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

[Scruffie]

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

If you PM me your e-mail address yeah.

[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.

Here ya go Taylor, this'd be the one to etch now, Fixed the Tube Heaters (As far as my knowledge goes) corrected two missing parts, spaced the Tubes further apart and shrunk the board a tiny amount... this should, fingers crossed, all be good now.

If you're etching one for yourself do you think I could buy one off you?

And I don't think I will be doing a PCB with the tubes corrected, it just doesn't come out as nicely without starting everything again and i'm pretty happy with this layout... plus I prefer the circuit to face me when I open an enclosure anyway. If it struggles to fit nicely in a 1590BB, the Smallbear 125BB would probably be perfect.




96.52 x 69.85mm

[Scruffie]

For @#$%s Sake, The Heaters are Still wrong aren't they, can someone explain how I wire them?

Am I right In saying 12V runs Directly into Pin 4 on Both Tubes and Both Pin 5s go to ground? Do the Pin 5s have to connect or just go straight to ground? Do I connect Pin 4 & 5 Together?

[frequencycentral]

Pin 4 of both tubes to ground. Pin 5 of both tubes to +12v. Pin 9 no connection. I *think* you can also do it the opposite way, ie pin(s) 4 to +12v, pin(s) 5 to ground. You definately do not connect pins 4 and 5 together. You may be getting confused due to the way the submini heaters in Superfly are wired in series (because they are 6.3v heaters), but this is not necessary with the 12##7 version. Would be worth you checking out DougH's original Firefly schematic.

[Scruffie]

Pin 4 of both tubes to ground. Pin 5 of both tubes to +12v. Pin 9 no connection. I *think* you can also do it the opposite way, ie pin(s) 4 to +12v, pin(s) 5 to ground. You definately do not connect pins 4 and 5 together. You may be getting confused due to the way the submini heaters in Superfly are wired in series (because they are 6.3v heaters), but this is not necessary with the 12##7 version. Would be worth you checking out DougH's original Firefly schematic.

Yeah I wired them like the Superfly reading that the heaters needed 6.3V thinking that seemed right as it was half of 12.6V, then looked at the 12AX7 again to see it said 12.6V and... well you get the idea.

I thought Pin 4 to +12V was the norm... All the information I keep finding starts off being for series and then the topic ends up being for parallel... i'll have to keep checking, having voltage to Pin 4 would be nice layout wise.

I did check Dougs original schematic and it has the Heaters wired in Parallel which wouldn't work here.

Edit: Question answered http://www.diystompboxes.com/smfforum/index.php?topic=86051.0 Both the same 

[frequencycentral]

^^^

Yeah, makes sense, as some amps use AC for the heaters. They like it both ways.

EDIT: There may be a benefit to using the 12##7 heaters at 6.3v in series, the total ma consumption would half in comparison with series. Both tubes combined would only draw 150ma in series versus 300ma in parallel. Might be worthwhile considering the ma hungry nature of SMPS's.

[Scruffie]

^^^

Yeah, makes sense, as some amps use AC for the heaters. They like it both ways.

EDIT: There may be a benefit to using the 12##7 heaters at 6.3v in series, the total ma consumption would half in comparison with series. Both tubes combined would only draw 150ma in series versus 300ma in parallel. Might be worthwhile considering the ma hungry nature of SMPS's.

Huh... I thought this was series wiring... I thought I put 12.6V into Pin 4 of Both Tubes and Pin 5 to Ground on Both Tubes and that was Series and parallel was when Pin 9 Got involved, i'm so very, very confused    Will that not be 150ma Then?

If not... what could I do... fitting a Regulator on at this stage would be a right bitch, fitting anything on at this stage would be really... a 6.2V Zener?

Is there any places suggested for learning this better, I keep searching but nothing really explains it to me in simple terms.

Here's two very slightly different PCB Versions to choose between though with it wired in series or parallel or whatever this is... One has 12V going to Pin 5 of Both Tubes which means that the Pin 4 ground is running between 12V & The Input Trace but it's a bit tight or there's one with Pin 4 Getting 12V on both Tubes and Pin 5 off to Seperate Grounds.

[Taylor]

If you're etching one for yourself do you think I could buy one off you?

Once the layout's all sorted, if I'm making any PCBs I would be happy to send you one gratis.  Thanks for putting that together (and thanks of course to Doug and Rick for the cool circuits).

[defaced]

Huh... I thought this was series wiring... I thought I put 12.6V into Pin 4 of Both Tubes and Pin 5 to Ground on Both Tubes and that was Series and parallel was when Pin 9 Got involved, i'm so very, very confused  icon_cry  icon_lol Will that not be 150ma Then?

You are correct.  Pin 4 and 5 are the ends of the heaters, pin 9 is the center tap.  So, with pins 4 and 5 connected to either end of the heater supply, it's 12.6v, 150ma (series heaters) - heaters are basically resistors, so there is no polarity.  With pins 4 and 5 tied together and connected to one end of the heater, and pin 9 connected to the other end of the heater supply, it's 6.3v 300ma (parallel).  

If the heater circuit is grounded properly, and the layout is good (*), there is no reason to rectify the heater supply for DC.  There are many ways of dealing with ground referencing AC heaters.  Usually either the center tap of the heater winding is grounded, or two 100r resistors are used to create and artificial center tap, or a pot is used instead of the 100R resistors with the wiper grounded so one can adjust for minimum hum.  All of these schemes balance the positive and negative sides of the AC power for the heaters more or less equally with respect to ground.  Unlike typical stomp box "grounds", this ground connection does not carry current, it simply provides a voltage reference for the AC heater supply.  I would not recommend grounding one side of the heater supply, primary because if the "real" amps don't do it often/ever, then there's probably a reason why.  

For the sake of heater induced hum, I have read there is some benefit of using 12.6v and 150ma because the lower current emits a lower electromagnetic field and is less likely to couple to the cathode of the tube (the more current in a conductor, the more EMF it emits).  I have never bothered to verify this, I'm lazy and elevate my heater supply by about 45v DC to reduce coupling and lower the cathode to heater voltage in cathode follower circuits which is often near or over max spec with many circuits.  

Since you are designing a circuit board, I'd advise prototyping it to make sure you don't have strange coupling going on between the different parts of the circuits.  Usually DC heaters are used because they don't couple very well to other parts of the circuit on a PC board, it has little to do with the heaters themselves and more to do with the board layout.  This may or may not be a problem for you; you'll have to test it to find out.  

[Scruffie]

Huh... I thought this was series wiring... I thought I put 12.6V into Pin 4 of Both Tubes and Pin 5 to Ground on Both Tubes and that was Series and parallel was when Pin 9 Got involved, i'm so very, very confused  icon_cry  icon_lol Will that not be 150ma Then?

You are correct.  Pin 4 and 5 are the ends of the heaters, pin 9 is the center tap.  So, with pins 4 and 5 connected to either end of the heater supply, it's 12.6v, 150ma (series heaters) - heaters are basically resistors, so there is no polarity.  With pins 4 and 5 tied together and connected to one end of the heater, and pin 9 connected to the other end of the heater supply, it's 6.3v 300ma (parallel).  

If the heater circuit is grounded properly, and the layout is good (*), there is no reason to rectify the heater supply for DC.  There are many ways of dealing with ground referencing AC heaters.  Usually either the center tap of the heater winding is grounded, or two 100r resistors are used to create and artificial center tap, or a pot is used instead of the 100R resistors with the wiper grounded so one can adjust for minimum hum.  All of these schemes balance the positive and negative sides of the AC power for the heaters more or less equally with respect to ground.  Unlike typical stomp box "grounds", this ground connection does not carry current, it simply provides a voltage reference for the AC heater supply.  I would not recommend grounding one side of the heater supply, primary because if the "real" amps don't do it often/ever, then there's probably a reason why.  

For the sake of heater induced hum, I have read there is some benefit of using 12.6v and 150ma because the lower current emits a lower electromagnetic field and is less likely to couple to the cathode of the tube (the more current in a conductor, the more EMF it emits).  I have never bothered to verify this, I'm lazy and elevate my heater supply by about 45v DC to reduce coupling and lower the cathode to heater voltage, which is often near or over max spec with many circuits.  

Since you are designing a circuit board, I'd advise prototyping it to make sure you don't have strange coupling going on between the different parts of the circuits.  Usually DC heaters are used because they don't couple very well to other parts of the circuit on a PC board, it has little to do with the heaters themselves and more to do with the board layout.  This may or may not be a problem for you; you'll have to test it to find out.  

I lost track after You are Correct... Thanks for taking the time for the thorough explanation though, hopefully during the course of this build i'll begin to understand tubes a little better, it's entirely new territory to me.

But, from my reading and from that, either one of the above two PCBs should now work, atleast in theory... any problems that come of the layout we'll have to find out with prototyping as you say.

I think... from what I gather having the heater wires run parallel is a good thing (I don't know why but it seemed to be what everyone was doing on there builds on the AX84 forum) so the 1st PCB of the Two should be best with the Tight Tracks (I'll remove the others now so there's no confusion anyway).

If you're etching one for yourself do you think I could buy one off you?

Once the layout's all sorted, if I'm making any PCBs I would be happy to send you one gratis.   Thanks for putting that together (and thanks of course to Doug and Rick for the cool circuits).

Seems to me to be sorted, well as far as we can tell untill we actually build it! So that'd be greatly appreciated  

And yeah thanks Doug and Rick... I may not understand these glass things but I know they sound good  

[defaced]

I lost track after You are Correct... Thanks for taking the time for the thorough explanation though, hopefully during the course of this build I'll begin to understand tubes a little better, it's entirely new territory to me.

No problem, you guys with your little chips and 9v batteries are new territory to me.  

Some suggestions for more knowledge that's easy to attain/understand:
- Wander over the the Music Electronics Forum and start reading.  That's where I learned most of my tube knowledge over the past several years. Some of the guys are old and grumpy, but they know their stuff.  They grew up with it.  
- Look at the datasheets of the tubes you're using and try to understand them, at least the pinout and what each piece of the tube does. The heater circuit, if you just think about it as two resistors, makes more sense once you see how the heaters are wired inside of the tube.  
- Schematics of old/popular amps to "see" what's doing on in the heater circuits of these amps.  
- Valve Wizard and Aiken Amps are also two other very good tube resources.  
- And last but not least, there's a tech help page here at DIYSB (on the main page) that covers tube anatomy and what each component does.  It was a HUGE help when I didn't know what a "plate resistor" was.  

Having heaters run parallel is actually a not the way you're supposed to do it, but it often doesn't matter.  Twisted pairs of wire are the "proper" way to do heaters because a twister pair shields really well.  Without knowing it, you're in lead dress land. http://www.geofex.com/article_folders/lead_dress/lead_dress_in_tube_amps.htm

This is twisted pair wired heaters (not my work, but a great example):

[Maik]

Hey Taylor, do you make some more?
I like your pcb´s and want to order one or two...

[Taylor]

Hi Maik,

I had no plans to sell these boards - I was just going to make one for myself, maybe make one for my father, and one for Scruffie as thanks for doing the layout and adapting it to full-size tubes. I'm not set up to do lots of etched boards, and before I could think of doing a fabricated one, I'd have to run it by everybody involved in the project first. I'm not even sure they'd all be ok with it, and my personal ethics or whatever precludes me from going forward in that case.

So, for the time being I can't, I'm afraid, but down the road, who knows?

[solderman]

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.

Hi Scruffie and thanks for posting the "big valve" version on Rick's (Doug H) super cool amp.

I just happen to have one EL90 pentode that I like to tri to use as power stage. So I'm in the process of making a layout for this purpose. Some questions though.

- Have you tried the tone stack, it does not appear to be a Big muff clone to me. The ones I have seen has no 4n7 and 3,9 nF and 39K in sted of 47K, is it??

- On the original from rick there is a 47 uF Cap from pin 1 to GND on the 12ax7 why did is it why did you omit that one?


The EL90 has only a 6,3V heater so I have to chip in a LM317 to regulate the voltage.

Thanks

[Scruffie]

Hi Scruffie and thanks for posting the "big valve" version on Rick's (Doug H) super cool amp.

I just happen to have one EL90 pentode that I like to tri to use as power stage. So I'm in the process of making a layout for this purpose. Some questions though.

- Have you tried the tone stack, it does not appear to be a Big muff clone to me. The ones I have seen has no 4n7 and 3,9 nF and 39K in sted of 47K, is it??

- On the original from rick there is a 47 uF Cap from pin 1 to GND on the 12ax7 why did is it why did you omit that one?


The EL90 has only a 6,3V heater so I have to chip in a LM317 to regulate the voltage.

Thanks

I have not tried any of this at all, The Tone stack has the values of the first schematic for the Big Muff Tone Stack Google Came up with, personally i'll be using 2 x 47k & 2 x 10n.

The 4n7 is there to act as a Shelving Filter type of set up so when you roll the tone stack back to the bass side, you don't loose all the highs, you don't have to have it but I prefer it that way.

The Schematic I worked from was Ricks 'Superfly Special' which is a couple of pages back and that did not include the 47uF Cap... You'll have to ask Rick that one, it's just for the Reference Voltage though.

Tube Heating isn't my strong point as we've found during these last few pages  but a LM317 sounds reasonable.

Good Luck with your Build!

[solderman]

OK thanks
I'll try this and send in an update as soon  as I'm done 

[MetalUpYerEye]

I'm going to start getting my stuff together for this build now that i've done a bit of reading on it...

I was wondering if this output xfmr will work... Or do I have to shell out $30+ for a Hammond 125a?
http://www.tubesandmore.com/scripts/foxweb.dll/moreinfo@d:/dfs/elevclients/cemirror/ELEVATOR.FXP?item=P-T125A

Also 1/4 watt resistors are fine right? Are there any higher voltage electrolytic caps that i'll need for the power supply?

[MetalUpYerEye]

bump. Just trying to get a bit of info so I can build this baby... 

[frequencycentral]

That transformer is fine.

All resistors are 1/4 watt.

The only high voltage electro you need is the reservoir cap(s) for the SMPS. I've used 2.2uF/450v as well as 4.7uF/350v. Any bigger value and you're looking at a physically big cap which may preclude a 'submini' build. I prefer 4.7uF/350v - just make sure you don't pop the cap by letting the SMPS voltage over run.

[MetalUpYerEye]

I'll have to see what my local parts place has for 350v/450v caps... I might just go 450v since i'll probably build this into an 8" combo so there should be plenty of space... I'm also going to add a three-band EQ section based off the P1 from AX84.com so that should be pretty nice... It'll be in place of the 'tone' control in the 'Superfly Special' schematic.

You have been tuning your trim pot to feed the 6111WA with 185 volts right?