NOS sealed factory matched transistors McIntosh MC250 / MC2505

# NOS Vintage McIntosh MC250 / MC2505 Transistor Master Rebuild Kit

# Factory Sealed Bags with Original McIntosh Factory Selection Codes

Up for sale is an incredibly rare, New Old Stock (NOS) semiconductor restoration lot for legendary McIntosh solid-state amplifiers, perfectly matching the required layout for the iconic MC250 and MC2505.

If you are restoring one of these classic amplifiers, you already know that generic modern substitute transistors frequently cause bias instability, high distortion, or thermal runaway. This lot consists entirely of original, factory-sorted McIntosh "House Code" components. They remain factory-sealed in their original vintage packaging, guaranteeing precise matching directly from the factory.

These packages feature authentic, original McIntosh factory ink color-dot selection marks used to bin components by strict gain/beta tolerances. The driver bags feature explicit factory "Replaced By" (r/b) designations for certified superceded tracking.

### 📦 What is Included in this Lot & Factory Markings:

* **(1 Bag of 4) 132-070 NPN Power Output Transistors:** Large TO-3 heavy metal cans. A perfectly matched quad-pack to completely overhaul the main output channels on the heatsinks.

* **(1 Bag of 2) 132-524 (r/b 023) NPN Driver Transistors:** Obsolete TO-66 medium metal cans. Factory-stamped replacement upgrade for base part 132-023. Marked with original **Black Dots**.

* **(1 Bag of 2) 132-530 (r/b 024) PNP Driver Transistors:** Obsolete TO-66 medium metal cans. Factory-stamped replacement upgrade for base part 132-024. Marked with original **Red & Green Dots** for perfect complementary balancing with the 132-524s.

* **(1 Bag of 2) 132-021 NPN Transistors:** Small-signal pre-driver stage components. Marked with original **Yellow Dots**.

* **(1 Bag of 2) 132-032 PNP Transistors:** Small-signal pre-driver stage components. Marked with original **Red Dots**.

### 🛠️ Circuit Overhaul Cross-Reference (Per McIntosh Service Manual):

This package populates the exact factory positions for a complete channel overhaul:

* **132-021 (Yellow Dot):** Board Positions Q15, Q16

* **132-032 (Red Dot):** Board Positions Q17, Q18

* **132-524 & 132-530:** Driver Board Driver Pairs Q19, Q20, Q21, Q22

* **132-070:** Main Power Output Heatsink Positions Q23, Q24, Q25, Q26

### 🔍 Condition:

* **New Old Stock (NOS):** Never opened, never soldered, never used.

* **Factory Sealed:** Components remain sealed inside their original vintage packaging. This preserves the original pin surfaces from oxidation and guarantees the integrity of the factory matching. (132-070 bag had a small slit in it so I sorta folded the corner on itself to prevent losing a transistor) you can see in the photos.

### ✈️ Shipping & Handling:

* Item will be packaged with extreme care in an anti-static bubble mailer and shipped securely via a tracked service.

* International shipping is available through the platform's global shipping program.

*Note: Due to the vintage, uninstalled nature of electronic components, this lot is sold as-is. Professional installation is highly recommended.*