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?
Bet you thought I'd already built it then????
No Subcaster...Not yet...But I could try it in the future, if I get some 6111...
18v might cause mis biasing
go with 12 volts all around (heaters, plate)
it appears to be the best voltage to run it on
Hmmmm, the 6111 spec sheet states heater voltage of 6.3v +/- 5%..........woulding applying any higher, ie 12v misbias it?
Quote from: frequencycentral on April 07, 2008, 04:06:29 AM
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
(http://www.beavisaudio.com/Projects/ValveCaster/SubCaster.gif)
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.
Quote from: frequencycentral on April 07, 2008, 05:36:25 AM
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
Wow! I just got my 6111 tubes today - they are tiny!
Here's one next to a LM324 quad opamp for size comparison:
(http://i210.photobucket.com/albums/bb292/frequencycentral/6111.jpg)
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 :)
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
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!
My Subcaster project: 6.3 volt tube heater supply completed!
(http://i210.photobucket.com/albums/bb292/frequencycentral/SC1.jpg)
Quote from: frequencycentral on April 10, 2008, 01:24:20 PM
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.
Quote from: Pushtone on April 13, 2008, 10:19:03 PM
Quote from: frequencycentral on April 10, 2008, 01:24:20 PM
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.
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?
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
Ya those DC jacks are a pain. I bought a ton, I just use em for prototyping.
I wrap the hole in tape.
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???
Short legs not shurt legs!
Quote from: Pushtone on April 13, 2008, 10:59:07 PM
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?
Mouser carries whole kits, with the rectangle of mica film, the non-conductive washer, and I think it comes with nuts and bolts too. $0.77 for quantities of one. Part number: 532-4880.
Or just search for TO-220 heatsink hardware.
-Alex
they have sockets for sub miniature tubes on ebay
or you can use an 8 pin DIL (for ICs) although you probably need longer leads for that
the 6111 is octal too, so make sure its an 8 pin socket
if the leads are still to short, your gonna have to get new 6111
I just finished building mine and I like it, but is there anyway to get some more gain out of it?
Hmm - out of sheer impatience I ended up directly soldering my short legged 6111 directly to the board - I think I blew it (or it was bad anyway).
The LM317 based regulator works fine, but when I hook up power to the main circuit I get a DVM reading of 0v between +V and earth, and the 6.3v supply drops to about 1.8v. I checked and checked again my layout and other components. A continuity test between the two heater terminals of the 6111 showed positive.
This is my first valve build, so I might just plead ignorance if I blew it!
I have some 12au7s and sockets on order, so I can build a Valvecaster real soon, but am finding it difficult to source 6111s this side of the pond. If I can source some more I will desolder the blown one and use SIL sockets to mount another. What I really like about the 6111 though is that the entire circuit can be less than an inch and a half square.
What do you guys think? Is the heater really sensitive to heat???
Quote from: frequencycentral on April 16, 2008, 05:45:05 PM
What do you guys think? Is the heater really sensitive to heat???
nope, its sensitive to to much current and or voltage
Bump! Bad 6111?
but a heater can over heat, and melt!
did the heater go RED when you soldered it to the board?
Hmmm, dunno, didn't look at the time!
Whats really making me think its something to do with the heater is that there is high continuity and no virtually no resistance between the two pins. Something is dragging the whole circuit to ground!
Heyho - I'll try another tube when they arrive!
Thanks for your help ambulancevoice!
Quote from: Berger on April 15, 2008, 07:46:52 PM
I just finished building mine and I like it, but is there anyway to get some more gain out of it?
There certainly is. Raise your plate voltage. I'm using a 35 VDC 900 mA wall wart and running it to a 78M24 fixed regulator for the plate voltage and an adjustable regulator for the 6.3 V heater supply. This has so much gain that I am going to scale it back in the tube circuit itself. Running these at 24 volts just makes it so much easier to toy with. Its much easier to decrease gain within a circuit than it is to try and squeeze every little bit of gain out of a circuit that really doesn't have it.
Just for the record. I've had problems with the LM317 for the heater voltage. I've used two motorola's and two fairchild's and all four worked for about an hour and died. I'm using a heatsink way oversized for the purpose. I swithched to an LM2931CT and its been problem free for two weeks now.
This is a whole different beast at a higher plate voltage, 6021, 6111, and 6112 all work great. I'm going to try tacking on a CK5784WA sub mini and see what kind of tone that delivers.
Try the higher plate voltage, it makes the subcaster a lot easier to taylor to your sound because you have more to work with. IMHO.
Jered
Seeing as how this thread is up top again - I got mine working - see my comments here:
http://www.diystompboxes.com/smfforum/index.php?topic=63479.480
Quote from: frequencycentral on May 02, 2008, 12:39:55 PM
Subcaster working!
All I did was remove C2, the 47nf cap across the supply rails and replace it with a different kinda 47nf cap. Weird. Hmmm, been bugging me for weeks!
So - I fired my Valvecaster into my Subcaster - WOW!!
It seems to me that the hassle of creating a 6.3 volt supply for the 6111 heater is a pain in the butt compared to powering a 12au7 heater at 12 volts. There really is no saving on space when you consider the extra circuitry required for the voltage regulator - and a heatsink on the LM317 too! There is a whole lot of heat generated by a 6111 in comparison to a 12au7. add that to the heat the LM317 gives out and you can warm the living room up nicely with a Subcaster!
My rule of thumb now will be to only use 6111's in pairs and run the heaters in series of 12 volts.
So - go ahead and build a Valvecaster. Or a dual Subcaster. Or a Pepper Shredder using two 6111's, like I'm doing next.
(sh*t, I would do it this weekend but I have to write some music for Volvo!)
Just don't build a single 6111 Subcaster!
Quote from: frequencycentral on May 11, 2008, 02:07:53 PM
Seeing as how this thread is up top again - I got mine working - see my comments here:
http://www.diystompboxes.com/smfforum/index.php?topic=63479.480
Quote from: frequencycentral on May 02, 2008, 12:39:55 PM
My rule of thumb now will be to only use 6111's in pairs and run the heaters in series of 12 volts.
If you do that they will glow like a lightbulb and die. 5.7 V min-6.9 V max on the heaters.
So - go ahead and build a Valvecaster. Or a dual Subcaster. Or a Pepper Shredder using two 6111's, like I'm doing next.
(sh*t, I would do it this weekend but I have to write some music for Volvo!)
Just don't build a single 6111 Subcaster!
Having built both I'll say this. If you just want to warm up your tone a little and add maybe a touch of gain, the Valvecaster works. If you want some high gain crunch, the subcaster wins hands down.
Jered
Quote from: Jered on May 11, 2008, 02:52:31 PM
My rule of thumb now will be to only use 6111's in pairs and run the heaters in series of 12 volts.
- If you do that they will glow like a lightbulb and die. 5.7 V min-6.9 V max on the heaters.
Are you sure they will die? Surely if they are in series each tube will get it's 6 volts? That's what I've read on Dano12's 'parent thread'.
This kinda makes sense because the 12au7 has the 6 volt centre tap on the heater, so in effect it has two series 6 volt heater element either of which can run at 6 volts, or both in series at 12 volts.
So running the heaters of two 6111 tubes in series with 12 volts is just the same as running both halves of a 12au7 heater with 12 volts without using the centre tap.
Therefore, you should be able to run half a 12au7 heater (using the centre tap) in series with a 6111 heater at 12 volts.
Yes? Or no? I'd love for someone to confirm this or deny it.
With the 12A_7 tubes it needs 12.6 volts for the heaters, which are pins 4 & 5, and the center tap is pin 9. So you have two ways to power the heaters. Run 6.3 volts to pin 4, 6.3 volts to pin 5, and ground pin 9. Or you can run 12.6 volts to pin 9, and ground pins 4 & 5.
Can you run 12.6 volts to pin 5, and ground 4 & 9? I don't know, never tried it. I'm sure someone else here with more experience will chime in and let us both know.
With the 6021, 6111, and 6112 submini's, you need 6.3 volts for the heaters, pins 3 & 6, but you don't have the luxury of a center tap. So its easiest to supply 6.3 volts to either pin 3 or 6 and ground the other. I guess you could run 3.15 volts to both pins, but then your just making things hard on yourself. Unless they make V. regulators for just this purpose? i don't know they just might.
Jered
Quote from: Jered on May 12, 2008, 02:03:13 AM
With the 12A_7 tubes it needs 12.6 volts for the heaters, which are pins 4 & 5, and the center tap is pin 9. So you have two ways to power the heaters. Run 6.3 volts to pin 4, 6.3 volts to pin 5, and ground pin 9. Or you can run 12.6 volts to pin 9, and ground pins 4 & 5.
Can you run 12.6 volts to pin 5, and ground 4 & 9? I don't know, never tried it. I'm sure someone else here with more experience will chime in and let us both know.
With the 6021, 6111, and 6112 submini's, you need 6.3 volts for the heaters, pins 3 & 6, but you don't have the luxury of a center tap. So its easiest to supply 6.3 volts to either pin 3 or 6 and ground the other. I guess you could run 3.15 volts to both pins, but then your just making things hard on yourself. Unless they make V. regulators for just this purpose? i don't know they just might.
Jered
the center tap only really needs to be used for the 6.3 volt heater situation
12.6v and its not really needed, just run it to pin 4 (or 5) and ground the opposite pin
or for center tap power, run half (6.3v) to pin 4 and the other half (6.3v again) to pin 5
6.3v and you run it to 4 and 5 (parallel) ground pin 9
or in case of center tap heater supply, run half the supply to 4 and 5 and the other half to pin 9 and ground the center tap on the power supply
and there are adjustable regulators, its used for the sub-caster.
Why would you want to make the extra work for yourself? For a single tube application, 6.3 to pin 4 and 6.3 to pin 5,...done. Float pin 9 or ground it, it doesn't matter.
As for the regulator, I stated "for just this purpose" meaning a 3.15 V. fixed regulator. I know they maked 6.2 V. fixed regulators among many others, 5,8,9,10,12, etc.
Here is a good starting point for the 5784 sub mini pentode. Great medium gain sound as is, but can probably be improved. I'm just a hack tuning the circuit by ear.
http://aronnelson.com/gallery/main.php/v/Jered/5784+circuit.jpg.html
Quote from: Jered on August 22, 2008, 01:15:01 AM
Here is a good starting point for the 5784 sub mini pentode. Great medium gain sound as is, but can probably be improved. I'm just a hack tuning the circuit by ear.
http://aronnelson.com/gallery/main.php/v/Jered/5784+circuit.jpg.html
Great!
Does it sound different compared to a subcaster?
Keep us posted anyway with your results.
Maybe it is a good idea, to put a 6111 in front of the 5784.
I read somewhere, that the 6111 tube works better starting from 24V DC.
I think they meant better cleans, but that is good for driving the pentode more.
Funny you should mention that. That's what's in front of me right now, but with a 6021 in the first stage. You are absolutely right about the voltage. At 24 or more volts the improvement in sound and responsiveness is dramatic. I've been testing everything at voltages between 12 and 32 volts. 6021, 6111 really come to life around 18 volts on up, 6112, 5784, 5703 really come to life 24 volts and up. To my ears anyway.
Someone who knows what they are doing could probably make any of these sound good with 12 volts. Time will tell.
Wow - I had forgotten about this thread - it was right at the start of my tube fetish. God, I've learned a lot since then!
The schematic looks good Jered . I have some 5672 submini pentodes - only five pin, unlike the 5784. I bought them to build some VCFs/VCAs - though I bought enough to have soem spare to experiment with something similar to your schematic - but that's way down the road yet - I have other fish to fry first.
Hey everyone - do me a favour and just let this particular thread die - no more replies please - I sound like such a newb/dork on page 1 !
Quote from: frequencycentral on August 22, 2008, 07:05:09 AM
Hey everyone - do me a favour and just let this particular thread die - no more replies please - I sound like such a newb/dork on page 1 !
So where should we post subcaster updates?
Quote from: Jered on August 22, 2008, 07:25:01 AM
Quote from: frequencycentral on August 22, 2008, 07:05:09 AM
Hey everyone - do me a favour and just let this particular thread die - no more replies please - I sound like such a newb/dork on page 1 !
So where should we post subcaster updates?
Hehehe - nah keep this thread going then!
Here's the results of experiments I have performed on how to power 6111 heaters:
(http://i210.photobucket.com/albums/bb292/frequencycentral/6111power.jpg)
Check out page 4 of this datasheet
http://www.mif.pg.gda.pl/homepages/frank/sheets/009/6/6021.pdf
6.0 and 6.6 are absolute min/max heater voltages. Your right on the border of shortening the life of your tubes. 6.3 volts for filaments is best when possible.
This pdf is for 6021's, but applies to 6111 and 6112 as far as heater voltage is concerned.
Quote from: Jered on August 25, 2008, 07:49:43 PM
Check out page 4 of this datasheet
http://www.mif.pg.gda.pl/homepages/frank/sheets/009/6/6021.pdf
6.0 and 6.6 are absolute min/max heater voltages. Your right on the border of shortening the life of your tubes. 6.3 volts for filaments is best when possible.
This pdf is for 6021's, but applies to 6111 and 6112 as far as heater voltage is concerned.
I happily within tolerance! If it drops to 5.99 I'll start to worry.............