Help with circuit

[pdf64]

... I get it just wanted to get a presence control in there but somehow the robrob version of it canceled out all the guitar signal...

Detail, both in design (eg schematic) and implementation (layout and actual build) is critical in this game.
Making vague references to things you've done as per above, isn't helpful. Also it conveys the impression you're flailing around trying random stuff, rather than taking a logical, reasoned approach.
The 5F6a includes a good presence control https://el34world.com/charts/Schematics ... _schem.pdf
Have you tried that?

the robrob version of it

link to what you're referring to?

canceled out all the guitar signal

what exactly did you do?

If you don't provide sufficient detail, no one's got a chance of working out and explaining what went wrong.

In isolation, photos of the boards aren't very helpful, as they don't show what the components are intended to be connect to.
Yes some of that stuff can be surmised / educated guess, but for other stuff the guessing will be much less certain le is that 270k resistor the correct value and it's a grid stopper, or has the wrong value been fitted and it should be a 2k7 cathode resistor?

[Kee22]

... I get it just wanted to get a presence control in there but somehow the robrob version of it canceled out all the guitar signal...

Detail, both in design (eg schematic) and implementation (layout and actual build) is critical in this game.
Making vague references to things you've done as per above, isn't helpful. Also it conveys the impression you're flailing around trying random stuff, rather than taking a logical, reasoned approach.
The 5F6a includes a good presence control https://el34world.com/charts/Schematics ... _schem.pdf
Have you tried that?

the robrob version of it

link to what you're referring to?

canceled out all the guitar signal

what exactly did you do?

If you don't provide sufficient detail, no one's got a chance of working out and explaining what went wrong.

In isolation, photos of the boards aren't very helpful, as they don't show what the components are intended to be connect to.
Yes some of that stuff can be surmised / educated guess, but for other stuff the guessing will be much less certain le is that 270k resistor the correct value and it's a grid stopper, or has the wrong value been fitted and it should be a 2k7 cathode resistor?

I get it sir, as a newbie all this stuff is new to me. I bought a homemade amp from another builder without a schematic or reference. Somebody told me it was a 5f6A but thats obvious that it aint. It's poorly built from the beginning but because it didn't have a presence control so i tried to add it from Rob Robinettes site with 5F6A mods. The strange thing that happened was that when i inserted the control in the circuit after the NFB resistor i cancelled out everything when i removed the wire from the pot everything worked fine again. I'm still learning and i will try to be more detailed in the future but without a schematic and being new to all it's not easy so any help is appreciated.

[timrobertson100]

Hi
The pictures on your other thread with the amp as you bought it give a lot of context. If I understand correctly, you’re replacing the original board with this new one you are making and then want to modify it a bit. Not a bad way to learn at all, and you’ll find people here are generous in their help.

Perhaps it would be a good route to get it working with your replacement board first as it was (I.e. addressing any soldering issues, and component values etc) and then we can help you get the modifications in. If you hit issues along the way, please post detailed pics so folk can guide you.

Keep an eye on component values, and the orientation of your capacitors.

[timrobertson100]

Another idea might be to build a known circuit making use of your chassis and transformers if you can identify them by part number. You’d have a good chance of a successful result. Just a thought…