Description

This is a matched quad of MMBFJ201 SMD JFETs pre-soldered to compact adapter boards with clearly labeled D / G / S pads. They’re ready to drop into through-hole layouts—just match D, G, and S on your PCB and go.

Note: These work on all phaser projects that require a matched quad set using 2N5952.

Why builders love these

• Matched for phasers & multi-stage FET circuits – quads are binned to a tight Idss window for a smooth, even sweep.
• Pre-soldered convenience – no SMD wrangling; adapters are 0.1″ (2.54 mm) spacing with D/G/S silk.
• Consistent modern parts – SMD J201s have a tighter tolerance than vintage through-hole lots.
• Includes gold pin headers – easy to solder and super low profile so they sit low off of the main PCB.

 

What’s included

• 4 × MMBFJ201 (SOT-23) JFETs, pre-soldered to adapter boards
• 4 × 3-pin gold pin headers
• Each adapter board silk-labeled: D / G / S. Note: the D pad is the square pad.

 

Compatibility

• Phase 90 / Phase 45-style phasers and most JFET phaser clones that originally called for 2N5952 transistors.
• Any circuit expecting J201 or 2N5952 through-hole, as long as you match the D/G/S pads.

 

Install notes

• Ignore any TO-92 outline on the PCB—follow the nets: D to D, G to G, S to S.

 

Specs

• Device: On-semi / Fairchild MMBFJ201 (SOT-23)
• Adapter: 0.1″ (2.54 mm) pin spacing; compact footprint; D/G/S labels

 

Many PCBs are laid out for the 2N5952 and use a large “D” silkscreen to mark the flat side (often without D/G/S text) — that footprint is reversed relative to a J201. On those boards the pad order (top → bottom) is G → S → D. When installing the J201 SMD adapter, match pins by name: D→Drain, G→Gate, S→Source.

• Place/rotate the adapter so its G pin goes to the top pad,
• its S pin to the middle pad,
• and its D pin to the bottom pad.