Bias pot mounting for plexi and JTM 45

Post by **VelvetGeorge** » Wed May 23, 2007 12:03 pm

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

Joe Popp · Post by **Joe Popp** » Thu May 31, 2007 9:04 am

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!

guitar007 · Post by **guitar007** » Thu May 31, 2007 12:12 pm

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.

Joe Popp · Post by **Joe Popp** » Wed Jun 06, 2007 6:28 am

Aha!! found it

The infamous Red Sharpie! I'm new and catching up on all of the old threads...

Wallace · Post by **Wallace** » Wed Jun 06, 2007 3:48 pm

that looks pretty thick for a sharpie

stokesdead · Post by **stokesdead** » Wed Jun 06, 2007 10:23 pm

liquid electrical tape?

Loganp · Post by **Loganp** » Sat Dec 15, 2007 9:01 pm

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?

toner · Post by **toner** » Sat Dec 15, 2007 11:33 pm

Solder every connection before turning the amp on.

mjbrown · Post by **mjbrown** » Mon Oct 27, 2008 12:29 am

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.

chubs · Post by **chubs** » Mon Oct 27, 2008 9:17 am

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""

syscokid · Post by **syscokid** » Mon Jun 01, 2009 10:29 am

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?

Structo · Post by **Structo** » Fri Jun 19, 2009 1:33 pm

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.

wrea398 · Post by **wrea398** » Sun Dec 20, 2009 7:39 am

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.

Twistingcrow · Post by **Twistingcrow** » Sun May 20, 2012 9:04 am

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...

maxwedge572 · Post by **maxwedge572** » Mon Feb 10, 2014 1:13 pm

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.

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Bias pot mounting for plexi and JTM 45

Bias pot mounting for plexi and JTM 45

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Re: Bias pot mounting for plexi and JTM 45

Re: Bias pot mounting for plexi and JTM 45

Re: Bias pot mounting for plexi and JTM 45