Frustration with electronic devices

My mixer looks like a planter that hasn't been tended.

• tend a garden 庭の手入れをする

What's more, some of the cables have been going bad, and they need to be replaced.

• 腐る (くさる) (v5r) to rot; to go bad; to corrode; (P);

This past weekend, the left channel was cutting out.

• cut out〔自動｛じどう｝スイッチなどが〕切れる、〔機械｛きかい｝・エンジンなどが〕急に止まる、故障｛こしょう｝する

As a result, I replaced the speaker cables. I found that when I replaced the cables, a significant amount of noise was reduced as well. There was a hiss before that disappeared with the new cables.

• hiss noise 《電》ヒス雑音｛ざつおん｝The Dolby system encodes signal transmission to eliminate high frequency hiss noises.
• hiss of static〔空電｛くうでん｝などの〕シーッという雑音

Maybe an engineer in this blog's audience can explain the reason.

My friend in Amsterdam says it's hard to think of any electronic device which you own that is more than five years old.

• 器 (き) (suf) (1) device; instrument; (2) vessel; container;

I think that's right, cables included. The oldest thing I can think of that I still use are my headphones at the lab, which are exactly five years old now. Maybe that means they are overdue for failure.

• 期限切れ (きげんぎれ) (n,adj-no) expiration of a term; becoming overdue; <- is this the right translation?
  

I hope you don't have to make any costly replacements any time soon.