Simple Cheap Compact IC-based High Performance Amp

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Fred
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

It's a ground lift, the idea is to disconnect earth and ground up to a limit (provided by the diode drops) while still being safe (provided by the 35A capability).
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TheRevva
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by TheRevva »

Uh oh... I just had ANOTHER case of 'open mouth... insert foot'.
Now that I actually LOOK at it again, (AFTER engaging the brain this time), I actually understand it properly.
That was closely followed by asking myself WHY it'd be desirable (and I think I got THAT bit all by myself without a repeat of my 'foot-in-mouth disease' post)

I'm not completely sure how much I am going to LIKE this forum... It's forcing me to actually THINK! <Grins>

OK McGyver, what ELSE can you do with a bridge rectifier?
(In some ways, this circuit has reminded me of an OLD contest. "Using the 555-timer for novel purposes")
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Fred
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

TheRevva wrote:OK McGyver, what ELSE can you do with a bridge rectifier?
My childhood hero, how did you know? James bond, too. Must have been one of those days, punched the front of a car running a red today, made a hell of a bang, everyone stared.

Been doing the bridge ground trick for a very long time:

Image

Top right, 220 ohm wire-wound resistor visible.

Fred.
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by masterkorp »

Wow this is taking shape quite nicely. Fun to watch.
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

TODO updated! Going to work on the switches/pot now, and the physical mounting tomorrow. Along with my other duties, that is.
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

All coax, switches, sockets, pot, lights, led, removed from PCB! Didn't measure the switches yet, time for bed.
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

TODO updated! Side next to toroidal transformer reinforced with two more screws! Hole drilled for mounting one of the two bridge rectifiers. Need to pick up another and figure out where to put it.

Time to look at switches and/or cap mounting.
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Anyone recognise this brand:

Image


Of the three switches, the one with 8 pins is just a DPDT switch with two unused pins, or seems that way. With the switch down/on the inner most pins (further from the panel) are connected, and with it up/off the second from inner-most is connected to the third from inner-most/second from outer-most.

The equal sized one with 14 pins instead of 8 is the same, but with an extra set of 6 DPDT and the dead pins are the front most. IE, the pins that are dead on the 8 pin one are functional on the 14.

And the longer one with 20 pins, the same deal, but 3 sets of DPDT contacts! Too easy :-)

So pretty:

Image

Image

Image
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Fred
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

Doh! Alps, of course. Just realised... :-)
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Re: Simple Cheap Compact IC-based High Performance Amp

Post by Fred »

POT! The variable resistance type:

50k Logarithmic, top 43.8 and bottom 46.4, pretty smooth, log action pretty obvious watching centre tap values while rotating. Unsure if it's dual slope or proper, but don't care, it fits the enclosure and is 30 years old.

With it keyed to the panel, pins down, looking at it from the front:
  • right: signal in
  • centre: signal out
  • left: ground
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