One BBC Audio Transformer LG/65
MSC
This is a high quality 4:1 (600ohm/20kohm)
Line to Grid audio matching transformer.
AI Description
The BBC LG65 is a classic, vintage broadcast-grade audio input and
line-matching transformer designed by the British Broadcasting Corporation
(BBC) for solid-state studio dynamics and monitoring equipment.
Historically engineered for
high-precision signal scaling, the LG65 is heavily valued today by analogue
hardware collectors, DIY builders, and mixing engineers who rack vintage BBC
sub-modules into standalone studio processors.
Technical Specifications &
System Roles
- Winding Configuration: It features a 2:1
step-down turns ratio. This allows it to step down high line-level
signals, providing a clean impedance transition into early transistor or
integrated circuit (IC) gain stages.
- Function & Naming: Following the
official BBC Audio Transformer Coding System, the "LG"
prefix represents Line to Grid (or Line to Input Gate). It
functions as an isolated input step-down link rather than a transparent
line-to-line bridge.
- Case Suffixes: Depending on the exact
sub-module or frame it was installed into, the transformer was catalogued
with different physical pinning footprints, such as the LG65/MSC or
LG65/MPC.
Prominent Historical
Applications
The LG65 was an essential
front-end component across several legendary pieces of BBC Designs Department
hardware:
- BBC AM6/11 & AM6/18 Limiting Amplifiers:
In these highly sought-after solid-state compressors, the LG65/MSC
serves as the primary balanced audio input transformer (T101). It feeds
the initial transistor circuitry (like the vintage BC109) to handle hot
incoming audio feeds cleanly.
- BBC AM20/3 PPM Amplifiers: In Peak Programme
Meter (PPM) driver cards, an LG65/MPC (T1) acts as the unbalanced
line-to-input interface. It handles active input attenuation networks,
allowing the PPM card to process incoming signals at standard broadcast
reference volumes (0 dB, -20 dB, or -43 dB).
See picture of BBC Eng Inf data
sheet which is included in the sale.
NB: Pound Coin NOT included in
sale...
Prompt payment please. No time
wasters.
Happy bidding!
Dispatched with eBay Simple
Delivery