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Thanks for the tip Dave. The right eye has very blurred and washed out vision but funnily enough it provides enough feedback to still see depth. Yesterday though, I looked at a PCB with my +3.0 reading glasses and was again amazed at all the details I could see but hadn't seen in months. I also looked at the previous soldering attempt before the operation...my oh my that was pretty bad. The thing to now get used to is having to switch out glasses a lot. Because the left eye has only one fixed focus point (about 2.5 meters away), looking at a computer screen requires +1.25 glasses, grading tests is +2.0 glasses and fine detailed work needs +3.0. So when the other eye has had surgery, I'm probably going to get +1.25 glasses with a hint of 2.25 in there and then it should be workable in most every situation. As you may know, I teach physics at the high school level, so I'm constantly doing eye experiments, determining and checking the focal length of the left eye lens. It still shifts around a bit, but is getting close to settling.

Update: had cataract surgery on my left eye last week. The left eye was almost blind. It was an amazing experience to have the veil lifted. I see details that I haven't seen in months. I was amazed of what my son actually looks like, that there are separate leafs on trees, tiny wrinkles in skin...that sort of stuff. I haven't tried soldering yet but hope to get to it this weekend. Next eye in 2 months.

I'm luckily on the way back to relatively normal. The eczema is quiet, hope to get the eyes fixed soon. That should help a lot.
Thanks to everyone for commenting, also some people sent me PMs, very much appreciated. If one thing is showing from this thread is how big of a problem this is, not just for me but for a significant portion of other people here. I'm thankful for all the positive support and hope that it has an effect both ways, that me writing about it may help some others.

@EBK: if there's anything to take from my story, be careful with the meds but do battle the eczema before it takes over.

@Gordy: I'm in the Netherlands. Compared to people in the US, we have 'free' health care...I'm reponsible for the first $800 of my total health care cost in a year, after that the community pays for it. Socialism, it works. So no need for a go fund me.

@DLW: very interesting meeting an expert on this here. The biological I've heard of is called Dupilumab and supposedly it's a bit of a miracle. One injection and you're clean for about 3 weeks or so. Estimated cost a year is $15k to $30k. As long as the creme works, I'm on creme. After that there's normally pills like ciclosporine which wrecks the kidneys. My dermatologist wants to argue the case to the health insurer to skip that in favor of the biological when it becomes necessary.

Right now, the skin is relatively quiet and my mind is pretty clear. Lots of stuff that I didn't get to over the past few months, hopefully I can make a dent in that pile soon.

A few weeks ago there was an article in the news paper of a woman who has a really, really, really severe case. When the wind graces her skin, it already starts to crack. Compared to that my stuff is peanuts (yet already unbearable at times).

I've been putting this write up off for a while. On the other hand I've seen others share very personal stuff here and I think it might be therapeutic...IRL I notice how much talking about it improves at least my mental state of being. So here it goes.

I was born with eczema. Lots of people have it in some form or the other. Standard treatment is steroid cremes. Some people out grow the disease. With me it's been getting steadily worse over time. The cause (at least for me) is very clearly auto-immune. My body basically attacks itself, specifically the skin. It becomes itchy, I sratch, bacteria get in and infect the place, regularly resulting in quite enormous inflamed bumps in random places. This ranges from a few centimeters to half of my face. When it's in the neck, it becomes hard to turn my head. Once it was actually pressing on my wind pipe. Stuff like that. The skin is very dry at times, red and raised, warm and itchy.

Last summer was very hot in The Netherlands. Basically I spent 4 weeks in bed, because anything else was unbearable. When I returned to work (teaching) in September I was not well rested and had not had my mental 'reset'. I had also lost my faith in dermatologists. So as the symptoms kept getting worse and worse, I did not go see the dermatologist. They'll just give me another creme, it'll work for a bit and then everything is back to being F'ed up, so why bother. I tried to ignore the urge to scratch but as soon as I got home from work I'd lose control. I'd regularly scratch my face raw in a towel for instance. The mechanism is this: for a brief moment you feel release and the pain from the scratch drowns out the itch. 10 seceonds after you stop you start to feel very sorry though, because of the damage done to the skin that will keep the cycle going. A few times a day I feel myself heating up from the inside and I go off, unless there's somebody else around...social pressure helps.

Something else...for some years I've rationalized the state of my skin: yes it feels nasty, there's some redness but in all it's not that bad. That myth shattered a bit over the year. In one incident some students sent anonymous e-mails to teachers with weird remarks. I got some about the skin. In another incident, where I crossed the street, some random dude in a car yelled at me and basically mocked my skin. Stuff like that has been happening, also adding to the psychological stress.

My physician suggested I use prednison when things get really rough. About half a week on a medium dose usually was enough to get back to a doable situation. I've done that about 7 times in two years. Starting december 2018 I started noticing weird stuff with my eyes. Over the past 3 months I've become very sensitive to light and I can barely read. Turns out I've developed cataracts in both eyes...I'm 36. Visus in the left eye is down to 20%, right is 60%. It's a known side effect of the prednison, but this is extremely fast and progressive. So two operations are coming. It's a pretty standard procedure but the fact that my skin disease has indirectly damaged my previously better than 20/20 vision is a real psychological hurdle.

Two weeks ago I finally got a appointment with the dermatologist again. Basically, there was not a healthy inch of skin left, something had to be done. I'm now on an even more aggressive type of steroid creme (dermovate). Within 12 hours of first applying it the lights went back on in my head. The creme suppresses the immune system, blocking the reaction and thus stopping all the signals that it produces from clogging up my brain. For the first time I really realized how much brain power was being occupied by coping with the dermatitis. I've been very lucid for two weeks now, but was numb for over 6 months. No other way to describe it.

I hope I can start being creative again real soon. Because of the cataracts I basically see jack shit during the day without wearing two sunglasses at the same time. Night time is much better. Road cycling and fine soldering will have to wait until after the surgery. I've started UV-B therapy for the skin, to see what the effects are and I'm going to discuss long term plans with the dermatologist soon. Three years ago, she mentioned that research was expected to find the cause of chronic eczema in 10 to 30 years. Two weeks ago, the said 1 to 3 years. There's new treatments but they are quite expensive so access to them is restriced.

Sorry for the long post, hope it's not a bother. Long story short: the eczema sucks, but I've come to realize that it also comes with a psychological component that, for me at the moment, is equally alarming.

I've always found it funny that, certainly by today's standards, these amps look very classy, vintage and modest yet they produce some of the best metal tones ever recorded.

It's to prevent leakage over a reasonably long time and to enable kids to measure the (dis)charge curves with simple means like a stopwatch. The series resistor is only a 100 Ohms. I could bump that up to maybe a 1000 Ohms but beyond that I lose too much resolution as the series resistor doubles as a current measurements device. The point of the experiment is to determine Planck's constant by discharging a capacitor over an LED until it no longer conducts. The capacitor will remain charged at (more or less) the forward voltage of the LED. There's some caveats here, because not all electrons actually produce a photon, but I'm not going to bother the high school students too much with that.

I bought some gold caps for a physics project (I'll share it sometime soon). These have a very small form factor, usually a disc of about 1 cm across, but a ludicrously high capacitance, like the 200 mF (0.2 F) I was looking for. They can only take up to 5.5 V though. Their main application is in motherboards and the like.

Some initial testing shows that these caps do not charge/discharge following a nice exponential. Rather, there is a fast initial step, followed by a slower exponential rise/decay. Curves match this technical guide.

I have some questions, hoping someone here is more savvy on these components than me:

- is there a way to force rise/decay to conform better with a single exponential function instead of two joined together? I kinda need that for the experiment to make sense for students.

- any other suggestions where I may find a capacitor in the range of 10 mF (0.01F) and up withouth it being quite bulky?

- these caps are quite affordable (about $1 a piece), any use for them in pedals? I'm thinking maybe capacitors for digital circuits, either high end or in the power supply of a PT2399 circuit?

The Sparkle Drive is a screamer, the Green Rhino is a screamer...so...yes

Breadboarding won't hurt your wallet or anything else, so go for it.

The 4558 was looking good on the DMM but with no sound coming through I thought that maybe something else shorted out as that cap was losing its mind. So I decided to replace it once more with a socket (should've done that in the first place). That way, future repairs on the IC won't damage the board.

It's 1:00 AM right now. I'll continue tomorrow (vacation time, so let's hope I fix it this week).

One step forward, one step back...I should've paid better attention, but when replacing the power filtering electrolytic cap I installed it with reversed polarity. On the original cap, the plus-side was marked instead of the standard minus side these days. Could've spotted that, but I blew the cap. Replaced it and the wire from the board to the switch had become detached. Fixed that. Desoldered the transformer, replaced the 4558 with a socket and installed a fresh chip.

Good news: power is now at 28V from the EHX supply to the board, 1st opamp sits at 6.7V bias, 14.6V input. So that seems fine. The clean signal is now very very faint however and most likely only induced in the wires, not really going through the switch. Probably another silly mistake somewhere.

Well if it's broken... cut the wires and test your theory

Yeah it was just dawning on me while I was typing the post. Will test this soon, it makes sense.

I'd like to keep the original regulator setup. I measure the voltage at the point where I clip it to the board. The old transformer is still attached. I was thinking that maybe, if the primary is broken but the secondary is still ok, that could be pulling down the supply because there's a lot of current flowing through the coil? I haven't noticed it heating up though.

I can connect it to a Strymon Ojai or PP2+ for 18V. Just to be double safe: I can use a 'regular' 18V supply, ground to ground and +18V to the power input?

I attached the wire from the boost switch to the board, replaced the top 4558 IC and the larger electrolytics. Sure did something. I can now blend between input signal and 'whine' signal and the boost also works. Here are some fresh measurements:

Voltage at board input: 11.6 V (as before), but supply voltages on the ICs have come down to about 9.5V.

4558 closest to the jacks
Pin 1: 4.9 V
Pin 2: 4.1 V
Pin 3: 4.1 V
Pin 4: 0V

Pin 5: 4.3 V
Pin 6: 4.4 V
Pin 7: 4.4 V
Pin 8: 9.7 V (no longer equal to supply?)

4558 middle of the board
Pin 1: 3.5 V
Pin 2: 3.5 V
Pin 3: 3.5 V
Pin 4: 0V

Pin 5: 2.4 V
Pin 6: 2.4 V
Pin 7: 5.5 V
Pin 8: 9.8 V

Thanks for all the help so far and apologies for taking so long to get back. I really only have a few minutes a day for this kind of thing at the moment...sigh.

Anyway, rechecked: I made a counting mistake. Pin 10 and pin 11 both at half supply after all!

Next baby step?