Princeton Reverb AA164 - no sound | The Canadian Guitar Forum

Princeton Reverb AA164 - no sound

Discussion in 'Amp Building/Technical/Repair' started by Lincoln, Oct 23, 2016.

  1. Lincoln

    Lincoln Gold Member

    Joined:
    Jun 2, 2008
    Location:
    Fort Saskatchewan, Alberta
    Fresh AA1164 build, fired it up for the first time and no sound. no hum, nothing. Only sound I've heard so far is when I touch the meter probe to the output wires on the power tubes (blue/brown wires to the PT). All the voltages are perfect except for terminal #1 on V4. Instead of 260V I'm seeing a fast oscillating voltage that my meter won't read on either DC or AC scale. I've double. triple checked, everything seems to be in all the right places. Anybody have an idea where this oscillation might be coming from? B#(*

    or what I need to do to track it down? :D
     
  2. StevieMac

    StevieMac

    Joined:
    Mar 4, 2006
    Location:
    Gananoque, ON
    I'm DEFINITELY no amp tech but, the first thing I think of when there's an absence of ANY sound is the speaker/SPKR jack. I'm not sure I've encountered an amp that ran absolutely silent with a functioning speaker/SPKR jack...

    Regarding the oscillating voltage on V4...could that simply be the Vibrato effect in action? I believe V4 serves both the Vibrato & PI functions on the AA1164, yes, no?
     
    Last edited: Oct 23, 2016
  3. Lincoln

    Lincoln Gold Member

    Joined:
    Jun 2, 2008
    Location:
    Fort Saskatchewan, Alberta
    I wish it was just a speaker or speaker jack. The speaker makes sound when I touch the power tube terminals that the output transformer is wired to, so I know that part of it is working.
    Yes, half the V4 is vibrato, the other 1/2 is phase inverter. But it's the only voltage I can find that doesn't match the info I've got. It could be normal for all I know.

    I'm thinking it's got to be the input jacks. All ideas welcome
     
  4. greco

    greco Gold Member

    Joined:
    Jul 15, 2007
    Location:
    Kitchener, Ontario
    This stuff interests me but I'm only testing my limited knowledge by asking questions/wondering about the logic of my suggestions.

    Can you use a function generator to put a signal into the amp from the input jack terminals (or anywhere after the jacks) to see it you are correct about the jacks?
     
  5. Lincoln

    Lincoln Gold Member

    Joined:
    Jun 2, 2008
    Location:
    Fort Saskatchewan, Alberta
    Total f'n brain-fart. I had a pair of what I thought were 6V6 equivalents so I put them in. Russian tubes........6H9C
    I just put in some real 6V6's and away the amp went, just like it should. So I googled those 6H9C tubes.......and they are 6SL7 equivalents not 6V6's. Talk about dumb.
     
  6. Lincoln

    Lincoln Gold Member

    Joined:
    Jun 2, 2008
    Location:
    Fort Saskatchewan, Alberta
    I did buy an old signal generator, but it crapped out on me. It's old enough it's all octal tubes.
     
    greco likes this.
  7. greco

    greco Gold Member

    Joined:
    Jul 15, 2007
    Location:
    Kitchener, Ontario
    Great news that is was only a brain-fart that you had to deal with!
    And, in addition, you had the correct tubes on hand.

    Sorry to hear about your function generator! ...Santa is coming soon...to Alberta for sure.

    While on the topic. Please be brutally honest...did my function generator idea hold water?

    Another electronic question for you.
    I had a tiny transformer from a clock radio (powered by 115VAC) and I put the approximately 12VAC (IIRC) with milliamps of current output into a speaker to break it in with 60 cycle hummmmmmmm (logical or not, who knows??!!...I read about the idea/concept somewhere).

    Could you reduce the output voltage and current (on the above) to a reasonable level and use it as a very restricted sine wave generator? I'm not suggesting YOU do this...I was talking about it recently to someone and am now wondering if it actually makes "functional" sense (Pun is intended...LOL).

    Thanks in advance for your response.

    Cheers

    Dave
     
    Last edited: Oct 23, 2016
    Lincoln likes this.
  8. Brett Pearson

    Brett Pearson

    Joined:
    Apr 25, 2016
    Location:
    Barrie, On
    Don't feel bad...I was working on a build a few years ago and it was working fine and I was doing some tweaking and when I tried the amp after making the changes there was no sound at all...nothing. I had the chassis on its edge with the bottom facing me so that I could access the guts and it took me 10 minutes to realize that I had removed all the tubes from the chassis and forgot to put them back in as the top of the chassis was facing away from me! LOL. Those Russian 6sl7 tubes are among the best I have ever heard. I have bought quite a few of them for my builds and they sound quieter and better tone wise to my ears than the American old vintage tubes...and they are cheap! I have used them instead of 12ax7's in Champs and other circuits and they just seem to sound bigger and more 3 dimensional to me. I once built a JCM800 hybrid using 6sl7's instead of 12ax7's. Very cool tubes.
     
    Lincoln likes this.
  9. Lincoln

    Lincoln Gold Member

    Joined:
    Jun 2, 2008
    Location:
    Fort Saskatchewan, Alberta
    I'm not sure Dave, but it's worth a try! There's not enough current there to hurt the speaker, so as long as the speaker will respond to 60hz, it should make sound. You need one of the experts to drop by, or try it on an old speaker you don't care about first rather than the brand new one you want to break in
     
  10. Lincoln

    Lincoln Gold Member

    Joined:
    Jun 2, 2008
    Location:
    Fort Saskatchewan, Alberta
    Oh, I did that last night too! I plugged in a speaker and reverb tank, plugged in a guitar, and was reaching for the on switch when I realized there were no tubes in it yet other than the old 12AU7's I put in when I'm soldering.

    Good to hear those 6H9C's may have a future, I won't throw them away just yet.
     
  11. greco

    greco Gold Member

    Joined:
    Jul 15, 2007
    Location:
    Kitchener, Ontario
    You misunderstood me. Sorry f I was not clear.

    I did build it and I used it for breaking in some speakers. It did what it was supposed to do (i.e., constant 60 cycle hummmmmmm).
    Who knows if it really "helped" to break in the speaker...LOL.

    My question was ...
    and it was meant to apply to using it as a basic sine wave function generator for other electronics applications. How dependent is one on making the frequency variable (i.e., +/- 60 cycles) for most of the typical applications? Make any sense?
     
  12. jb welder

    jb welder

    Joined:
    Sep 13, 2010
    Location:
    Melonville, Canada
    You can get by with a tone generator that just puts out 1 frequency for most purposes. Unfortunately, 60Hz is not a good one if it's exclusive. It will cause some confusion with hum, and also most guitar amps don't reproduce down that far.
    There are lots of free online tone generators and also test tones. Do you have a portable cd or mp3 player? Record some tones and set up for looping. Or if you have a metronome or tuner with a 440hz tone, try to use that.
    1K tone is really annoying. I usually use 400hz.
     
  13. greco

    greco Gold Member

    Joined:
    Jul 15, 2007
    Location:
    Kitchener, Ontario
    Very helpful and interesting. Thanks.
     
  14. ampaholic

    ampaholic Gold Member

    Joined:
    Sep 19, 2006
    Location:
    NB
    I have a wonderful sounding BC Audio No. 7 amp built by Bruce Clements in San Fransisco. All of Bruce's amps use the big octal preamp tubes and he believes this is a big part of what sets his amps apart from others. As you mentioned NOS 6SL7's are plentiful and inexpensive and I too can vouch for the tone. Surprising that more builders don't use them.
     
    Brett Pearson likes this.
  15. High/Deaf

    High/Deaf Gold Member

    Joined:
    Aug 19, 2009
    Location:
    LM,BC,CAN
    I've used white noise for this as it's working the speaker at many frequencies, not just one. It's easy to find a pseudo-white noise generator. Tune an FM receiver to a spot where no one is broadcasting in your area - a ghetto blaster works fine for this. An old hi-fi trick is wire the output to two stereo speakers, one out of phase, and put the speakers face-to-face. The speakers cancel each other out and it makes very little noise in the room (coupling isn't perfect). You can run that scenario for a long time without much annoyance.
     
    greco and Lincoln like this.

Share This Page