What happens when a stage hand drops an amp off the top of your speaker stack? I'm proud to say, "Nothing much!"
Fabian, the guitarist for Boyce Avenue, told me the accident occurred during a set change. His amp, a 50W head, was perched 5 -6 feet high on top of the stack when it slipped through the fingers of the stage hand. Fortunately, the stage was carpeted. My guess is that the amp landed on one of the top corners. The mahogany case was unscratched.
Now for the guts. Both relays popped out of their sockets. I build with sockets for ease of maintenance. Maybe I need to rethink that. But for now a dab of silicon holds them back in place.
The impact jarred a couple of the big orange drops out of position. No broken leads; just the long leads allowed the caps to pull away from the board. See attached photo for details. Next build I'll look at shortening those leads and using jumpers to connect to the other components.
All wiring seemed to stay in place. I'm a big fan of wiring my builds to NASA standards. Here's one of my favorite references: http://workmanship.nasa.gov/insp.jsp. Some builds thread their wires through the board and then to outboard components. I've seen other builds where the wiring bundles are zip-tied every half-inch or so. Probably not required. My guess is that the wiring is stiff enough and doesn't have enough mass to be effected by jolts or impacts.
Speaking of mass, how did the transformers do? The chassis held up just fine. I've started using .090 inch thick aluminum chassis from Watts Tube Audio. Total speculation here, but I'm not confident a less substantial chassis would have held the transformers in place. If you do opt to construct your amp with thinner material, I would recommend using fender washers to beef up the mounting holes. Unfortunately, one of the KEPS nuts did pull free from the chassis; however, I was able to press this back in place.
Finally, I inspected all the solder joints with a magnifying glass and then fired it up with a voltage limiter and no tubes. Basically, I ran it through all the initial checks that I do with a new build. All went well until I put the tubes back in. The bias on the 6L6s was way out of tolerance -- one at 58.5 and the other at 30.6 mV. So, I put a new set of tubes in and Boyce Avenue had their guitarist back!
Hope this never happens to you, but it is nice to know that this style of build is very road worthy!
Amp Abuse
Moderators: pompeiisneaks, Colossal
-
sixstringer
- Posts: 186
- Joined: Wed Feb 03, 2010 11:13 am
- Location: SoCal
Re: Amp Abuse
Here is what opens using your workmanship Nasa link:
<html>
<head>
<title>Inspection Pictorial Reference</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="orgcode" content="562">
<meta name="rno" content="Jeannette.F.Plante.1">
<meta name="rno" <meta name="content-owner" content="Jeannette.F.Plante.1">
<meta name="webmaster" content="Carl.M.Szabo.1">
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<body bgcolor="#FFFFFF" onLoad="MM_preloadImages('./img/guidadv_1.gif','./img/help_1.gif','./img/charter_1.gif','./img/contacts_1.gif','./img/wkstds_1.gif','./img/training_1.gif','./img/feedback_1.gif','./img/links_1.gif','./img/memlogin_1.gif','./img/mem_doc_1.gif','./img/mem_act_1.gif','./img/mem_ipc_1.gif','./img/mem_mtg_1.gif')">
<img src="./img/header.jpg" width="640" height="60"><br>
<table width="640" border="0" cellpadding="0" cellspacing="0">
<tr>
<td colspan="2" bgcolor="#333333" align="right"><font color="#FFFFFF"><b>Pictorial
Reference </b></font></td>
</tr>
<tr>
<td width="113" align="left" valign="top"><img src="./img/tealbar-left.gif" width="167" height="28"><br>
<a href="./index.jsp" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('CHARTER','','./img/charter_1.gif',1)"><img src="./img/charter_0.gif" width="167" height="24" name="CHARTER" border="0"></a><br>
<a href="./insp.jsp" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('INSP','','./img/insp_1.gif',1)"><img src="./img/insp_1.gif" border="0" name="INSP" alt="inspection pictorial reference" width="167" height="33"></a><br>
<img src="./img/menubottom.gif" width="167" height="64"> </td>
<td width="527" valign="top" align="left"><img src="./img/tealbar-right.gif" width="473" height="28"><br>
<table width="473" border="0" cellpadding="0" cellspacing="3">
<tr valign="top">
<td width="17"><b><img src="./img/20X20.gif" width="20" height="20"></b></td>
<td width="445">
<div align="center"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="2" color="#666666">INSPECTION
PICTORIAL REFERENCE</font></b></div>
</td>
</tr>
<tr valign="top">
<td width="17"> </td>
<td rowspan="2">
<p class="MsoNormal"><b>All diagrams and visual aids included in
this section are intended to provide <u>insight</u> to certified
operators, inspectors and instructors who visually assess the
compliance of flight hardware to locally
applicable requirements. The statements found in this pictorial
reference are <u>not</u> intended to be applied as requirements and
this pictorial reference should not be applied to contracts. Your
project or contract requirements should take precedence over the
pictures and statements in this pictorial reference if there is a
conflict. Refer to your local project or contract documents for
applicable workmanship requirements.</b></p>
<p class="MsoNormal"><font face="Verdana" size="2">
<span style="font-size: 10pt; font-family: Verdana;">This document
is not available in hard copy. However, links to printable Adobe™
Portable Document Format (PDF) files are provided. Be aware that
certain PDFs may be very large (15+MB) and require extensive
download time.</span></font></p>
<p align="center"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="2"><a href="./lib/insp/2%20books/frameset.html" target="_blank">
OPEN THE PICTORIAL REFERENCE IN A NEW WINDOW</a></font></b></p>
</td>
</tr>
<tr valign="top">
<td width="17"> </td>
</tr>
</table>
</td>
</tr>
</table>
<br>
<!-- #BeginLibraryItem "bottombar.lbi" --><table width="640" border="0" cellspacing="0" bgcolor="#CCCCCC">
<tr>
<td><font face="Verdana, Arial, Helvetica, sans-serif" size="1"><a href="./banner.htm#privacy" target="_blank">NASA
Privacy Statement</a>, <a href="./banner.htm#security" target="_blank">NASA
Security Banner</a><br>
Curator : <a href="mailto:cszabo@pop500.gsfc.nasa.gov?subject=Workmanship_site">Carl Szabo</a><br>
Responsible NASA Official : <a href="mailto:jfplante@pop500.gsfc.nasa.gov?subject=Workmanship_site">Jeannette Plante</a><BR>
</font></td>
<td>
<div align="right"><img src="./img/logo-nasa.gif" width="182" height="48"></div>
</td>
</tr>
</table><!-- #EndLibraryItem --></body>
</html>
so....I'm looking forward to the info but cannot decipher this.
<html>
<head>
<title>Inspection Pictorial Reference</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="orgcode" content="562">
<meta name="rno" content="Jeannette.F.Plante.1">
<meta name="rno" <meta name="content-owner" content="Jeannette.F.Plante.1">
<meta name="webmaster" content="Carl.M.Szabo.1">
<script language="JavaScript">
<!--
function MM_preloadImages() { //v3.0
var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
if (a.indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a;}}
}
function MM_swapImgRestore() { //v3.0
var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a)&&x.oSrc;i++) x.src=x.oSrc;
}
function MM_findObj(n, d) { //v4.0
var p,i,x; if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[n];
for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers.document);
if(!x && document.getElementById) x=document.getElementById(n); return x;
}
function MM_swapImage() { //v3.0
var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
if ((x=MM_findObj(a))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}
//-->
</script>
</head>
<body bgcolor="#FFFFFF" onLoad="MM_preloadImages('./img/guidadv_1.gif','./img/help_1.gif','./img/charter_1.gif','./img/contacts_1.gif','./img/wkstds_1.gif','./img/training_1.gif','./img/feedback_1.gif','./img/links_1.gif','./img/memlogin_1.gif','./img/mem_doc_1.gif','./img/mem_act_1.gif','./img/mem_ipc_1.gif','./img/mem_mtg_1.gif')">
<img src="./img/header.jpg" width="640" height="60"><br>
<table width="640" border="0" cellpadding="0" cellspacing="0">
<tr>
<td colspan="2" bgcolor="#333333" align="right"><font color="#FFFFFF"><b>Pictorial
Reference </b></font></td>
</tr>
<tr>
<td width="113" align="left" valign="top"><img src="./img/tealbar-left.gif" width="167" height="28"><br>
<a href="./index.jsp" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('CHARTER','','./img/charter_1.gif',1)"><img src="./img/charter_0.gif" width="167" height="24" name="CHARTER" border="0"></a><br>
<a href="./insp.jsp" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('INSP','','./img/insp_1.gif',1)"><img src="./img/insp_1.gif" border="0" name="INSP" alt="inspection pictorial reference" width="167" height="33"></a><br>
<img src="./img/menubottom.gif" width="167" height="64"> </td>
<td width="527" valign="top" align="left"><img src="./img/tealbar-right.gif" width="473" height="28"><br>
<table width="473" border="0" cellpadding="0" cellspacing="3">
<tr valign="top">
<td width="17"><b><img src="./img/20X20.gif" width="20" height="20"></b></td>
<td width="445">
<div align="center"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="2" color="#666666">INSPECTION
PICTORIAL REFERENCE</font></b></div>
</td>
</tr>
<tr valign="top">
<td width="17"> </td>
<td rowspan="2">
<p class="MsoNormal"><b>All diagrams and visual aids included in
this section are intended to provide <u>insight</u> to certified
operators, inspectors and instructors who visually assess the
compliance of flight hardware to locally
applicable requirements. The statements found in this pictorial
reference are <u>not</u> intended to be applied as requirements and
this pictorial reference should not be applied to contracts. Your
project or contract requirements should take precedence over the
pictures and statements in this pictorial reference if there is a
conflict. Refer to your local project or contract documents for
applicable workmanship requirements.</b></p>
<p class="MsoNormal"><font face="Verdana" size="2">
<span style="font-size: 10pt; font-family: Verdana;">This document
is not available in hard copy. However, links to printable Adobe™
Portable Document Format (PDF) files are provided. Be aware that
certain PDFs may be very large (15+MB) and require extensive
download time.</span></font></p>
<p align="center"><b><font face="Verdana, Arial, Helvetica, sans-serif" size="2"><a href="./lib/insp/2%20books/frameset.html" target="_blank">
OPEN THE PICTORIAL REFERENCE IN A NEW WINDOW</a></font></b></p>
</td>
</tr>
<tr valign="top">
<td width="17"> </td>
</tr>
</table>
</td>
</tr>
</table>
<br>
<!-- #BeginLibraryItem "bottombar.lbi" --><table width="640" border="0" cellspacing="0" bgcolor="#CCCCCC">
<tr>
<td><font face="Verdana, Arial, Helvetica, sans-serif" size="1"><a href="./banner.htm#privacy" target="_blank">NASA
Privacy Statement</a>, <a href="./banner.htm#security" target="_blank">NASA
Security Banner</a><br>
Curator : <a href="mailto:cszabo@pop500.gsfc.nasa.gov?subject=Workmanship_site">Carl Szabo</a><br>
Responsible NASA Official : <a href="mailto:jfplante@pop500.gsfc.nasa.gov?subject=Workmanship_site">Jeannette Plante</a><BR>
</font></td>
<td>
<div align="right"><img src="./img/logo-nasa.gif" width="182" height="48"></div>
</td>
</tr>
</table><!-- #EndLibraryItem --></body>
</html>
so....I'm looking forward to the info but cannot decipher this.
Re: Amp Abuse
This is probably what the OP was referring to.
http://workmanship.nasa.gov/lib/insp/2% ... meset.html
Pertinent data:
http://workmanship.nasa.gov/lib/insp/2% ... ments.html
http://workmanship.nasa.gov/lib/insp/2% ... nents.html
http://workmanship.nasa.gov/lib/insp/2% ... nents.html
http://workmanship.nasa.gov/lib/insp/2% ... inals.html
http://workmanship.nasa.gov/lib/insp/2% ... meset.html
Pertinent data:
http://workmanship.nasa.gov/lib/insp/2% ... ments.html
http://workmanship.nasa.gov/lib/insp/2% ... nents.html
http://workmanship.nasa.gov/lib/insp/2% ... nents.html
http://workmanship.nasa.gov/lib/insp/2% ... inals.html
Re: Amp Abuse
If you picked sockets that have a bit of clearance under them, a zip tie can keep those suckers in place without complicating repair.
Hope this helps!
Hope this helps!