Replies to This Discussion

Permalink Reply by Cause the Blue rat on May 20, 2018 at 3:56pm

The back of the CBG has been open for years now. Just never decided to glue it back together. So i took a flashlight and looked at both the cap and resister. The cap is a standard 0.047. The resister looks to be a 10K ( brown, black, yellow then gold) 

below is a gif I made to show how this is wired. Does this look right? It's sounds right, The tone control works. But still don't know what value the pot is. 

Attachments:

• tone gif.gif, 16 KB

• ▶ Reply

Permalink Reply by Cause the Blue rat on May 20, 2018 at 7:50pm

Already made some mods. Not going to go under the neck pocket. I've had to shim up necks so this would put a gap between the piezo and wood. Moving it to the space usually occupied by the neck pickup. 

• ▶ Reply

Permalink Reply by Cause the Blue rat on May 22, 2018 at 9:48am

Found this thread on the forum. Glenn includes a video showing the tone control to work better than the circuit in the CBG I have. 

Passive tone control for piezo - solved

It has a few more components but not difficult to solder up. Lists and shows all the values of the components used. The circuit in my CBG works but is sporadic. I like bit because it cuts down on the harshness of the piezo.   

• ▶ Reply

Permalink Reply by Paul Craig on May 25, 2018 at 9:51am

I wired 2 piezo in parallel with 500k volume, but they were still a bit bright.

If you wire them to a 3-way toggle or blade switch, then you could play either or both in parallel. Ted made a good volume and tone circuit for these in the CBG wiring group that I haven't tried yet. It involves 2 - 1meg pots with .0022 caps on both pots.

The pot situation with a piezo works different than magnetic pickups due to the impedance. Mag pickups will get brighter with bigger value pots, but piezo's tame with the higher value pots. Weird.

• ▶ Reply

Permalink Reply by Cause the Blue rat on May 25, 2018 at 10:00am

Their brightness is why I'm looking into tone controls. The one made in this old CBG kinda works. I think it's on an audio taper instead of linear. But I'm going to keep it original. Because as is I can get a good tone from it. 

Yep. Plan on having a three way switch. 

• ▶ Reply

Permalink Reply by Paul Craig on May 26, 2018 at 8:57am

I've always used the audio taper for volume and the linear taper for tone. On the round piezo and rod piezo that I've used, I've only used A500k or A1meg volume pots alone so far closer to the neck piezo position. Just been too busy to experiment with the tone circuits.

Hope you find one that works good for you.

• ▶ Reply