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Topic: UPDATE: Weird sound from my LTD 400 |
Dan Beller-McKenna
From:
Durham, New Hampshire, USA
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Posted 26 Sep 2016 5:05 am |
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A while back I posted that I was going to replace the caps in my 1970s Peavey LTD. I never got around to it, and now I may have waited a little too long. I recently noticed an annoying 60 cycle hum when the amp is idle. I chalked it up to the bad wiring in my study, especially since it appeared after a power outage. Now (today) it has started making a "wind-roar" on power up and power off:
https://soundcloud.com/dbmck-1/wind-roar
It makes the same sound when I turn it off.
Are the caps telling me they're gone with the wind?
Anyway, the amp is definitely going to the tech tomorrow!
Dan
Last edited by Dan Beller-McKenna on 17 Oct 2016 4:14 am; edited 1 time in total |
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Dan Beller-McKenna
From:
Durham, New Hampshire, USA
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Posted 28 Sep 2016 3:38 am
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| Anyone? |
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Jon Light
From:
Saugerties, NY
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Posted 28 Sep 2016 4:25 am Re: Weird sound from my LTD 400
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| Dan Beller-McKenna wrote: |
..... Are the caps telling me they're gone with the wind? ....
Dan |
Frankly, Dan, nobody gives a damn.
Sorry. Couldn't resist. I always learn from questions like this so I hope someone has some (informed) ideas. |
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Dan Beller-McKenna
From:
Durham, New Hampshire, USA
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Posted 17 Oct 2016 4:18 am
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Finally got this done. Wow! Amp runs as quiet as a mouse and is noticeably crisper and cleaner.
I probably should have done this when I got the amp. Problem was, I got the amp for such a low price, the cap job cost more than I paid for the amp(!) If I had done it right away, I wouldn't have felt like I got such a good deal. Now that it corrected some growing noise issues, the repair cost feels like it is worth it. Perspective is a funny thing. |
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Steven Paris
From:
Los Angeles
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Posted 18 Oct 2016 5:01 am
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I am wondering if you would post how much $$$ a cap job cost? Did you send it to Peavey or have it done locally?
_________________
Emmons & Peavey |
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Dan Beller-McKenna
From:
Durham, New Hampshire, USA
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Posted 18 Oct 2016 5:37 am
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| I had it done locally and, although I don't think my tech ripped me off, I think he spent way too much on the caps. The parts were $150, which I believe is much more expensive than it would have been from Mouser. Labor was $70, so $220 total. |
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Dan Beller-McKenna
From:
Durham, New Hampshire, USA
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Posted 18 Oct 2016 5:53 am
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Ooops!
I just looked at the bill: it was $70 parts, $150 labor. Still a lot more than the parts would be from Mouser. |
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Steven Paris
From:
Los Angeles
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Posted 18 Oct 2016 5:55 am
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Well, I think it depends on how many caps he replaced. Did he replace the coupling ceramic/electrolytic caps with film types (as recommended), or just the large power supply electrolytics?
_________________
Emmons & Peavey |
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Dan Beller-McKenna
From:
Durham, New Hampshire, USA
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Posted 18 Oct 2016 5:59 am
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He replaced a whole ziplock full (judging from the removed ones he returned to me), and I believe he worked from Sarno's recommended upgrades.
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Rick Kreuziger
From:
Merrillan, Wisconsin
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Posted 18 Oct 2016 2:26 pm
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| I did the Sarno mods on a 400 LTD a month or so ago and I had $72 in parts from Mouser. |
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Dan Beller-McKenna
From:
Durham, New Hampshire, USA
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Posted 18 Oct 2016 3:15 pm
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Thanks for that info, Rick. I thought they came to more like $45. My bad. As I said, I've worked with this tech a lot, and I didn't think he'd over-charge me knowingly. Looks like he didn't overcharge period.
Counted the parts in the ziplock when I got home this evening. Looks like 18 in all. |
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Steven Paris
From:
Los Angeles
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Posted 19 Oct 2016 3:39 am
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Well, let's see.....the "Sarno" mod recommends the replacement of 12 ceramic/electrolytic capacitors with film types. There are 7 x 2 uF; 2 x .01 uF; 2 x .02 uF; and 1 x .05(.047) uF. Going with polypropylene dielectrics (the best) from Mouser, that comes to $18.54. There are also 9 additional power supply bypass electrolytics (1 x 25uF; 3 x 50uF; 4 x 100uF; and 1 x 200 (220) uF) shown on the schematic I got from Peavey. That's an additional $4.03, making a total of $22.50. That Peavey schematic does NOT show any additional LARGE (~ 6,800uF) power supply caps across the +/- 50 volt rails, but I would think that they ARE there; that's an additional $10.40. Add $6 for shipping and ~$4 for tax for a total of $42.90 for 23 capacitors.
_________________
Emmons & Peavey |
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Carl Mesrobian
From:
Salem, Massachusetts, USA
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Posted 19 Oct 2016 6:16 am
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You did fine..
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--carl
"The better it gets, the fewer of us know it." Ray Brown |
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