"Superfly" - submini tube version of Doug H's Firefly

[frequencycentral]

The tubes' heater will burn out at 15 volts. But you could use a 7812 to feed the circuit from a 15 volt supply. Tonestack? Personal preference, you lose some volume.....

[Poste]

Ok so it sounds like it is possible then, I actually stuffed up the power supply I have is 16V.

Now here are a few more questions
1) How could I use the 7812 to feed the curcuit?
2) Should I switch the power in between circuits, my thoughts are that the tubes "wear" out with power going through them so switching power would prolong the life of the tubes to the time when they will be in use instead of being in standby. But tubes like to be in standby, or need to be heated up correct? What would be the best approach here?
3) If I have the 16V power supply feeding both curcuits will there be enough power without overloading the supply?

Sorry if these sound like silly questions, I only have a basic knowledge of things electric.

[danielzink]

Ok so it sounds like it is possible then, I actually stuffed up the power supply I have is 16V.

Now here are a few more questions
1) How could I use the 7812 to feed the curcuit?
2) Should I switch the power in between circuits, my thoughts are that the tubes "wear" out with power going through them so switching power would prolong the life of the tubes to the time when they will be in use instead of being in standby. But tubes like to be in standby, or need to be heated up correct? What would be the best approach here?
3) If I have the 16V power supply feeding both curcuits will there be enough power without overloading the supply?

Sorry if these sound like silly questions, I only have a basic knowledge of things electric.

1) you need to research the 7812 and see how it is utilized in a circuit to see how you could best implement it.

2) can you maintain power to both circuits ? you need to sort that out as well...

3) 16v is 16v...... question is.....do you have the amperage ? you haven't actually said yet - exactly what kind of power supply you'd like to power both of these circuits with...and how will you "split" the power ? You can supply 12 volts to two car engines....but will you have the amps to start either one of them ?

Sorry if these sound like silly questions, I only have a basic knowledge of things electric.

In light of this last statement...
Let me give you some advice that Rick himself gave me recently........

Superfly: SMPS power supply, 180 + volts, difficult to get exactly right, the right inductor matters. Trimmer needs adjusting just right. Be careful....the power supply can give you a real jolt. Just be warned - the Superfly SMPS is not for beginners. With the Superfly you gotta know what you're doing and take care of yourself while you do it.

Don't get me wrong - I am not trying to talk you out of this build - I just think you need to figure out every aspect of it before you go charging in....this is an amplifier...not a 9V tubescreamer...

I did 2 months worth of research before I ever put an iron to a board on my Firefly build..

nobody wants you to smoke your power supply...or yourself...

Dan

[Taylor]

I also think that, since the Tiny Giant's power demands are special too, you're pairing up 2 projects with special power needs and trying to run them off the same supply. I think it could be a recipe for one or many disasters.

I would build them separately.

Since you say you only started building electronics a couple of months ago, don't try to push yourself too quickly. Both of these projects require some serious thought and attention by themselves, and you can potentially hurt yourself and/or smoke/melt parts if something goes wrong. Attempting to do some special trickery with already tricky projects when still relatively new to the craft is probably not a good idea.

[Scruffie]

Would using an IRF840 & UF4007 in this be possible or is it just asking for trouble to mess around with the delicate nature of the charge pump?

The IRF840 has specs of 500V Vdss, 0.85 Rds & 8A Id... Fairly close to the 740 and I think the UF4007 just has a higher voltage rating than the 4004.

Edit:Bugger, just noticed the answer to the IRF840 question on the page before... and a Semi-Answer to the UF4007 question... i'll probably just risk that.

[frequencycentral]

Close enough for jazz I should say.  

BTW, the next one I build will have a panel mount pot in place of the trimmer to act as a kinda poor man's variac. I just need to calculate the voltage divider ratios so the 'brake' pot can only be at 185v at it's maximum.

[Scruffie]

So... I took a stab at this making a PCB layout to fit a 1590BB with Onboard Pots & Tube Sockets using the MAX1771 Charge Pump & Standard Sized Tubes with an Added Big Muff Tone Stack (With Shelve Filter) and this is where my first attempt got me...



(96.52mm x 71.12mm)

I'm not overly happy with how it's come out so I wondered if you had any tips for how you go about laying them out Rick? I keep trying to lay it out like a Stompbox which just doesn't work and leads me into corners...

Any suggestions would be appreciated.

[Perrow]

Any suggestions would be appreciated.

There's an area just south west of the AU tube that makes five lines take a detour.

There's a (ground) line just north west of those lines that takes a voluntary detour, looks odd.

The 12V+ line could go from the MAX1077 pin 2 direct to a point just above C8 instead of running all the way down to C10.

You could possibly move the FET to the side and nail it to the enclosure.

Not the most solid comments, but my 2c anyway

[Scruffie]

There's an area just south west of the AU tube that makes five lines take a detour.

There's a (ground) line just north west of those lines that takes a voluntary detour, looks odd.

The 12V+ line could go from the MAX1077 pin 2 direct to a point just above C8 instead of running all the way down to C10.

You could possibly move the FET to the side and nail it to the enclosure.

Not the most solid comments, but my 2c anyway

I've been going over it all morning and I can't beleive I didn't notice those Detours were unneccesary

Looks much better now, i've also adjusted the FET to be in line with the PCB design advice given in the original Nixie Document and noticed that this version doesn't need a Heat Sink so I could move it much closer and have shorter traces.

Version 2:




There are two R12s to Parallel them due to the obscure value of 0R050 (0R1 is a little more common) and two pads to the side of the inductor to accept other sizes.

[frequencycentral]

Pete, I find that type of layout really hard to visualise compared to DIYLC, but I think it's really neat how you've got everything onboard. The whole concept is very attractive to me actually, I'll have to build one! BTW, I've used a single 0R1 resistor in MAX1771 based builds with success. I also altered the trimmer and associate voltage divider values slightly.

[Taylor]

This does look great. I've been wanting to try one of these amps again, now that the wound of my previous attempt is healed and forgotten. Would this 12ax7 version use the same or similar transformer?

[Scruffie]

This does look great. I've been wanting to try one of these amps again, now that the wound of my previous attempt is healed and forgotten. Would this 12ax7 version use the same or similar transformer?

The only difference here would be the Tubes are Full Sized & The Nixie Supply is different, the rest is the same and the 125A Would still be the Tranformer to use, it's kinda the best of both worlds in my book (Except for the slightly larger enclosure).

I did consider making a version with the original 555 Nixie aswell, but I think the MAX1771 is more efficient so will work better with Full Tubes if I understand it correctly... which I don't.

Pete, I find that type of layout really hard to visualise compared to DIYLC, but I think it's really neat how you've got everything onboard. The whole concept is very attractive to me actually, I'll have to build one! BTW, I've used a single 0R1 resistor in MAX1771 based builds with success. I also altered the trimmer and associate voltage divider values slightly.

Ahh, I did wonder about visibility, if you try and print the image of the layout the same as DIYLC though it all comes out in all black and looks even more confusing... or in colour in XML documents but I have sod all clue what an XML document is or how to use it.

It does connect up properly though, i'll tweak it and check it some more and add a final version up tommorow, i'm certainly going to build one up in the future once i've got hold of a PCB and Transformer, let me know if you beat me to it though! Be great to verify this one.

Cause I think we can all agree... wiring Pots by hand is a right pain in the Arse.

I'll leave the extra pads for the parallel resistor... just incase someone can only find a 0R2, doesn't really make a whole lot of difference to the layout.

[Scruffie]

Here we go, altered it now, this should be the Final Version, Checked it over and it all looks good.

[Scruffie]

Well I thought it looked good but I realise i've made what can only be described as a Monumental %^&* up... I neglected to notice that on the 12AX7 Datasheet the Diagram Said... 'Bottom View... so they are in fact... backwards 

What's the view on mounting them on the back of the board? Would there be enough depth in a 1590BB to get away with it with the Board Mounted pots?

While we're here anyway as I did catch one more mistake on that past layout (The Heaters don't go back to ground) I am right in saying that Pin 9 shouldn't be in use here right?

I'll keep trying to do a layout with the Tubes orientated correctly but it's not quite as easy to get away without Jumpers...

[Perrow]

While you're at it, the tubes are mounted quite close to each other, are they wider than the sockets? I haven't had first hand experience with 12A_7 tubes so I don't really know, so if you've taken that into consideration don't bother about this comment, just thought they looked rather close to each other.

[Perrow]

And you might think about trimming your pcb image next time. A little too much white space in the ones you've posted here 

[Scruffie]

While you're at it, the tubes are mounted quite close to each other, are they wider than the sockets? I haven't had first hand experience with 12A_7 tubes so I don't really know, so if you've taken that into consideration don't bother about this comment, just thought they looked rather close to each other.

Yeah the new one will have them spaced a bit farther apart, I haven't got any Tubes, Sockets or Enclosures to hand so it's all a bit of a judgement call as to what constitutes too close... they'd fit but I don't know how tightly.

And you might think about trimming your pcb image next time. A little too much white space in the ones you've posted here 

Haha, yeah I will do, I don't like to mess about with the images for PCBs when they come out of Express PCB so I just stick them up as is, point taken though 

[Taylor]

I'm a little confused about the revision history here, but assuming I'm ok with mounting the tubes on the back of the board, is that last layout good to go Scruffie? I'd love to build one of these up.

[Scruffie]

I'm a little confused about the revision history here, but assuming I'm ok with mounting the tubes on the back of the board, is that last layout good to go Scruffie? I'd love to build one of these up.

Not quite, I misunderstood how to wire the heaters on that, i'll try and get both updated versions on here today.

[Maik]

Hey Scruffie, may we have the Expressfile? I want to have the lines thicker...
Thanks for the pcb