Reactionary/alarmist solid-state build

[vigilante398]

Tube pedals are kind of my bread and butter, so when things started getting weird everyone I knew messaged me to the effect of "DUDE THE TUBES ARE GONE WHAT ARE YOU GOING TO DO?!?!?!?!" I don't expect it to be a long-term problem, but hope for the best, plan for the worst. So I took a page from bajaman's book and came up with a solid-state design to mimic one of my more popular tube preamps. The tube version is called "Underground Accelerator" so I'm calling this one "Silicon Accelerator." Also I figured I'm straying from my usual tube designs, so I may as well stray from my usual UV print/powdercoat artwork as well, and designed a PCB faceplate for it. I like how it came out.

 

[JamieJ]

Love it @vigilante398 - out of interest, how does the tube circuit and solid state version compare when A/B’d?

Do you have an oven to do all of your SMD soldering or is it done by a contractor?

 

[vigilante398]

Love it @vigilante398 - out of interest, how does the tube circuit and solid state version compare when A/B’d?

Do you have an oven to do all of your SMD soldering or is it done by a contractor?

I need to tweak the circuit a little bit as it's currently completely clean, whereas the tube circuit had some grit when cranked, but clean for clean it admittedly sounds very close. I'm planning to do some real A/B tests this weekend when I get the circuit adjusted a little better.

On soldering, the answer is both. I got a small reflow oven as a birthday present in 2018 and I used it consistently until August of 2021 when I was getting overwhelmed with trying to keep up with builds. I order my boards from JLCPCB and they have assembly services as well, so I upload a couple extra files when I order boards and they show up straight from the factory fully assembled.

The solder paste/stencil/reflow oven setup is amazing for doing a couple SMD builds at a time, but the absolute fastest I've ever done a board that way was 10 minutes per board (average was closer to 30 minutes), and when you're doing up to 40 builds a month that adds up. So when I was building mostly for myself with the occasional customer build it was perfect, but with the shift of mostly for customers and occasionally for myself, it makes sense to go to pick-and-place.

 

[jubal81]

From what I'm reading, tube supply should rebound before too long, though I don't think prices will be as low as we've gotten used to. A lot of the problem is panic buying - including me, who got caught without a backup set el84s.

@vigilante398 you never cease to impress me. That was fast!
Wondering if you'd considered sticking with the same design, only swapping in LND 150 or another depletion mosfet. I'd think you could even use the same PCB for tube or solid state that way.

 

[vigilante398]

From what I'm reading, tube supply should rebound before too long, though I don't think prices will be as low as we've gotten used to. A lot of the problem is panic buying - including me, who got caught without a backup set el84s.

@vigilante398 you never cease to impress me. That was fast!
Wondering if you'd considered sticking with the same design, only swapping in LND 150 or another depletion mosfet. I'd think you could even use the same PCB for tube or solid state that way.

So far the only impact I've had was that half of my latest 12AX7 order was unexpectedly backordered after being listed as in stock, but they said they expect them to ship in late April, so I'm still not worried. I have enough tubes to get me through May, and when that comes through I can get through June. Should have things sorted by then.

I tried using LND150 as a drop-in replacement for the tubes, but I didn't really like it. They have potential, and I think with some additional filtering they could be made to work, but as a straight drop-in they're a bit harsh and bright sounding compared to tubes. I haven't given up on the idea, but I shelved it for now when I saw that it wasn't as easy as I wanted it to be.

 

[fig]

The solder paste/stencil/reflow oven setup is amazing for doing a couple SMD builds at a time, but the absolute fastest I've ever done a board that way was 10 minutes per board (average was closer to 30 minutes), and when you're doing up to 40 builds a month that adds up. So when I was building mostly for myself with the occasional customer build it was perfect, but with the shift of mostly for customers and occasionally for myself, it makes sense to go to pick-and-place.

I really like my little oven so far (I may have mentioned it).

Great looking build!