My FM Tuners

Last February I mentioned being distracted by my favorite FM stations in metro Philly. Here are the tuners I've been tuning with. 😉

Vacuum Tube

Sherwood S-3000-II

This mono FM tuner courtesy of J-Rob got me started exploring the airwaves of the area. It blends perfectly with the mono hi-fi installation in our mid-century-modern themed living room. Aside from MCM aesthetics, it made me realize that there are a couple of noteworthy FM stations in our area, which inspired me to restore my out of commission FM MPX tuners and acquire a few more.😉

Scott LT110B

I acquired this tuner from Angela Instruments while working there as a tech in the early 90s. It was later aligned and tweaked in the workbench of the late Tom Cadawas. When it started having issues pulling stations a couple of years ago, I boxed it up. I recently unearthed it and traced the issue to a cracked solder joint in the antenna terminals. This tuner is the most modern sounding of the three tube tuners - tonally reminiscent of the Yamaha T-2, but with narrower stereo separation.

Dyna FM3

This Dyna FM3 factory-wired sample died during my sojourn in Manila. I discovered that each section of the quad filter capacitor all read "0" uf! After replacing the quad capacitor it performed back to factory specs - darker in timbre than the Scott, similar tonal balance to the Sherwood. A tube lover's delight!

Solid State

Yamaha T-2

Back in the early 80s, I bought my NAD 3020 from a fellow in the NYC metro area who was listening to WNCN on this tuner. It left an indelible mark in my memory since I never thought FM broadcasts could sound that good! Alas, I couldn't afford it then, so when I found this at a flea market, I grabbed it! Radio X Tuners (highly recommended) tweaked it to equal or exceed factory specs. It lacks the tube warmth in the midrange but goes deep in the low frequencies with extended and airy highs. Stereo separation is superior to any of the FM tuners in this survey.

Kenwood KT80

I remember seeing this KT80 tuner with its matching KA80 integrated amp at a closeout sale back in the early 80s at Harvey Electronics' West 45th store in NYC. Slim-line was the fashion statement of the era. It may be a notch below the Yamaha T-2 sonically, but still very listenable.

NAD 4300

I got this NAD 4300 tuner because of the AM section, which, unfortunately, is unlistenable! However, the FM section is pretty good. It sounds at par with the KT80, if not better, in the frequency extremes but not quite in the T-2 class. It offers 8 presets + a tuning knob, which almost feels like a true weighted knob/dial string assembly.

Kenwood KT880D

I almost didn't take the KT880D seriously due to its late 80s digital age/jet black/slim-line styling + modern comforts of preset buttons, auto tuning, etc. My ears can't get attuned to the dry and analytical sound. But I'm keeping this (or not?) because it pulls in the most stations and does the best job of squelching FM background noise/hiss.

Coda

Winegard HD-6010

Stellar Labs 30-2435 Omni

All the tests were done using either of these two antennas. The Stellar Labs Omni is mounted on a mic stand while the Winegard HD6010 is in the garage attic. I haven't tried them outdoors because I'm afraid of heights. 😆 

If we play the numbers game, the S-3000-II, LT-110B and FM-3 are no match in terms of sensitivity, selectivity and stereo separation (note: the Sherwood is mono) compared to any of the solid state designs above. Even when properly aligned, tube tuners are prone to drifting. However, tube tuners offer fatigue-free listening and FM background hiss and birdies are a lot easier to psycho-acoustically tune out.

All these tuners would have been obsolete if I didn't live in a metropolis that still offered quality FM broadcasts. Here's to my favorite local FM stations: WRTI, WPRB and WXPN! 🍻🍻🍻

A visit to J-Rob's and the Silbatone 755A box by Dr. Stefano Bae

OB/755A

Despite the fact that Joe Roberts and I both revere the 755A, he never thought highly of my open baffle set-up. To this day, I'm still baffled as to why he featured my home-brewer article in Sound Practices. 😉 I enjoy the engulfing planar-like airiness of the 755A/OB combo which Joe finds lifeless, boring and lacking in snap. 

OB + 755A

Could the dip in this RTA trace be indicating a lack of snap? 😜

Custom-built Altec 618 + 755A

J-Rob custom 618 cabinet

  Back in the mid-90s, I owned a pair of original Altec 618s. Those sounded boxy and colored, perhaps due to their lightweight construction. So I traded them for a pair of early sand casted 811 horns...😧 Oh well, live and learn. 😁

When my friend Chong gave me a pair of well braced vintage DIY 618 boxes (allegedly built by an ex-WE engineer and used to house a pair of WE755As), I understood the snap that ticked the Joe-man.

ex-J-Rob Altec 618 + 755A

This is the nicest and most modern looking RTA trace in this survey! Loaded with Altec 755As, the sound is snappy and dynamic while retaining that warm and realistic sheen in the midrange, which evades most speakers marketed in the past 50 years. Although some listeners may still find that quality a vintage coloration...

A visit to J-Rob's

People don't always have to agree to remain friends

Case in point: Joe seems to prefer the Japanese 755 - Lafayette SK98/Hamlin/Pioneer PIM8L - over the ferrite 755C. However, if push comes to shove, I'd take the 755C over the various permutations of the PIM8/20L even if I played a role in reintroducing its virtues to the world. Maybe it's just my sentimental attachment to the 755Cs since they were my very first high-efficiency drivers?

J-Rob sez, "I shouldn't even be talking to you since you like 755Cs." 😆

When I visited Joe in the summer of 2018, he had a pair of 4 cubic foot WE753A look-alike cabs that house Western Electric WE728Bs driven by a spruced up Dyna SCA35 which was recently replaced by a J-Rob cloned Peerless A100 PP 6A5G amp built during the Sound Practices era. Signal source is a Mac Mini>Tidal>Audirvana>Wavelength Audio Brick DAC.

Despite the natural high frequency roll off of the 12" WE728B, it sounded very full-range because of its rich overtones. That is, overtones as musicians use it to describe musical instruments. A high quality violin, piano, or any musical instrument for that matter, possesses rich overtones and this has nothing to do with high frequency extension. Even FFT analyses have failed to identify why del Gesus and Strads sound harmonically richer and have greater carrying power in a good acoustic space compared to a painstakingly crafted modern violin.

I was looking forward to hearing the Silbatone SE300B amp on the floor but Joe hasn't gotten around to re-wiring it for 120V, and also to LPs, but the Gates CB500 was waiting for a resurfaced idler wheel. Then he showed me his next project - Klangfilm horn repros (center background) + Altec and JBL large format compression drivers.

Finally, I was introduced to the pair of Altec 755As perched on top of the WE753C-like cabs. I was quite impressed with the sounds emanating from the 755As!

This 755A/box combo was featured in the Silbatone exhibit at the Munich High-End 2018 Show. Prior to that, Joe spoke fondly about the box and gave DIY hints in this Audiokarma thread. I was hoping that he'd be inspired to update his Junkyard Jukebox blog for a formal presentation of this cabinet design before he went on a sabbatical from the internet.

Since there's no sign that he'll be back anytime soon, with his permission, I took it upon myself to write about this 755A cabinet breakthrough.

Silbatone/Dr. Bae WE/Altec 755A box plan
Copyright Silbatone Acoustics

I re-drew the box plan based on a quick sketch Joe uploaded in the Audiokarma thread. Please note that this cabinet plan is published solely for the Audio/DIY community as a public service of Silbatone Acoustics. 

Under no circumstances should this be used for commercial purposes! 

Let's see if that works...truth be told, I am well aware that there have been a few enterprising individuals who have benefitted commercially from projects published in this blog. So I'm not holding my breath.

John Piro Clone Build
Interior walls + back lined with two layers of Kimpak

I sent the drawing to my buddy John Piro shortly after my Altec 753C cabinets were delivered.

Can anyone distinguish JP's clone from the original Silbatone box? 

Dr. Bae designed Silbatone box + 755A

J-Rob comments:

"The cabinets were designed by genius Silbatone engineer Dr. Stefano Bae as a group project for the Silbatone-sponsored DIY/Western Electric forum in South Korea. 100 pairs were quickly sold out, immediately driving up the world price for 755As. The original uses Silbatone's custom silver litz wire, which is said to be an essential ingredient of the original recipe, and top shelf WBT connectors.

Over the years Silbatone designed and made literally dozens of experimental boxes, including back horns for up to four (755A) drivers per side. This was probably the most successful, although rather modest.

My analysis of this untuned little cabinet is that it falls under the 'small box with a hole in it' design paradigm."

Unlike before when I felt the need for at least SE300B power to make the OB/755A sing, now I'm enjoying near-field sounds from my JP cloned Silbatone/Dr. Bae boxes + Altec 755As driven by an SE46 amp with tiny Noguchi FM6WS Finemet OPTs.

The SE2A3dx which normally drives the Altec 753Cs in the main listening area had no trouble driving the Altec 755As in Silbatone boxes to moderately high SPL levels.

 Even without the silver litz wire and high tech WBT connectors, I heard all the virtues of the slant 618 box + open baffle combined = detail, snap, macro and micro dynamics from the 618 box + airiness and lack of vintage boxy colorations from the open baffle.

The Dr. Bae/Silbatone cabinet transported the 70 year old 755A design to the 21st century in a monitor-sized package!

First Philippine Triode Festival June 15-16, 2019

Makati City, Philippines

Featuring a G.I.P. Laboratory + Harana Audio collaboration

GIP 597A field coil high frequency horn

GIP CH-65 midrange horn + GIP 555W field coil compression driver

GIP 815 = 15" field coil woofer loaded in Harana Audio V-Vent II bass cabinets

+

Flea-powered triode amplifiers built by Filipino enthusiasts and guests from our Southeast Asian neighbors.

The Enablers

more info

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. 😉

Altec 753C

After many years of raving about the Altec 32 horn, the only stone left unturned was using it as it was originally designed, that is, with the compression driver oriented to radiate upwards.

Last year, I received a message from John Piro, whose beautifully crafted preamp project was previously featured in this blog. He sent me pictures of his interpretation of the legendary WE753C using an Altec 414-16B woofer + Altec 32A + Faital Pro driver. 

Altec 414A + 32C + 802D + 20275 

I was very impressed and requested if he could build a pair for me. We finally met at the Kutztown Radio Show last September. He and his wife had dinner here at home when he delivered my beautiful cabinets!

A Western Electric 753C used as a monitor at WABF in the early 50s

As an homage to the legendary Western Electric 753C, which was a major inspiration for this project, I henceforth christen this speaker system as the Altec 753C.

Altec 2-way XO redux

I've settled on running the 414A woofers in full range mode (ala J-Rob) and replaced all the crossover resistors with non-inductive 12W Mills. This took away the last vestiges of grain in the upper frequencies.

RTA Graphs

Altec 2-way

Altec 614 + 414A + 32C + 802 with GPA34258

The above RTA was taken from this blog entry

VS

Altec 753

Altec 753 + 414A + 32C + 802D with 20275

I could've lived happily with my Altec 614 or repurposed 861 (aka Madrid) cabs + the inverted 32 horn situated on top. However, with proper horn orientation, the sound was taken to another level of refinement. Now the blend between the 414A and horn is practically seamless and I bask in the airiness of the top end, which I attribute to significantly improved high frequency dispersion, precisely as envisioned by Western Electric engineers.

In spite of the stellar midrange performance of the Open Baffle mounted Altec 755As, I started the Altec 2-way project in the late 90s to address the following issues:

1. More efficiency
2. Extend the frequency extremes
3. Less congestion in dynamic peaks with complex musical passages

After 20-some odd years, those goals have been realized. The Altec 753C is pretty much end game!

Thanks to my buddy Joe Roberts, who explained the intricacies of proper 32 horn orientation. The idea was carefully stored in my mind. I just had to wait for the right opportunity to implement it. And of course, a big thanks to my friend John Piro (aka RCA NUT), craftsman extraordinaire!

Let's hear some music. 😊

Ikea Knarrevik

Ikea Knarrevik 

I use it as:

component stand

turntable stand

speaker stand

Best $10 I ever spent on Hi-Fi! 😉