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Chip Amps Amplifiers based on integrated circuits

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Old 15th September 2012, 02:40 PM   #11
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Well here is good film one B32560J475K - EPCOS - CAPACITOR, 4.7UF, 63V | Farnell United Kingdom
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Old 15th September 2012, 03:10 PM   #12
gohar is offline gohar  Pakistan
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Quote:
The Signal Ground must not be connected to the Power Ground
Yes its good point.

And which schematic should I follow?
This one?
Click the image to open in full size.

Or this one?
Click the image to open in full size.
I have planned to go with Point to Point or "Bug style" construction, no PCB or other boards.
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Old 15th September 2012, 03:15 PM   #13
gohar is offline gohar  Pakistan
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BTW, I am new to Electronics and Audio. But I am interested in these.
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Old 15th September 2012, 03:31 PM   #14
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by AndrewT View Post
post5 shows the complete implementation.
Quote:
Originally Posted by gohar View Post
And which schematic should I follow?
read !
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Old 15th September 2012, 04:31 PM   #15
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AndrewT,

I'm kinda surprized (and maybe even a little disappointed!) that you didn't catch the problem with the input and feedback network time constants on the second schematic. Fc at input is lower than feedback Fc, clearly a less than optimal implementation.

Mike

Last edited by Michael Bean; 15th September 2012 at 04:33 PM.
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Old 15th September 2012, 05:00 PM   #16
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Quote:
Originally Posted by AndrewT View Post
post5 shows the complete implementation.

BUT !!!!!
there is a standard convention used in allmost all schematics.
All the Ground connections are shown as having the same symbol !!!!!

The Signal Ground must not be connected to the Power Ground.
Instead:
Connect bottom of Ci directly to bottom of Rin.
Connect bottom of Rin directly to Bottom of Rv (vol pot).
Connect bottom of Rv directly to Barrel of RCA input socket.
This group of 4 connection are the Signal Ground.

One more:
Connect the Signal Ground to the Main Audio Ground using a low value resistor. 10r is usually adopted. Any value from 1r0 to 100r will probably work. You can even use 0r0 when you build a monoblock.
like this?
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Old 15th September 2012, 05:28 PM   #17
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AudioSan,

That looks good, except for the issue I mentioned in my last post. The input fc is about 3.4Hz and the feedback fc is about 7.2Hz which allows the possibility that the amp may be asked to pass a signal that the feedback network can't control. I recommend at least 100uf (or more) for Ci, that will lower feedback fc to about 1.6Hz (or less) which is much better.

Mike
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Old 15th September 2012, 05:38 PM   #18
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michael. yes. i was only refering to the seperat signal ground
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Old 15th September 2012, 07:30 PM   #19
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Quote:
Originally Posted by gohar View Post
BTW, I am new to Electronics and Audio. But I am interested in these.
If you gonna do p-to-p I might suggest start from Mick Feuerbacher project as it is, use 100W light bulb in series with your trafo primary. Use some cheap speaker to test your new amp.

Once it's working you can go further with schematic improvements, speaker protection addendum. I would not recommend dealing with more complicated schematics than Mick's one without PCB.
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Old 16th September 2012, 08:27 AM   #20
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by Michael Bean View Post
AndrewT,

I'm kinda surprized (and maybe even a little disappointed!) that you didn't catch the problem with the input and feedback network time constants on the second schematic. Fc at input is lower than feedback Fc, clearly a less than optimal implementation.

Mike
I'm kinda surprised and even disappointed that you did not read my post3
Quote:
Ci restricts the bass output.
Expect the bass to roll off from about 10Hz. I would use 220uF, or maybe 150uF
which applies universally when the same, or similar, schematic is re-posted. I try not to repeat myself, it's flouting of the Forum Rules to do so.
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