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Help identifying amp builder + power ratings |
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jbl_man 
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Joined: 12 January 2005 Location: London. Status: Offline Points: 11155 |
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 Posted: 08 July 2021 at 11:01am |
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As Simon points out, looks like conventional Hitachi mosfet design, transformer is quite small, so about 450 to 550w would seem about right. He has used standard Redpoint heatsinks, those are the exact ones bolted to the old MM AP360 amps of the later 70's.
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Be seeing you.
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Earplug
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Joined: 03 January 2012 Location: Europe Status: Offline Points: 7216 |
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Posted: 08 July 2021 at 12:57pm |
Yup. The module I linked to is a slightly modified/modern version of the Hitachi design. They also do smaller 150W & 250W modules, similar to the old Maplins thing.  |
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Earplugs Are For Wimps!
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Boxes-R-Blue
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Posted: 14 July 2021 at 12:12am |
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Def a Tubbies, no use for Mid-Hi, they were built for solid low end, not fast HF...
Despite low power will make a nice sound... |
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Kinda Been there, Kinda done that, YOU COULDN'T handle my bar bill!
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dnbpc
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Posted: 05 August 2021 at 9:37am |
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Cheers for all the input guys, I've given it a blast with some compressed air and powered it up but when connecting it to some speakers it had a big 50hz hum and the LEDs on the front dim. Guessing this is an grounding issue?
Where is the best place to start trying to resolve this? |
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Pick & Mix Soundsystem
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Chris LDN
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Posted: 14 August 2021 at 9:35pm |
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Visually inspect grounds, test for continuity with power off. Put a meter in AC mode, after the diode bridge, at the highest setting, and work the voltage dial down until you get a reading for any ripple.
That's what I'd do first. Had to do something similar to fix a broken Seck 1882 power supply. Other peoples troubleshooting methodology may differ. The above applies, if it's definitely a 50 Hz hum, as opposed to a 100 Hz hum. |
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Earplug
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Joined: 03 January 2012 Location: Europe Status: Offline Points: 7216 |
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Posted: 15 August 2021 at 8:22am |
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Maybe check the large filter caps. If they are bad, it could cause hum - and a dimming due to leakage. |
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Earplugs Are For Wimps!
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jbl_man wrote: