TH Black Eye (Soldano GTO) prototype build

So far I have not been able to stop the pedal from squealing. Swapped to a 1spot power supply, added shielded in and out wires, put tube shields on, still squeals 🤦🏻‍♂️🤷🏻‍♂️
 
I had some major grounding issues till I realized that I was using isolated jacks (duh...). I'm using a 1Spot as well. The paint, btw, is Rust-Oleum Painter's Touch 2X Ultracover. The color is called French Lilac Satin. Worth noting that although it covers well its a good idea to lightly sand and then thoroughly clean the enclosure. The paint itself was no issue but when I shot satin clean over the decals part of the backside wrinkled up. Heartbreaking to say the least but I managed to sand it out and reshoot with no issues. Go really light on the clear coat and shoot a bunch of light coats rather than soaking it.
 
So far I have not been able to stop the pedal from squealing. Swapped to a 1spot power supply, added shielded in and out wires, put tube shields on, still squeals 🤦🏻‍♂️🤷🏻‍♂️
Do you have it mounted in the enclosure? Putting the circuit into a grounded enclosure helps with a lot of things, but I would also encourage you to take a look at the board and make sure there aren't any solder bridges or accidental shorts. A lot of the pads are pretty close together, and I could definitely see it happening.

Do the tubes glow with this circuit?
The brightness of the heaters depends largely on the brand of the tube, but 12AX7 heaters don't glow as brightly as power tubes like EL84, 6L6, etc or submini tubes like 6N21B. The reason being the filament current draw is lower, they don't need to heat up as much for the electrons to flow. If glowing tubes is important to you, you could:
  1. put an LED behind the tube. How you do this is up to you, but this is the easiest and probably best to get increased tube glow.
  2. run the heaters at a higher voltage. The filaments in the tube are a fixed resistance, so the higher the voltage you give them the more power they will dissipate, and therefore the brighter they will glow. This will negatively impact the lifespan of the tube at the expense of looking neat, and I do not recommend it. 12.6V is the recommended heater voltage per the datasheet, and at that voltage they will be more noticeable than at 9V, but you could probably get away with running a little higher without immediately frying it. It will fry faster than it would otherwise though. That's an added benefit of running it with 9V on the heater, it prolongs the life of the tube.
 
I went over the board looking for any shorts but didn’t find any. After I got it mounted back up it started working right so who knows lol. There is still a little squealing if the gain is turned up all the way and the volume is at unity. Backing off of the gain a little takes care of the squealing with no noticeable change in tone so I’m guessing it’s normal.

Now that the squealing is gone and it’s being powered correctly it sounds amazing!
 
The original GTO was a chonky boi!

GTO-original.jpeg
 
The original GTO was a chonky boi!

GTO-original.jpeg
Yup, I hope to own an original someday if I can find a reasonable deal on one. I had a chance to pick one up for $600 a year ago, but I thought $600 was too steep at the time so I turned it down :cry: I obviously don't need one, but it really is my favorite tone in the world and the nostalgia of owning an original would be cool.
 
Meanwhile I had never heard of this pedal til this thread
Yeah it wasn't a super popular one for some reason, they didn't make very many. I had actually never heard of it until someone on another forum did a DIY project for it (that wasn't very well-designed and I hated it) and started looking into it. I built my first one in 2018 with 6N21B and fell in love with the sound, it's been my go-to dirt pedal ever since.
 
Mike Soldano said the originals got a bad rap for being noisy because of ground loop issues. He said lifting the ground would take care of the issue but he couldn’t put that in the instructions for liability reasons.
 
It was pretty spendy in its day as well. To say nothing of the fact it’s the size of a toaster oven. Instead of cranking on the heaters I want to fiddle with some led backlighting.
 
It was pretty spendy in its day as well. To say nothing of the fact it’s the size of a toaster oven. Instead of cranking on the heaters I want to fiddle with some led backlighting.
I was debating putting spots for LEDs under the tube sockets on the board, but there was just no room for CLRs in there :rolleyes: if I was really clever I could have put the spots in there and put SMD pads for resistors so people that wanted them would have to really want them but could get them. Too late now though I'm afraid, and naturally there are traces running everywhere under the sockets so there aren't any safe spaces to drill into the PCB to make room for an LED. Sorry guys :confused:
 
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