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Repair / Help Forum => Repair / Help => Topic started by: EmperorNorton on May 30, 2018, 10:19:11 AM

Title: Heathkit AA151 Volume Control Issue
Post by: EmperorNorton on May 30, 2018, 10:19:11 AM

Hello guys,

Thought that tubes would be more fun and end up with more problems as I go.   I noticed some variation in right and left channel on my Heathkit.  Seemed like the Heresys should be cranking at 12 oclock.   All the connections are good.   Sprayed a little DeOxit in the volume pot but made no difference.  Any suggestions before I take it out to Don at Phils TV?  thanks in advance

Title: Re: Heathkit AA151 Volume Control Issue
Post by: rgpit on May 30, 2018, 10:44:11 AM

Swap the right and left channel tubes and see if the volume issue follows the tubes. BTW you should not use contact preservative on any tube pins or sockets.

Title: Re: Heathkit AA151 Volume Control Issue
Post by: OldiesButGoodies on May 31, 2018, 12:29:56 AM

Quote from: EmperorNorton on May 30, 2018, 10:19:11 AM

Hello guys,

Thought that tubes would be more fun and end up with more problems as I go.   I noticed some variation in right and left channel on my Heathkit.  Seemed like the Heresys should be cranking at 12 oclock.   All the connections are good.   Sprayed a little DeOxit in the volume pot but made no difference.  Any suggestions before I take it out to Don at Phils TV?  thanks in advance

They can be more fun but can also be a pain,  as you can be witness to now.  For now I am using solid state,  where I know I will get roughly the same result every time.  Do I miss tubes?  Yes,  particularly in the preamp section.  So would not be surprised  if I end up with tubes again there.   

Try Ron's suggestion - see if you have a weak tube somewhere. 

Pepe

Title: Re: Heathkit AA151 Volume Control Issue
Post by: MacGeek on May 31, 2018, 06:02:26 AM

What is your source?  Channel imbalance issues can come from anywhere in the signal chain.  If the tube swap doesn't identify the problem, I suggest swapping every wire pair, a component at a time, including the speakers

Title: Re: Heathkit AA151 Volume Control Issue
Post by: EmperorNorton on June 03, 2018, 06:57:19 AM

I will swap out components and swap the tubes.  The volume seems balanced but low.  I can listen to the Heresys with the volume knob at 3 o'clock and it's not too loud.

Title: Re: Heathkit AA151 Volume Control Issue
Post by: Sir Thrift-a-Lot on June 03, 2018, 10:38:00 AM

Quote from: EmperorNorton on June 03, 2018, 06:57:19 AM

I will swap out components and swap the tubes.  The volume seems balanced but low.  I can listen to the Heresys with the volume knob at 3 o'clock and it's not too loud.

Yeah, that's not right.   I can drive my Hereseys with the headphone jack of my DAC.   Did you give a good cleaning to the mode switch?  That could give all of the symptoms you have described.

Title: Re: Heathkit AA151 Volume Control Issue
Post by: MacGeek on June 03, 2018, 03:53:17 PM

Tape monitor switches are notorious for causing problems as well, in my experience.  It may take more than one  cleaning.