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.😆

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!

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...😔    

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 500, Shure M3D + 7D, SC35C, 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

Speakers = Altec 755C in Silbatone cabinets

Pioneer PL6U + Shure M44

Preamp = JEL Loctal

Amp = Radiotron SE2A3

Speakers = Altec 755C in Silbatone cabinets

Pioneer PL6U + Denon DL103

MC step up = Altec 4722

Phono preamp = Shure M65

Line stage = JEL Loctal

Amp = SE71A

Speakers = Altec 755C in Silbatone cabinets

Collectors of 45 rpm vinyl, take note!😊👍

It can also be the heart of a mono hi-fi set up!👍😊

Pioneer PL6U + GE VRII mono cartridge

Mono preamp = JEL Variable EQ phono 

Amp = JEL SE2A3

Speaker = Altec 756B + 32C + 806 + 23744

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.

Go to Part 2