DIY Hybrid poweramp noise and hum problem

[maxpou]

Hi everyone,
i have diy hybrid power amp no feedback with tube 6922 input circuit SRPP and 6 output mosfets IRF130, 9130 class ab. My power supply for output stage 1 transfo by each channel and 20000uf by rail. PS for tube is regulated by this circuit (see this adress)
http://www.diyaudio.com/forums/showthread.php?s=&threadid=78629
i have a noise and hum how i place my GND? thank you!!!

 

[jleaman]

Can you show us an pictures how you have it connected now and have it running. ? what about a full schematic ?

 

[maxpou]

Hi Jleaman, thank's for your answer.
here the schematic of my poweramp.

description of wiring gnd:
1- input rca gnd is on resistor input to gnd
2- all gnd of tube circuit is on my transfo CT
3- low voltage gnd is on transfo CT and there is a aluminium jumper which connect each channel and ground tube circuit.

thank you!!!

 

[jleaman]

Is this all on a bread board or is it on a circuit board ?

 

[maxpou]

Hi Jleaman,
i have three boards, one for my power supply, one by channel with small circuit bias for mosfet. i don't have a board for my big cap because it's a cap with screw. thank you!!!

 

[maxpou]

Hi,
somebody can help me to find my hum and noise problem? thank you! Maxpou

 

[Ryssen]

You don´t have a schema with all the components values on,and any data on the amp?🙂

 

[rdf]

Let me begin by stating I'm a solid state 'idjit', but if someone handed me that circuit to diagnose the first thing I'd do is remove the tubes and clip a couple thousand ohms across the interstage switch to see if the hum disappears or changes. The output stage gates don't appear to have any reference to ground.

 

[SY]

rdf: It looks to me like they do via the PS rails. Nonetheless, I don't see how that bias scheme could be stable.