JE Labs Simple 46

I've been hoarding type 46 power tubes gathered from radio shows I attended with my buddy Chong in the late 90s. Building an SE 46 amp was in my to do list when I packed up for Manila in '08. But things got in the way. Finally, after a round trip across the Pacific, the amp has come into fruition.

Given its designation, one would think that it is just a 45 with dual grids. However, aside from the UX-5 tube socket requirement, the 46 is not quite a 45. It only puts out 1250 mWatts, 750 mWs less than the 45's 2000 mWs. Maximum plate dissipation with grid 2 tied to the plate is 5.5W compared to 10W for the 45. Although it will perform very well loaded with a 5k primary Z output transformer, the textbook recommended load is closer to 7k, due to its higher plate resistance of 2380 ohms vs. 1700 ohms for the 45.

46 tube base
diagram

chassis is punched out and ready for painting

It's been over 20 years since the Simple 45/2A3 was uploaded to the now defunct DIY section of the old Angela Instruments website. So I wanted to reprise that old-school topology with a twist. I considered retaining the octal base and using a grid capped 6F5 or a UX6 based + grid capped type 75, as a tribute to Asano-san. 🙏

However, since I am in loctal mode, I settled on the 7B4 hi-mu triode which is more in unison with the simple theme. The 7B4 is readily available NOS and can be had for less than $5 each from tube dealers. Tube rollers take note, even if loctal tubes are boxed/labelled RCA, Tung Sol, Raytheon, etc. most of them came from the Sylvannia factory in Emporium PA. 😞 

under the hood

!!!WARNING!!!

The voltages found in this circuit can be lethal! Build at your own risk!!!

JEL Simple 46 schematic

Adjust the dropping resistor* (use at least a 10W) so that the operating point for the 46 tube is as close as possible to the tube manual specified 250V max. plate voltage x 22 ma. current draw = 5.5W.  Ideally, the 46 should see 285 volts at the plate - 35V in the cathode = 250V. As shown in the schematic, I am still running my output tubes about 8% over because I was anxious to listen and got lazy to lower the B+ further. 😎

The big surprise was, subjectively, the triode-wired 46 sounds more powerful and authoritative especially in the lower register than the 45. It sounds like the union of virtues between the dark and mythical 10/VT25  + the refreshing airiness of a 45. I've been listening to this amp for over three months and haven't had the itch to switch on my other amps. 😄

CODA

Left to Right - Globe 46, ST 46, ST 45 and 2A3

Globe tubes look really cool and usually sound more lush than their ST counterparts. I personally prefer a Globe 45 over the later ST glass bottled samples. However in the case of the 46, the difference is not as apparent and close to negligible to my ears, So save your $$s and do something less nerdy, like going out on a date. 😉

Addendum

I received this email recently from a seasoned DIYer/audio enthusiast known in various audio forums as Salectric.

"I just saw your blog post about your Simple 46 amp and I read the question someone posed in the Comment section about a suitable power transformer. I actually had Edcor build a custom PT for my 46 amps and the voltages worked out perfectly so I recommend it to anyone wanting to build a 46. I don't know if the particular unit is listed on their website but it should be available through the part number which is the Edcor XPWR 258-120.

The B+ windings have two secondary voltages. It is 345-235-0-235-345 @ 300ma. The purpose of the two voltage taps is to let the transformer function for either choke input or cap input. The lower voltage windings with a 5U4GB and cap input filter give a roughly 290v B+, and so do the higher voltage windings with a 5R4GY and choke input. With a little loss in the OPT and a 32v bias, the 46 has almost exactly 250v across it. There is also a 5V@3A and 6.3VCT.

I ordered it this way because I wanted to compare choke input and cap input with as close to exactly the same conditions as possible. (I tried a 5U4GB with the choke input as well as cap input just to be as consistent as possible.) The best sounding setup was the choke input with 5R4GY so that's how mine is set up. The Edcor is super-quiet. No mechanical buzzing at all."

Cinestill Cs-41 Color Film Developing Kit

Intrigued by an e-newsletter from Freestyle Photographic Supplies, I ordered this color film processing kit, which promised to be just as straightforward as developing B&W film.

Mixing the Chemicals

Developer = 20 oz of distilled water heated to 120° F + Parts A, B & C to make 1 quart

Blix (Bleach/Fixer) = 18 oz of distilled water heated to 125° F + Parts A, B & C to make 1 quart

Preparation

As suggested by the Cs41 website, I got a $25 foot spa from Walmart as a tempering bath for the chemicals and the developing tank.

Temperature is most critical with the developer. Since the foot spa is just a tempering bath and does not heat up water, I filled it up with hot water from the tap, which was between 105-110°F.

Meanwhile, I filled up a pot with hot water from the tap and heated up the developer in this water bath on the stove to my chosen 102° F developing temperature.

Pre-wash

 I did a pre-wash to stabilize developing tank temperature at 102°F.

Developing

The developer is ready.

I dumped the pre-wash and poured the developer into the tank. I developed for 3.5 minutes doing 4 inversions every 30 seconds. Tank is submerged in the bath in between inversions.

Developer is poured back into the container. I turned off the foot spa since the Blix stage is not as temperature sensitive.

Blixing

Blix can be used anywhere between 75°F-102°F,  so 90.9°F is perfect.

I filled up the developing tank with Blix and did 4 inversions every 30 seconds for the next 8 minutes. After 8 minutes, the temperature inside the developing tank would be just about equivalent to room temperature tap water, which will be used for the wash/rinse cycle.

Blix is poured back into the container.

Wash and Rinse 

I filled up the tank with room temperature tap water, did 5-10 inversions and then dumped the water. Repeated this at least 7 times.

Photo-flo

Filled up the tank with fresh tap water (or distilled) and added two drops of photo-flo or the stabilizer from the kit. Left it standing for at least a minute.

Hang to dry

I let the film dry for at least an hour.

Developing at other temperatures

As shown in the above chart, processing can also be done anywhere from 72°-102° F, but developing time can take as long as 50 minutes at colder temperatures.

The Cinestill Cs41 color film developing kit is just as fool-proof as B&W film processing. The only difference is that they are at both ends of the temperature spectrum. Since I've relegated taking color pictures to my trusty Fuji X-E1, I've seriously been considering an upgrade to a full frame digital body. However, this recent experience processing color film has taken the upgrade itch away...😊

Sample pics

Rollei 35 + Kodak Gold 200

Rollei 35 + Kodak Gold 200 

Rollei 35 + Kodak Gold 200

Rollei 35 + Kodak Gold 200

Rollei 35 + Kodak Gold 200

Nikon FG20 + Nikkor E series 50mm f1.8
Expired Fuji Color 100 

Leica M6 + Summicron 35mm f2
Kodak Portra 160

Darwin D. Martin House
by Frank Lloyd Wright
Buffalo, NY

more pics

Shure Mic Transformers

Ben C was hunting for Altec 32s, Emilar EH800s 
and EH500s at Jammin' Jersey

Tipped off by my buddy, Ben C (dude in the middle), I scoured eBay for Shure Mic transformers that can be repurposed for MC step-up duty. These transformers typically sell for under $50/pair shipped within the USA.

They don't have model numbers so I'll identify them based on their step-up ratio.

Primary DCR = 35 ohms and 3500 ohms in the secondary. 

I measured a step up ratio of about 1:17, which suits the Denon DL103 and DL103R well. It can be a pinch hitter for the Ortofon SPU in my system, but ideally more gain is needed.

This unit has slightly less gain at about 1:12, primary DCR = 20 ohms and secondary = 2000 ohms. What it gives up in gain is made up for by slightly wider bandwidth. If I were to split hairs, I'd pick this over the 1:17 model above if I were using a DL103 exclusively.

The tonal balance of both Shure transformers is actually quite similar to the Altec 4722 with just a touch less transparency and authority throughout the audio band. At their present asking price, I can highly recommend these transformers to those who want to sample the delights of listening through a classic Denon DL103 low output moving coil cartridge.

Happy listening!

Lens Filter Ring Vise

I recently fixed two lenses from my collection which had dented filter rings using this $36 tool from Micro-Tools.

The tool didn't come with instructions but using it is pretty straightforward. As a precaution, I covered the front element with cardboard. First, I positioned the moving jaw of the tool on the dent and aligned the threads from the jaws of the tool to mate with the threads of the filter ring. Then I gently spread out the jaws of the tool to press out the dent. I cannot over emphasize going slowly but surely!

Dent was between 10 and 11 o'clock
impossible to fit a hood or filter

After the procedure, a 46mm
screw-in lens hood fits with
minimal fuss

Dent was between 3 and 4 o'clock

Not perfect but better than it was

The tool has paid for itself ;)

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

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.

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! 

!!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.

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!