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OK. nothing went pop and no smoke . got 0.07 measured L and R speaker contacts
Guitar amp hum no signal
- Thread starter Rabbitbreth
- Start date
did that . I have a low level white noise and a low level signal from the guitar . what do you think ?
no scope but have dmm and powered speaker
I would try to use the powered speaker in order to trace where your signals are going.
Firstly, you need to put a capacitor in series with the input of the powered speaker (this will be your test probe) to prevent any DC path across your amplifier test points. Any capacitor from 1μF to 10μF polar or non-polar would do.
First, test the powered speaker (with the capacitor probe) with a music sound source such as mp3 player or output from your computer or other electronic device.
Firstly, you need to put a capacitor in series with the input of the powered speaker (this will be your test probe) to prevent any DC path across your amplifier test points. Any capacitor from 1μF to 10μF polar or non-polar would do.
First, test the powered speaker (with the capacitor probe) with a music sound source such as mp3 player or output from your computer or other electronic device.
hows this ? 4uf
Attachments
so in series , cap goes inline to one wire of probe only . is that right ?
So the hum is gone?
Did you try turning up the volume, or are you waiting to be told to try that?
hum is gone . just hiss of white noise and low level guitar signal . volume is slightly raised when halfway up the dial . gain increases dirty sound slightly as I turn it up . I havent done max volume .
Is this all you can get your hands on?
I was thinking more something like this
or this.
ok. will route around some more . see if I can come up with something . thanks for the pics that helps alot
ok. found a 1uf 50v cap . ? could I get a pic of your tester rig perhaps . just to be clear on how to make mine
That resistor that I replaced . I noticed the solder joins the track and I was wondering if it is intended or my sloppy soldering that I only just noticed .
Attachments
MisterBill2
- Joined Jan 23, 2018
- 27,504
It looks like an actual connection, as I see it. That is a single-side PCB and there is no other nearby location that the single component lead could be connected to.
Thanks Mr Bill2
Last edited:
You can salvage or sacrifice an audio cable or you can buy a 3.5mm plug or jack as required.
You can do whatever works for you.
There is no need to connect both LEFT and RIGHT channels. MONO will work just as well.
If your powered speaker has a cable with a male 3.5mm plug, then get a mating 3.5mm jack.
If the speaker has female 3.5mm jack, then get a connecting cable or sacrifice a spare cable.
You can omit the plug and jack if you want to sacrifice an old cable. Just cut off the plug at the end of the cable and solder the wire directly to one leg of the capacitor .
One leg of the capacitor is your test probe. The other leg of the capacitor goes to the left or right input channel of the speaker. The capacitor is in series with the input to block DC. Polarity of the capacitor is not important. The GND is brought out to connect to the GND of your guitar amp.
You can do whatever works for you.
There is no need to connect both LEFT and RIGHT channels. MONO will work just as well.
If your powered speaker has a cable with a male 3.5mm plug, then get a mating 3.5mm jack.
If the speaker has female 3.5mm jack, then get a connecting cable or sacrifice a spare cable.
You can omit the plug and jack if you want to sacrifice an old cable. Just cut off the plug at the end of the cable and solder the wire directly to one leg of the capacitor .
One leg of the capacitor is your test probe. The other leg of the capacitor goes to the left or right input channel of the speaker. The capacitor is in series with the input to block DC. Polarity of the capacitor is not important. The GND is brought out to connect to the GND of your guitar amp.
