Pirx

True, I would do independent filament PS for each 300B, probably with LDO. Ad the rest of circuit invisible from bottom - I guess the main HV PS is hidden under cover from top side. There is too much space there only for transformer.

For me it is DC heating, look at wires at left bottom 300B, wires come from PCB with capacitors and some silicon under it.

Hahaha, ok, now it’s clear, apparently my neurons decided to slack off for a bit

Are you talking about yours earspeakers? Any details, what happened?

Ofc such metal piece cannot be placed inside driver, only outside of stator, your right.

My mistake - that green/yellow PCB part I mentioned is from the other side of driver (facing outside). So no changes here probably. Back to stators - I was wondering about covering it partially with some thin sheet of metal, to make more compression inside drivers (similar to drivers from 007). That would change tonality, but in which direction ...🤔

Nice work, thanks for sharing. You report more bass and little different tonality that made them more enyoable for you. In summary the most important parts of this project: 1. Internal dimensions and stators are unchanged. 2. Protecting membranes are changed. 3. Diaphragms are new. 4. Green PCB changed to your own black PCB with higher distance for earpads's lips. Is it correct? I cannot find if you sealed them in any special way more than they were? If so, I guess that tension of new diaphragrams and dust covers are responsible for more bass.

And this is the way i tried to do that - it worked and is still working. Thanks!

Hi, The time has come for my broken SRA-3S, unfortunately I don’t like what I have found inside there Any idea if this kind of slot is for sale nowadays anywhere?

New rings/spacer for new diaphragm, thicker rings for dust covers suggests that new mylar will be also used - that should give different results in tonality, very interesting project. Maybe your experiment will push me to mod mine 009. As for the hole in the stators, its purpose has me curious as well. I do not remember if I ever asked your here for this - can you share what you are using for coatings? Licron?

True, any modifications you make there won't allow you to predict results on genuine drivers. But I’ll still be interested in your work.

Ah, ok, so mods for cables. I was wondering if you found a way to trim tonality of drivers a little.

I would like to see your ideas about fixing SR-009 drivers. Are you going to use some 3D printed parts?

I was hopping that the latest version will be a lot better than the old I still have ... and not using. Now my hope was killed by Spritzer, thanks!

But what about humidity? It doesn't seems to be immune for it.