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Amp Internals 2
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shaun1264 View Drop Down
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Points: 242 		Post Options Post Options   Thanks (0) Thanks(0)   Quote shaun1264 Quote  Post ReplyReply Direct Link To This Post Posted: 12 March 2023 at 8:14pm
Crown DC300A Series II.  Well used.  Original components,  Still running well after all these years. Another one of Crowns Gerald Stanleys designs. Amazing clever early design.   Topology is the patented class AB+B.  The outputs carry no bias.  Outputs are lowish bandidtrh but durable.  The drivers run in class AB.  The outputs act as "boosters" in Class B over a certain wattage.  Very low THD, low DC offset and good power down to DC.

THD at 1Khz into 8 ohm load just before IOC lights show.

Output just before IOC lights show into a 8ohm load


Edited by shaun1264 - 12 March 2023 at 8:16pm
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EmPro View Drop Down
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Points: 356 		Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 12 March 2023 at 8:33pm
This design among with Ground Bridge design are the legends that made Crown a trusted and well reputed PA manufacturer...Thumbs Up

Edited by EmPro - 12 April 2023 at 9:23pm
EmPro Audio
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M4trix View Drop Down
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Points: 425 		Post Options Post Options   Thanks (0) Thanks(0)   Quote M4trix Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2023 at 12:49am
Now imagine those days when you had to populate the board without component markings printed on PCB. Pain in da arse ! LOL
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kedwardsleisure View Drop Down
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Joined: 20 January 2009
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Points: 4813 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2023 at 8:42am
I doubt they'd be hand built, the auto insertion machine would know where everything went!
Kevin

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4D View Drop Down
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Points: 4221 		Post Options Post Options   Thanks (1) Thanks(1)   Quote 4D Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2023 at 7:55pm
Qsc EX4000 





Edited by 4D - 13 March 2023 at 8:01pm
DMZ. "The bass was intense. Girls were literally running up to stand next to the subs"
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EmPro View Drop Down
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Points: 356 		Post Options Post Options   Thanks (0) Thanks(0)   Quote EmPro Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2023 at 8:07pm
Some serious amps there 👍👍👍👍
EmPro Audio
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M4trix View Drop Down
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Points: 425 		Post Options Post Options   Thanks (0) Thanks(0)   Quote M4trix Quote  Post ReplyReply Direct Link To This Post Posted: 13 March 2023 at 9:39pm
A lot of iron there. Good. Iron deficiency can cause all sorts of problems like, fatigue, shortness of breath etc. LOL
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Joined: 20 January 2009
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Points: 4813 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2023 at 10:00am
can see a few domed/vented capacitors by the looks of it, expensive repair!
Kevin

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4D View Drop Down
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Points: 4221 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 4D Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2023 at 10:42am
Originally posted by kedwardsleisure kedwardsleisure wrote:

can see a few domed/vented capacitors by the looks of it, expensive repair!

These are some of  the amps I mentioned in another thread as I was quoted £380.00 per amp to service, replace the 24 capacitors,  redo the thermal paste reset bias etc .  I have sent one in to be done as a test & will collect early next week.. 


Edited by 4D - 14 March 2023 at 10:44am
DMZ. "The bass was intense. Girls were literally running up to stand next to the subs"
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kedwardsleisure View Drop Down
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Joined: 20 January 2009
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Points: 4813 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 14 March 2023 at 3:54pm
NAD CI9120.
At over 80lbs I can see why they call them 'Nads'.

Kevin

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voron View Drop Down
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Points: 164 		Post Options Post Options   Thanks (0) Thanks(0)   Quote voron Quote  Post ReplyReply Direct Link To This Post Posted: 18 May 2023 at 10:18pm
Originally posted by kedwardsleisure kedwardsleisure wrote:

Transistors were getting hot working in the heatwave so they took their tops off.   




L-Acoustics / Camco LA8 SMPSU


I can repair Lacoustics LA8 PSU even all MCU's are faulty :) 




Edited by voron - 18 May 2023 at 10:21pm
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kedwardsleisure View Drop Down
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Points: 4813 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 24 May 2023 at 11:07am
New one on me!
Samick SMP-4000

2 x 200W into 4R
Being used as the main PA for a 5-piece rock band. Really.
Kevin

North Staffordshire
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