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Simple, no-math transformer snubber using Quasimodo test-jig
Simple, no-math transformer snubber using Quasimodo test-jig
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Old 15th June 2021, 02:11 PM   #2161
Windcrest77 is offline Windcrest77  United States
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Join Date: Feb 2019
Location: Lockport, IL USA
Simple, no-math transformer snubber using Quasimodo test-jig
Quote:
Originally Posted by trobbins View Post
No fuse?
Good idea, a fuse to protect the transformer secondary. I got the board down to 1 x 2.5 inches if I go 1.25 x 2.5 I can maybe get a PCB fuse holder on it.

I want to make a half wave version board also, with only two diodes.

I'm setting it up for TO220 diodes, that way the board can mount on a small piece if 1.5 x 1.5 aluminum angle stock with all the TO220 diodes hanging off the long edge, heatsinked to a little piece of angle stock. this way the whole bottom of the board is shielded from shorts and the other leg of the aluminum sinks the diodes, and its small.
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Old 15th June 2021, 11:34 PM   #2162
Rick PA Stadel is offline Rick PA Stadel  United States
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That sounds like a fair bit of trouble to go to, for only your personal use -- maybe you'll have extras made and sell them on here ??

1,5 x 1,5 inch angle stock will place a good bit of aluminum in the thermal pathway between the TO-220 device and the heat sink though (assuming I correctly understand what you have in mind ). x " has worked well for me in the past, other TO-220's in different service, albeit.

Cheers

edit: Also don't forget: The flatness spec for the outside surfaces is usually much tighter, than the inside surfaces; many extrusions, anyway.

Last edited by Rick PA Stadel; 15th June 2021 at 11:55 PM.
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Old 16th June 2021, 01:25 AM   #2163
Windcrest77 is offline Windcrest77  United States
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Simple, no-math transformer snubber using Quasimodo test-jig
I thought of 3/4 or 1 inch, you have to subtract 1/8 inch for the stock thickness. A TO220 diode pops up over an inch once you get some !/4 inch standoffs under the board. I'll be glad to share some boards though when I finally get them back. I'll post the copper layout here for criticism before I send it off to jlcpcb (separate thread).

Last edited by Windcrest77; 16th June 2021 at 01:32 AM.
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Old 18th June 2021, 05:21 AM   #2164
Rick PA Stadel is offline Rick PA Stadel  United States
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Sorry -- I was thinking upside down, where the PCB would be supported by the TO220 legs using the angle stock as mechanical support.

The plan sounds good. Thanks for that.

Regards
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Old 18th June 2021, 12:28 PM   #2165
Schlaudi is offline Schlaudi
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Hi guys,

I'm designing a new rectifier board for my B&M Loudspeakers with center tapped transformer. I didn't found a recommendation where to place the snubber circuit.

I have two different PCB designs and want your recommendation which one to choose. Must the snubber circuit be in line (version 1) or would you recommend to choose the parallel version 2. Or doesn't it matter?!

Version 1: AC in => Snubber => Rectifiers
Version 2: Snubber <= AC in => Rectifiers

In my opinion Version 2 could be better due to short AC tracks...
Attached Files
File Type: pdf Snubber_Position.pdf (299.0 KB, 64 views)

Last edited by Schlaudi; 18th June 2021 at 12:35 PM.
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Old 19th June 2021, 10:25 AM   #2166
ticknpop is offline ticknpop  Canada
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Simple, no-math transformer snubber using Quasimodo test-jig
Version 1 is my preference, best to snub before the bridge, but what do I know?
You should take advantage of the two capacitors on each polarity and use a low value 2 or 3 watt resistor like 0.22r between the caps to get some HF filtering. Maybe a 0.1uf in series with a 1 ohm resistor in parrallel with each electrolytic

Last edited by ticknpop; 19th June 2021 at 10:31 AM.
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Old 19th June 2021, 12:01 PM   #2167
Mark Johnson is offline Mark Johnson  United States
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Simple, no-math transformer snubber using Quasimodo test-jig
As far as damping out oscillatory ringing ("snubbing") is concerned, the two layouts in #2165 are equally good. #1 is not preferred over #2, and #2 is not preferred over #1.

I suggest positioning the 6.35mm FastOn blade connecters wherever is most convenient for the person who assembles the final amplifier in its chassis. Spaced far enough apart from other components (and each other) to allow unconstrained, easy access by fingers or pliers. Placed such that sharp bends in the wires are not necessary. Accessible by voltmeter probes, that sort of thing. "Designed For Manufacturability" , "Designed For Testability" , etc.
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Old 2nd July 2021, 04:11 AM   #2168
DaveFred is offline DaveFred  Canada
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Simple, no-math transformer snubber using Quasimodo test-jig
Super dumb question,

Is snubbing of ringing required for amplifier transformer types other than Toroidal, i.e R-core transformers?
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Old 2nd July 2021, 04:41 AM   #2169
ticknpop is offline ticknpop  Canada
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Simple, no-math transformer snubber using Quasimodo test-jig
All my R cores are Quasimodo snubbed, never used them without snubbing
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Old 2nd July 2021, 02:06 PM   #2170
Mark Johnson is offline Mark Johnson  United States
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Simple, no-math transformer snubber using Quasimodo test-jig
Snubbing is completely optional. It's your choice.

Some builders go to the trouble of listening without, and with, snubbers, then choosing the one that sounds best.

Some just optimize the snubbers with Quasimodo, solder them in, and with great peace of mind: forget about them forever after. I'm one of those.

Yet others assemble the entire audio project but leave out the snubbers. Then they connect a load, play at maximum output, and connect up a battery powered, not connected to mains earth, oscilloscope to investigate ringing, using the external highpass filter member peufeu* described in post #142 of this thread. If the unsnubbed equipment does exhibit ringing, then they turn everything off and solder in the snubbers. On the other hand if the unsnubbed equipment exhibits no ringing, then they don't install snubbers. And they bask in the glow of reduced costs, having just saved the price of the C+RC snubbing components.

*posted to diyAudio in December 2013, fyi



_

Last edited by Mark Johnson; 2nd July 2021 at 02:09 PM.
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