Tube Driver 2.0 DOA

jhaneyzz

jhaneyzz

Well-known member
Just completed a TubeDriver 2.0 build but not getting any sound when engaged.

Bypass works properly.
Tube is getting 60v.
LED doesn't even light

It must be something with the relay or IC controlling the relay but I've never built a pedal with a relay switch.

The relay specified in the documentation called for an "FTR-B4CA4.5Z". I got an F.T. B4CA4.5Z
The rows of relay pins on the relay I installed were closer together than the holes on teh PCB but I bent them to make it work. I assumed it was same part, in smaller package.

The relay seems to work because the pedal passes signal, but when I press the switch everything goes silent.

Interestingly, if the pedal is in this state. guitar signal going in, but engaged and silent, and I unplug the power, I get bypass signal. if that helps.

I am powering with 9v 500ma. (center negative this time jimilee! center negative... :)
 

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jhaneyzz said:
LED doesn't even light
Click to expand...
I'd say that's a good start. Probably a short somewhere messing with 9V, preventing it to light up.

Then, the shortest way to narrow it down might be following the signal path with your audio probe, circuit switched on ? But i don't think it's safe to poke around such a high voltage circuit though...

A picture of the solder side could help (and i am curious to discover your soldering style).

I guess you triple checked the wiring ?

Stay safe, may your hands remain always steady !

Edit : here is the link to build doc, for other forumites (click on the blue window link) :

 
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Did you test the tube in an amp before installing? I've had more than a few DOA tubes, mostly electro harmonex, but also a J/J and a umm.... uhh... I forgot the name, it's a chinese tube. shinzin or something.... like that....
 
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Well the relay is just a remote controlled switch, so break out the multimeter, turn it on and touch the output side to see if the voltage is there. Do not hug the relay! Or you could use jumper wires to bypass the relay to see if it works with a direct connection. Probably.

edited: A relay allows a low voltage circuit to activate a higher voltage circuit without frying the low voltage circuit. Under no circumstances should you jump the low voltage to the high voltage circuit, or frying will result. You would bypass the relay by hooking high to high voltage, being aware your battery will drain quickly.
 
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OK, I put my big boy pants on and read the damn data sheets. I now understand how the relay works and yes, it is working fine.

Also hooked up the indicator LED so ignore the mention in the first post of that not working.

On to Audio Probing.

I've attached a schematic with Audio Probing notes and voltages on the Tube pins.

I'm unsure of the function of the section labeled "here be dragons"
 

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Soldering side is impressive. Very weighted and balanced touch. Very clean and pleasant shapes, with a feeling of freshness.

However, I suspect that some intruder sneaked his way inside your bunker in the dead of night, and badly messed up a few pads on your board, maybe on purpose.

I don't want to point fingers at anyone, but where was Vigilante398 that night ?

You're probably caught in a crossfire between TH Custom Fx and Sushi Box...

I think the perpetrator commited multiple probable shorts (green), some pads looks suspiciously in need of reflowing (red), and even a bubble-shaped eccentric soldering joint (blue).
driver.jpg
I would start by changing the codes on your reinforced doors.
 
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eh là bas ma said:
Soldering side is impressive. Very weighted and balanced touch. Very clean and pleasant shapes, with a feeling of freshness.

However, I suspect that some intruder sneaked his way inside your bunker in the dead of night, and badly messed up with a few pads on your board, maybe on purpose.

I don't want to point fingers at anyone, but where was Vigilante398 that night ?

You're probably caught in a crossfire between TH Custom Fx and Sushi Box...

I think the perpetrator commited multiple probable shorts (green), some pads looks suspiciously in need of reflowing (red), and even a bubble-shaped eccentric soldering joint (blue).
View attachment 41655
I would start by changing the codes on your reinforced doors.
Click to expand...
In fairness ONE of your green items warranted attention. The rest are pure, rampant, Gallic poetic fabrication… (for any casual observers, we’re just joking around here) To preserve my dignity, I will not disclose which pad I destroyed in a botched unsoldering job… although it’s pretty obvious. I just ordered a $2,000 (€2,000) oven for sweat-setting my solder joints and a blowtorch for burning off the cotton fibers my diligent scrubbing leaves behind.

The locksmith is arriving at 8:00 am…
 
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I totally destroyed one of the pads on the voltage regulator while I was getting it to fit in the enclosure with the heat sink.

Fixed that but the output is still way too low.

I’ve got some doubts about the BOM specs on some items in the build…
 
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That was me painting the tube holder that for some reason was made out of PINK material.... WTF??? They must have gotten a real deal on that or they were using the 3D printer to make My Little Pony knockoffs for their daughter at work and didn't bother to change the filament.
 
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Dang tube pedals, they're more trouble than they're worth if you ask me.

If your high voltage rail (60V in this case) is running fine but the tube isn't passing signal, the first place to start is the tube heater. If the tube isn't heating up then it's not going to pass signal. IC2, your 7806 regulator, is solely for the purpose of powering your heaters. Make sure you have 6V on the output of that. 12AX7 heaters don't glow super bright, but if you look at the right angle you should see a little glow in the top, and it should start getting a little warm. Not burn your hand warm, but like a warm, soothing hug.

It looks like you're getting signal to the first grid of the tube (I-2) which means your TL072 section is passing signal, but if it stops there then the problem is in the tube section. As soon as you can get signal on your probe at the second grid (I-7) then you're in business. So again, start with the heater.
 
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