This was the last extensive testing and listening session I did in the attic before we moved back to the states. 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 HUGE iron + HIGH inductance and thumping bass frequencies is your idea of high-fidelity you should STOP 🛑 here!😉However, if the finesse and realism a WE/Altec 755A can provide within its 70-13 kHz bandwidth is your idea of a GREAT time, please proceed!😊
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.
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!
If I didn't already have Tamura and Tango Permalloy OPTs the bigger Finemet offerings from Noguchi are very tempting!
!!UPDATE!!
The entire line of Noguchi is now represented by General Transformer in the same location at Tokyo Radio Department Store in Akihabra and they accept international orders.
