Fuji X-E1 R.I.P. (Oct. 2013 - Aug. 2019)

After 6 years of great service, my beloved Fuji X-E1 died during our NYC trip. 😞

I miss its real camera ergonomics. Ideally, I'd like to have Fujifilm RF aesthetics, ergonomics + a full frame sensor. Perhaps a digital Leica M? 🤔

But my reality is a compromise. 😜

I'm just beginning to appreciate the benefits of a full frame sensor from this Sony device. 😊

Summer 2019 Amp Projects and 6X6 Folding Rangefinder Cameras

Radiotron SE2A3 with Noguchi PMF-15WS

Shot with an Ansco Super Speedex loaded with
Foma 100 and developed in Kodak HC110 dilution B

Ansco Super Speedex
more pics

JE Labs Simple 46 with Noguchi FM-6WS

Shot with a Super Fujica 6 loaded with
Foma 100 and developed in Kodak HC110 dilution B 

Super Fujica 6
more pics

Good light and happy listening!

JE Labs Flea Market

My boss told me we are running out of storage space and before I can acquire more audio toys, I have to free up some space.... 😜

Just like the olden days, I decided to revive the JE Labs Flea Market as an outlet for my surplus equipment and other goodies.

Multi-bit DACs from yesterday and today

Multi-bit DACs from yesterday and today

Since I listen primarily to 16-bit/44.1 kHz sources and have found the decoding capabilities of the USB DACs and DACs using sigma-delta chips musically challenged for that purpose, I searched for alternative ways. I backtracked and then moved forward.

Listening Set-Up

Magnavox CDB650 + Sony CDP505ESD
used as CD transports

Raspberry Pi 3B+/Volumio/Allo Digi One
+
Anker Power Bank

1:1 line level audio transformers
as digital filter
between DAC and preamp 😊

Near-field 

Altec 755Cs in 618 Cabs

Main System 

Man Cave HiFi

Audio Alchemy Dac In The Box

 To alleviate my disappointment with the performance of my Philips CD921 bitstream CD player, I bought this Dac In The Box in the 90s with the optional high current power supply. After the Philips CDP died, this unit soldiered on, hooked to the digital out of my Sony DVP NS755V.

While taking the circuit board out of its case, I realized that this may have been the ancestor of the Topping D30 due to its packaging. The main difference is, the D30 is powered by a cheap (potentially noisier) wall wart containing a Switch Mode Power Supply. OTOH, the basic DITB was still equipped with a linear power supply with a real transformer - silicon steel laminations + copper windings - a luxury item nowadays!

The CS8412 input receiver dwarfs all the other ICs including the 2 x Analog Devices AD1860 18-Bit DAC chips. Unlike the Burr-Brown PCM-63P below (or the Philips TDA1541), the AD1860 has a built-in op-amp that serves as an I/V converter. There's provision for coaxial and optical inputs but no USB. "Designed and manufactured in USA" is something we rarely see nowadays...

This was a highly-rated budget DAC in the 90s. Almost 30 years later, I still find it to be a pleasant sounding unit - detailed yet smooth overall, with a nice midrange and good frequency extension at both extremes. Maybe I'm yearning for more dynamics, because compared to the three other DACs, this is not as musically exciting. However, I'd much rather listen to this than either of my CS4398 chip'd DACs.

Adcom GDA600 - specs

Another American-made device from the 90s, this DAC was designed to a high standard. Because of the 2 x Burr-Brown PCM-63 DAC chips in its circuit, it has developed quite a following amongst classic multi-bit DAC aficionados. This DAC chip, along with the Philips TDA1541A S1/S2 single/double crown and the Ultra Analog U20400A, are considered the epitome of multi-bit DAC design.

To the left is a well-regulated and filtered power supply, while to the right is the digital and audio board, liberally populated by period correct plastic film capacitors for audio coupling. Just like the Audio Alchemy DITB, this predates USB. Instead, there are two coaxial inputs, an AES/EBU input and optical input plus a digital coaxial output.

The digital bits are fed to a CS8412 input receiver, oversampled eight times by a Burr-Brown DF1700 digital filter and processed by 2 x Burr-Brown PCM63P 20-Bit DAC chips (one for each channel). Finally, two Adcom 7AA op-amps serve as an I/V converter for each channel's output.

The sound of the GDA600 is very authoritative and detailed. It easily has the best extension at the frequency extremes. Starting from the deep and well-controlled bass all the way to crisp and extended highs. I found the midrange just a touch lean and dry. The sound field is the widest in this survey but not quite as deep compared to LPs or even the Audio GD below. It sounds very exciting due to the excellent rendition of dynamics. The tonal balance is very neutral and should appeal to listeners who value accuracy and detail.

This is a popular model amongst DIYers for tweaking and parts upgrades. Maybe replacing the op-amps with FET equivalents and the plastic film caps in the audio signal path with paper in oil type will warm this unit up a bit.

Muse TDA1543 x 4 mini DAC

This was a very popular entry-level Non-Over-Sampling  (NOS) available at Amazon and eBay until a couple of years ago when supplies dried up. I got this unit from the used market for an Alex above the original going rate of $55, shipped.

To keep costs down, 4 x TDA1543 DAC chips are employed to produce line level output without resorting to an active I/V converter stage for each of the two channels.

Polyester Wima caps replaced the original electrolytic output caps

I replaced the stock electrolytic output caps with film types and the stock SMPS wall wart with a linear power supply. 

SMPS vs Linear PS

With these two simple upgrades in place, this DAC portrayed a natural and vivid midrange which is musically captivating. After extended listening, I realized that the frequency extremes were truncated. It also lacks the ability to resolve complex musical passages which get compressed and congested. Based on my experience with TDA1543 chip'd CD players, an active I/V converter may address these issues. That said, I'm not sure if it is possible to get this level of musicality in reproducing a jazz trio or chamber music for under a Ben! 

Audio GD R2R-11 - specs

Mid 2018 model

Audio-GD is an audio company that prides itself with using discrete components in their designs. Since this is an NOS type DAC, the digital bits are processed directly (no oversampling filter) by an R-2R ladder (2 x DA 8 modules as pictured below) to convert digital data into analog signals. Unlike the older two DACs above, the Amanero USB input supports PCM, DSD and DXD.

From the Audio GD website

I will skip the technical description and let this picture speak for itself. Suffice it to say, I love the handcrafted/cottage industry vibe. Hence, the $384 landed cost is justified!

 This DAC has a tube-like three-dimensional quality and clarity in the midrange. The layering of vocals and instruments in the sound field easily bested the other two even if it wasn't quite as wide as the Adcom. Very good extension at the frequency extremes, second only to the GDA600. Excellent in presenting micro dynamics (even better than the Adcom), there's no need to turn the volume up to high SPLs for excitement. However, at the louder side of the spectrum, the GDA600 has the upper hand in control and authority.

I listened to the R2R-11 in the neutral setting since the warm setting was too mushy in the context of my two set ups. Although I'm just an occasional headphone listener, I heard the same tubey quality through my Grado SR80 headphones. With my CS4398 DACs,  I always found the coaxial input to sound superior to the USB. However, with this unit I could not detect a difference, so the Amanero USB input must be doing a good job!

This DAC reminded me very much of my JLH 1969/Nobsound NS-02g Class A amp - a solid-state device that tries very hard to emulate a tube unit. Almost there, but not quite...

The DAC Wrap

After listening casually and intensively to these four DACs this past year, I realized that I want the virtues of all four devices without their vices - the dynamic presentation at louder levels of the GDA600 and the micro dynamics of the R2R-11, the transparency and tube-like quality of the R2R-11 (is it because of NOS?🤔), the frequency extension and detail resolution of the GDA600, the wide sound field of the Adcom and depth of the Audio GD, the long-term listenability of the Audio Alchemy AND the affordability of the Muse Mini TDA1543x4. Can I have my cake and eat it, too?😊

KS12027 Horn

The KS12027 horn perched on top of my repurposed Altec 861 cabinet loaded with an Altec 414A woofer should actually be residing inside a ~ 4 cubic foot slanted cabinet with a Western Electric WE713C compression driver  bolted to its throat + a WE728B 12" woofer = Western Electric WE757A monitor speaker system.

I was honored to host this KS12027 horn and provide more modest accommodations for a couple of weeks courtesy of my audio preservationist buddy John Piro.

He rescued this KS12027 horn with a damaged 0.7" aperture and repaired/modified it so that mere mortals like myself can sample its delights using a more pedestrian 1" exit Altec 802 compression driver. 

Mono Hi-Fi set up: Neat P58H + Calrad SV16 + GE RPX or DL102, JEL SE2A3 mono integrated amp with Hashimoto H-203S OPT.

All of my listening was done with the above set up.

Altec 414A + mod'ed KS12027 + 802 + GPA34852

From the moment I mounted the KS12027 + Altec 802 combo above the Altec 414A woofer, the first adjective that came to my mind and stuck for the rest of its stay was, natural! Just like its WE/Altec 32 and KS12024 relatives, this is also a horn that doesn't sound like a stereotypical horn. In fact, the articulation (attack and decay of notes) and overall presentation of harmonic overtones via the KS12027 is even more natural and realistic. It made the Altec 32A/32C and Azzolina KS12024 sound merely like very high quality Hi-Fi which mainstream audiophiles may find more appealing. These findings were echoed by my friend Ding during his recent visit to the man cave.

Altec 32C, KS12027, Azzolina KS12024

Even if I loved the KS12027 so much, I didn't want to get attached to something I may never be able to own. So this past weekend I met up with John at a ham fest and handed back this valuable piece of audio history. After giving him my rave report, which is hardly representative of what most audiophiles like nowadays, he was not dissuaded. He is still seriously considering reproducing them. 😎

Darling Amp, JE Labs Style

It's been 20 years since jc morrison started hosting the new york noise audio design exhibition at his Hoboken, NJ loft. One of the highlights of that year's exhibit was Darlingfest '99 as reported by Jeremy Epstein in the final issue of Sound Practices. The Darling amp was the brainchild of Bob Danielak and was published in Sound Practices Issue 15.

Jeremy's octal driven Darling amp made a lasting impression on me but I never got a chance to build my own version due to a busy performing schedule.

While I was organizing my workshop in the basement this past winter, I found power and output transformers from a Sony TC500A tape recorder + other parts to build a Darling amp.  

The chassis cleaned up nicely with a wire brush. Then I drilled, cut and punched the necessary holes before spraying a fresh coat of silver Hammerite.

I chose the 6F5 hi-mu triode with a cool grid cap as the input/driver tube.

To qualify as a Darling amp, the indirectly heated 1626 transmitting triode  output tube is de rigueur.

The TC500A donated a healthy 6CA4 rectifier.

!!!WARNING!!! 

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

My interpretation of a Darling amp is ready for testing and listening!

Bench Testing

Both channels driven

P = V²/L

2.415 x 2.415 = 5.832/8 = .729 or 729mW per channel

Hum and Noise = 1.8mV

100Hz

1kHz

10kHz

I did not expect this level of performance from the cheap looking Sony OPTs, which I also verified while listening to the amp!

Bass extension is surprising from this 3/4 watter! It is deeper and tighter compared to my Tango'ed SE171A amp. However, in the midrange, the true Directly Heated Triode shines. The 1626 was just a touch veiled in comparison. Although it sounds more powerful than the similarly rated SE171A, it also doesn't overload as gracefully. I remember hearing a similar phenomenon when Steve @ Angela Instruments asked me to build the Simple 5691 > EL34 SE amplifier. The Simple 45/2A3 clips with more finesse. Is the cathode causing the relative lack of transparency and harder clipping?

The days of $5 Type 45s and 2A3s are long gone. But NOS 1626 tubes can still be acquired for under $10 a piece. Since it has a cathode, with careful wiring less than 2mV noise is achievable on AC heating which is quiet enough for me even on headphones. There's no need to hunt for hard to find 25-75 ohm, 2W hum nulling pots. That's just a couple of reasons as to why a Darling amp derivative is one of the cheapest and easiest routes to a DIY SET amp nowadays.

Did I mention that it also does a great job driving headphones?

headphone adapter/attenuator schematic for 
efficient headphones ex: Grado SR80, Koss KPH30i/Porta Pro
Lower efficiency/high impedance classic headphones like the 600 ohm AKG K240 Monitor, 
Sennheiser HD420, HD6xx and Orthodynamic/Planar magnetic: Echo TDS-16, 
Fostex T10 and Yamaha YH-1, can be driven directly from the speaker terminals

Happy listening!