My First Build the GR-1SF

[DrNomis_44]

You could try checking the instrument lead you're using to connect the guitar to the amp, if you hold the plug by it's sleeve and try touching the tip of the plug with the other end of the lead plugged into the amp, you should hear a noise in the speaker, if not it indicates that the lead is faulty.

My other thought is that there's a missing ground wire somewhere.

[ShazzRandom]

You could try checking the instrument lead you're using to connect the guitar to the amp, if you hold the plug by it's sleeve and try touching the tip of the plug with the other end of the lead plugged into the amp, you should hear a noise in the speaker, if not it indicates that the lead is faulty.

My other thought is that there's a missing ground wire somewhere.

Heya doc, The test lead I'm using is my husbands daily one he uses, so it's def not faulty.

[ShazzRandom]

Shaz have you pulled the wiring out to have a good inspection ? a hum could mean a bad earth to a pot/switch or output jack. Have you run an earth wire from a bridge post and all 4 pots are earthed ?
can you please post a close photo of the wiring loom may give us some answers

Also check the 3 lugs on the volume pots aren't making contact with neighboring lugs.

Heya Wokka, yeah the loom is all out. Reput back in my cardboard cut out. I re-did some joins just to make sure it was all ok. Even triple checked the schematic. Think I may have to just start over cause I really can't find any visible faults 😩

[WeirdBits]

Post some pics of the loom and maybe we can spot something.

[DrNomis_44]

Heya doc, The test lead I'm using is my husbands daily one he uses, so it's def not faulty.

No worries, at least we can rule that out as being the cause of the hum noise.


By the way, I finally got my STA-1M kit ordered last night so it's official, pretty excited about it, I'm going to make sure I keep making regular updates to my build diary so stay tuned.

[ShazzRandom]

Post some pics of the loom and maybe we can spot something.

Shall do! Will do tomorrow night as the husband is going out so I will have time again! Woo!!

[ShazzRandom]

So the gremlins have got the better of me and I went for it again tonight! Here is the schematic I went off.

Here is the close ups of my work... I'm hoping it's just my novice soldering... Though my husband says it's ok (he's an ex avionics tech so I believe him haha)

[ShazzRandom]

A couple more.
This is also the sound that it is making.
https://youtu.be/br4CdLptv88

[ShazzRandom]

No worries, at least we can rule that out as being the cause of the hum noise.


By the way, I finally got my STA-1M kit ordered last night so it's official, pretty excited about it, I'm going to make sure I keep making regular updates to my build diary so stay tuned.

Awesome doc! Congrats on the first kit purchase will be looking forward to your diary!

[DrNomis_44]

Hey ShazzRandom, now that you have all the wiring on your cardboard template, plug it into the amp and if it is still causing hum, go through all the wires and try giving them a wiggle, do the same for each end of the wire close to where you've soldered them, if you come across a wire, or wire connection where you can make the hum come and go just by wiggling it that indicates where you have found the fault causing the hum, try starting close to the pickups and work your way towards the output jack .


Eventually you'll probably find the cause of the hum, good luck with it, hope that helps.


That's one of the standard techniques Electronics Techs use to find the cause of a fault in electronic equipment.