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Square State Solid State


::EQUALIZER model one b::

Design Concept

The Square State Solid State model one b is a single channel, three band equalizer housed in a 1 RU chassis. The equalizer stages are comprised of inductor-capacitor filters, components commonly found in classic EQs. The EQ offers 6 frequency selections per band, each offering roughly 20 dB of cut/boost. The bell-shaped (bandpass) response curves are broader than similar equalizers, lending themselves to a very musical sound. Additionally, the high and low frequency bands offer both shelving and bell responses.

The model one b is a swinging input equalizer. This is an equalizer circuit topology that is based on inductor-capacitor-resistor (LCR) filter networks. These filter networks are crossfaded between the inverting and noninverting inputs of an operational amplifier, resulting in adjustable cut/boost for each band. While the LCR filters are passive, the opamp provides makeup gain and buffering, such that the overall circuit is active.

While the underlying circuit is old, the design for the model one b is new, and provides more versatility than common vintage swinging input implementations.


Product Downloads

pdf icon model one b Product Manual

pdf icon model one b Recall Sheet



Q: How do I run the model one b with balanced connections?

A: Use 1/4" TRS jacks to connect the unit, with the tip wired to signal + (hot), the ring wired to signal - (cold), and the sleeve wired to the shield.

Q: How do I run the model one b unbalanced?

A: Simply use 1/4" TS connectors, as found on common guitar cables, or insert cables. The unit will adapt itself to unbalanced mode.

Q: Can the input be balanced, while the output is unbalanced (or vice versa)?

A: Yes. If your signal chain dictates, the model one b can be connected between balanced and unbalanced (or unbalanced and balanced) units.

Q: How do I get a repair authorization number?

A: Email tech@squarestatesolidstate.com.

Q: I'm interested in becoming a square state solid state retailer, what do I need to do?

A: Call Joe at 303-604-1266 or write him at sales@squarestatesolidstate.com.