Friday, September 16, 2022

Realistic 42-2109 phono preamp upgrade

Even if I was a Radio Shack devotee in the early 80s, I didn't pay much attention to this RIAA phono preamp because it didn't have high-end audio pretensions. As the saying goes, ignorance is bliss.πŸ˜†

scanned from page 36 of the 1989 catalog

This unit was first introduced in the 1980 catalog (p. 22) as part number 42-2101 at $19.95, then as part number 42-2109 for $24.95 in 1989, and made its final appearance for $27.95 on page 103 of the 1992 catalog.

Realistic MKVII idler-driven turntable, a future feature😊

With the resurgence of interest in LP playback, it was rediscovered by aficionados and has developed quite a following. No ICs or op-amps are to be found inside. It's a simple discrete circuit, which minimizes signal processing.

!!!WARNING!!! 

The voltages in this circuit are potentially lethal! Proceed at your own risk!



The circuit is a basic two stage cascade + a negative feedback RIAA EQ looped from the output back to the input. It is very similar in topology to its tube forebears - the Shure M65 and the phono section of the Dyna PAS.


Typically, I don’t subscribe to a wholesale approach of replacing caps but this is a very simple circuit that was built at a certain price point. Since I had some decent quality parts surplus from my CD player and DAC modification projects, I replaced the electrolytic capacitors in the signal path with film type WIMAs and increased the filter capacitance in the power supply section.


In stock form, I was already impressed by this preamp's listenability when passing through my loctal tube line stage. The parts upgrade tidied up the sound further, but it wasn’t a magical transformation.


In terms of midrange presence and transparency, low level detail, micro and macro dynamics, this preamp isn't the equal of the Shure M65 or a refreshed stock Dyna PAS phono section. Its main advantage over its vacuum tube forebears is low output impedance. This could plug into the 10k input Z of the Nobsound NS02g/JLH 1969 with no loss of frequency extremes. I won't recommend that with the M65 or PAS. There's also a slight graininess in the midrange that wasn't ameliorated by parts upgrades. That said, I don't know if one can find a "plug 'n play" phono preamp in the $100 range (or possibly more?), which will provide as much musical pleasure!




Saturday, September 3, 2022

Japanese Idler-Driven Turntable Part 1: Pioneer PL6U


Ever since I discovered the Shield MO19 (aka Neat P58H) and Realistic MkVII at the turn of the new millennium, I've become fascinated by, and in the process have collected a few Japanese idler-driven turntables. To my ears, none of them measure up to the Garrard 301, 401 or Thorens TD124. However, the models I'll be covering in this series, IMHO, offer great musical value for money when properly sorted.


For this initial installment, I'm featuring the Pioneer PL6U, which I used as an interim turntable when I returned to the US in 2016. It's the little brother of the Pioneer PL7, which was built to much higher specifications.


With a 100V AC motor fitted, the PL6U was a 3-speed turntable made for the Japanese domestic market. Both 50Hz and 60Hz pulleys are supplied since both AC frequencies are used in Japan, depending on which part of the country you're in. As pictured, the 60Hz pulley is installed since that's the AC frequency in the US. I use a 100W step up/step down transformer to make sure the motor is fed exactly with 100VAC.


The 4-pole AC synchronous motor + switch linkage are on a sub-chassis that's mounted beneath the stamped steel main chassis.


Removing the bottom cover revealed a box. Originally, this box would have contained the tonearm, auxiliary tonearm weight, head shell, an oil vial, 45 rpm adapter, 50 or 60 Hz pulley, stylus pressure gauge and screw driver. I got the turntable with the tonearm mounted sans head shell but the 50Hz pulley + screw driver were inside the box. Sadly, all the other accessories were gone...πŸ˜”    


The cast aluminum platter is quite hefty at almost 2 lbs. 


It's undersized at 10" (25mm) diameter but it spins on a finely machined 3/8" (10mm) spindle.


The tonearm is a very simple static gimbal type and thus, a tracking force gauge is necessary to set proper VTF. Other cartridges that match well with the relatively massive (albeit also undersized) tonearm include the Pickering V15/Stanton 500Shure M3D + 7DSC35C, etc. Practically any magnetic cartridge with a conical stylus that tracks over 2 grams will work well. In fact, the bearings are good enough to even handle a Denon DL103 moving coil! Watch and listen below.


Except for perished motor mounts, the unit is in excellent condition. After fitting a fresh set of rubber motor mounts, a thorough cleaning + lubrication, the unit played beautifully on its original idler wheel!

Let's hear some tunes!



Pioneer PL6U + Shure SC35C
Phono Preamp = Shure M65
Line stage = JEL Loctal
Amp = SE71A


Pioneer PL6U + Shure M44
Preamp = JEL Loctal


Pioneer PL6U + Denon DL103
MC step up = Altec 4722
Phono preamp = Shure M65
Line stage = JEL Loctal
Amp = SE71A


Collectors of 45 rpm vinyl, take note!πŸ˜ŠπŸ‘


It can also be the heart of a mono hi-fi set up!πŸ‘πŸ˜Š

Pioneer PL6U + GE VRII mono cartridge
Amp = JEL SE2A3

Despite the solid engineering that went into this record player, it was and still is an entry-level unit. It portrays the musical energy idler-driven turntables are known for, but not quite up to the refined standards of the Realistic MKVII or Shield MO19. That said, the videos show how much fun I had with this unit!

More information about the almost identical Pioneer PL6A can be found at audio-heritage.jp.


Hopefully this vinyl feature from NHK-World will tide you over while I prepare for the next installment.πŸ˜‰





Monday, August 1, 2022

OJAS @ Lisson Gallery NYC

Our dear friends Charito and Joey, whom we haven't seen for over five years, were in NYC visiting for a couple of days. On short notice, Tish was able to take a day off so we were able to meet up with them. Joey is an avid audio DIYer and was a frequent collaborator especially during the annual November Hifi Show when I was still based in Manila. He represents G.I.P. Laboratory in the Philippines. 


It was also timely that Devon (OJAS) Turnbull's HiFi Dream Listening Room No. 1 exhibit at the Lisson Gallery NYC was on its penultimate week. So Joey and I agreed that this was going to be our meeting place! 


The OJAS loudspeaker system utilizes Great Plains Audio drivers, which are currently produced using original Altec tooling - GPA 416B 16" woofers + GPA 288H 1.4" compression drivers. The latter compression drivers are coupled to bespoke OJAS 1505 horns, which are remastered versions of the classic Altec 1505B multi-cells, while Pioneer PTR9 ribbon super tweeters fill-in the top-end octave harmonic overtones. At the center is a Fostex FW800HS super woofer. Devon starts with Werner Jagusch crossovers but driver loading and alignment are all developed in-house and then fine tuned by ear!

Having spent almost a decade studying at The Juilliard School twenty years before the Diller Scofido + Renfro reboot, I developed an immediate affinity for the brutalist vibe of the speakers!


The OJAS gestalt brought back cherished memories of the late Don Garber's Fi audio gallery from the early 90s, which was along 30 Watts Street in SoHo NYC. I wasn't able to ask Devon if he got the chance to meet Don. I bet they would have gotten along really well!


A pair of Altec/Peerless 4722 SUTs are mounted directly on a FET-based phono preamp using vacuum tubes as constant current sources. This was designed by jazz guitarist Steve Berger, who's also the man behind Aprilsound NYC. The adjacent chassis with two large knobs houses a transformer volume control wound by Dave Slagle of Intact Audio.


Being a devoted Garrard 301 listener for many years, Devon is cognizant of the finite supply of these idler driven classics. So for this project, he chose the platter + motor from a Technics SL1200G and mounted them in a custom layered plywood plinth. To assure absolute speed stability and smoothness in operation, a 3-speed linear power supply was specially designed by Linear Tube Audio. Having done DJ work during his younger years, he admits that his choice was partially in reverence to the marque.

Mounted at the back is an Ortofon RMA309 tonearm + a restored vintage SPU-A for stereo LPs and a Dynavector DV505 tonearm + SPU mono CG 65 Di for 78 rpm shellac discs.


Devon's pair of SE300B mono-blocks (fitted with Tango XE20S output transformers) is an homage - not a slavish copy but his own interpretation - to Herb Reichert's Flesh and Blood amplifier published in Sound Practices Issue 8. 


Unlike a typical hi-fi show swarming with silver-haired or balding guys, it was refreshing to be surrounded by a twenty-to-forty something crowd. Devon is attracting and developing a niche market uncharted by mainstream high-end audio publications such as Stereophile and The Absolute Sound. Due to his background in design and interaction with the upper echelons of the fashion and music industries, the whole Sound Practices ethos of music reproduction spearheaded in the early 1990s by Joe Roberts will hopefully reach a larger audience. 


Joey and I spent a couple of hours listening to Blue Note jazz, contemporary classical music, and talking shop with Devon. He was a very gracious host, who candidly gave credit to his collaborators as well as to those people who've influenced and inspired him.

Me, Devon, and Joey

Bravo, Devon, very well done! 
After several years of PMs, it was great to finally meet you. I look forward to more shop talk when you visit my man cave.


Devon's HiFi Dream Listening Room No. 1 exhibit at the Lisson Gallery in Chelsea NYC is really worth hearing and seeing! 

Open Monday - Friday from 11am - 6pm until August 5, 2022.


This 'zine contains comprehensive information about the whole hifi installation + more! 
The poster + 'zine is available at Printed Matter Inc.