Repair the PreSonus Eris E4.5 speaker

audiodiy

I’ve been using the PreSonus Eris E4.5 for nearly three years. Affordable, compact, built-in amp, flat frequency response — it’s been one of my favorite pieces of gear.

At some point it started producing a persistent noise even with nothing connected to the inputs.

Since the warranty had long expired, I opened it up for a visual inspection. The electrolytic capacitors from an unfamiliar brand called “Cap-top” immediately looked suspicious — some were visibly bulging at the top.

The brown resin appears to be anti-vibration adhesive.

Bulging Cap-top electrolytic capacitors on the PCB Close-up of Cap-top capacitors on the PCB Close-up of Cap-top capacitors on the PCB Close-up of Cap-top capacitors on the PCB

Checking them with a multimeter confirmed it: several capacitors had failed. Replacing them all was the obvious fix — though I did wonder if it was even worth the effort.

Measuring capacitors with a multimeter

So I went ahead and replaced the full set of electrolytic capacitors — using audio-grade caps wherever I could find matching specs. Total parts cost came to ¥1,800.

Parts replaced

No.spectypeqty
11000μF 25Velectrolytic capacitor2
2470μF 25Velectrolytic capacitor2
3220μF 25Velectrolytic capacitor4
4100μF 400Velectrolytic capacitor1
5100μF 16Velectrolytic capacitor1
610μF 50Velectrolytic capacitor1
74.7μF 100Vnon-polarized electrolytic capacitor2

Newly replaced audio-grade capacitors on the PCB Close-up of replaced capacitors on the PCB Close-up of replaced capacitors on the PCB Close-up of replaced capacitors on the PCB

The noise disappeared completely and the frequency response was back to normal. The new caps look impressively shiny, but honestly I couldn’t hear any difference.

Frequency response:

Frequency response after repair