Sub Caster anyone?

[frequencycentral]

Anyone built one? I just ordered all the parts. I'm thinking of powering it from two 9 volt batteries wired in series - anyone done this? Will I have to change anything? Will it change the tone or anything else?

[frequencycentral]

Bet you thought I'd already built it then?

[Renegadrian]

No Subcaster...Not yet...But I could try it in the future, if I get some 6111...

[ambulancevoice]

18v might cause mis biasing
go with 12 volts all around (heaters, plate)
it appears to be the best voltage to run it on

[frequencycentral]

Hmmmm, the 6111 spec sheet states heater voltage of 6.3v +/- 5%..........woulding applying any higher, ie 12v misbias it?

[ambulancevoice]

Hmmmm, the 6111 spec sheet states heater voltage of 6.3v +/- 5%..........woulding applying any higher, ie 12v misbias it?

yeah i just remembered that the heaters on the 6111 need to be 6v 0r 6.3v max
use this subcaster schematic

[frequencycentral]

So if I give the heater 6.3v and the main circuit 18v?

........or i should just try it and post the results - just don't want to blow a tube in the process! I've never construced with tubes before, though I have a fair amount of experience with transistor,opamps etc.

[ambulancevoice]

So if I give the heater 6.3v and the main circuit 18v?

........or i should just try it and post the results - just don't want to blow a tube in the process! I've never construced with tubes before, though I have a fair amount of experience with transistor,opamps etc.

18v wont blow the tube, the 6111 can handle up to 165v volts or something like that
but i think when biasing tubes with low voltage, the voltages have to be even and balanced
hence a 12 supply with the 6v heater

besides, i dont think 18 volts would make much of a difference

[frequencycentral]

Wow! I just got my 6111 tubes today - they are tiny!

Here's one next to a LM324 quad opamp for size comparison:

[dano12]

Just a reminder on the heatsink approach--IT GETS HOT!!!!!

Unless you want a tatoo on your finger that says LM317, be careful.

Oh yeah, also: have fun

[ambulancevoice]

also, i dont think you should use batteries either
i think in the tube boost thread, it says something about how the tubes just devour the battery
also, as the battery runs out, the tubes will mis bias and change sound

[frequencycentral]

Hey guys, thanks for all the advice,

I shouldn't use batteries - I'll go with a 12 volt wallwart.

I'm planning to fix the LM317 to the metal enclosure itself.

I'll post some results at the weekend!

And yes! I will have fun!

[frequencycentral]

My Subcaster project: 6.3 volt tube heater supply completed!

[Pushtone]

I'm planning to fix the LM317 to the metal enclosure itself.

I've only done this once, use the enclosure as a heatsink for a regulator.

But...

The enclosure became charged positive and the PSU shorted because the jacks are grounded to the enclosure.
I swapped out the open frame metal 1/4" jacks with isolated plastic ones. That fixed the problem but the case is still charged +.
I worry it might touch another enclosure and short out.

[earthtonesaudio]

I'm planning to fix the LM317 to the metal enclosure itself.

I've only done this once, use the enclosure as a heatsink for a regulator.

But...

The enclosure became charged positive and the PSU shorted because the jacks are grounded to the enclosure.
I swapped out the open frame metal 1/4" jacks with isolated plastic ones. That fixed the problem but the case is still charged +.
I worry it might touch another enclosure and short out.

That's right.  The tab is tied to Vout, if I recall correctly.  However, you can buy these sweet little TO-220 shaped pieces of mica, and tiny little non-conductive shoulder washers that isolate the 317 from whatever you put it on.  Oh yeah and get some of that white heatsink grease on there (but not on your clothes).

I just did this with the adjustable power supply on my prototyping rig.  It works, and the metal chassis is grounded via the guitar in/out jacks.

[Pushtone]

Hey a picture or Mouser link to the TO-220 mica thing would be appreciated.
Or how about a name to call it. An insulator perhaps?

[ambulancevoice]

also, with that dc jack your using, you need to insulate it from the enclosure
its not completely plastic (insulated) so it needs like rubber washers or liquid electrical tape in and around the hole that the jack is mounted on, in order to isolate the dc jack from the metal enclosure

also, sorry to say but i dont think using the enclosure as a heatsink is the best idea either
a die cast aluminum enclosure might not be the best thing to dissipate the heat from the regulator
also, as Dano said, it GETS HOT! and if your transferring this heat to the enclosure, it maybe damage or overheat certain
things inside and outside the enclosure
what you can do, it cut out a square hole on the side of the enclosure (probably larger than the regulator itself), mount a proper heatsink on the side over the hole, and attach the regulator to it with a mica or silicon insulator (TO220) and either a metal or nylon bolt
because this proper heat sink will dissipate the heat effectively, it wont go into the enclosure and heat it up (although a little may, but thats ok), it will just dissipate into the surrounding air, like heatsinks are supposed to

[kurtlives]

Ya those DC jacks are a pain. I bought a ton, I just use em for prototyping.

I wrap the hole in tape.

[frequencycentral]

My 6111 has shurt legs, like a conventional tube, I can't find a socket to fit it. Will I fy it if I solder it directly to the board???

[frequencycentral]

Short legs not shurt legs!