2
Foma 100 in Rodinal

Leica M6 + Canon 35mm f2
Foma 100 in Rodinal


But time has taken its toll...I was expecting to see familiar faces here but some have dropped out of sight or may even have joined our ancestors ;(

Radioactivity loot: some guy practically gave away a mammoth Omega C-II 4x5 enlarger, a couple NOS loktal triodes a filament transformer and choke

Cumberland Valley Amateur Radio Club Hamfest

June 17, 2017
Chambersburg, PA

Pentacon F + Helios 44M-4
Foma 100 in Rodinal

While some of my favorite hamfests have shrunk or gone extinct, the Cumberland Valley Amateur Radio Club inaugurated their first hamfest. 

Pentacon F + Helios 44M-4
Foma 100 in Rodinal

 I didn't have to wake up too early for this event since it was less than 30 miles away.

Pentacon F + Helios 44M-4
Foma 100 in Rodinal

Pentacon F + MIR1B
Foma 100 in Rodinal

Pentacon F + MIR1B
Foma 100 in Rodinal

All the best to CVARC !

  NOS loktal triodes + EV LS12 = Loot

Baltimore Amateur Radio Club Father's Day Hamfest

June 18, 2017
Upperco, MD

Pentacon ZI + Tessar 50mm f3.5
Foma 100 in Rodinal

From what I gathered from my hamfest buddies, this event is what is left of what was once the mighty Timonium hamfest ;(

Pentacon ZI + Tessar 50mm f3.5
Foma 100 in Rodinal


There were more vendors than the previous day in Chambersburg, PA. I even saw some of the same faces at both events ;)

More NOS loktals, another 10Y and a Fujica M42 mount SLR which turned out to be much better than its Pentacon ancestors, but that's another story ;)


Bye for now...gotta go fiddle for food and toys again ;)

Thursday, June 22, 2017

2017 Update: Hi-Fi Room


One year progress report


Stereo


Garrard 301 + Ortofon RMG 309/SPU GME or
SME 3012 + Denon DL103

Digital line level sources processed 
through UTC A20 transformers

JEL Stereo Preamp DX

JEL Stereo SE2A3 DX amp with Tango NY15S OPTs

Altec 414As in 3.5 cf bass reflex enclosures + Altec 32A horns with 802D compression drivers






Monday, May 29, 2017

Dad



My mentor and best friend







I am forever grateful!

February 22, 1927 - May 23, 2017





Sunday, May 21, 2017

Electro-Voice EV 209-8A - 8" wide-range


During a visit to Sakuma's Direct Heating website, I encountered a cool SE 801 amp schematic designed for either a Lowther PM6 or an Electro-Voice 209-8A. I googled the EV 209-8A and nothing came up in Audio/DIY centric English language websites. But there were a lot of US dealers stocking the driver from as low as $18 each.

basic specs

After downloading and studying the detailed specifications at the EV website, I chose the cheapest internet seller and phoned-in an order for a pair. 


It cost $40/pair from Full Compass delivered within a couple of days to my doorstep. In spite of their great customer service, their packing left a lot to be desired - see the slightly wrinkled whizzer in the above right picture - the drivers were free floating in the box, not even tied down face to face ;( 


Due to lack of resources to build the recommended 1.8 cubic foot sealed cabinet, I loaded the EV 209-8A in a Heathkit 1.2 cubic foot ported cabinet, which used to house a Jensen P8RL + RP103. 

Heathkit 1.2cf + EV209-8A

Sharp fall off below ~ 90hz, otherwise the in-room RTA result was satisfactory. The tonal balance reminded me of a good mini-monitor speaker with no upper midrange nasties. It was also quite extended in the high frequency and at no time did I crave for a super tweeter.

Further internet research yielded this Japanese website which did an in-depth study of the EV 209-8A. Based on Chrome browser translation, transmission line loading was used to get around the bass deficiency.


Regardless of Qts values ;) and in keeping with JE Labs tradition, a trial in an open baffle is de rigueur. Since my original pair of OBs are currently in storage, I improvised a 55" wide x 32" high flat baffle using a 24" x 24" x 1/2' thick pine plywood baffle from my experiments in the 90s as the core, supplemented by cardboard extension wings.

OB + EV209-8A

Despite the even sharper fall off in mid bass response as shown in the RTA, subjectively, the bass extension was similar to the EV209-8a/Heathkit box combo. But the scale of the sound field produced by the EV209-8A/OB combo was a lot larger than when it was loaded in the Heathkit cabinet.



Since I discovered that my very first high efficiency speaker (a green KS 14703/Altec 755C) was carefully stashed in a box in the basement, I installed it in the OB to take a trip down memory lane. 

OB + Altec 755C

I've covered the Altec 755C in the Sound Practices No. 17 Homebrewer feature many moons ago, so I will spare adjectives to describe the subjective performance of the KS14703/755C. Suffice to say that the above RTA graph shows it all. It is just in a different class sonically and affordability! Perhaps not a very fair comparison for the EV209-8A because this driver with an intact cone and voice coil is worth about 20 times more when they come up for sale.


So even if I couldn't coax Altec 755C performance from the EV209-8A, its street price, efficiency, relatively flat impedance curve and midrange to upper frequency performance quality impressed me enough to bring it to the attention of the Audio/DIY world.