IGS Audio T4BX

IGS Audio T4bX

It is widely known that the LA-2A unique character is a result of the applied T4B photocell. In the original TELETRONIX design a electroluminescent panel provided a light source for the photo resistors. This component was very variable in parameters, and this affected the result compression and stereo image of the audio.

In IGS Audio we developed a new photocell parallel to the T4BX. By precisely selecting, testing and pairing subcomponents used in the assembly of this photocell we have created a product line consisting of nearly identical devices in parameters and sound.

Recently I had an opportunity to gather together a few T4B photocells used in the legendary TELETRONIX LA2A. Basing on the IGS 2LA replica I compared the T4B opto-cuplers. The T4B photocell is the single most important element responsible for the compressor’s sound. Every T4B circuit is composed of an electroluminescent panel (EL panel) and 2 photoresistors. One of them reduces gain and the other influences the meter. The setting for the compressor are: GAIN 60, PEAK REDUCTION 100.