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Contrary to popular belief I've found Fuller to be very helpful when I was in contact with him. I was trying to fixg some Fulltone pedals but couldn't quite figure it out and he gave me enough pointers so that anyone with a little experience would know what to look for without sending out the schematic. Very short reply time, a bit on the edgy side but helpful nonetheless. More than I expected based on all the sh*t I read online.

Ironically, Fulltone will now become a TRUE boutique brand

I may have used the wrong figure of speech

I don't know that's it's popular belief so much as experiences. I'm glad you had a pleasant one, but a lot that I've read, but not all, has been first hand experience.

Contrary to popular belief I've found Fuller to be very helpful when I was in contact with him. I was trying to fixg some Fulltone pedals but couldn't quite figure it out and he gave me enough pointers so that anyone with a little experience would know what to look for without sending out the schematic. Very short reply time, a bit on the edgy side but helpful nonetheless. More than I expected based on all the sh*t I read online.

Ironically, Fulltone will now become a TRUE boutique brand

I use a looper pedal to send signal through at guitar level. What you are hearing when using the headphone out is probably just cross talk. The switch terminals are little antennas that send signals to each other. Same goes for PCB traces. With a signal that has been boosted enough it becomes audible. It has tricked me in the past into thinking "well, it's passing signal" but actually it's not. You've just created a transmission line. Something to keep in mind.

Hey, welcome back Rockhorst

Thanks MJG and Muadzin!
I designed a bunch of PCBs during the first lock down, then lost interest. Working on getting them verified and on the website again after a break Fun stuff coming.

Eagle is so counter intuitive with parts editing. I have to figure it out from scratch everytime. Luckily that not often. Once you have the part, it's for keeps.

Just saying I haven't visited this forum in a looooong time and I should change that

If they can still lock us down, even though we're vaccinated, then what is the point of getting the jab of an experimental vaccine? It's basically like nothing will ever change.

To be fair Muadzin, I'd say the Netherlands are 90% opened up right now. The only thing I see with much restrictions is outdoor festivals and university. Let's see what the fall brings. I'm fine with getting the vaccine and even getting a booster shot while we figure out how to solve this thing. It's funny how all those scenarios painted at the beginning of the pandemic are coming true, yet people act surprised.

The picture you posted has a nucleon watermark on it, that's the name of my little pcb company (see my signature).

Jump means: wire the two pads together, so you make a connection but there's no component. You 'jump' from one place of the schematic to the other.

Omit means: install nothing, not even a jumper wire.

Whatever takes the external power from a battery or power supply to the rest of the board we'll refer to as 'power supply' or section. If you want to install polarity protection use the 'in line' diode method and use a 1N1518, not the 1N4001 parallel. The latter will just burn up and scorch your board. It's just a way for companies like Boss to tell if you misused the pedal and voided your warranty.

The multiple 9V and G points are just to allow for flexibility so you can keep wires shorter and fit your needs. They are all connected with each other directly through a +9V plane and a ground plane (copper fill on the board).

Someone called?

The updated version / build doc of that schematic, including the 1N5817, can be found here: Nucleon Fusion Clean Blend. That may help you out.

If you're using stripboard or anything, what 'parent pcb' do you want to mix clean into? Tap off the power after the polarity protection on that board and use that to power the blend circuit.

About C4 in the original schematic as you posted: use a MLCC cap valued 100n or higher (like 1u or 10u, they are available, cheap and small). They do a much better job of filtering the power than regular film capacitors. It helps with some extra smoothing/decoupling. I find that these caps work very well when place close to opamps from the power line to ground.

Cheers

I've heard that the high power resistors on the back side of the PCB can become desoldered. I would look over the board with a magnifying glass and look for cracked or damaged solder connections.

I used an audio probe to tap off the signal just before and after the tube and feed that through an external power amp. So the Valvestate's power amp is out of the equation.

*note: schematic attached at the bottom*

A friend of mine came by with his Marshall 8280 Valvestate Bi-Chorus. It has a clean/crunch and a OD1/OD2 channel. When OD2 is selected, playing chunky riffs through high output pickups (passive or active) on the lowest string, especially with palm mutes in there, the amp clamps down the signal. Trying to describe it in words I would say it sounds like your signal is 'sucked' away. It's like a really aggressive compressor that sucks away tone, volume, crunch and only releases when you let the guitar ring out again. The amp was in storage for a long time but my friend does believe that it didn't do this in the past. What I've tried so far:

- replace 12AX7
- replace power filtering caps
- replace the caps around the 12AX7

I then audio probed through the preamp circuit and found that the problem is really early on in the circuit, before the tone controls and also before the tube, although it gets more pronounced/amplified by the tube stage. Something around the dual opamp gain stage is causing problems. My friend also has the 40W version of this amp and he claims that it slays the 2x100W version. I've put the partial schematics of the input stages side by side and attached it. Note that the dual opamp has an internal switch: only one half is active at every time (neat trick to switch channels by the way, could be useful for projects!). The 8280 has a discrete mosfet input stage before the opamp. The 40W version uses a TL072 instead and according to the schematic has a 720Hz roll off.

My working hypothesis right now is that there's too much bass going into the amp and that I may be able to tame that down by lowering C2.
That said, I'd like some alternative suggestions if there's anything on offer.

That actually looks handy and much easier than trying to find a signal source

Use a looper

Alpha SR1712F series. I use 'em myself -- they work nicely with 9mm pots (mostly...)

They can be a bugger to get, though.

Thanks that should help the search. I'll bring a sledgehammer

I'm looking for a bulky, square SPDT switch used in the EHX Qtron+. It's the boost switch on the unit that's gone faulty. I reached out to EHX but haven't hear back.

Picture attached, it's the switch on the far right.

One cap is rated at 50V and measures 26V across the terminals, the other one is rated at 25V and measures 15V across the terminals. So that should be all within safe limits although there's probably some unnecessary heat dissipation. Would you advise to swap it for the 15V?