Help identifying a symbol in GA30RV AMP SCHEMEATIC

[Gar]

I am designing a layout of the Gibson Super Goldtone GA30RV amp and having trouble identifying one particular symbol I have not come across in the way it is used.
Note in the attached image what appears to be a single side of a transformer symbol.
This appears on the Heaters, Switches and Connectors page of the Pre-Amp supply.
Since it states ECC83(12ax7) tubes and has reference to the Valve number(V1, V2, etc.) and ref's nodes 4 & 5 (as well as 9?) I am assuming the coils are referencing the heaters of those tubes.
Please note also the ref's to the valve are named V1-C. etc. What the heck is the C telling me? Center tap? And why the Capacitors. I have not seen this done before.(see attached)
Please note also that while I have built 1 Marshall amp and 3 Fender amps and the Fender Reverb unit in the past I am still a noob. Though I understand how it all works and I could possibly design an extremely simple amp from scratch - I am still learning.

[Xena E]

Yes the "coils" are depicting the heaters within the valves.

C = Centre tap, who knows, it's as good a reason as any.

The capacitors are for local decoupling across the heaters, these are DC fed to minimise Hum.

It's a poorly drawn circuit.

Good luck with the build.
X

[BennoG]

The center tap is for 6.3V driving of the filament.
then you connect both ends together and put them in parallel.
In the drawn schema the filament is in series so 12.6 V
This is in later tubes to reduce the current draw for all filaments together.
In old radio's the 6.3V tap of the transformer was a very beefy tap that could deliver a lot of amps for all the filaments.

Benno