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Old 4th November 2012, 11:57 AM   #91
Marra is offline Marra  United Kingdom
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Old 4th November 2012, 08:02 PM   #92
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Ok, started it, but :-(... I have: +/- 33.7V rail, DC on output -6.2V, voltage on source resistors(1ohm) -- 0.35V. R8(R11) source of Q3. --5.2V, R14(R18) -- 4.75V.

(BrianGT boards notation).

So everything looks perfect except DC offset. My Q1 and Q2 are matched perfectly, but I have a 100k R8(R6) resistor, maybe it is it?

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Old 4th November 2012, 08:21 PM   #93
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Is that 6V of DC offset?
Is that at initial start up? Also, did it settle any after running for a few minutes?
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Old 4th November 2012, 08:22 PM   #94
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Ok, i removed R8, DC offset dropped to -16mV, but after 3 min of working rising again, now it is -28mV :-(
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Old 4th November 2012, 08:23 PM   #95
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everything up to 100mV is considered as OK

still - lesser is better
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Old 4th November 2012, 08:26 PM   #96
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Anything i can do to reduce it? My input pars were matched super close.

-35 mV still going up... :-(
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Old 4th November 2012, 08:27 PM   #97
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ya have Algar_emi's Aleph pdf ?
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Old 4th November 2012, 08:33 PM   #98
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Let her run for a bit and settle down, and measure it then.

Like they said 35mv is not really "bad", but it will change after warmup so let her run some now.

Steve
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Old 4th November 2012, 08:35 PM   #99
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Quote:
Originally Posted by Zen Mod View Post
everything up to 100mV is considered as OK

still - lesser is better
Is it pdf for an Aleph 30 in red and blue collors?
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Old 4th November 2012, 08:37 PM   #100
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File Type: pdf Aleph30by Algar_emi.pdf (29.9 KB, 69 views)
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