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Bias pot mounting for plexi and JTM 45
Posted: Wed May 23, 2007 12:03 pm
by VelvetGeorge
Thought I would share how I've been mounting the bias pots lately. It's a little more secure.
I bend the rounded tabs out to the side and solder them to the top of the bias circuit ground terminals.
One pointed contact goes to the bias cap lead and the other gets a 47k-68k resistor as normal.
george
Posted: Thu May 31, 2007 9:04 am
by Joe Popp
George:
What is the red stuff on your solder joints? Nail polish to prevent corrosion? Or is it some super solder paint?
Loving the site and the parts you just sent!
Posted: Thu May 31, 2007 12:12 pm
by guitar007
Joe Popp wrote:George:
What is the red stuff on your solder joints? Nail polish to prevent corrosion? Or is it some super solder paint?
Loving the site and the parts you just sent!
Yeah...what's it called and where can we get it.
Posted: Wed Jun 06, 2007 6:28 am
by Joe Popp
Aha!! found it
The infamous Red Sharpie! I'm new and catching up on all of the old threads...
Posted: Wed Jun 06, 2007 3:48 pm
by Wallace
that looks pretty thick for a sharpie
Posted: Wed Jun 06, 2007 10:23 pm
by stokesdead
liquid electrical tape?
Posted: Sat Dec 15, 2007 9:01 pm
by Loganp
question about this Bias pot. I am at the point of testing all the voltages and final tweaking of my amp and bias. Should i solder the bias resistor and pot on now then tweak it as needed. or wait till i test all the voltages and am actually ready to set the bias?
Posted: Sat Dec 15, 2007 11:33 pm
by toner
Solder every connection before turning the amp on.
Re: Bias pot mounting for plexi and JTM 45
Posted: Mon Oct 27, 2008 12:29 am
by mjbrown
The red stuff is what Marshall used starting in 1968 and onwards for Quality Control on the solder joints (I believe)
I think the closest equivalent to this today is Glyptal (this is what high-performance
engine builders coat the porous cast iron inside engine blocks for better oil flow/circulation.)
Just do a search for it.
Re: Bias pot mounting for plexi and JTM 45
Posted: Mon Oct 27, 2008 9:17 am
by chubs
Actualy... I asked George not too long ago and his answer was:
""Red Insulating Varnish. Like they use in alternators and motors.
I get it from Allied.
VG""
Re: Bias pot mounting for plexi and JTM 45
Posted: Mon Jun 01, 2009 10:29 am
by syscokid
chubs wrote:Actualy... I asked George not too long ago and his answer was:
""Red Insulating Varnish. Like they use in alternators and motors.
I get it from Allied.
VG""
What happens when you have to R&R a component with this "varnish" on the solder?
Re: Bias pot mounting for plexi and JTM 45
Posted: Fri Jun 19, 2009 1:33 pm
by Structo
I just use a red sharpie.
The purpose for me to do this especially when I get a customers amp in is to inspect the solder joints.
As I move through the amp I color the tops of the joints, that way I know I have looked at it.
Plus it looks cool as hell and when the customer sees it I tell them that is for quality assurance and means I have thoroughly checked through the amp.
Re: Bias pot mounting for plexi and JTM 45
Posted: Sun Dec 20, 2009 7:39 am
by wrea398
The original stuff is called "Glyptol". It's made for just this kind of "anti corrosion" use. It is red insulating varnish. You can get it on the web or a good electrical shop. The original stuff is more transparent and rustier in color.
Re: Bias pot mounting for plexi and JTM 45
Posted: Sun May 20, 2012 9:04 am
by Twistingcrow
wrea398 wrote:The original stuff is called "Glyptol". It's made for just this kind of "anti corrosion" use. It is red insulating varnish. You can get it on the web or a good electrical shop. The original stuff is more transparent and rustier in color.
It's actually called "Glyptal", with an "a" instead of the "o"... But any efficient search would have found it anyway... Pretty tough to find though, especially in the EU...
Re: Bias pot mounting for plexi and JTM 45
Posted: Mon Feb 10, 2014 1:13 pm
by maxwedge572
This too funny!
I've had a quart of unopened Glyptal for about 35 years! I used to be into hot rodding and they used to paint the valley area (where the cam and push rods are) of V8 engine blocks with this stuff because it was really slippery. The oil would drain back to the pan faster.
Is this what they really used? I think that this what I have is a bright red and the marshal stuff looks much darker. I haven't tried to look but maybe they have different tints.
