DIY Hybrid poweramp noise and hum problem

maxpou · 30th April 2006, 08:28 PM

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)
High Voltage regulator PS
i have a noise and hum how i place my GND? thank you!!!

jleaman · 30th April 2006, 09:10 PM

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

maxpou · 2nd May 2006, 12:21 AM

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 · 2nd May 2006, 06:06 AM

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

maxpou · 2nd May 2006, 11:36 PM

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 · 7th May 2006, 04:37 PM

Hi,
somebody can help me to find my hum and noise problem?

thank you! Maxpou

Ryssen · 7th May 2006, 04:53 PM

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

rdf · 7th May 2006, 04:55 PM

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 · 7th May 2006, 05:26 PM

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

30th April 2006, 08:28 PM	#1
maxpou diyAudio Member Join Date: Apr 2006 Location: Québec	DIY Hybrid poweramp noise and hum problem 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) High Voltage regulator PS i have a noise and hum how i place my GND? thank you!!!

7th May 2006, 04:53 PM	#7
Ryssen diyAudio Member Join Date: Dec 2003 Location: Sweden--> Here	You don´t have a schema with all the components values on,and any data on the amp? __________________ Regards Åke

7th May 2006, 04:55 PM	#8
rdf diyAudio Member Join Date: Jun 2004 Location: big smoke	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. __________________ Ears aren't microphones.

7th May 2006, 05:26 PM	#9
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	rdf: It looks to me like they do via the PS rails. Nonetheless, I don't see how that bias scheme could be stable. __________________ If there's a sucker born every minute, where do the rest of them come from?

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30th April 2006, 09:10 PM	#2
jleaman Banned Join Date: Apr 2002	Can you show us an pictures how you have it connected now and have it running. ? what about a full schematic ?

2nd May 2006, 06:06 AM	#4
jleaman Banned Join Date: Apr 2002	Is this all on a bread board or is it on a circuit board ?

2nd May 2006, 11:36 PM	#5
maxpou diyAudio Member Join Date: Apr 2006 Location: Québec	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!!!

7th May 2006, 04:37 PM	#6
maxpou diyAudio Member Join Date: Apr 2006 Location: Québec	Hi, somebody can help me to find my hum and noise problem? thank you! Maxpou

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