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Peach Audio M196sx

Stereo Valve Mic Preamp By Hugh Robjohns

Peach Audio M196sx

Once in a while, a new preamp brings something genuinely worthwhile to the table...

David Peach started repairing and modifying audio gear in the '70s. Having developed a fascination with what made equipment sound good (or not!) he eventually concluded that the power-supply design, and especially the internal grounding arrangements, are critical. That has guided his designs ever since.

Engineering Elegance

The new M196sx dual-channel, all-tube mic preamp is the first of Peach's new rackmounting Savannah range (which will also include EQs and dynamics processors) and it builds on the success of two previous incarnations. Weighing 13kg and extending 430mm behind the rack ears, this 2U device is very substantial — yet it's also elegant and purposeful. Its lilac front panel is littered with silver switches and buttons (in momentary, latching and interlocked forms) but the layout doesn't feel crowded. Contributing to this elegance is that all the controls and buttons are mounted on a sub-chassis behind the front panel; there are no visible screws or fixings. The traditional, old-school engineering approach is continued inside, where the construction is heavy-duty and most impressive.

The input transformers (in mu-metal cans) sit just behind the front panel, on PCBs which host much of the input conditioning circuitry, while the output transformers are contained in a box bulging from the rear. All are made by Harbuch Transformers in Sydney. A substantial toroidal mains transformer on the right-hand side of the chassis sits on a main PCB, which occupies most of the chassis floor and carries the power-supply circuitry and both preamp sections. Each channel employs a 7025 dual-triode (low-noise 12AX7WA/ECC83 equivalent) for the front-end gain, and a 6189 dual-triode (12AU7/ECC82) to power the output, and all these valves are mounted vertically.

Under the hood: the input–conditioning circuitry and input transformers can be seen on the boards at the top, mounted on the controls sub-chassis. All the valves are mounted vertically on the motherboard, which hosts high–quality through-hole components throughout. Relays for switching the output modes and M‑S matrix can be seen on the vertical board at the bottom.Under the hood: the input–conditioning circuitry and input transformers can be seen on the boards at the top, mounted on the controls sub-chassis. All the valves are mounted vertically on the motherboard, which hosts high–quality through-hole components throughout. Relays for switching the output modes and M‑S matrix can be seen on the vertical board at the bottom.

A grounded IEC mains inlet, switchable for 120/240 V, is joined by a sextet of XLRs for the mic and line inputs, and the line outputs. A removable Option Access panel covers a port which will accommodate future plug-in modules, adding functions such as digital converters, remote-control facilities, or a multi-channel summing mixer.

Instruments can be connected via front-panel quarter-inch sockets using normal 'mono' unbalanced TS plugs. Neatly, these sockets also serve as unbalanced insert points, allowing effects pedals or other processing to be applied to mic or line input signals. To access this, a Y-cord (TRS to dual-TS) is required, and it must be used in the opposite way to most applications, as the send is necessarily on the ring and the return on the tip. The insert point is post the input source selection, input...

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Published May 2020