Bottlehead Forum

Bottlehead Kits => Eros Phono => Topic started by: olegreg on November 28, 2022, 09:00:28 AM

Title: EROS Major Hum
Post by: olegreg on November 28, 2022, 09:00:28 AM

I have a major hum coming from both channels on new build.
Also, there is no separation between channels. Source connected to one channel comes out on both sides.

Title: Re: EROS Major Hum
Post by: olegreg on November 28, 2022, 09:08:35 AM

I wanted to add that the input is shorted to rule out outside sources.

Title: Re: EROS Major Hum
Post by: Paul Birkeland on November 28, 2022, 10:13:36 AM

How are your DC voltage checks?

Summing channels would tend to indicate a substantial miswire, which should also throw off the DC voltages.

Title: Re: EROS Major Hum
Post by: olegreg on November 28, 2022, 10:53:45 AM

Rechecked
1A 235 vdc
1B 230
OA 155
OB 156
OC 98
OD 98
OKA 99
OKB 100
OKC 1.63
OKD 1.89

Title: Re: EROS Major Hum
Post by: Paul Birkeland on November 28, 2022, 10:59:09 AM

Can you post some build photos? 

Title: Re: EROS Major Hum
Post by: olegreg on November 28, 2022, 11:42:32 AM

Here you go

Title: Re: EROS Major Hum
Post by: olegreg on November 28, 2022, 11:57:15 AM

Hum was with SUT wired in per instructions. Rewired without SUTs (pictured) and no hum through headphone.
I must have done something wrong with the SUT wiring.
It was not clear on where to land A1 and B1. I landed on 2 and 15 putting the loading resistor on the secondary of SUT.

Title: Re: EROS Major Hum
Post by: olegreg on November 28, 2022, 12:46:55 PM

New Hum...
Open or shorted input sounds the same.
Repeating sewing machine sound
I tried to send video with sound, won't accept mp4

Title: Re: EROS Major Hum
Post by: debk on November 28, 2022, 01:50:27 PM

From the pictures it looks like D2 on the B side of the shunt regulator board is in backwards

Title: Re: EROS Major Hum
Post by: Paul Birkeland on November 28, 2022, 03:33:19 PM

Quote from: olegreg on November 28, 2022, 12:46:55 PM

Repeating sewing machine sound

That kind of noise is often wireless interference from a nearby device.

Title: Re: EROS Major Hum
Post by: olegreg on November 29, 2022, 08:34:40 AM

First: Debra K, Good eye!  Those LED Diodes where probably the hardest component to install on a board. I'm surprised the VDC all checked out, but on close inspection in a darkened room, it was not glowing.  Thank you, Debra

Second: On the sewing machine hum. Paul nailed it... My Sonos sound bar is causing the hum. I will just have to turn it off when I want to listen to music. Thank you, Paul.

BTW, first couple of minutes listening, the EROS sounds great.

I have SUT questions on a different thread.

Title: Re: EROS Major Hum
Post by: debk on November 29, 2022, 03:27:14 PM

Glad you got it working