trinityamps.com

Is there a standard out the for the Spit? I have a guy who want me to build him one, but I want to be sure of the circuit before I get started. I have a layout drawn by Jim Jones in 2002. Is that one correct or is there a better one out there?

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--s2
www.s2amps.com
www.category5amps.com

I'm pretty sure it's good. Jim is on this forum so you can message him. Basically follow the same layout as the Lightning just minus a few parts.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

I drew up one based on my own build: http://www.diyguitarist.com/PDF_Files/S ... hassis.pdf

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PJM

http://www.diyguitarist.com

Nice job Paul! What did you use to do the original drawing?

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thanks coco. I used AutoCAD and then converted it to a PDF file. I use AutoCAD quite a lot at work (and at home), so I am very familiar with the program.

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PJM

http://www.diyguitarist.com

Very nice Layout Paul! Very simular to my T=bolt 8 & T-bolt 9 except I use a ground buss onboard.

S2;

You can put a 2.2K Shared Cathode Resistor on V1 and an 820 in parallel on a switch on the Shared Cathode Resistor on V2 for a bit more grind.

CR ><>

WoodCross Amps.

Thanks Maccabee. What exactly do you mean by a "shared cathode resistor"? I follow in concept, but I'm having trouble seeing how that would be implemented...

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PJM

http://www.diyguitarist.com

At the risk of being an a$$ and answering for the expert on his own amp, if you look at V1 on the Spit, you will see it is running in parallel. So, it has a shared plate, a shared grid, and a shared cathode. That R/C pair is what he is referring to.

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--s2
www.s2amps.com
www.category5amps.com

Paul;

Both V1 and V2 have triodes that share the same cathode risistor. 1.5 K on V1 and 1.2K on V2. Raising the resistor on V1 to 2.2K increases the voltage and increases the clean heardroom a bit. The PI on the Spitfire uses values that are the same as vintage Plexis except the Plexis use a 470 Ohm Shared Cathode resistor instead of the 1.2K of the Spitfire. Putting the 820 Ohm resistor in parallel with the 1.2K on V2 brings it down to around 480 ohms and less voltage. Less voltage = Mo Dirt. Putting that 820 Ohm on a Switch back to the cathode's ground (before the tail resistor) allows standard Spit vibe and a very satisfying Plexi-type Overdrive when engaged. Not as much grind as a Marshall 18 Watt TMBMV but, that's not what I was going for.

Thanks!!!

CR ><>

WoodCross Amps

I know it's running in parallel and that the plate, cathode and grid resistors are all shared. Thanks for the news flash.



Ok, now I follow what you were suggesting. I was looking at my layout and saw that pair of shared cathode resistors (V1 & V2) but I didn't follow where the placement of the 820 ohm resistor would be, but it all makes sense now...

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PJM

http://www.diyguitarist.com

Any problems with any extra hum or induced noise by using this wiring option?? Did you shield the wires to the switch? In our experiment, it seemed to add some extra hum into the circuit. We were switching the cathode resistor[s] on V2 of the TMB

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps