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Old 4th May 2013, 11:24 PM   #1501
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TonyTecson's Avatar
Join Date: May 2003
Location: Palatiw, Pasig City
Originally Posted by Junie View Post
So is it safe for 2SC5200 and 2SA1943 to run on that supply voltage? so far my amp not smoking yet, it sounding good.
these devices are best used at +-55volts, above that you will have to use many in parallel.....

if your standby rails are +-75 and they drop near the 55volt levels at full power, then you are safe....

the MJL21193/21194 are a better choice at high rails...
planet10 needs your help: Let's help Ruth and Dave...[B
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Old 5th May 2013, 03:15 PM   #1502
Junie is offline Junie  Philippines
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Sir Tony, Thanks for that clarification.
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Old 31st July 2013, 08:23 PM   #1503
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Default Also new to this thread, need four sets of PCB's

I'm need to this thread also. I would like four sets of PCB's.
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Old 1st August 2013, 01:40 AM   #1504
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I hope you can find some. Jen's boards are really nice.
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Old 4th August 2013, 12:29 PM   #1505
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You can download the Gerbers and have some boards made.

DELTA AUDIO - Leach Amp Clone
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Old 5th August 2013, 04:33 AM   #1506
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Hi Bob, On Delta Audio website, they didn't mention how to adjust the biasing and DC offset of the Leach amp. It seems like the build instructions was incomplete.
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Old 5th August 2013, 08:09 AM   #1507
AndrewT is offline AndrewT  Scotland
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The output offset is set by the imbalance of the 4 transistors in the input stage.
Expect <<10mVdc output offset (<2mVdc is typical with very little drift with temperature) if you can match your transistors using any of the Leach options.
regards Andrew T.
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Old 5th August 2013, 12:01 PM   #1508
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Bias setting is done by adjusting the trim pots. Professor Leach discusses how in his article suggesting 100 - 120 mA for 2 output pairs. You can also use the ~0.025 V across the emitter resistor rule or just choose what sounds best without running too hot.
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Old 16th August 2013, 03:41 AM   #1509
mj777 is offline mj777  Australia
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Originally Posted by mrsavage View Post
I'm need to this thread also. I would like four sets of PCB's.
I'm interested for one set also if somebody can organize a groupbuy.

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Old 31st August 2013, 08:18 PM   #1510
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Hi all,

I thought I was among the few left who are interested in the leach amp, but I guess I was wrong.

I would be very interested myself as well for about 10 of the 10 transistor versions layed out by Jens.

However I was wondering if there were any newer versions of the gerbers for that 10 trans board, which would include the latest tweaks that were done to the 6 trans version.

I would gladly join the group buy.
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