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seth

Ruby Baby

Posts: 5,626 Member Since: 26/01/2011

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May 19 17 9:41 PM

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Anyone have a schemo for the reissue UA LA-3A? Mine is making some noise in the output amplifier. I have the schemo for the original and I'm told it's the same, but I'm not sure it's really the same.

Thanks.
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silvertone

Aqua Marine

Posts: 2,774 Member Since:26/01/2011

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May 20 17 6:17 AM

From what Will at UA told me it is the exact same Seth. I looked into buying one and called him on it when they first came out.

The boys really did (and do) try to stay faithful to their fathers designs... Bill Putnam junior told me they found his hand drawn notebooks in the attic of the family house many years after his dad passed away and they felt they could finally start remaking these classics. This was back in the 90's.

Silvertone Mastering, celebrating 28 years in business.

www.silvertonemastering.com

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zmix

Aqua Marine

Posts: 4,159 Member Since:20/01/2011

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May 20 17 7:38 AM

seth wrote:
Anyone have a schemo for the reissue UA LA-3A? Mine is making some noise in the output amplifier. I have the schemo for the original and I'm told it's the same, but I'm not sure it's really the same.

Thanks.

What's the noise sound like? Is it intermittent or steady? Does it happen Immediately?

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seth

Ruby Baby

Posts: 5,626 Member Since:26/01/2011

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May 20 17 8:58 AM

Thanks Larry. Chuck, it's a gentle low level crackle, sort of a soft windstorm sound. It's after the gain control, so I figure it's probably a resistor or transistor in the output amp. Does that sound right? Haven't had time to check it out yet. I thought I'd go at it with a tweaker, tap on components and see if anyone shouts.

image

Last Edited By: seth May 20 17 9:00 AM. Edited 1 time.

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zmix

Aqua Marine

Posts: 4,159 Member Since:20/01/2011

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May 20 17 11:17 AM

Check any connectors first to see if there might be oxidation, same with any transistors that might be socketed, then see if touching any components on the audio board affect the noise.. (be careful to stay away from the mains voltages..

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seth

Ruby Baby

Posts: 5,626 Member Since:26/01/2011

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May 23 17 11:03 PM

Either it was connectors, or I misidentified the source of the noise altogether. After unplugging the connectors a couple of times the LA-3A is definitely quiet.

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ssltech

Aqua Marine

Posts: 4,058 Member Since:22/01/2011

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May 25 17 7:25 PM

Not just the schematic, but the PCB print is exactly the same.

Stuff happens. Today I spent a few hours chasing a misattributed issue. It was solved in the end, but we all miss stuff!

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