Marantz sc-5

Preamplifier related to the PM-15 - in all-out fashion and with a battery-powered external power supply !


sc-5 : stereo control preamplifier
The sc-5 has all the (nowadays impossible for the same price point) goodies of the Pm-15 : fully copper-plated from top to bottom, massive aluminium feet, front and sides.

Fully symmetrical circuit design, symmetrical up to the grounding of the L and R channels.
New HDAM modules (op'amp with discrete components in a shielded copper box) for the phono, balanced CD and preamp outputs, ultra-short signal paths.

The massive two carbon tracks 2x 10kOhm potentiometer was custom made by ALPS (yes... ALPS as usual) and allows a maximal ± 1dB in channel balance accuracy.

The 0...-14dB Left and Right gain attenuators each use resistance arrays within an NFB loop.

7 single-ended inputs (including phono MM/MC and CD unbalanced), two tape loops, one balanced CD input and two preamp outputs, s-e or balanced.


bb-5 : dc power-supply
The bb-5 is a battery-powered power-supply which delivers clean DC current to the sc-5 preamp and one or two sm-5.
One sc-5 and two sm-5 can be fed by way of 7-pin terminals, each terminal giving DC 24V / 0,15A for each sm-5 and DC 24V / 0,25A for the sc-5.
Each pin feeds a different portion of the sc-5 and sm-5's respective circuits.

The chassis is built like the that of the sc-5 and a microprocessor monitors the state of the two batteries to allow automatic charging or step to AC powering if they are completely discharged.

The power transformer has four windings, two of which are for its own micro-processor and control, the other two for the batteries' charging and "audio".

The two batteries are lead-less but I have no details as to which type of material is used, nor the amount of charging cycles available or charging time.

The looky-looky VU meter indicates available voltage while the operation button selects one of three modes : charge, AC or DC operation.

The back plate holds the three DC terminals, power-on switch, fuse and "power remote" selector to allow power on of all four units through the bb-5's (back) power button only - four because the customer was supposed to use one sc-5 and two sm-5 in BTL mode.

Three CCNE circuits are present to further clean power supplies ; CCNE are made of a resin-shielded cap and precision resistor added between power transformer and the rectifying diodes.

Slightly revised in september 1997 : reinforced power-supply and changes to the operating conditions of each unit amp. Probably changes as well in the bb-5 itself but these remain sans details.
These revised versions are T-tagged MCJ (Marantz Company of Japan), while the originals were MJI (Marantz Japan Inc.).


Of all the "new" Marantz design slant which started with the PM-15, PM-17, CD-17 etc, I believe the sc-5 / bb-5 to be the most elegant and well balanced.

Despite winning the Components of the Year Award from Stereo Sound, the sc-5 and bb-5 seemingly sold very poorly.
I have no idea if this was due to pricing, final sound or distribution problems.
Or if the PM-15 was, after all, just as good :)


A real sc-5 & bb-5 here.