Tone Stack

[djroge1]

The next part in my amp build.

 

This may well end up being one of the hardest parts for me because I'm color defecient (so the military says). On those resistors there are reds, greens, browns, violets and all of those other colors that look the same to me. I had to have my wife help me see the colors.

 

As a result, I have started labeling my storage bin with the various caps/resistors for future builds. Then as I buy some I'll just put them in the appropriate bin.

 

In the pics you can see that I moved my vol/tone pots to the outside of the amp. I did this to make soldering easier. I imagine those who build a lot of amps probably has a jig.

 

1. I started with the input jacks. Wire all the connects between the two jacks. In this amp the FET input jack has 6 lugs whereas the normal input has only 4.

 

Some of the resistors are not soldered just wrapped around the connection point. This is done because there are other wires to be connected in the same place - no need to solder twice.

 

 

 

2. Oddly, I then went to the far left pot that gets a resistor. In this case it happens to be a 500k bass control. The 10k connects to the left lug on the pot and to the brass buss bar. The other orange resistor connects between the outside lugs on the same control.

 

The I worked left to righ for the other caps/resistors in the tone stack.

 

Far left shot:

 

working to the right:

 

Next, I'll move the controls back inside the chassis and begin making some ground connections and other connections that go to the other side of the chassis into the poweramp in and preamp out (effects loop).

 

EDIT: I forgot to mention. There are some spots where a wire from a cap or resistor may or does touch something it should not like a pot. I took some 20 or 18 guage wire and trimmed off a length and used the trimmed insulation and placed it over the cap wire. An example is on the big orange drop cap on the tone pot.

[deepblue]

dj...

You are my hero!...I cant imagine taking the time to assemble an amp. I get frustrated trying to get the last Olive out of the jar, so I cant imagine undertaking such a project. You must have alot of patience.

 

When shes all done have you thought of a name?

[G u e s t]

.

.

 

As we (more blasphemous) Brits say - "cor blimey guvnor....."

 

That is well impressive. I don't know how you have the patience to just do a little bit one day, some more the next etc; I would be rushing headlong to get it finished (and making tiredness induced boo-boos along the way, no doubt).

 

Keep the updates a-comin' - most informative, and good fuel for our anticipation.....

[djroge1]

Thanks for the encouragment and support.

 

I have to work this way - a little here and little there because I just don't have the time to work hours on end. In fact most of this is and will be done between the hours of 10-1am depending on what day I work on it.

 

It is addictive though as I already have planned out my next two amps - a train wreck type amp and a Marshall 18watt.

[elantric]

 

 

 

Observe on the right - the separate "Ground plane" created by the folded brass sheet which ALL PREAMP pots are mounted to.

 

Just a heads up - "Ground path management"

 

this is a crucial detail which majority of home brew builders omit, or barely understand.

 

If you merely rely on the star washers and nuts on each pot to "ground" the pots and switches to the cadmium plated steel chassis, you may experience RF noise anomalies that will have you chasing your tale.

 

I advise insert a brass plate between the pots and the steel chassis. Drill mounting holes in this brass sheet for each pot and switch. Clone this same concept in your build, like Leo did when he designed the Fender Twin ( see pic above)

 

Mount each Pot and switch with a star washer - these teeth will "bite" into the brass.

Run a dedicated wire from the brass plate to a Star Ground point in the center of the Amp.

 

This strategy results in more effective ground management, and low noise floor.