Posted by rich gallagher on February 17, 2010 at 10:37am
i just built a ruby amp and it works fine with my strat, but when i plug in my cbg w/2piezo pickups in series it just makes an obnoxious loud sort of hum - help!
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thanks for the confirmation - i had about given up on it - now i will build another and be doubly careful
Jon Pruett said:
The ruby I built sounded great at first - and then when I switched to a longer set of wires going to my jacks (so it would fit in the box I wanted to use) it developed a horrible hum. If I put my finger on the negative wiring post of the jack the hum would decrease a lot, and with my finger on the positive wiring post the hum would almost completely disappear.
After a good night of sleep and a polarity check in the morning I discovered I switched the positive and negative wires on the incoming jack. After I resoldered to the correct post the hum was gone and the sound was clear again.
I know you said above that you've checked and rechecked the polarity at the piezo, so I don't have any new ideas for you - just a confirmation that the schematic does work with piezo's from at least two different manufacturers that I have used.
The ruby I built sounded great at first - and then when I switched to a longer set of wires going to my jacks (so it would fit in the box I wanted to use) it developed a horrible hum. If I put my finger on the negative wiring post of the jack the hum would decrease a lot, and with my finger on the positive wiring post the hum would almost completely disappear.
After a good night of sleep and a polarity check in the morning I discovered I switched the positive and negative wires on the incoming jack. After I resoldered to the correct post the hum was gone and the sound was clear again.
I know you said above that you've checked and rechecked the polarity at the piezo, so I don't have any new ideas for you - just a confirmation that the schematic does work with piezo's from at least two different manufacturers that I have used.
thanks for the replies guys - i even communicated with runoffgroove.com for awhile and they thought the prob might be that the piezo just doesn't like the buffer on the ruby - i think the noisy cricket has a similar buffer - have you built any of those wes? i will try a 500k - and wes, i don't ground my piezos - could it be that simple?
Hi Rich
I've been trying a few things lately and 500K vol pot should give better results. Make a try (if you haven't already)
with a 500K and let me know :-)
rich gallagher said:
warren, i too have built a lil gem and it works fine - i also have the schematic for that buffer tho i haven't tried it yet - i did stick a 250k vol pot on one piezo cbg and it took away the noise, but muddied up the sound - i'll keep trying to make the ruby work just because i'm stubborn
warren, i too have built a lil gem and it works fine - i also have the schematic for that buffer tho i haven't tried it yet - i did stick a 250k vol pot on one piezo cbg and it took away the noise, but muddied up the sound - i'll keep trying to make the ruby work just because i'm stubborn
I built a little gem (same website) and it works great. Just a wild guess (folks, if I'm wrong, say so but no flames please). Could the pickups in series mess up the impedance?
In another discussion, Bluesdog recommends using a pre-amp to match impedance. Not sure this is the right direction, but though I'd share the info.
thanks, but it's not that - it works fine in my store bought amps
Ricky Martin said:
Ricky Martin said:
Morning, check your pickups in the cbg. The positives arr soldered to the small circle and negatives to the large one. If correct, change them on the jack. Ricky Martin
Morning, check your pickups in the cbg. The positives arr soldered to the small circle and negatives to the large one. If correct, change them on the jack. Ricky Martin
Morning, check your pickups in the cbg. The positives arr soldered to the small circle and negatives to the large one. If correct, change them on the jack. Ricky Martin
Replies
Jon Pruett said:
After a good night of sleep and a polarity check in the morning I discovered I switched the positive and negative wires on the incoming jack. After I resoldered to the correct post the hum was gone and the sound was clear again.
I know you said above that you've checked and rechecked the polarity at the piezo, so I don't have any new ideas for you - just a confirmation that the schematic does work with piezo's from at least two different manufacturers that I have used.
I've been trying a few things lately and 500K vol pot should give better results. Make a try (if you haven't already)
with a 500K and let me know :-)
rich gallagher said:
In another discussion, Bluesdog recommends using a pre-amp to match impedance. Not sure this is the right direction, but though I'd share the info.
I have the parts for this one, but haven't built it yet so no feedback (pardon the pun):
http://www.scotthelmke.com/Mint-box-buffer.html
Ricky Martin said: