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Colin James Wonfor

Colin James Wonfor

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To make more interesting you can also use IGBT like this one Alan Brown did with a little help from. At 27W mono.

10698569_1409128266072200_7623223506385862077_n.jpg


You can make out the huge IGBT's on the heatsink the white bricks.

11150301_1409128272738866_4200224723773227735_n.jpg


It sounded amazing and now 3 years old still on all day and still sounds amazing, made from scrap parts for about £100.00

Power consumption each 190W a baby ah sweet beast.
 

DonH56

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I was just about to suggest IGBT's... I have not had time to read the whole thread (family emergency) but appreciate seeing the design and discussion, carry on please!

I have a pair of those heat sinks, somewhere... Used them with their fans attached for a 100 W class A behemoth ages ago, also single-ended, small world...
 

amirm

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I like low gate capacitance low RdON, high current and the bigger the better PDs.
But the nice thing is this type of FET at low Voltage and low Vgs is common you can thank the Automobile electronics for that.
Thanks. I am designing some power electronics and those are the requirements I look for just the same! Crazy that my application is full on/off and this one is for linear audio!
 
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Colin James Wonfor

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No man I can get you pills to stop the spread of that dreadful digital lies virus, and if they do not work well we can put you out of your pain with a nice analogue favourite.

41694.jpg


See it works.
 
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Colin James Wonfor

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I have used these and there bigger brother with great success.
I made 100KW Xray generator with a few in a resonant convert, input 3 phase 440V output 50KV-150KV max current 1A DC. Transformer are fun at that voltage and so are the output change over switches. All using a bigger bruv of the same family.
 
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Colin James Wonfor

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Now we can look at the linear PSU with hum busting and a trick for peak power to be increased, which increases the dynamic range.

Here is the cct, nothing special but it work and is simple.

psu%20dynamic_zps7zgpzrno.jpg


Here is the PCB layout.

psu%20dynamic%20pcb_zps5knxhjy3.jpg


And here is the anti thump cct which is not needed in most cases as the DC offset is very low on power up.
anti%20thump%20nu_zpsgatfevvd.jpg
 
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Colin James Wonfor

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This is the power up Soft Start supply if you want a push once button as to a toggle switch.

power%20cntl%201_zpshm8tvct9.jpg

power%20cntl%202_zpsm7dksilf.jpg

Configured thus.

12045384_1518540221797670_3875302107393835799_o.jpg


Note it is also fitted with over temperature thermal switches and on the back a isolating toggle switch, fuse and a large NTC to reduce the inrush current.
 
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Colin James Wonfor

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A fully loaded PSU PCB.

PSU%201_zpsddvocmsf.jpg


Here is a SECA mounted into a old PC case cheap and easy to work, note the two large heatsinks.

IN%20BOX%201_zpsn532mvsn.jpg


Two of these babies mmm nice

42260694_zpsdvdiqic6.jpg


Wiring without the Soft Start.

PCB%20CONNECTIONS_zpswr9r3snf.jpg


A version of the SECA with FET's and the Darlington replaced.

KIT%20FET%20LEADED%20A_zps7vcedsfx.png


Oh here is a 300W SECA with Amanda Arrow standing next to it she is 5 ft 5 inchs tall.

MANDY%20WARRY%20amp%20300W%20A_zpsh6j4pemq.jpg
This monster has 80 FET's and 80 Darlington Transistors with 3 Farads at 80V and a 3KVA transformer. The heatsink is 1.8M tall 300mm wide with fins 200mm long.
 

amirm

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Thank you so much Colin for your generosity to share your knowledge and designs with us and the general community of DIY audiophiles. Much appreciated.

A question: have you looked at using capacitor multipliers in the power supply as a replacement for regulation in the supply to reduce hum?
 
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Colin James Wonfor

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No because it is constant current O/P and peaks from a IQ of 3A -6A so the heat will be increased in the PSU not good you can get slow voltage drift with post regs. Sub 1Hz not nice
 
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Colin James Wonfor

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If the 22V-0-22V transformer used and set to about 18V on the reg each reg will be about 32W but each a total on each PCB of 64W , the power amp will 90W if the IQ is set to 2.5A, so a big heatsink.
Allowing for approx of 700mV of ripple on the main bulk caps(33,000uF 35V).
 
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Colin James Wonfor

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The best audio in the world is in the north and in the snow, " A Class Rules" at the Antarctic and the Arctic. Music warm seal meat a treat.
 
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