AliEx amorphous, Hashimoto HL20K6 + Sony TamRadio line output transformers

L>R: 6AH4 + AliEx, 12B4A + Sony/Tamradio and 6AH4 + Hashimoto HL20K6

The last time I saw my buddy J-Rob was pre-COVID, but we keep in touch via email and text messages. During one of those hello/how you doin' moments, the chat progressed to line preamp transformers and how the $100/pr. amorphous jobs from AliExpress perform. 

I used to own a pair of Tango/Hirata NP216N nickel line OPTs, which were featured in my Sound Practices issue 17 homebrewer article. In hindsight, I don't think I gave them a fair chance so this was a good opportunity to revisit the topology.

SETUP 2024

Single Ended Triode Users of the Philippines 2024

At the dawn of the 21st century, I uploaded hifi systems owned by audio buddies who had been inspired by the Sound Practices ethos. These were the guys who originally coined SETUP. After a couple of decades, the number of Filipinos who indulge in this hobby has increased exponentially.

Here's what I saw and heard during my recent visit.😊

Harana Audio Workshop

Altec 311-60 horns + 288 drivers with Fostex super tweets on top of a pair of Harana V-Vent bass bins with partial horn loading

JE Labs Choke-Capacitance Coupled SE2A3 amp

Canon P + Canon 50mm f1.8 LTM 
Foma 100 in Rodinal

Inspired by my plate choke-loaded 76 line stage preamp adventures, I was curious how a similar driver circuit configuration would sound in an SE2A3 amp. So I pulled out my Radiotron Designer's Handbook, 3rd Edition to gain a better understanding of choke-capacitance coupling (aka plate choke loading) vis-à-vis resistance coupling.

Below are highlights of relevant information I gathered.

MC step up transformer redux + Hashimoto HM-7

A Cousin's Listening Room

 

This is a hifi system I built for a cousin who loves music!

Hashimoto H-203S from Kasuga Wireless

In September 2018, I lamented the demise of Noguchi Transformers. Fast forward to November, my brother-in-law visited Tokyo, and was kind enough to pick up a couple of transformers at Kasuga Wireless.

How to get to Kasuga Wireless

Kasuga Wireless

Address: 1F, New Akihabara Center, 1-16-10, Kotobuki, Chiyoda-ku, Tokyo 101-0021

Hashimoto H-203S

The H203S was installed as a 3.5k primary Z output transformer in the je2a3 mono integrated amp. 

Testing

Top trace = audio generator

Bottom trace = amplifier output

100Hz

1kHz

10kHz

5.324Vrms to an 8 ohm load = 3.5W 

In the past, I've used Hashimoto transformers for a pair of SE2A3 and a pair of SE10 mono-blocks I built for friends. I know these transformers are well designed, are of high quality construction and sound excellent. Thus, before Hashimoto ceases production, I had to add it to my collection. 

My mono SE2A3 integrated is ready for prime time!

Now I have to find a nice circuit for a pair of Kasuga KA6625ST OPTs. 😉

Listening Room - Minimalist no more?

Among the audio systems of my friends, this is the only set up that has no LP playback ability. Neither does the owner have interest in DVD-A, SACD or a music server/streaming device - only16 bit linear PCM sampled at 44kHz red book mastered CDs, period!

Hashimoto HC-203U SE output transformer

Listening Room - Minimalist

A music lover's system based on a CD transport + DAC as source, JEL 76/6SN7GTB line stage preamp with remote volume control, JEL SE10 mono block amps driving PHY-HP 2-way 12" co-axial speakers housed in Hans Kortenbach enclosures.

JEL SE10 amp

A Harana Audio/JE Labs collaboration

After the November 2009 Hi-Fi Show, a friend commissioned a pair of mono block SE10 amps. Given my busy concert schedule I needed the expertise and assistance of our friend Joey of Harana (Serenade in Filipino) Audio for the chassis and woodwork.

Me and Joey drafting the layout and marking pilot holes

Hashimoto H20-14U output transformers, C10-10W chokes

+  proudly Filipino wound power transformers on M6 laminations by Edrel Sison

Wiring, scope and ear testing at the attic 

E-P1 + Summicron 50/2-IV

JEL SE10 monoblocks' new home driving (1600mW per side!) PHY-HP drivers in Hans Kortenbach enclosures

E-P1 + Summicron 35/2-I

Thanks for waiting and happy listening!