Aleph 60 building thread - Page 10

Marra · 4th November 2012, 10:57 AM

One channel at a time.

PKI · 4th November 2012, 07:02 PM

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?

HIPCHECK · 4th November 2012, 07:21 PM

Is that 6V of DC offset?
Is that at initial start up? Also, did it settle any after running for a few minutes?

PKI · 4th November 2012, 07:22 PM

Ok, i removed R8, DC offset dropped to -16mV, but after 3 min of working rising again, now it is -28mV :-(

Zen Mod · 4th November 2012, 07:23 PM

everything up to 100mV is considered as OK

still - lesser is better

PKI · 4th November 2012, 07:26 PM

Anything i can do to reduce it? My input pars were matched super close.

-35 mV still going up... :-(

Zen Mod · 4th November 2012, 07:27 PM

ya have Algar_emi's Aleph pdf ?

HIPCHECK · 4th November 2012, 07:33 PM

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

PKI · 4th November 2012, 07:35 PM

Quote:

Originally Posted by Zen Mod

everything up to 100mV is considered as OK

still - lesser is better

Is it pdf for an Aleph 30 in red and blue collors?

Zen Mod · 4th November 2012, 07:37 PM

.

4th November 2012, 07:21 PM	#93
HIPCHECK diyAudio Member Join Date: Jun 2004 Location: ARKANSAS	Is that 6V of DC offset? Is that at initial start up? Also, did it settle any after running for a few minutes? __________________ If a inch of duct tape will fix it, 3 feet should fix it for life!!!!

4th November 2012, 07:23 PM	#95
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	everything up to 100mV is considered as OK still - lesser is better __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

4th November 2012, 07:27 PM	#97
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	ya have Algar_emi's Aleph pdf ? __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

4th November 2012, 07:33 PM	#98
HIPCHECK diyAudio Member Join Date: Jun 2004 Location: ARKANSAS	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 __________________ If a inch of duct tape will fix it, 3 feet should fix it for life!!!!

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4th November 2012, 10:57 AM	#91
Marra diyAudio Member Join Date: Nov 2009 Location: Near Lincoln	One channel at a time.

4th November 2012, 07:02 PM	#92
PKI diyAudio Member Join Date: Aug 2011	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?

4th November 2012, 07:22 PM	#94
PKI diyAudio Member Join Date: Aug 2011	Ok, i removed R8, DC offset dropped to -16mV, but after 3 min of working rising again, now it is -28mV :-(

4th November 2012, 07:26 PM	#96
PKI diyAudio Member Join Date: Aug 2011	Anything i can do to reduce it? My input pars were matched super close. -35 mV still going up... :-(

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