100W Ultimate Fidelity Amplifier - Page 2

butch_vlad · 30th March 2010, 12:29 AM

I'm not much of an expert but I agree about C7, can't comment about the rest.
Thank you for the feedback.

apexaudio · 12:48 AM

Quote:

Originally Posted by wahab

R8 and R2 values are reversed..
R8 must be 560R and R2 22K...

C7 value ,is plain wrong , and should be much lower,
something between 3.3 and 18pF..

As i pointed it with many of his designs, R5 and C3
must be removed as they create a hard rail sticking when
the amp is overloaded.
There s better means to achive stability.....

Thanks Wahab,
R2 and R8 values are reversed on schematics, on PCB is OK,
C7 can be lower 47pF is minimum
C9,C10 can be lower 22pF is minimum
Rest is OK
Regards Mile

apexaudio · 30th March 2010, 12:52 AM

Quote:

Originally Posted by butch_vlad

I'm not much of an expert but I agree about C7, can't comment about the rest.
Thank you for the feedback.

C7 330pF is maximum value for stability, but can be lower after tested.

butch_vlad · 30th March 2010, 12:55 AM

If you can provide the PCB layout I'm willing to give it a try these days.

wahab · 30th March 2010, 01:04 AM

Quote:

Originally Posted by apexaudio

C7 330pF is maximum value for stability, but can be lower after tested.

At 330pF, it will severly affect the bandwith of the amp,
having influence below 20khz.

At 47pF , although i find the value still high, the bandwith
will be large enough, over 100khz...

Anyway, i appreciate that you re proposing many ideas
to help people make some builds, particularly your
well done PCBs.

regards,

apexaudio · 01:15 AM

Wahab do you know Marfy's Law in electronic: Amplifiers always oscilate and Oscilators always amplify.
Regards Mile

wahab · 30th March 2010, 01:17 AM

Quote:

Originally Posted by apexaudio

Wahab do you know Marfy's Low in electronic: Amplifiers always oscilate and Oscilators always amplify.
Regards Mile

Lol...That s a good one, Mile..
Perhaps that to make a good amplifier, we should start
designing a good oscillator...

regards

wahab

apexaudio · 30th March 2010, 01:42 AM

Quote:

Originally Posted by butch_vlad

Can we have the PCB layout to etch our own boards? I'm looking for new amplifier to try.
Apex do you have something similar with this one but with 2 pairs of output transistors? That is what I'm looking for but is hard to find. Was looking at Bora's Techno amplifier but I don't have enough info to make my own...yet...who knows.

You have on my other thread PCB layout with 2 pairs of output transistors irfp240/irfp9240 mosfets in "DC servo mosfet amplifier" and bdw83d/bdw84d darlingtons in "Amplifier motherboard". I sugest you DC servo mosfet amp. There is PCB for PSU and protect.
Regards Mile

sumaudioguy · 30th March 2010, 02:02 AM

I suppose if one is locked into the idea there can only be one plus and one minus supply this is a good design- now if you leave that idea behind then... a lot of improvement can be made and a lot of those slow current sources can be replaced by fast resistors. Every current source slows the propagation through the amp.

apexaudio · 30th March 2010, 02:14 AM

We always must made so many compromise, and never made best amplifier we can. Never can be made best amplifier, nothing is perfect.

30th March 2010, 12:29 AM	#11
butch_vlad diyAudio Member Join Date: Feb 2008	Thumbs down for this design so far I'm not much of an expert but I agree about C7, can't comment about the rest. Thank you for the feedback.

30th March 2010, 01:12 AM	#16
apexaudio diyAudio Member Join Date: Feb 2010 Location: Serbia	Wahab do you know Marfy's Law in electronic: Amplifiers always oscilate and Oscilators always amplify. Regards Mile Last edited by apexaudio; 30th March 2010 at 01:15 AM.

30th March 2010, 02:02 AM	#19
sumaudioguy diyAudio Member Join Date: Jan 2010 Location: Midwest U.S.A.	I suppose if one is locked into the idea there can only be one plus and one minus supply this is a good design- now if you leave that idea behind then... a lot of improvement can be made and a lot of those slow current sources can be replaced by fast resistors. Every current source slows the propagation through the amp. __________________ What the other guy said----Standing on the shoulders of giants. New avatar- no more little array

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30th March 2010, 12:55 AM	#14
butch_vlad diyAudio Member Join Date: Feb 2008	If you can provide the PCB layout I'm willing to give it a try these days.

30th March 2010, 02:14 AM	#20
apexaudio diyAudio Member Join Date: Feb 2010 Location: Serbia	We always must made so many compromise, and never made best amplifier we can. Never can be made best amplifier, nothing is perfect.