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DIY Stompboxes => Building your own stompbox => Topic started by: Samy on July 03, 2006, 08:17:10 PM

Title: GGG Tube Driver
Post by: Samy on July 03, 2006, 08:17:10 PM
Iīve build a TubeDriver from GGG and i have a huge amount of hummm !
Iīve tried shield wire, iīve tried moving the valve socket far away from the pcb iīve tried DC for heaters and thereīs no change in "hummm" noise !  ???
The GGG layout itīs wrong in some places, the led cannot be used that way with AC Voltage, Volume and Gain pots are working backwards, signal wires are too close from AC wires on the pcb and that can be a problem ! The humm appears when the gain itīs more than 50%, with the gain lower that that, the humm itīs very very low or not present.
Iīve tried several 12AX7 Valves and the noise remains ...
Iīm tired of fooling around trying to debug this ! Nothing that i do seems to work !

Any tip ?
Iīm thinking seriously thrashing this pcb and build a new one with a new layout that i found around here ...
Title: Re: GGG Tube Driver
Post by: mikey on July 04, 2006, 07:17:43 AM
did you notice the...

Please Note: this project has some problems with noise, build it at your own risk. Update to fix the problem coming soon, we hope.

...at the top of the project page at GGG?

You're probably better off with a different layout.
Title: Re: GGG Tube Driver
Post by: mac dillard on July 04, 2006, 09:25:31 AM
E-Mail communication with J.D. just last week and he told me that he was in the process of up datiing the Tube Drive PCB and lay out. Asked me to wait before building it.
Title: Re: GGG Tube Driver
Post by: Samy on July 04, 2006, 11:14:25 AM
No, i didnīt notice that !  ???
The sound itīs quite good, but i canīt push the Gain pot too much ... too bad !

I have a different pcb, i got it from here: http://www.diystompboxes.com/smfforum/index.php?topic=44779.0 , can anyone tell me if itīs all ok with this ?

Thanks.
Title: Re: GGG Tube Driver
Post by: Ardric on July 04, 2006, 09:10:49 PM
C3 is wrong in GGG's schematic, as I wrote in the thread linked above.  Try moving the + end of C3 to the opamp and see if that helps.  All the layouts I've seen have this error, because it's in the original schematic.

Title: Re: GGG Tube Driver
Post by: Samy on July 07, 2006, 03:22:32 PM
Iīve finished the Tube Driver, the pcb that i used is OK, much better than the GGGīs layout !
I only have some noise with gain and vol. at max. with a 12AX7, i believe if i change for a 12AT7 i donīt have that problem.

Itīs a nice pedal !