Saturday, February 11, 2017

Carver TFM-35X Amplifier LED Upgrade & Test

Carver TFM-35X Power Amplifier

The TFM-35X is one of Carvers most popular amplifiers at a bargain price when new delivering over 250dBW featuring a Gold Plating inputs and heavy duty 5-way binding jacks. The topology is mounted on a single symmetric PCB design and uses modern TO-264 output devices mounted on a single heatsink mount to the chassis. At rated power and dissipation factors these unit run extremely hot and without proper mounts for the TO-264 devices its a long term concern of mine. 

On many online sites Ive seen folks do the LED conversion using single diodes which I found to have poor dispersion. We opted to make copper brackets and use commonly used custom multi-SMD LED’s 8V fuse type for easy replacement or color changes in the future. 

The schematic and units exhibit a series connection via a 24VAC Vs. Using Ohms law we determine; (Vs-Vf)/I  or 24V-16V/.050A for a minimal resistor of 160OHM. We opted for dispersion and brightness to go with a 200OHM 1 WATT resistor.

Comparing Blue & Green SMD LED’s

Custom Fuse Mounting

Audio Notizen
While on the bench we performed an 8OHM Bandwidth response and Output Verification reports...quite impressive though I should note Carver used filters to obtained these results while still..again impressive with a slight discrepancy on one channel I suspect due to age and health of the unit.

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