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I’ve been working on Chuck’s mini-toob pedal. It’s my first experience with these and I’ve learned a few things, but mainly that you have to pay close attention when breadboarding as they are easily rendered useless with stray current.

This, mostly unbeknownst to me, though I had suspicions…I built it and fired it up!

WiOIMnE.jpg


Pretty, huh? Pretty dead. A couple of misplaced nodes convinced me there was trouble, so I rigged a test unit.

ripcagH.jpg


Impressive eh? Not really, but it tells me a) if the toob is functional and b) what the current draw for matching. Using 9vdc through an 820Ω resistor into pin 5. Jumper pins 1&2, then 3&4. Now set your DMM to DCA (100uA or greater) and connect the positive lead of the DMM to the positive rail and the negative lead to pin 1.

NKPiQvE.jpg


That’s what I like to see! My DMM also reports current draw but not as accurately.

5Qr5nk7.jpg


Now to make certain the breadboard is wired the way I intend it to be ;)
 
I forgot to mention…in the above configuration;

Pin 1 (plate) 9vdc
Pin 2 (screen) 9vdc
Pin 3 (GND) 0vdc
Pin 4 (cathode) 0vdc
Pin 5 (filament) 1.23vdc

zBo4hjm.jpg
 
fig said:
:ROFLMAO:

Did I use it improperly? Our daughter was telling us that she felt old because someone used that term and she didn't know what it meant. I took a stab in the dark there.
Click to expand...
Nah, I think you used it pretty much the right way. I was never really up to date with the lingo in my own generation, and I’m even less so aware of the new zoomer trends. The squidward dab just felt like the appropriate response
 
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As it turns out, I only overloaded V1. They show a much higher filament voltage when damaged. The test rig is noisy but provides proof that audio is passing.

I first turn on the filament power, freeing those captive electrons from their cold negative rail. Then I power up the main attraction, the B+ anode @ 25V to make an offer the freed electrons cannot refuse.

I turned the anode voltage up slowly at first, seeing if there were any ledges along the way…not really, and the output increases incrementally with the voltage. I think it’s supposed to, so yay!

Even with a single stage you can tell it’s a valve-driven circuit. Especially when powering up/down. (y)

Next I’ll try to get the whole enchilada together with power filtering and all the other bells and whistles. Well, it won’t have a tube-drive IR-loader but I didn’t see one on Chuck’s schematic so…whew!

Now, I’m off to order Mexican…I have this sudden craving….😋
 
I nearly forgot to mention, the mag-lamp made a bzzzp! noise and the lights went out. :( Looking for a replacement bulb.
 
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