Active | Solid State Copy

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SSPB.V3 solid state buffer

The active solid state version of the LDR3000x.V3 adds our SSPB.V3 solid state preamp buffer module to our core V3 Max stepped attenuator to deliver clean, robust current drive. A highly neutral yet dynamic solid state buffer, the SSPB.V3 enhances performance when a passive attenuator alone may not satisfy.

The SSPB.V3 is our 3rd generation solid state buffer that is designed as both a stand-alone buffer board and also as a plug-in module. When used as a plug-in, it mounts directly on to the V3 Max attenuator/controller board turning the V3 Max into a compact, high performance solid state preamp engine that transforms the LDR3000x from a passive into an active preamp.

SSPB.V3 solid state preamp buffer diagram

Dynamic authority without editorializing

Our goal in offering an active solid state preamp is to augment the performance of our core V3 Max LDR attenuator/controller while retaining all its positive characteristics and not adding any coloration of its own. For this we chose the proven low-noise dynamic current drive of the LSK170 JFET together with a neutral high impedance unity gain stable JFET op amp as an input buffer.  The result is a neutral buffer with robust dynamic authority with minimal editorializing. Just the way we like. it.

Buffered input stage with optional gain

The SSPB.V3 employs a high impedance audio op amp input buffer stage that is set by default to unity gain (no signal amplification).  The simple fact is most audio systems require no actual gain (voltage boost) from their preamp in order to deliver adequate volume headroom.  But just in case your system does needs it, you can increase the gain by swapping out a a simple pair of plug-in gain resistor modules that provide either +6 dB or +12 dB gain. Other gain levels can be achieved by using a custom set of plug-in gain modules which can be ordered by request.

Also, since the 8-pin dual channel input stage op amp is socketed, those wishing to explore alternative input stage op amps can do so.

No coupling capacitors

The input and output of the solid state drive are both direct coupled. This means there are no input or output coupling capacitors in the signal path of the solid state LDR3000x.V3. This is made possible by using a dedicated 2 stage split voltage power supply for powering both the op amp input stage and the JFET output stage. This power supply is separate from the power supply for the V3 Max attenuator/controller.

The DC offset of the preamp output can be trimmed to near zero levels through easily adjustable trimmer pots that require only a small screwdriver and a volt meter to measure each output signal. Doing so does require removing the top cover of the preamp to access the solid state buffer board.

Operating Instructions

The operation of the LDR3000x.V3 is indistinguishable from the underlying ePot.V3 Max Controller/Stepped Attenuator at the heart of the LDR3000x. The operating instructions for the V3 Max are available in our online product documentation and can be found here.


(coming soon)

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