Leach clone, pretty good looking

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Today I got some of the parts needed, so I started putting together two boards.
 

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To all builders:

Change of value for R28 and R30, both must be 330 ohm.

This is only important if you run the amp above +-60V rails

The change is in the componentlist on the website now.

I am making a table with values for different rail voltages, it will be included in the manual that I'm working on.

Sorry for any trouble this may cause, I know that removing components from the PCB is hard work, so please be carefull when you perform the operation

\Jens
 
Hi Jacco,

Nope, my prototype is running at +-75V as we speak, but on a test supply.

I just made a calc that suggested that 330 ohm was better for higher voltages ;)

I'm waiting for my 1000 VA 2x55V AC trafor, when it arrives I will make a short circuit test at see what happens :eek:

EDIT: Did you have a look at the new graphs I mailed you Jacco?

\Jens
 
BUMMER, Oh well, maybe next time :clown:

I have read the manual revision, Jens.
I figured weekend is J&J time.
And i am not the other J !!!!!!!!!!

The load line for the MJ15003/15004 on the 3 device version does point out how little the powerhandling of a device is worth.

I chose 0.22 Ohm emitter resistors instead of the 0.47 Ohm, or the original 0.33.
So i have to change R28/R30 anyway to activate the protection gear.
Setting it around 25 amps per device.
I am going to use an intelligent protection circuit that will activate the output relays depending on the product of Vce value and output current, with a delay of 10 mS.
Within the 10 mS its up to the Leach driver protection

btw: did you get my skype messages ?
first time i tried it, maybe you could give a hint for a convenient skype talk time schedule
 
I plan to use only one trafo and one railvoltage. You can improve effeciency by using lower rails for the output .

I have not tested this, so if you try it please tell us the result, as it might improve performance with a more "silent" supply for the input part of the amp.

At the moment I'm waiting for my trafo. I will post results when it arrives. This will test the amp at 75V rails.

I was hoping on some more response on the manual - there are some things that might make the TO-3 vs. TO-264 debate come to life again.

\Jens
 
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