The prelude
I have acquired one of these amps that has a particular problem. Having searched the site, I realise that others may have had a similar problem and I am hoping someone might recommend a sensible plan of attack.
The problem
The amp is in lovely nick, but on firing it up, there is a loud steady hum. This hum is not affected in any way by adjusting the volume or any of the controls, including the push button channel switch.
On reading previous posts, I checked if the speaker moved in one direction on start up and it does. So, I measured for DC at the speaker and this came out at 9.5V.
I haven't had it apart yet, as it only came in today, but am hoping for a plan of attack. But if there is DC at the speaker, this points to one of a number of potential causes, and I wondered if someone might suggest which to tackle?
I cannot find the Audition Plus anywhere as a schematic, so wonder if the difference was just branding. I have attached the Audition 20 schematic.
A whinge about the paucity of adult education
And if anyone is wondering why I haven't learned more since my first posts, I have been trying. I even tried to find a part time/evening course in electrical engineering or electronics and its a nightmare.
There are no electronics ones any more – I KNOW there used to be. As for the electrical engineering ones, they are either long vocational courses, or do little more than qualify the individual in PAT testing.
If anyone knows of any in the east London/south Essex areas, I'm all ears. Or a good correspondence course.
The thanks
Thanks in anticipation.
I have acquired one of these amps that has a particular problem. Having searched the site, I realise that others may have had a similar problem and I am hoping someone might recommend a sensible plan of attack.
The problem
The amp is in lovely nick, but on firing it up, there is a loud steady hum. This hum is not affected in any way by adjusting the volume or any of the controls, including the push button channel switch.
On reading previous posts, I checked if the speaker moved in one direction on start up and it does. So, I measured for DC at the speaker and this came out at 9.5V.
I haven't had it apart yet, as it only came in today, but am hoping for a plan of attack. But if there is DC at the speaker, this points to one of a number of potential causes, and I wondered if someone might suggest which to tackle?
I cannot find the Audition Plus anywhere as a schematic, so wonder if the difference was just branding. I have attached the Audition 20 schematic.
A whinge about the paucity of adult education
And if anyone is wondering why I haven't learned more since my first posts, I have been trying. I even tried to find a part time/evening course in electrical engineering or electronics and its a nightmare.
There are no electronics ones any more – I KNOW there used to be. As for the electrical engineering ones, they are either long vocational courses, or do little more than qualify the individual in PAT testing.
If anyone knows of any in the east London/south Essex areas, I'm all ears. Or a good correspondence course.
The thanks
Thanks in anticipation.