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Author Topic: Amp Advice  (Read 7800 times)

Dmoney

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Re: Amp Advice
« Reply #15 on: August 30, 2011, 12:58:27 PM »
just to be complete, I replaced the choke with a couple of parallel resistor to get about 500K at 7watts.

can still hear the noise inside the caps. I re attached the elevated heater reference divider and that made the ticking worse. So yeah. The ticking always seems to be there, just gets worse when you add stuff after that stage.

hopefully new caps will turn up tomorrow.

EDIT: scratch some of that. With no HT fuse I can actually hear the first 2 caps making the noise, though really quiet.
« Last Edit: August 30, 2011, 01:10:15 PM by Dmoney »

Dmoney

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Re: Amp Advice
« Reply #16 on: September 01, 2011, 07:02:27 PM »
ok.

I'm waiting on two more caps.
I swapped two out (2nd stage) and added some voltage balancing resistors again but the noise is the same.

I also thought the rectifier diodes might be an issue since they took a bit to heat and get the solder flowing and they are cramped together a bit, so i replaced them with some spare 1N4007's with the snubbing caps and carefully soldered them in place. This made no difference to the ticking/noise.

so next it's the wait for the 2 caps I need to swap out the 1st filter stage.
might also get some spare switches, I think if the 1st stage getting swapped doesn't solve the issue, the standby switch is the last think to try.

HTH AMPS

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Re: Amp Advice
« Reply #17 on: September 02, 2011, 12:36:28 PM »
is there any ticking in the PT with all the secondary taps isolated from the circuit? - might be the PT.

Dmoney

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Re: Amp Advice
« Reply #18 on: September 02, 2011, 01:18:02 PM »
If i put my ear to the PT I can hear it hum, but the ticking doesn't seem to be in there. though the hum and the ticking noise seem related, but then they are both probably related to the mains.

I changed all the caps. No Difference.

Soooo. the only things left to swap at that end of the chassis are the switches, and maybe using a different rectifier again. My rectifier diodes are squashed together a bit, maybe using a discreet bridge rectifier with snubbers might help? I can mount that on the chassis and give it some space.

I've started to wonder if its just me being over the top.


EDIT: when I say all the caps, I mean the first 4 making the first 2 filter stages.
« Last Edit: September 02, 2011, 01:24:29 PM by Dmoney »

Dmoney

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Re: Amp Advice
« Reply #19 on: September 08, 2011, 05:18:40 PM »



I JUST GOT THIS FIXED WOOOOOOOOO!

jpfamps

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Re: Amp Advice
« Reply #20 on: September 08, 2011, 05:30:24 PM »
So what was it?



Dmoney

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Re: Amp Advice
« Reply #22 on: September 08, 2011, 06:14:13 PM »
I think it was the placement of the rectifier. It was pretty jammed into a cramped space on the board.

I did try replacing the diodes are one point, which didn't do anything.
after trying everything else, i got some tag strip and built the full wave with UF5408's on it and ran flying leads to the standby switch and the 1st filter stage.

problem solved. No ticking. The snubbing caps I had were cut too short to fit the tag strip though, but its still pretty quiet.

Transcend

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Re: Amp Advice
« Reply #23 on: September 08, 2011, 06:15:29 PM »
glad its working.

Now

Clips or it still ticks!

Dmoney

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Re: Amp Advice
« Reply #24 on: September 08, 2011, 06:20:06 PM »
glad its working.

Now

Clips or it still ticks!


hahah! i'll try!