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PostPosted: 02 Jan 2014, 22:59 
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Joined: 10 Jul 2011, 04:45
Posts: 68
Location: Banda Aceh, Indonesia
Hi All..... Very Merry X-Mast n Happy New Year...!

I want to know about TDA2050 sounds performance in many type of PSU....? Personaly I was trying that amp with 12 volt regulator psu (Walt Jung design) then using 22volt unregulator (snubberize)....then trying 22 volt psu base on simple emiter follower with zener diodes as voltage references....

and the last I was trying 24 volt psu base on simple emiter follower but using 12 x green led (2 volt) as voltage references ....

this is very subjective opinion.... I think the sound is very good when i using 12 volt walt jung design.... the second is when i use 24 volt reg psu (simple emiter follower with LED) and the third is with 22volt unregulator snubberize psu.

so what your experiences guys....?

regards...

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Small is enough. Clean is good. Simple is easy. Small, Clean and Simple is ZCA. And this is so beautiful....

Salam,
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PostPosted: 08 Jan 2014, 02:31 
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Location: Banda Aceh, Indonesia
pic and schematic for positive rail.


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_________________
Small is enough. Clean is good. Simple is easy. Small, Clean and Simple is ZCA. And this is so beautiful....

Salam,
Arie


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PostPosted: 29 Jan 2014, 06:38 
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Joined: 28 Jan 2014, 16:37
Posts: 4
Hello,
I started your project and I finished the amplification part
I used this components :

C1 - Solen Fast PA100 1uF/400V
C2 - Nichicon 22uF/250V
C3+C4 - Wima MKP-10 (100nF/400V)
C5 + C6 - Matsushita 470uf/63v
C7 - Wima MKS-4 (470nF/400V)
R1+R3 - 22 kOhm/1W sau (22kOhm/0,6w)
R2 - 680 Ohm/1W
R4 - 2.2Ohm (2R2)/2W

And now I am looking forward doing the power supply.
Are there some modification on this part or the schematics with 4700uf filtering is good ?


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PostPosted: 05 Mar 2014, 16:35 
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Joined: 05 Mar 2014, 16:28
Posts: 1
I want to thank Thomas Bethe for the details of his project. I followed most of it and made my own amp with a few additions. There's a few things I would have done differently as I'm re-learning electronics since I did it back at school.

It works well, puts out a good volume but I really need some better speakers to hear the highs better.


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PostPosted: 06 Mar 2014, 18:02 
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Joined: 28 May 2008, 21:53
Posts: 4580
Location: Winnipeg, CANADA
Nice work. I'll bet you will end up enjoying the amp a lot more than the wine. :wine:

Welcome to the forum.

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PostPosted: 09 Mar 2014, 05:06 
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Joined: 09 Mar 2014, 04:56
Posts: 7
Location: .nl
Hello,

I'm a total beginner at this stuff and was hoping one of you might clarify something for me.
The TDA2050 takes -/+ 25V. When I look at a typical transformer it has a regulation of 10%. If 18V is an RMS value at full load, wouldn't I get 18V * 2^0.5 * 1.1 = 28V at no or very little load? Or is that not a problem for the TDA2050?
Because of this I was thinking of using a 2x15V transformer.

Thanks.


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PostPosted: 10 Mar 2014, 21:08 
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Hi hrs, welcome to the forum.

For a quick calculation I just multiply the rated VAC by 1.4 (square root of 2). 18VAC will give you about 25VDC. Need to use a transformer rated 18V or less. A 16V secondary would also be a good choice.

Cheers

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PostPosted: 11 Mar 2014, 03:23 
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Joined: 09 Mar 2014, 04:56
Posts: 7
Location: .nl
Hi Gio, thanks for your reply.

Gio wrote:
For a quick calculation I just multiply the rated VAC by 1.4 (square root of 2). 18VAC will give you about 25VDC. Need to use a transformer rated 18V or less. A 16V secondary would also be a good choice.

Yes, to get from 18VAC to the rectified VDC I'd need to multiply by the square root of 2 which is what I meant by " * 2^0.5" in my previous post. However, as I understand it this is at full load (the volume knob turned to 11) where the maximum VDC voltage drop occurs compared to the open circuit secondary VDC (volume knob to 0). With regards to the typical regulation of a transformer the table here http://sound.westhost.com/xfmr2.htm#s113 is in line with the datasheet of a 230VAC / 2x18VAC transformer I thought of buying.

Is my understanding correct that the VDC is thus ~10% higher (28 VDC) at very low load / low SPL / volume knob turned to 1?
Noone that I can see in this thread complained about blowing up the TDA2050 by using a 18VAC secondary so does the TDA2050 actually have a higher voltage capacity than specied?
This is what I'd like to understand.

Thanks.


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PostPosted: 22 Mar 2014, 08:57 
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Location: Winnipeg, CANADA
Hi. The tda2050 data sheet does not specifically say so. Just +/-25v. And as you noted there have been no problems by using 18vac. Good question.

Cheers

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[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


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PostPosted: 24 Mar 2014, 10:08 
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Joined: 09 Mar 2014, 04:56
Posts: 7
Location: .nl
After thinking about it some more I reccon that if you heed the advise and use a 160VA transformer you'd get ~7% regulation. With some voltage drop over the rectifier would yield about 26VDC which I could imagine is within the unspecified tolerance of the IC.


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