A Little Agency Laney Model 18 Sets33 Fix May 2026

The phrase “sets33” appeared inside the chassis, written in sharpie on the fiberboard. No schematic reference. No service bulletin. But the PI (phase inverter) tail resistor measured 33k instead of the stock 47k. And the negative feedback loop had a 33k in parallel with a 4n7 cap.

Someone had been in here. Someone with an agenda.

We traced it. The “sets33” fix is a pre-gain cathode mod—on V2, pin 3, they had swapped the 1k8 for a 1k and slammed a 33µF bypass cap in parallel with a 33k resistor. It looks wrong. It is wrong. But it's also right. a little agency laney model 18 sets33 fix

"The Laney 18 sets33 amplifier features:

Device: Laney Model 18 (unit sets33)
Problem: Intermittent channel output with reduced gain and occasional hum.
Root cause: Intermittent cold solder joint on preamp output and worn coupling capacitor on channel 1.
Fix implemented: Reflowed solder joints, replaced faulty coupling capacitor (47µF/25V), cleaned connector contacts, verified grounding.
Result: Full channel output restored, no hum, stable gain, passed 1-hour burn-in. The phrase “sets33” appeared inside the chassis, written

Warning: This fix requires advanced model-making skills. If your Laney Model 18 is mint, consider professional services. Attempt at your own risk. Component & Hardware (shop-level)