Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Colonl_Charisma on January 22, 2025, 08:24:27 AM

Title: Slight hum possibly from power transformer
Post by: Colonl_Charisma on January 22, 2025, 08:24:27 AM

Hi everyone,

I've had my Crack since 2020. I was doing some tube rolling (power tube) yesterday. This particular tube is noisy and has a bit of an audible hum when in use, so I replaced it with one of my reliable, non-microphonic tubes.

However, when I placed my ear near the power transformer after replacing the tube, I still hear a hum. I should note that my headphones are very quiet, and I cannot discern any noise coming through them when placed over my ears.

Is a slight hum from the power transformer (or the general area) normal, or should it be quiet?

Title: Re: Slight hum possibly from power transformer
Post by: Paul Birkeland on January 22, 2025, 01:37:26 PM

If you're in a country with 50Hz mains, a tiny but of transformer hum from the Crack might not be that surprising.  If you're in a 60Hz country, then I'd be tightening down the transformer screws and double checking your voltages.

Title: Re: Slight hum possibly from power transformer
Post by: Colonl_Charisma on January 22, 2025, 04:01:21 PM

Hi Paul,

I'm in the USA, so it looks as if I'm using a 60 Hz mains.

I'll make sure the transformer screws are tight, and I'll check the voltages before the end of the week. I'll report back!