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Transformer Power Rating

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Hello Everyone , i have a query . The BDW84D BDW83D darlington pairs were really hard to find but luckily i found them. i am wondering if we can use substitute parts for the BDW84D and BDW83D , which are available like BDW84A and BDW83A is really easy to find and even BDW84D is easy to find . So my question is that is there a substitute for BDW84D and BDW83D.
one more thing i am remaking the inductr and this time winding it on another resistor of 1W with smaller length , i will send some pictures soon of the inductor and the darlington transistors i found also...

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The last letter is the voltage! ;)



I know that the last letter is the voltage, but I wonder what would happen if I put my BDW83 & 84 "C" version? I'm about to finish the project soon, and I plan to put these transistors...what do you propose?
Also, do you think that it will be enough if I put transformer which has 2x23V in the secondary and use it with the electrolyth capacitors 3x4700mF/63V = 14100mF for (+) and 14100mF for (-) voltage?

Thanks.

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Hi there

I checked the voltage of the BDW 83/84 transistors and the C stands for 100V collector voltage and the D stands for 120V collector voltage!
This means that either the C or the D verson can be used in this cirquit!

Mickey, the tranny shall be a 2X28V/8A type, not a 2X23 Volt type! 3X4700uF/63V lytics will be just fine!

I have not built this amp, and will never do, there are better amps!


//Staigen

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Datasheetarchive.com found a difference: The ability to dissipate heat.

Only 3 companies make the BDW83D and BDW84D. Many companies make the C version.
A "no name brand" company makes the D with a 150W rating but ST Micro who make only the C version have a rating of only (!) 130W.

I also wouldn't build this amp that looks like it is a very old design. Check www.ampslab.com and www.sound.westhost.com/index2.html for much newer and better amp projects. 

post-1706-14279142633332_thumb.png

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I like the retros...javascript:replaceText(' :)', document.postmodify.message);
Smiley I'm building this amp 'cause I want to use it in my combo guitar amp project... I don't know, I looked at the written characteristics of the amp and it looked very, very nice to me... If I'm wrong with this, I will be very, very dissapointed...javascript:replaceText(' :-\\', document.postmodify.message);
Undecided
BTW, I know that the transformer SHOULD be 2x28V/8Amps, my question was WHAT WILL HAPPEN when I put this one that I have? I think that the electrolytics will raise the voltage to about 35-38V... Will it provide less power or what?

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Oh my God.... look at this message!!!!
HERE IT IS HOW IT SHOUD LOOK:

I like the retros... I'm building this amp 'cause I want to use it in my combo guitar amp project... I don't know, I looked at the written characteristics of the amp and it looked very, very nice to me... If I'm wrong with this, I will be very, very dissapointed

BTW, I know that the transformer SHOULD be 2x28V/8Amps, my question was WHAT WILL HAPPEN when I put this one that I have? I think that the electrolytics will raise the voltage to about 35-38V... Will it provide less power or what?

And, I do have ST Micro transistors. They'll work fine, I think...

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Damn, I hope this one that I have will be big enough... I'm putting a NTC controlled cooling fan, so I think I'm doing right....


It will work, but, yes, it will deliver much less power!)


//Staigen

How much less power? Can we calculate that?

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Hi

I'm putting a NTC controlled cooling fan

Run the fan at full speed all the time instead, i suppose it is a fan from a computer.

How much less power? Can we calculate that?

Audioguru is much better in calculating this kind of things. We can ask him.
Hey Audioguru, what do you think?

//Staigen

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No, it's not a fan from the computer, it's actualy twice as big and it blows really good. It's PAPST cooler, you might heard of those... Hello, audioguru, we're waiting for you... Will I get an answer to my question?

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Since 100W into 8 ohms has a p-p voltage of 80V, then this project can't produce anywhere near its rated 100W with only a positive and negative 40V supply from a dual 30VAC transformer.
It has a voltage loss of about 7V so the dual 30.5VDC from a dual 23VAC transformer is reduced to 54VDC, which is 45.5W into 8 ohms at clipping.

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Hi Guys,

The newer package (SOT-93) has a better ability to dispose heat than the older (TO-218). At least that’s how it seems! These two packages are very similar to look at but internally the “chip” has probably a better thermal contact to the metal tab. :)

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