Replies to This Discussion

Permalink Reply by Jkevn on January 3, 2010 at 4:29pm

The squeal on a piezo rig is usually caused more by sound waves re-exciting the piezo and getting amplified over & over. The only way to solve it is by isolating the piezo...and distance from the speaker. I havent done it myself....some here have. The lil artec type amps would be easy enough to mount in cbg....isolating the pup from speaker would be a problem.

• ▶ Reply

Permalink Reply by Bluesheart on January 3, 2010 at 5:49pm

I have not done it yet but have plans to. I have speaker I think my work well. It is a mid driver pulled from a trash pile speaker cab. 4" 8 ohm, has a solid frame w/o the usual openings in back so it will be acoustically isolated from the inside of the box . Wiil make another Ruby amp to go with it I think.

• ▶ Reply

Permalink Reply by stan bryars on January 5, 2010 at 7:00am

I was planning one but can't get past the theory that piezoes respond to vibration and speakers create vibration
If the piezo is to do it's job it must be attached in such a way that it is in contact with vibrations from the box
Therefore any speaker attached to the box will activate any piezo attached to the box

Hopefully I will prove myself wrong
I had a whole self contained solar rechargeable weather resistant campers system planned out

• ▶ Reply

Permalink Reply by Randy Webb on January 5, 2010 at 7:10am

Just use a magnetic pickup instead. It would be less challenging than the Peizo and they sell manufactured little solid bodies like that already, so im sure it would work.

• ▶ Reply

Permalink Reply by David L. on January 5, 2010 at 8:12am

Hi, I have built a few with onboard amps using mylar speakers - I like the smokey type amp with the LM386 chip but the one time I tried it in a CBG I got major humming issues ( it needs the overdrive circuit to be heard and this makes the problem worse). I have used a 3W amplifier kit from Maplins
http://www.maplin.co.uk/Module.aspx?ModuleNo=2904 but more recently have used these 3.5W Universal Amplifier Module - even easier all you have to do is hook up the wires
http://www.maplin.co.uk/Module.aspx?ModuleNo=37734 (I don't know the USA equivalents sorry). I tend to use both magnetic pups and piezo discs for the increased toanal options.

With this setup I find the bridge magnetic pup works fine at all volumes. The neck magnetic pup gives feedback at high volume (being closer to the speakers) and the piezo discs squeal a bit but only at high volume. Through an external amp all are fine. The black box in the CBG is a preamp and if bypassed the above is true. If switched on the neck and disc piezos feedback a bit more - but even so are still loud enough for using at home with the volume below the feedback threshold. Regards, David

• ▶ Reply

Permalink Reply by RETROROD on January 5, 2010 at 12:10pm

Thanks all, for the responses thus far! Good stuff. Thanks David, for exposing the "belly of the beast"! Thats what I,m talkin' 'bout! An unassuming cigar box guitar, loaded with lethal tonal magnets and transducers... I think I must "give it a go" as ya'll say in the UK. I figure if the onboard speakers don,t perform up to snuff, it will still be cool through an outboard amp...
...or go straight magnetic as Randy suggest.
I have built one CBG with a magnetic and piezzo pickup and a 3-way switch and as David says..."I like the tonal options" especially with a volume pot for each. Keepin' on brain-stormin'...Rod

• ▶ Reply

Permalink Reply by James Bush on January 5, 2010 at 7:03pm

Shield everything you can and play it in a mud puddle and it should work fine.

• ▶ Reply