audioguru Posted February 1, 2006 Report Share Posted February 1, 2006 Your resistor doesn't look like it is the same as a modern one. Use a modern one. Quote Link to comment Share on other sites More sharing options...
faizanbrohi Posted February 3, 2006 Report Share Posted February 3, 2006 Audioguru i have compared the 1W resistor diameter with the modern one also , the diameter is actually the same ... but the difference is its length... and ofcourse we are only interested in the diameter... Quote Link to comment Share on other sites More sharing options...
audioguru Posted February 3, 2006 Report Share Posted February 3, 2006 Many other amplifiers I've seen have nothing inside their coil at the output. Since your 1W resistor is the correct diameter then it will be fine. Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 3, 2006 Report Share Posted February 3, 2006 HiI dont think you need the resistor, the coil can be airwound, its so small and have enough gauge to support itself! :)//Staigen Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 3, 2006 Report Share Posted February 3, 2006 Hehe Audoiguru, replying at the same time//Staigen Quote Link to comment Share on other sites More sharing options...
audioguru Posted February 3, 2006 Report Share Posted February 3, 2006 Hehe Audoiguru, replying at the same timeI beat you by less than 3 minutes!Great minds think alike. ;D Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 3, 2006 Report Share Posted February 3, 2006 Hi AudioguruWhat do you think of making the coil airwound?//Staigen Quote Link to comment Share on other sites More sharing options...
audioguru Posted February 3, 2006 Report Share Posted February 3, 2006 Hi AudioguruWhat do you think of making the coil airwound?Yes, but its wire size is small so it might get crushed.I would use 1mm wire for an airwound coil. Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 3, 2006 Report Share Posted February 3, 2006 HiI would use 1mm wire for an airwound coil.I think 0.8 mm will be just fine, its only 10 turns//Staigen Quote Link to comment Share on other sites More sharing options...
faizanbrohi Posted February 5, 2006 Report Share Posted February 5, 2006 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... Quote Link to comment Share on other sites More sharing options...
ante Posted February 5, 2006 Report Share Posted February 5, 2006 The last letter is the voltage! ;) Quote Link to comment Share on other sites More sharing options...
Mickey Posted February 5, 2006 Report Share Posted February 5, 2006 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. Quote Link to comment Share on other sites More sharing options...
Mickey Posted February 5, 2006 Report Share Posted February 5, 2006 P.S. did anyone of you guys actually finished the amp? iS pcb CORRECT OR NOT? How does it work, huh? Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 5, 2006 Report Share Posted February 5, 2006 Hi thereI 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 Quote Link to comment Share on other sites More sharing options...
audioguru Posted February 5, 2006 Report Share Posted February 5, 2006 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. Quote Link to comment Share on other sites More sharing options...
Mickey Posted February 5, 2006 Report Share Posted February 5, 2006 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);UndecidedBTW, 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? Quote Link to comment Share on other sites More sharing options...
Mickey Posted February 5, 2006 Report Share Posted February 5, 2006 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 dissapointedBTW, 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... Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 5, 2006 Report Share Posted February 5, 2006 Hi MickeyIt will work, but, yes, it will deliver much less power!And the BDW83/84 C transistors will also work!//Staigen Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 5, 2006 Report Share Posted February 5, 2006 If you gonna use as for a guitar amp the put the output transistors on a real BIG cooling flange(i dont remember the right name for it now, this was in my dictionary)//Staigen Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 5, 2006 Report Share Posted February 5, 2006 Hehe, heatsink was the name for it, but it slip my mind, when i needed it! ;D ;DI belive i'm getting old ;D ;D ???//Staigen Quote Link to comment Share on other sites More sharing options...
Mickey Posted February 5, 2006 Report Share Posted February 5, 2006 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!)//StaigenHow much less power? Can we calculate that? Quote Link to comment Share on other sites More sharing options...
Staigen Posted February 5, 2006 Report Share Posted February 5, 2006 HiI'm putting a NTC controlled cooling fanRun 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 Quote Link to comment Share on other sites More sharing options...
Mickey Posted February 5, 2006 Report Share Posted February 5, 2006 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? Quote Link to comment Share on other sites More sharing options...
audioguru Posted February 7, 2006 Report Share Posted February 7, 2006 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. Quote Link to comment Share on other sites More sharing options...
ante Posted February 7, 2006 Report Share Posted February 7, 2006 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. :) Quote Link to comment Share on other sites More sharing options...
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