Presonus M80 8 Channel Microphone Preamp with Jensen transformers LT1357 op amp
This is an early model Presonus M80, when they were using Jensen input transformers. They later switched to an inferior generic. The op amps have been upgraded to LT1357. Many of the components are installed on sockets, so it's easy to modify without even soldering. All of the channels work for dynamic mics, but 4 of the channels are not supplying phantom power correctly. This is a known issue, and one I had serviced in 2012. The issue you describe is one I'm familiar with. There is a resistor that literally wears out or develops a cold solder joint due to thermal issues from phantom power being engaged/disengaged over years of use. We replace and upgrade those resistors to a higher watt component (1/8 watt through-hole opposed to 1/16 watt surface mount) and it's good to go.
Unfortunately the repair technician just used surface mount resistors in the repair, which I believe have failed again. Everything else is working as expected, with some scratchiness in pots from lack of use. Sounds great on all channels with dynamic mics, I used primarily for drums in a mobile recording rig. The item "Presonus M80 8 Channel Microphone Preamp with Jensen transformers LT1357 op amp" is in sale since Wednesday, January 9, 2019. This item is in the category "Musical Instruments & Gear\Pro Audio Equipment\Preamps & Channel Strips".
The seller is "newttheband" and is located in Pittsburgh, Pennsylvania. This item can be shipped to United States.
- Brand: PreSonus
- Model: M80
- Number of Channels: 8
- Type: Microphone Preamp
- Features: Headphone Output