Echo Foxtrot build issue

[iamjackslackof]

I've finally got all the parts and completed my build of the build Echo Foxtrot, and it's having an odd issue. When I apply power with my test rig, it will work fine for about 30 seconds. Tone control works, volume control works, sounds nice and tube-y. Then the sound slows fades to nothing. If I pull the power and put it back, the cycle repeats.

In computers when this happens I would say something is overheating and shutting down. I've never experienced something like it in a pedal, but this is my first tube-based effect. I know the voltage in these is much higher, and a couple of the parts have heatsinks...

Any ideas? Pics attached, and I can do more on request.

Shout out to @vigilante398 for making these kits, super cool stuff and great work!

 

[MichaelW]

Is the BJT tight in the sockets?

 

[MichaelW]

Is the BJT tight in the sockets?

I've got mine built out but was short the voltage regulator. It's supposed to arrive tomorrow, really looking forward to this. We'll see how it sounds.

 

[iamjackslackof]

Is the BJT tight in the sockets?

I will double check that, thanks! Mine was short the voltage regulator too, but I snagged one off Amazon pretty quickly, as I was too excited to build it and wait for Tayda/Mouser lol.

 

[vigilante398]

What are you using to power it? If it consistently runs for 30 seconds or so then shuts down then it sounds like the L7806 may be overheating as I believe that's the only component on the board that has thermal protection. If you're using a 9V power supply I wouldn't expect it to get hot enough to shut down, but at 12V or higher the voltage difference may be enough to push the regulator into thermal shutdown. It could also help to check the general temperature of the regulator during operation. It should be warm to the touch, but if it's hot enough to burn then that's the problem.

The only other thing I can think of is a bad solder joint, I've seen cases where a solder joint will hold at low temperatures then fail when it heats up. Nothing in the pictures looks particularly suspect but couldn't hurt to look for bad/cold solder joints and reflow the ones that look like they could use it.

 

[MichaelW]

I will double check that, thanks! Mine was short the voltage regulator too, but I snagged one off Amazon pretty quickly, as I was too excited to build it and wait for Tayda/Mouser lol.

Me too! I got the little kit with a couple of different values....

 

[iamjackslackof]

Thanks @vigilante398 . I am using a standard 9V wall wart that I used for all my building and testing, so shouldn't be an issue there. I will check the temperature of the voltage regulator, and make sure it's the right voltage, etc. The shutting off thing made me think heat, and the regulator seems like a good candidate for the issue. I wonder if I shouldn't have gotten the Amazon ones... I'll reflow some joints as well. The BJT is in tight and same issue too.

Good luck @MichaelW with your regulators lol. I hope yours fare better than mine, and I'd be really curious to see if yours have any issues.

 

[MichaelW]

Thanks @vigilante398 . I am using a standard 9V wall wart that I used for all my building and testing, so shouldn't be an issue there. I will check the temperature of the voltage regulator, and make sure it's the right voltage, etc. The shutting off thing made me think heat, and the regulator seems like a good candidate for the issue. I wonder if I shouldn't have gotten the Amazon ones... I'll reflow some joints as well. The BJT is in tight and same issue too.

Good luck @MichaelW with your regulators lol. I hope yours fare better than mine, and I'd be really curious to see if yours have any issues.

How many ma does the wall wart have? The Sushi tube pedals need 500ma. (At a minimum 300ma).

 

[MichaelW]

Thanks @vigilante398 . I am using a standard 9V wall wart that I used for all my building and testing, so shouldn't be an issue there. I will check the temperature of the voltage regulator, and make sure it's the right voltage, etc. The shutting off thing made me think heat, and the regulator seems like a good candidate for the issue. I wonder if I shouldn't have gotten the Amazon ones... I'll reflow some joints as well. The BJT is in tight and same issue too.

Good luck @MichaelW with your regulators lol. I hope yours fare better than mine, and I'd be really curious to see if yours have any issues.

Seriously, I'm starting to second guess myself, maybe I should have gotten the cheap no name Asian made ones from Tayda as opposed to the cheap no name Asian ones from Amazon....... .

But, it's a freaking voltage regulator....I mean, not much to go wrong..........right?

 

[iamjackslackof]

Ohh, good point about the mA of the wall wart, I forgot these need more than usual. I need to make sure it's high enough. Thanks for the tip! Hoping that does the trick.

Fingers crossed your cheap no name Asian made one works

 

[vigilante398]

Ohh, good point about the mA of the wall wart, I forgot these need more than usual. I need to make sure it's high enough. Thanks for the tip! Hoping that does the trick.

Fingers crossed your cheap no name Asian made one works

Ah, that's also a possibility. The pedal will try to pull as much as it can on startup which is why I usually recommend at least 500mA for a single tube pedal, but if your wall wart is under spec then that may be an issue as well. If the wall wart is spec'd for 300mA or less then it may be straining to get the tube heated up, causing the wall wart itself to overheat and potentially shut off.

EF86 will pull 200mA just for the heater alone, so 300mA would be absolute bare minimum, I would be much more comfortable with at least a 500mA supply.

 

[iamjackslackof]

I did notice that it took a few seconds to put out sound, like it gradually ramped up to normal output volume. I bet this is my problem. Now to ditch work and try it out lol.

 

[iamjackslackof]

Well crap, no luck. I tried with a power brick that has 2 500mA outputs, no dice. And I checked the one I was using, listed at 9V 1.7A, so I assume that means 1700mA. And neither the MOSFET nor the voltage regulator feel even a little warm.

I'll try reflowing some joints, but beyond that I'm stumped. I guess I could swap out the voltage regulator and or the MOSFET?

 

[vigilante398]

I did notice that it took a few seconds to put out sound, like it gradually ramped up to normal output volume.

That's normal, the tube will take a little bit to warm up enough to pass signal. 500mA should be enough to get it going though, so I guess we're back to square one for the debug

 

[MichaelW]

Ohh, good point about the mA of the wall wart, I forgot these need more than usual. I need to make sure it's high enough. Thanks for the tip! Hoping that does the trick.

Fingers crossed your cheap no name Asian made one works

@iamjackslackof
Sigh, of course, the one blasted component I'm waiting for to finish this build is "lost" by Amazon.....Was supposed to to arrive two days ago.

Did you get your issues worked out? One thing for sure about these builds, (I have both a failed Black Eye and Space Heater under my belt to prove it...hahah) you have to really be clean with your soldering. Some of the pads are pretty tightly spaced.

On my 3 successful Sushi builds, I slowed down, made sure each pad only received "just" enough solder to get a good mechanical bond and some flow through. I didn't try to build a "Hershey kiss dome" with each joint like I normally do.

Then I made sure to clean the snot out of the boards. None of the components (besides the pots) can be damaged by isopropyl alcohol, so I dunked the whole board liberally in a small plastic dish with about 1/4" of IPA and swished it around and scrubbed with a tooth brush. Then inspect your boards and solder joints very carefully before powering up. Once it's been powered up I'm not touching it anymore. Either it works or doesn't at that point. I simply don't have the experience working around high voltage caps.

 

[vigilante398]

One thing for sure about these builds, (I have both a failed Black Eye and Space Heater under my belt to prove it...hahah) you have to really be clean with your soldering. Some of the pads are pretty tightly spaced.

Yeah I use bigger pads than a lot of people so they're effectively closer than they are on paper. I shrunk the pads on the revised Space Heater boards so that should help for future builds, but obviously that doesn't help anyone that got the first batch.

 

[MichaelW]

Yeah I use bigger pads than a lot of people so they're effectively closer than they are on paper. I shrunk the pads on the revised Space Heater boards so that should help for future builds, but obviously that doesn't help anyone that got the first batch.

All good man! Just gotta be on your game with the soldering is all. No sloppy work allowed hahahaha!

 

[music6000]

I've finally got all the parts and completed my build of the build Echo Foxtrot, and it's having an odd issue. When I apply power with my test rig, it will work fine for about 30 seconds. Tone control works, volume control works, sounds nice and tube-y. Then the sound slows fades to nothing. If I pull the power and put it back, the cycle repeats.

In computers when this happens I would say something is overheating and shutting down. I've never experienced something like it in a pedal, but this is my first tube-based effect. I know the voltage in these is much higher, and a couple of the parts have heatsinks...

Any ideas? Pics attached, and I can do more on request.

Shout out to @vigilante398 for making these kits, super cool stuff and great work!

Looks like a Cold Solder Joint here:

 

[music6000]

Supersized!


This is how your Hookup wire should look prior to soldering to PCB, Jacks, Footswitch's:

 

[Nic]

Not sure, but the right ground too ?