Dan0h
Well-known member
Cool. Excited for this weekend.
TH Black Eye (Soldano GTO) prototype build
- Thread starter vigilante398
- Start date
Something I should have asked ya sooner, what's the max input voltage source? Is it 9v max or can it be brought up slightly but maybe no higher than 15~18v w/o toasting tubes or that poor capacitor...
vigilante398
Authorized Vendor
The NE555 used in the SMPS has an absolute max input of 18V, so that's the hard limit, but also note that the input voltage is going directly to the tube heaters, which are spec'd to 12.6V. The tube will still run at a higher voltage as tubes are more robust than solid-state devices and it won't fry immediately at 15V or so, but it would absolutely have a negative impact on tube life.
So for all practical purposes I would recommend an input of no less than 9V and no more than 12V.
thank you, that means the 12v 1.5 amp PSU I had been considering for this https://forum.pedalpcb.com/threads/power-regulators.12792/post-141256 won't cook anything. And also safe advice for those who use multi-tap PSU's like Onespot and forget to drop the 12v back to 9v.
Dan0h
Well-known member
Sweet. Once done, I will A-B 9v and 12v and see what they sound like.
vigilante398
Authorized Vendor
Oh I should have mentioned that, the SMPS has feedback and regulation, so it will give the same output voltage regardless of the input voltage. I've actually run this SMPS as low as 6V on the input and I still get about 240V on the output.Sweet. Once done, I will A-B 9v and 12v and see what they sound like.
Dan0h
Well-known member
So the only difference would be what the heaters get directly?
vigilante398
Authorized Vendor
Correct.
vigilante398
Authorized Vendor
With the filaments it's about the same thing; the more voltage you give them the hotter they get. That's another reason I like running them on 9V instead of 12V, they run a little cooler.
Aye, Fig found for me a proper regulator for 9v, I'll likely socket that spot and try both or finger out where to put a 68k and 220k resistor to drop the 12 down to 9.1(digikey'svoltaqge divider calculator's results). the drop for the 60 watt to black eye is a new animal unless I run 2 transformers..
Dan0h
Well-known member
Does your squeal sound like feedback? On my build, gain past 11 o’clock I get insane feedback, which I could just ignore because I am in absolute love with the sound with the gain around 8-10 o’clock and I literally sit right in front of my amp in my bedroom so there might be that causing feedback too. But I was digging around and found people having similar issues with tube diy pedals and it was all about lead dress. So my plan is to shield all the internal spaghetti and see if that knocks out the feedback issue. I just want to see what this thing sounds like at max gain. Even though I’m 100% never going to use all that gain. Just wanted to share, the findings.
Betty Wont
Well-known member
Its self oscillation I'm getting. It changes in pitch and intensity with the gain and vol pots. It sounds like a theremin trying to tune in Tokyo. Does yours feedback with nothing plugged into the input? Moving the unit doesn't effect the oscillation, like feedback might.
Last edited:
vigilante398
Authorized Vendor
Does physically holding the tube change anything? I had a unit a few years ago that was self oscillating, and putting tube dampers over the tubes helped a lot.
That being said lead dress helps a lot, which is why I like the ribbon cable. I obviously won't say it's required and I understand some people don't like the look or are uncomfortable running it right behind the tube, but short, straight wire runs with the wires perfectly in parallel and a pair of DC (ground and V+) signals separating the input and output seems to help for stability.
Dan0h
Well-known member
@Betty Wont Maybe I do have a case of the oscillation, and I’m pretty sure it’s my wire runs. I opted for the long route and I should have known better. Still on the fence if I want to do anything about it, as I am able to max gain and play, it’s just annoying when nothing is played with the squeal. But under 11 o’clock is perfectly free of squeal and where I will live on this pedal.
@vigilante398 good point about the parallel runs.
Pretty amazed at how close the protien Blue side sounds like a pretty close imitation of the black eye at low gain. Black eye wins by a long shot but the protein does a great job sounding tube-ish.
Betty Wont
Well-known member
I tried swapping tubes and holding them down. I have tube dampers on them too. And I have short direct parallel wire runs the same as your proto. I'm down to it being a non-tube component issue. But I haven't built up the courage to probe. I'm going to try a fresh build and see what happens.
vigilante398
Authorized Vendor
It would be unlikely, my builds all use NE555 from Tayda and I haven't had any issues, but I guess I can't rule it out.
Finally tried mine out. Gain past 9 o’clock and I get a squeal. Output past 3 o’clock too. I ran my wires in parallel over the tube. I’ll add a photo shortly.
Also, the tone knob doesn’t seem to have a very large range. I really had to clear my ears to hear much of a change.
Also, the tone knob doesn’t seem to have a very large range. I really had to clear my ears to hear much of a change.
Attachments
Last edited:
Dan0h
Well-known member
I ordered some faraday tape and going to wrap all the wires when it shows up. I’ll let you guys know if that helps. Sounds like all three of us have the same issue. @Betty Wont
Similar threads
