Author Topic: Heathkit AA151 Volume Control Issue  (Read 165 times)

Offline EmperorNorton

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Heathkit AA151 Volume Control Issue
« 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
Yamaha PF800/Dual 721
DBX D5/Sony CA8ES
Yamaha C-2X
Hafler Five Hundred/Sansui AU9500/Heathkit SA-2/Parasound HC-1000
Canton CT800s/Vandersteen 2CE/Klipsch Heresy/Dahlquist DQ-10

Offline rgpit

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Re: Heathkit AA151 Volume Control Issue
« Reply #1 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.
Primary System: Pioneer PLX-1000 with Nagaoka MP-150, Sony XDR-F1HD, Tascam CD200 transport, Squeezebox Touch, Benchmark DAC2 HGC, Prima Luna Dialog Two, Analog Research Velluto, Harbeth Compact 7ES-3, Elac 10" subs, Alesis Masterlink ML9600 master disc recorder

Offline OldiesButGoodies

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Re: Heathkit AA151 Volume Control Issue
« Reply #2 on: May 31, 2018, 12:29:56 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

Spkr: Harbeth 30.1 on Sound Anchor 4 post stands
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Power:  CI Audio D-200 MkII monoblocks
Phono: VPI Aries 1,  Van de Hul Frog
CD: Oppo 203
Cass: Tascam 122MkII
R2R: Revox B77
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Offline MacGeek

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Re: Heathkit AA151 Volume Control Issue
« Reply #3 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
MAC C-46 pre, MQ 108 eq, MC 352 amps (2), MR 78 tuner, MCD 500 CD, MPI-4 scope, LS 352 speakers, Sony HDR-F1HD AM/FM/HD tuner, Denon DRS 810 cassette, Denon CDR-W1500 CD recorder, Music Hall MMF-9 w/B&O MMC2, Revox A-77 R to R.

Offline EmperorNorton

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Re: Heathkit AA151 Volume Control Issue
« Reply #4 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.
Yamaha PF800/Dual 721
DBX D5/Sony CA8ES
Yamaha C-2X
Hafler Five Hundred/Sansui AU9500/Heathkit SA-2/Parasound HC-1000
Canton CT800s/Vandersteen 2CE/Klipsch Heresy/Dahlquist DQ-10

Offline Sir Thrift-a-Lot

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Re: Heathkit AA151 Volume Control Issue
« Reply #5 on: June 03, 2018, 10:38:00 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.
« Last Edit: June 03, 2018, 10:40:56 AM by Sir Thrift-a-Lot »

Offline MacGeek

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Re: Heathkit AA151 Volume Control Issue
« Reply #6 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.
MAC C-46 pre, MQ 108 eq, MC 352 amps (2), MR 78 tuner, MCD 500 CD, MPI-4 scope, LS 352 speakers, Sony HDR-F1HD AM/FM/HD tuner, Denon DRS 810 cassette, Denon CDR-W1500 CD recorder, Music Hall MMF-9 w/B&O MMC2, Revox A-77 R to R.