Atom Feed - Twisted Pear Audio Support - Forum:RevC AmplifierTwisted Pear Audio Support - Atom Feedurn:twistedpearaudio-com:AtomFeed:TwistedPearAudioSupport:Forum:RevCAmplifier:1Copyright 2024 Twisted Pear Audio Support2024-03-29T08:11:26Zhttp://www.twistedpearaudio.com/forum/Images/YAFLogo.pngForum Adminhttp://www.twistedpearaudio.comfeedback@twistedpearaudio.comemerthhttp://www.twistedpearaudio.com/forum/profile/26352-emerthemerthhttp://www.twistedpearaudio.com/forum/profile/26352-emerthBrian Doneganhttp://www.twistedpearaudio.com/forum/profile/8-Brian-Donegansteinholienhttp://www.twistedpearaudio.com/forum/profile/389-steinholienhifi-alexhttp://www.twistedpearaudio.com/forum/profile/531-hifi-alexBrian Doneganhttp://www.twistedpearaudio.com/forum/profile/8-Brian-DoneganBrian Doneganhttp://www.twistedpearaudio.com/forum/profile/8-Brian-Doneganthegeekhttp://www.twistedpearaudio.com/forum/profile/129-thegeekullushttp://www.twistedpearaudio.com/forum/profile/104-ullusMrMajestichttp://www.twistedpearaudio.com/forum/profile/125-MrMajesticmaxlorenzhttp://www.twistedpearaudio.com/forum/profile/64-maxlorenzRuss Whitehttp://www.twistedpearaudio.com/forum/profile/9-Russ-Whitethegeekhttp://www.twistedpearaudio.com/forum/profile/129-thegeekullushttp://www.twistedpearaudio.com/forum/profile/104-ullusBrian Doneganhttp://www.twistedpearaudio.com/forum/profile/8-Brian-DoneganBrian Doneganhttp://www.twistedpearaudio.com/forum/profile/8-Brian-Doneganullushttp://www.twistedpearaudio.com/forum/profile/104-ullussqualorhttp://www.twistedpearaudio.com/forum/profile/87-squalorsqualorhttp://www.twistedpearaudio.com/forum/profile/87-squalorBrian Doneganhttp://www.twistedpearaudio.com/forum/profile/8-Brian-DoneganBrian Doneganhttp://www.twistedpearaudio.com/forum/profile/8-Brian-DoneganYetAnotherForum.NETurn:twistedpearaudio-com:ftTopics:st1:tid3567:lmid22261:1Rev C 9/1/2006 PCB Relay?<table class="content postContainer_Alt" width="100%"><tr><td>Thanks Brian! I had looked at the post but missed the zipfile link.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m22261-Rev-C-9-1-2006-PCB-Relay#post22261" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2015-02-03T22:01:20-07:002015-02-03T22:01:20-07:00emerth<table class="content postContainer_Alt" width="100%"><tr><td>Thanks Brian! I had looked at the post but missed the zipfile link.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m22261-Rev-C-9-1-2006-PCB-Relay#post22261" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid1551:lmid8305:1Schematic, Parts List, etc<table class="content postContainer_Alt" width="100%"><tr><td></td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m8305-Schematic--Parts-List--etc#post8305" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2011-01-07T09:13:26-07:002011-01-07T09:13:26-07:00Brian Donegan<table class="content postContainer_Alt" width="100%"><tr><td></td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m8305-Schematic--Parts-List--etc#post8305" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid1295:lmid6717:1Hum and vibration noise.<table class="content postContainer_Alt" width="100%"><tr><td>I assume you have isolated the problem to your turntable? The noise probably originates from either the platter bearing or the motor in your turntable. Two tings you can try is clean and change oil in the platter bearing and then start experimenting with your turntable stand. I generally get good results by putting the turntable on a solid, heavy piece of wood, concrete or stone. You can try different kinds of coupling/decoupling material (spikes/rubber/sorbothane etc) under the piece of wood. Make sure the turntable is in level. <br /><br />If this doesnt work; many RIAAs have a rumble filter, if your doesnt have one then you can make one yourself. Its a highpass filter with rolloff at appr 20Hz.<br /><br />Good luck!</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m6717-Hum-and-vibration-noise#post6717" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2010-09-06T14:39:55-07:002010-09-06T14:39:55-07:00steinholien<table class="content postContainer_Alt" width="100%"><tr><td>I assume you have isolated the problem to your turntable? The noise probably originates from either the platter bearing or the motor in your turntable. Two tings you can try is clean and change oil in the platter bearing and then start experimenting with your turntable stand. I generally get good results by putting the turntable on a solid, heavy piece of wood, concrete or stone. You can try different kinds of coupling/decoupling material (spikes/rubber/sorbothane etc) under the piece of wood. Make sure the turntable is in level. <br /><br />If this doesnt work; many RIAAs have a rumble filter, if your doesnt have one then you can make one yourself. Its a highpass filter with rolloff at appr 20Hz.<br /><br />Good luck!</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m6717-Hum-and-vibration-noise#post6717" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid107:lmid1398:1Doesn't work, now what?<table class="content postContainer_Alt" width="100%"><tr><td><div class="quote"><span class="quotetitle">Russ White wrote:</span><blockquote>That's is definitely not right. It should be right around 0.</div></div><br />I ordered a few LM318 and BC546 & BC639 transistors and will replace them as soon as they arrive.<br /><br />Thanks for your help for now!<br /><br />Best regards,<br />Alex</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m1398-Doesn-t-work--now-what#post1398" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2008-09-24T07:28:43-07:002008-09-24T07:28:43-07:00hifi-alex<table class="content postContainer_Alt" width="100%"><tr><td><div class="quote"><span class="quotetitle">Russ White wrote:</span><blockquote>That's is definitely not right. It should be right around 0.</div></div><br />I ordered a few LM318 and BC546 & BC639 transistors and will replace them as soon as they arrive.<br /><br />Thanks for your help for now!<br /><br />Best regards,<br />Alex</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m1398-Doesn-t-work--now-what#post1398" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid110:lmid709:1final connections on revC (i.e. not shocking myself :-)<table class="content postContainer_Alt" width="100%"><tr><td><div class="quote"><span class="quotetitle">Dougie085 wrote:</span><blockquote>Is 30VAC too much? I have some large heatsinks I plan on using with them and the transformer I have is 30VAC 300VA.</div></div><br /><br />Yes, 30VAC is too high.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m709-final-connections-on-revC--i-e--not-shocking-myself#post709" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2008-01-22T14:07:31-07:002008-01-22T14:07:31-07:00Brian Donegan<table class="content postContainer_Alt" width="100%"><tr><td><div class="quote"><span class="quotetitle">Dougie085 wrote:</span><blockquote>Is 30VAC too much? I have some large heatsinks I plan on using with them and the transformer I have is 30VAC 300VA.</div></div><br /><br />Yes, 30VAC is too high.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m709-final-connections-on-revC--i-e--not-shocking-myself#post709" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid177:lmid603:1LED, do I need it?<table class="content postContainer_Alt" width="100%"><tr><td>I thought about including an LED in the RevC kit, but decided against it as there are so many choices available (color, size, brightness), and it's really an aesthetic choice of the builder. Glad everything works! </td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m603-LED--do-I-need-it#post603" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-10-16T03:08:07-07:002007-10-16T03:08:07-07:00Brian Donegan<table class="content postContainer_Alt" width="100%"><tr><td>I thought about including an LED in the RevC kit, but decided against it as there are so many choices available (color, size, brightness), and it's really an aesthetic choice of the builder. Glad everything works! </td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m603-LED--do-I-need-it#post603" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid163:lmid551:1Kits out of order<table class="content postContainer_Alt" width="100%"><tr><td>Hi.<br />Do you plan to make any more kits?<br />I've already bought a stereo kit, but I might want another one in order to biamp my speakers.<br /></td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m551-Kits-out-of-order#post551" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-09-08T12:39:50-07:002007-09-08T12:39:50-07:00thegeek<table class="content postContainer_Alt" width="100%"><tr><td>Hi.<br />Do you plan to make any more kits?<br />I've already bought a stereo kit, but I might want another one in order to biamp my speakers.<br /></td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m551-Kits-out-of-order#post551" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid133:lmid508:1potential between signal ground and case ground <table class="content postContainer_Alt" width="100%"><tr><td>the problem with the potential can be solved with a 100 ohm resistor as shown in this article <a target="_blank" rel="nofollow" href="http://perso.wanadoo.fr/francis.audio2/La_ronfle.doc" title="http://perso.wanadoo.fr/francis.audio2/La_ronfle.doc">La Ronfle</a> (in french, "La ronfle" means "The hum"), referenced from <a target="_blank" rel="nofollow" href="http://francis.audio.monsite.wanadoo.fr/page4.html" title="http://francis.audio.monsite.wanadoo.fr/page4.html">this page</a> (in french).<br /><br />the illustrations in the article should be self-explaining even without understanding french.<br />(for printing the article I had to convert the DOC into PDF first, using the free PDFcreator tool.)<br /><br />some of the problemes discussed in the article don't materialize with the RevC design since the bridge and capacitors are on the monoblocks. in addition, if you use a passive pre-amp like me, there is no pre-amp signal mass, since both, Darwin selector and Joshua attenuator use the seperate PSU only for switching the relays and have no contact with any signal mass.<br /><br />in case your amp <em>hums</em> if you connect chassis-earth and signal-ground (mine doesn't), the 100 ohm resistor shou</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m508-potential-between-signal-ground-and-case-ground#post508" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-08-03T09:54:29-07:002007-08-03T09:54:29-07:00ullus<table class="content postContainer_Alt" width="100%"><tr><td>the problem with the potential can be solved with a 100 ohm resistor as shown in this article <a target="_blank" rel="nofollow" href="http://perso.wanadoo.fr/francis.audio2/La_ronfle.doc" title="http://perso.wanadoo.fr/francis.audio2/La_ronfle.doc">La Ronfle</a> (in french, "La ronfle" means "The hum"), referenced from <a target="_blank" rel="nofollow" href="http://francis.audio.monsite.wanadoo.fr/page4.html" title="http://francis.audio.monsite.wanadoo.fr/page4.html">this page</a> (in french).<br /><br />the illustrations in the article should be self-explaining even without understanding french.<br />(for printing the article I had to convert the DOC into PDF first, using the free PDFcreator tool.)<br /><br />some of the problemes discussed in the article don't materialize with the RevC design since the bridge and capacitors are on the monoblocks. in addition, if you use a passive pre-amp like me, there is no pre-amp signal mass, since both, Darwin selector and Joshua attenuator use the seperate PSU only for switching the relays and have no contact with any signal mass.<br /><br />in case your amp <em>hums</em> if you connect chassis-earth and signal-ground (mine doesn't), the 100 ohm resistor shou</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m508-potential-between-signal-ground-and-case-ground#post508" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid145:lmid491:1RevC size and Heatsink<table class="content postContainer_Alt" width="100%"><tr><td><div class="quote"><span class="quotetitle">ullus wrote:</span><blockquote><a target="_blank" rel="nofollow" href="http://www.twistedpearaudio.com/forum/default.aspx?g=posts&t=68" title="http://www.twistedpearaudio.com/forum/default.aspx?g=posts&t=68">Someone</a> earlier posted that he used a socket 7 computer CPU heatsink and that it doesn't get very hot.<br /><br />Board size w/o heatsink (from earlier post):<br />4.115" from back of LM3886 to front, 3.27" wide,<br />2" high (2.5" incl. standoffs).</div></div><br /><br />Thanks, just what I was looking for.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m491-RevC-size-and-Heatsink#post491" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-07-23T03:13:22-07:002007-07-23T03:13:22-07:00MrMajestic<table class="content postContainer_Alt" width="100%"><tr><td><div class="quote"><span class="quotetitle">ullus wrote:</span><blockquote><a target="_blank" rel="nofollow" href="http://www.twistedpearaudio.com/forum/default.aspx?g=posts&t=68" title="http://www.twistedpearaudio.com/forum/default.aspx?g=posts&t=68">Someone</a> earlier posted that he used a socket 7 computer CPU heatsink and that it doesn't get very hot.<br /><br />Board size w/o heatsink (from earlier post):<br />4.115" from back of LM3886 to front, 3.27" wide,<br />2" high (2.5" incl. standoffs).</div></div><br /><br />Thanks, just what I was looking for.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m491-RevC-size-and-Heatsink#post491" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid24:lmid470:1Rev-C's substitution parts<table class="content postContainer_Alt" width="100%"><tr><td>Hi,<br />I finally got the time to assemble the first monoblock. The box is all hand made, from spare materials. I will post photos to see if anybody has seen an uglier enclosure :-)<br /><br />It uses an EI 250VA transformer (locally made, with EMI filter/screen) closely mounted to the PCB: the amp is totally silent! <br />The sound as usual is awesome. I can't compare yet with my unmodded Myref but sound is very promising: soft, yet punchy and detailed throughout the spectrum.<br /><br />The only drawback is a big turn-off "tump"! (DC offset is 2mV only!)<br /><br />Could this tump be caused by swapping the electrolytic caps from the LM3886 PS from 220uf to 470uf???<br /><br />Should the relay disconnect speakers on power off and thus avoid tumps? Sorry I don't remember that.<br /><br />Regards,<br />M </td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m470-Rev-C-s-substitution-parts#post470" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-07-11T17:52:12-07:002007-07-11T17:52:12-07:00maxlorenz<table class="content postContainer_Alt" width="100%"><tr><td>Hi,<br />I finally got the time to assemble the first monoblock. The box is all hand made, from spare materials. I will post photos to see if anybody has seen an uglier enclosure :-)<br /><br />It uses an EI 250VA transformer (locally made, with EMI filter/screen) closely mounted to the PCB: the amp is totally silent! <br />The sound as usual is awesome. I can't compare yet with my unmodded Myref but sound is very promising: soft, yet punchy and detailed throughout the spectrum.<br /><br />The only drawback is a big turn-off "tump"! (DC offset is 2mV only!)<br /><br />Could this tump be caused by swapping the electrolytic caps from the LM3886 PS from 220uf to 470uf???<br /><br />Should the relay disconnect speakers on power off and thus avoid tumps? Sorry I don't remember that.<br /><br />Regards,<br />M </td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m470-Rev-C-s-substitution-parts#post470" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid134:lmid450:1pictures of my first DIY amp (RevC with JoshuaTree and Darwin) in UPS case<table class="content postContainer_Alt" width="100%"><tr><td>It does not produce much change, but the theory is that any residual waveform from the rectification that gets by the PSRR of the amp will be present in opposite phase from each stereo speaker, thus "cancelling" in theory. In pactice out of phase waveforms on speakers in a room rarely actually fully cancel. But I still do this out of habbit. :) I just like symmetry. And wiring them up opposite just feels right. :)<br /><br />Cheers!<br />Russ</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m450-pictures-of-my-first-DIY-amp--RevC-with-JoshuaTree-and-Darwin--in-UPS-case#post450" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-07-02T07:00:23-07:002007-07-02T07:00:23-07:00Russ White<table class="content postContainer_Alt" width="100%"><tr><td>It does not produce much change, but the theory is that any residual waveform from the rectification that gets by the PSRR of the amp will be present in opposite phase from each stereo speaker, thus "cancelling" in theory. In pactice out of phase waveforms on speakers in a room rarely actually fully cancel. But I still do this out of habbit. :) I just like symmetry. And wiring them up opposite just feels right. :)<br /><br />Cheers!<br />Russ</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m450-pictures-of-my-first-DIY-amp--RevC-with-JoshuaTree-and-Darwin--in-UPS-case#post450" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid120:lmid420:1Various questions from a diy noob regarding the myrefC.<table class="content postContainer_Alt" width="100%"><tr><td>I posted this same post at diyaudio, so for posterity:<br /><a target="_blank" rel="nofollow" href="http://www.diyaudio.com/forums/showthread.php?s=&threadid=103119" title="http://www.diyaudio.com/forums/showthread.php?s=&threadid=103119">http://www.diyaudio.com/...p?s=&threadid=103119</a></td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m420-Various-questions-from-a-diy-noob-regarding-the-myrefC#post420" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-06-26T09:21:58-07:002007-06-26T09:21:58-07:00thegeek<table class="content postContainer_Alt" width="100%"><tr><td>I posted this same post at diyaudio, so for posterity:<br /><a target="_blank" rel="nofollow" href="http://www.diyaudio.com/forums/showthread.php?s=&threadid=103119" title="http://www.diyaudio.com/forums/showthread.php?s=&threadid=103119">http://www.diyaudio.com/...p?s=&threadid=103119</a></td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m420-Various-questions-from-a-diy-noob-regarding-the-myrefC#post420" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid126:lmid396:1first monoblock works ! :-))) - question for transformer <table class="content postContainer_Alt" width="100%"><tr><td>doppelbock ;) twinmonoblock, twinpower with a light bulb.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m396-first-monoblock-works-----------question-for-transformer#post396" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-06-22T10:02:59-07:002007-06-22T10:02:59-07:00ullus<table class="content postContainer_Alt" width="100%"><tr><td>doppelbock ;) twinmonoblock, twinpower with a light bulb.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m396-first-monoblock-works-----------question-for-transformer#post396" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid108:lmid340:1Pre-Amp for RevC?<table class="content postContainer_Alt" width="100%"><tr><td><a target="_blank" rel="nofollow" href="http://www.apexjr.com" title="http://www.apexjr.com">ApexJr</a> is a great place for this stuff.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m340-Pre-Amp-for-RevC#post340" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-05-17T13:36:16-07:002007-05-17T13:36:16-07:00Brian Donegan<table class="content postContainer_Alt" width="100%"><tr><td><a target="_blank" rel="nofollow" href="http://www.apexjr.com" title="http://www.apexjr.com">ApexJr</a> is a great place for this stuff.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m340-Pre-Amp-for-RevC#post340" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid101:lmid307:1A question or two before I power up...<table class="content postContainer_Alt" width="100%"><tr><td>Usually, yes. I would check it though to be sure. Check for continuity between the ground prong on the plug and the green wire. Can never be too safe.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m307-A-question-or-two-before-I-power-up#post307" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-04-30T11:09:38-07:002007-04-30T11:09:38-07:00Brian Donegan<table class="content postContainer_Alt" width="100%"><tr><td>Usually, yes. I would check it though to be sure. Check for continuity between the ground prong on the plug and the green wire. Can never be too safe.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m307-A-question-or-two-before-I-power-up#post307" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid70:lmid299:1PSU voltage<table class="content postContainer_Alt" width="100%"><tr><td>Thanks for not strangling me with a twisted pair ;)<br /><br />Too bad it doesn't work. I only thought about the middle man (center tap) after I'd posted my question.<br /><br />The good news: fortunately, I've not yet bought the 2 x 48VAC transformer which I happened to come across at eprey. ;)<br /><br />I agree if you'd put my question on top of the hall of shame ;)</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m299-PSU-voltage#post299" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-03-12T09:48:49-07:002007-03-12T09:48:49-07:00ullus<table class="content postContainer_Alt" width="100%"><tr><td>Thanks for not strangling me with a twisted pair ;)<br /><br />Too bad it doesn't work. I only thought about the middle man (center tap) after I'd posted my question.<br /><br />The good news: fortunately, I've not yet bought the 2 x 48VAC transformer which I happened to come across at eprey. ;)<br /><br />I agree if you'd put my question on top of the hall of shame ;)</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m299-PSU-voltage#post299" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid68:lmid265:1RevC Amplifier ***for dummies***<table class="content postContainer_Alt" width="100%"><tr><td>I know, my heatsinks look weak. They are for a socket 7 computer CPU but they stay cool to the touch, I can even put my finger on the edge of the LM3886. <br />How big of a fuse is everyone using ? What hardware is best for bolting the heatsink to the LM3886 ? (i bought the wrong size twice)<br />Oh yea, I got to tell you guys about my Sony Walkman. It's FM reproduction is the best i've heard. I got a modified SRF-s84 from <a target="_blank" rel="nofollow" href="http://www.fixup.net/tips/srfs83/srfs83.htm" title="http://www.fixup.net/tips/srfs83/srfs83.htm">Xin Feng</a>. Wish I could use it to build a integrated amp/reciever.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m265-RevC-Amplifier------for-dummies#post265" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-02-22T20:37:58-07:002007-02-22T20:37:58-07:00squalor<table class="content postContainer_Alt" width="100%"><tr><td>I know, my heatsinks look weak. They are for a socket 7 computer CPU but they stay cool to the touch, I can even put my finger on the edge of the LM3886. <br />How big of a fuse is everyone using ? What hardware is best for bolting the heatsink to the LM3886 ? (i bought the wrong size twice)<br />Oh yea, I got to tell you guys about my Sony Walkman. It's FM reproduction is the best i've heard. I got a modified SRF-s84 from <a target="_blank" rel="nofollow" href="http://www.fixup.net/tips/srfs83/srfs83.htm" title="http://www.fixup.net/tips/srfs83/srfs83.htm">Xin Feng</a>. Wish I could use it to build a integrated amp/reciever.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m265-RevC-Amplifier------for-dummies#post265" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid64:lmid263:1Schematic and Board view<table class="content postContainer_Alt" width="100%"><tr><td>Hola Mauricio,<br /><div class="quote"><span class="quotetitle">Quote:</span><blockquote>I can't help myself dreaming about a dedicated supply for LM318</div></div><br />I think that's what Rudi did. And he did away with the zeners. Someone else was talking about using a 12AX7 preamp tube in place of the 318. Me, I'm just glad mine works.<br />I want to ask you about your speakers, the 8" horns. Could you tell me more about them. I'm a fan of horns. Here are mine <a target="_blank" rel="nofollow" href="http://fullrangedriver.com/gallery/albums/userpics/10017/DallasRight.JPG" title="http://fullrangedriver.com/gallery/albums/userpics/10017/DallasRight.JPG">@ fullrangedriver</a></td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m263-Schematic-and-Board-view#post263" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-02-22T19:56:16-07:002007-02-22T19:56:16-07:00squalor<table class="content postContainer_Alt" width="100%"><tr><td>Hola Mauricio,<br /><div class="quote"><span class="quotetitle">Quote:</span><blockquote>I can't help myself dreaming about a dedicated supply for LM318</div></div><br />I think that's what Rudi did. And he did away with the zeners. Someone else was talking about using a 12AX7 preamp tube in place of the 318. Me, I'm just glad mine works.<br />I want to ask you about your speakers, the 8" horns. Could you tell me more about them. I'm a fan of horns. Here are mine <a target="_blank" rel="nofollow" href="http://fullrangedriver.com/gallery/albums/userpics/10017/DallasRight.JPG" title="http://fullrangedriver.com/gallery/albums/userpics/10017/DallasRight.JPG">@ fullrangedriver</a></td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m263-Schematic-and-Board-view#post263" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid74:lmid252:1sound quality compared to TPM-LM3886?<table class="content postContainer_Alt" width="100%"><tr><td>The RevC sounds better than the TPM-LM3886. The TPM is pretty much a standard GainClone, which we actualy designed for use with the TXO amp, but decided to sell on it's own as well, as many people like them.<br /><br />The RevC is a hHowlan current pump design, which better fidility and phase linearity. It also includes built in speaker protection and is a true dual-mono design... pretty good for the price ;).</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m252-sound-quality-compared-to-TPM-LM3886#post252" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-02-18T13:19:10-07:002007-02-18T13:19:10-07:00Brian Donegan<table class="content postContainer_Alt" width="100%"><tr><td>The RevC sounds better than the TPM-LM3886. The TPM is pretty much a standard GainClone, which we actualy designed for use with the TXO amp, but decided to sell on it's own as well, as many people like them.<br /><br />The RevC is a hHowlan current pump design, which better fidility and phase linearity. It also includes built in speaker protection and is a true dual-mono design... pretty good for the price ;).</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m252-sound-quality-compared-to-TPM-LM3886#post252" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>urn:twistedpearaudio-com:ftTopics:st1:tid20:lmid223:1Dimensions, Preferred trafo voltage<table class="content postContainer_Alt" width="100%"><tr><td>On that trafo, the two Orange wires are the Primaries (to mains AC), and the Blue/Black wires are the secondaries. The two Blue wires are 24V and the black is 0V (center tapped).<br /><br />You should be able to use a decent length of wire to connect the trafo to the RevCs, as it is still AC (travels distances much better than DC). I would test it this way... Attach three wires to the secondaries about the length you are considering, and measure the voltage at the ends. Compare this to the voltages without the extended wires attached. I would recommend, if you decide to go this route, to use at least 16ga wire (bigger is better) to reduce resistance and associated losses.<br /><br />Be careful. I would also recommend fuses on the primaries, and each of the secondaries where they leave the transformer.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m223-Dimensions--Preferred-trafo-voltage#post223" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>2007-02-06T08:04:54-07:002007-02-06T08:04:54-07:00Brian Donegan<table class="content postContainer_Alt" width="100%"><tr><td>On that trafo, the two Orange wires are the Primaries (to mains AC), and the Blue/Black wires are the secondaries. The two Blue wires are 24V and the black is 0V (center tapped).<br /><br />You should be able to use a decent length of wire to connect the trafo to the RevCs, as it is still AC (travels distances much better than DC). I would test it this way... Attach three wires to the secondaries about the length you are considering, and measure the voltage at the ends. Compare this to the voltages without the extended wires attached. I would recommend, if you decide to go this route, to use at least 16ga wire (bigger is better) to reduce resistance and associated losses.<br /><br />Be careful. I would also recommend fuses on the primaries, and each of the secondaries where they leave the transformer.</td></tr></table><table><tr><td><a href="http://www.twistedpearaudio.com/forum/posts/m223-Dimensions--Preferred-trafo-voltage#post223" ><img src="http://www.twistedpearaudio.com/forum/Themes/GreyGrey/icon_newest_reply.png" alt ="Go to last post" title ="Go to last post" /></a></td></tr><table>