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Q. I want to make sure that I'm understanding the ohm selector switch -- When looking at the from back of the combo chassis at the ohm selector switch, with the transformers facing down (just like we were working on the amps), if I rotate the switch clockwise, does this engage the 16ohm tap? 8ohm is obviously the middle, but I want to be sure re the 4 & 16ohm taps. Is there a way that I can test which tap is selected?

A. 4 ohms should be fully counter clockwise looking from the back so you are correct. Once connected up to the Output Transformer (OT), you can't measure because the resistance is measured through the transformer as well so it's very difficult to confirm where the switch is connected.


Q. If I wanted to tidy up some of the end-of-course rushed wiring, how do I ensure that the caps have discharged. I know to unplug the amp, but I'm not sure what to do next.

A. Unplug the Amp!! The 220K bleed resistors should drain the caps. After a few minutes, measure the DC voltage from the positive terminal of the 50 uf to chassis / ground and for the 33 uf filter caps to confirm B+ is less than 10 volts. Refer to the presentation for other details.

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

Hey Stephen,
I have a question on the "tude" switch:
- The Boost in volume between tweed and tude is really significant. I expected a bit of extra volume, I guess I am just getting a bigger boost that what I would have expected. To try to put it more in to perspective, if I was playing rythm in tweed mode...and wanted to boost for a solo....switching to tude mode would be a bit too extreme and I would have to roll off the volume to make it work. Is this normal with the other build you have done/seen? If this is normal, I was thinking about modifying the circuit a bit to make this option footswitchable....would there be a way for me to tone down the volume boost just a little so it could also work as a solo type boost?
Thanks for all your help!
-Dana

That's kinda the nature of the switch.

Your increasing the gain a bunch in Tude mode and trying to dirty the amp up. With an increase in gain you get an increase in volume, nature of the beast.


However....
Try removing R8 (this is the 2K7 resistor in parallel with the 0.47uF cap).

This resistor when in Tude mode lowers the cathode resistance to a lower value than in Tweed mode. If you remove it you might get the volume levelling out a bit more. You might loose a bit of gain though, so keep that in mind.

You don't have to totally remove the resistor btw. Just desolder or snip one end of the resistor.


Chris...

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Thanks Chris, I'll give that a shot and see what it sounds like. I'll let you know after I make the change.
Thanks again!
-Dana

Cool, already into 'Mod Mode'!!

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

I have to do something to satisfy the "itch" until I can talk my wife in the next kit!
-Dana