BeePree-2 almost no sound output

Jay · 9111

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Offline Jay

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on: April 26, 2023, 11:55:13 AM
My BeePre-2 makes barely a whisper at full volume.  I tried it through my Stereomour and also feeding into my crack. (that sounds pretty bad)  The Stereomour and the Crack were at full volume.  I redid all resistance and voltage tests, and all pass.  I retraced all the wiring instructions and found no error.  I would appreciate any help or suggestions!
Jay

Jay L.


Offline Paul Birkeland

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Reply #1 on: April 26, 2023, 01:17:36 PM
Can you double check that the correct pots are in the correct holes? 

Can you post a link to the meter you have for your build?  If it's not something simple like a pot that's swapped, we'll need to have you play a 60Hz tone into the preamp to see where it's dropping out.

Paul "PB" Birkeland

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Offline Jay

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Reply #2 on: April 26, 2023, 01:42:26 PM
A10k in the volume position. Klein mm1000 multimeter

Jay L.


Offline Jay

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Offline Paul Birkeland

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Reply #4 on: April 26, 2023, 01:59:48 PM
To trace signal, you'll need a source that can play a 60Hz tone.  A computer or phone with a heapdhone jack and an 1/8" to RCA cable is typically used for this.  The first test can be done with the BeePre off, which is to play the signal at full volume and measure the AC voltage with your meter at the RCA plugs, then plug them into the preamp and be sure you can measure similar AC voltage coming out of the selector switch (one probe on black and one on white for left channel, one probe on the other black and the other on the red for the right channel).

Paul "PB" Birkeland

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Offline Jay

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Reply #5 on: April 26, 2023, 02:15:12 PM
with probes on center post and sleeve of r channel v=1.1
                                                                  l channel v=1.1
with probes on selector switch black and white, v=1.1 v
                                                 black and res, v=1.1 v

Jay L.


Offline Jay

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Reply #6 on: April 26, 2023, 02:51:59 PM
following the wires, between terminals 2 and 4, I get 0v with the balance pot turned all the way to the left, and 1.1v with the balance pot turned all the way to the right.  between terminals 12 and 14, I get 1.1v with the balance pot to the left, and 0v with the bal pot turned to the right.  I guess the next steps involve turning the preamp on, so I'll wait for further instructions
« Last Edit: April 26, 2023, 02:56:25 PM by Jay »

Jay L.


Offline Paul Birkeland

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Reply #7 on: April 26, 2023, 03:01:04 PM
Now put the balance pot in the middle and check the AC voltage at pin 3 of each 300B (the preamp can still be off).

If you still see appreciable AC voltage there (it will be less than 1.1V with the balance pot centered), then turn the preamp on and check the AC voltage at 10 and 20.  For all of these measurements, you can use whatever ground you'd like in the preamp for the black probe (terminal 4 is fine).

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Jay

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Reply #8 on: April 26, 2023, 03:11:39 PM
both pins 3 measure 1.02 with preamp off.
with preamp on terminal 10 measures 2.7 v
                                        20                 2.7 v

Jay L.


Offline Paul Birkeland

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Reply #9 on: April 26, 2023, 03:32:17 PM
Can you post your DC voltages on each 4 pin socket? 

Also measure the AC signal voltage at all 6 pins on the volume pot with the volume pot all the way up.

Paul "PB" Birkeland

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Offline Jay

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Reply #10 on: April 26, 2023, 04:03:18 PM
well, I must have jostled a flaky solder joint or something because it is working now with my quicksand.  I'll reflow and revive this thread if it quits working. I'm sorry to have wasted your time, but very grateful for your help!
Jay

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Offline Paul Birkeland

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Reply #11 on: April 26, 2023, 04:18:40 PM
I bet you have a black wire that's loose, as you mentioned that both channels were gone and some grounds are common between channels.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man