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Old 15th November 2004, 07:50 PM   #121
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Just let me know if you want any changes made to the PCB

All systems are up and running after the last big crash.....
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Old 15th November 2004, 07:58 PM   #122
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Jan,

R145 shouldn't be in parallel with R130 - that will affect the gain.
The new resistor should sit between R301-R302-R120 etc. star point and R201-R202-R203-R204 star point. Then if you leave it open (R140=inf) you leave the ouptut stage completely out from the feedback loop ("overal feedback free"), or if you have wire link (R140=0) output stage is 100% inside the feedback.

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Old 15th November 2004, 08:15 PM   #123
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Default Bratislav

Regarding your question to R130/R145, then I must have misunderstood your suggestion in post 79.....

And I think you mean R145 in the last bit of your post. Right ?

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Old 15th November 2004, 10:27 PM   #124
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Yes I meant R145. Sorry for the confusion.
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Old 16th November 2004, 01:28 AM   #125
troystg is online now troystg  United States
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Hi-

Like wim I would also like to see this become a GB.

I think it looks VERY good in my unqualified opinion.

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Old 16th November 2004, 09:13 AM   #126
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I'm at work right now, but I will hopefully get time to make some mods to the schematic and layout later today.

Are there other suggestions, while I'm at it ????
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Old 16th November 2004, 11:42 AM   #127
argo is offline argo  Estonia
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Quote:
Originally posted by ACD
I'm at work right now, but I will hopefully get time to make some mods to the schematic and layout later today.

Are there other suggestions, while I'm at it ????
Jan,

I am definitely no expert on PSB design but anyhow here are my observations/comments:
The board is really small which may be advantage for some builders with limited amp enclosure space but the penalty is if somebody wants to use bigger size components. Also there is not enough space to mount the heatsinks for Q109/110
The tracks should be wider and a component pads bigger makes it easier to solder and desolder for newbies. Especially the ground track should be much wider for low impedance.
Separate ground paths for signal (R102, C101, C103, C104) and power return currents ( ZD101/102, D109/110) would be beneficial. Star grounding for signal.
Feedback path from output should be separate track from protection circuit connections to output.

Regards,

Argo
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Old 16th November 2004, 12:07 PM   #128
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Quote:
Originally posted by argo



The tracks should be wider and a component pads bigger makes it easier to solder and desolder for newbies. Especially the ground track should be much wider for low impedance.

Argo
Both problems could be addressed by using a double-sided board, using the top layer as a ground plane. D/S boards are more robust as the holes are plated-through so it's not so easy to lift a pad when removing a component.

I know the reason for single-sided was so we can make our own boards with a lightbox and some ferric chloride, but it really doesn't cost that much to have D/S boards done by Olimex or similar, and even less if we do a group buy.
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Old 16th November 2004, 12:14 PM   #129
AuroraB is offline AuroraB  Norway
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Just a few minor comments....
It is really no more problem making a double sided board yourself than making a single sided.....
For standard leaded components, it is as simple as using the component leads as feed throughs, - has been done for ages!
As for plated holes... these can be a real PITA to desolder!!!
Specially for newbies without proper equipment!
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Old 16th November 2004, 12:49 PM   #130
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Quote:
Originally posted by AuroraB
Just a few minor comments....

As for plated holes... these can be a real PITA to desolder!!!
Specially for newbies without proper equipment!
It's never caused my **** any pain - unless the holes are too small for the wires, of course. Which they won't be on this lovely board.
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