# Princeton Reverb AA1164 - no sound



## Lincoln (Jun 2, 2008)

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?


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## StevieMac (Mar 4, 2006)

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?


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## Lincoln (Jun 2, 2008)

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


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## greco (Jul 15, 2007)

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?


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## Lincoln (Jun 2, 2008)

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.


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## Lincoln (Jun 2, 2008)

greco said:


> 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?


I did buy an old signal generator, but it crapped out on me. It's old enough it's all octal tubes.


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## greco (Jul 15, 2007)

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


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## Brett Pearson (Apr 26, 2016)

Lincoln said:


> Total f'n brain-fart


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.


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## Lincoln (Jun 2, 2008)

greco said:


> 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).
> ...


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


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## Lincoln (Jun 2, 2008)

Brett Pearson said:


> 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.


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.


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## greco (Jul 15, 2007)

Lincoln said:


> 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


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 ...


greco said:


> Could you reduce the output voltage and current to a reasonable level and use it as a very restricted sine wave generator?


 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?


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## jb welder (Sep 14, 2010)

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.


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## greco (Jul 15, 2007)

jb welder said:


> 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.


Very helpful and interesting. Thanks.


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## ampaholic (Sep 19, 2006)

Brett Pearson said:


> 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 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.


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## High/Deaf (Aug 19, 2009)

greco said:


> 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).


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.


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## keithb7 (Dec 28, 2006)

Double post...Weird.


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## keithb7 (Dec 28, 2006)

I picked up a simple tone generator on Ebay super cheap. Its mounted on a small PCB board with a small display, a couple of switches, and a couple of line outs. Does more wave types than I'll ever need. Sine, square, sawtooth, white noise, and more. Adjustable frequency. It helped me trouble shoot my 73 Twin. Ran a signal into the input and traced it with my scope. Problem is the annoying noise. I'd love to have a 100W 4 ohm resistor. Those things are pricey.


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## jb welder (Sep 14, 2010)

The metal shell chassis mount ones are around $15 bucks?
Your ears are worth it!


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## Larson (Jan 1, 2020)

Hey guys sorry to bring a dead post back to life but I am having the same exact problem that the OP had but I have 6V6s in the amp and it still won't work. Any ideas?


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## Lincoln (Jun 2, 2008)

Larson said:


> Hey guys sorry to bring a dead post back to life but I am having the same exact problem that the OP had but I have 6V6s in the amp and it still won't work. Any ideas?


Hi! That's an old thread you bumped.

I would say start by checking voltages. Especially where there is a jumper wire under the board. For example, the "B" voltage goes to 3 places on the board. The "D" voltage also goes to 3 places. There is also an "X" jumper marked on the drawing.
Do your tubes light up? Is there 6 volts to all the tube heater connections? Is the cap can grounded? That's a recap of mistakes I've made while building these amps. It's usually something simple. Those jumpers I mentioned are real easy to miss.
Good luck

EDIT: and did you ground pin #8 on the 6V6's???


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## epis (Feb 25, 2012)

[/QUOTE] I'd love to have a 100W 4 ohm resistor. Those things are pricey.[/QUOTE]

Here we go !

https://www.amazon.ca/NGCAT-Resisto...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

You can put a switch(es) and have all impedance options.
Wires aren't soldered under shrink tubing, I would solder it.

P.S.

Sorry I didn't see this was an old thread, but somebody else could benefit from my replay.


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## greco (Jul 15, 2007)

@epis From the above link...
Does this mean that they might not work? (j/k)


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## epis (Feb 25, 2012)

greco said:


> @epis From the above link...
> Does this mean that they might not work? (j/k)
> View attachment 286872


Maybe for their application, as amp load they should be mounted on some kind of heat sink, best would be to mount it in aluminum enclosure like hammond for effect pedals.


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## Larson (Jan 1, 2020)

Lincoln said:


> Hi! That's an old thread you bumped.
> 
> I would say start by checking voltages. Especially where there is a jumper wire under the board. For example, the "B" voltage goes to 3 places on the board. The "D" voltage also goes to 3 places. There is also an "X" jumper marked on the drawing.
> Do your tubes light up? Is there 6 volts to all the tube heater connections? Is the cap can grounded? That's a recap of mistakes I've made while building these amps. It's usually something simple. Those jumpers I mentioned are real easy to miss.
> ...


Tube filaments all light up. The heater voltages are 3.15 for each triode (total of 6.3) per preamp tube however I'm confused because I thought preamp tubes got 12.6V? The cap can is indeed grounded. My last thought is that it could possibly be the input jacks. If I think I might have soldered 1M resistor incorrectly. Would that totally make the amp dead quiet with no hum at all?


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## greco (Jul 15, 2007)

epis said:


> Maybe for their application, as amp load they should be mounted on some kind of heat sink, best would be to mount it in aluminum enclosure like hammond for effect pedals.


I meant it all as a joke.

"...._When they work_..."

and this...for the giggle factor...
"_Must be don't touch by hand directly_"


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## oldjoat (Apr 4, 2019)

Ikea or china translation ?


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## dtsaudio (Apr 15, 2009)

6 volts is correct. Depending on how the small tubes are wired, the filaments can be 6.3 or 12.6 volts.
More importantly, is there high voltage present?


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