The Manley Balanced Moving Coil RIAA Phono Stage was built from 1994 to 1997. In that time we sold a whopping 8 units so this product is hardly worth a web page, but anyway...
This unit was based on that wacky but clever balanced input for the moving coil where one leg off the MC cartridge fed the grid of the 6072A while the other leg fed the cathode. The MC inputs showed up on a 5-Pin XLR so you'd probably need a custom made cable to get into this unit. On the faceplate was a phase flip per channel for the MC input. The input impedance of the MC circuit was fixed at around 1000 Ohms and I have no idea what the input MC capacitive loading was. It was probably whatever the cable capacitance was! Anyway, this MC stage pumped about around 15dB of gain before hitting the general RIAA stage. (Front panel trimpots allowed for a little adjustment of gain but unless you have the equipment to recalibrate them like we do, I'd leave 'em well alone!)
On this point, there's not gobs of (quiet) gain in this unit for the MC, so really with this unit you need to be up over 0.7mV output MC cartridges. Get a new Manley Steelhead if you want to use a 0.2mV MC cartridge! Hell, everyone should have a new Manley Steelhead! Me first!
Sorry for the digression... At this point was where the Moving Magnet input came in. RIAA equalization was performed in the feedback loop of this 12AX7 stage. MM input impedance was fixed at 47 KiloOhms with usually 100 picofarad polystyrene capacitor soldered right at the MM RCA input jacks. From there a 12AT7 fed the output jacks via some nice MIT-MutliCaps. The chassis was made of aluminum and the tubes poked through the top of this chassis which didn't do much for shielding did it? So yeah, you don't want this thing next to that huge light dimmer for your fluorescent lights hanging over your turntable... ugh. The printed circuit board was gold-plated-- how nice!
There was an outboard (thank god!) power supply housing a Mercury Magnetics power transformer and your basic rectifiers and pi filter caps and such. A 4-core grey umbilical cord carried the AC heater and B+ DC volts up to the audio chassis. Heater rectification took place in the audio chassis.
Rest In Peace!
The guts of the Balanced Coil RIAA Phono Stage
Get the owner's manual for the Manley Balanced Moving Coil RIAA Phono Stage.
Features and Specifications
Manley Balanced Moving Coil RIAA Phono Stage:
- Factory set for 100V, 120V or 220-240VAC operation for original destination country's mains voltage.
- Operating Mains Voltage changeable with power transformer re-wiring and fuse value change.
- Mains Voltage Frequency:
Manufacturer's Suggested Retail Price
- Manley Balanced MC RIAA Phono Stage Original Retail Price: $2,750 clams (USD $) each