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

[iccaros]

My leg still in plaster, but already able to walk somehow, so I moved home.
And couple of minutes ago I had 260V on my breadboard. Impressive.  Just for a second - I didn't want to push it, but it seems that I am ready for putting the SMPS on vero.
Had a little stupid accident mistaking the big 330uF cap for the big 2,2uF/450v cap. Wondered why it didn't work, but found out the mistake before anything bad could happen.
Can't wait to try the amp then.

l_s

I found I got oscillation at low volumes with the 2.2uf and none with a 4.7uf

[iccaros]

My next Superfly.. Building for a Kid who plays.. These make great gifts..

[iccaros]

I have an issue, I can not figure out. This is a single volume version, I have used this PCB in my other ones, so I know its good layout.  I have replaced everything in the Power Supply but the Inductor and the 4.7 350V capacitor. 
Symptoms..
If I run this at 120 volts all is good, just quite..
Runs at above 120V (I like the head room and volume of  180 volts) I get oscillation if I turn the volume up more than 1/4. I have tried putting a 500K resistor in series  with the volume pot, but does not make a difference.

the only change is one the 6112 second stage where I used a 87K plate.

I am wondering if that plate resistor could be the problem..  or could it be the volume pot wiring?

I used my phone, I start @120v and then move up, I turn down the volume until there is no oscillation. 
I am using the 3" speaker.. as my son moves the camera the sound changes.. that is not the issue

[Madkatb]

I've worked my way through this entire thread, noted all the changes to the original circuit and now I'm ready to start building. Just received my order of 7327 and 5840 tubes and parts for the nixie power supply. I'm not sure if I'm going to build this exact pedal but something along the booster/overdrive/preamp lines.
After checking several power supply circuits I'm still a little confused about what supply voltage is required. Most circuits say 9-12V but some I've seen go as low as 5V. I'd like to be able to use 6V so that it can power the filament of a single tube. Will that still work? Using 9 or12V and resistors to lower the filament supply voltage seems a bit of a waste.
I've found 6 and12VDC, 1A supplies readily available at Thrift stores for less than $5 each.
Now, just gotta make sure I keep the magic smoke in...

[iccaros]

12V, you run the filaments in series..  so the 12v divides mostly evenly over each tube to 6 volts
the 5840 is not used in this design.. Two of 7327's would be used.
the SMPS is designed with 12v 1A in mind. Well not sure 1amp, but its what I figured is min..   
Plus this is a AMP not  a Pedal, while it is possible to turn into a pedal, its not its design.

[lopsided]

Finally came back to this project. The original schematic seems to be gone, can only find the version with the tone control. I want to make the tone control switchable. Can anyone confirm there is a 470K with 470p in parallel in place of the tone control - just like in the Firefly - in the original version?

[frequencycentral]

Finally came back to this project. The original schematic seems to be gone, can only find the version with the tone control. I want to make the tone control switchable. Can anyone confirm there is a 470K with 470p in parallel in place of the tone control - just like in the Firefly - in the original version?

I still see it in the opening post.

Yes you are correct, however I removed the 470p on every 'non-tonestack' Fly I made, was getting some squeal and the removal solved it.

[lopsided]

I still see it in the opening post.

And now I do to... Swear it did not load for me before...
Thanks for the quick answer, finally have all parts home, so I will give it a try.

[lopsided]

One more quick question, if you don't mind:
Going through my stuff, I found that I screwed up a little and got myself a 125A20B reverb transformer instead of the 125A - problem is there is no center lug at the primary wiring.
I did a quick search and found out that some small amplifiers use this as OT and wire the output triodes in parallel: http://www.prowessamplifiers.com/schematics/misc/ThunderTweak_HeavyWatter-Thunder_Tweak_Heavy_Watter.html

Do you think is it worth giving a try to use the output section of this amp in the Superfly? Or is it a no-go for some reasons.
It is my first work with transformer, and as they are on the more expensive side I don't want to just hook them up and see smoke. So I rather ask...

[frequencycentral]

I'm sure that's work out fine - good luck!

[lopsided]

yep, I will give it a try.
found a good explanation of output stages topologies here:http://www.aikenamps.com/SingleEnded.htm

[lopsided]

Excited to report I have just build my first (semi) functional tube amplifier.
It's actually a mixture of Rick's Superfly - uses the Superfly Special schematic with the accompanying nixie supply, Doug H.'s firefly - uses 12ax7 tubes, and the Thunder Tweak Heavy Watter - uses single ended output stage, because I have messed my order of the output transformer.
Why "semi" functional? I get pretty nice sound with maxed gain and mid volume, but when I lower the gain or rise volume I get some annoying whine, probably from the nixie, and sometimes unpleasant distortion kicks in. But in the working setting it sounds pretty good.

I have spent the whole afternoon building it, so I need a little break now, but will be back with a fuller report and possibly questions, if I will not be able to figure it by myself.

[lopsided]

ok, so there is just one little question I would appreciate if Rick or somebody else could answer me:
Do you ground enclosures in the amp builds?
I think I remember reading somewhere that it should not be done, is it true and does it apply to these small projects too?
I originally did not ground it but then by experimentation found out, that if I do, most of my noise problems go away and the amp sounds good on most of the both pots rotation.
So, to ground or not to ground?

[frequencycentral]

Ground.

[Mustachio]

Well I've been planing on making a superfly , for my first sub mini amp project. gonna make a standard one first from the superfly special layout(thanks Rick!). Now that the turkey day contest is over I can start working on this.

Early in the turkey day contest I seen some one making a pcb by hand drawing the traces and I thought I'd like to give it a try. I had some black pcb material on hand and a pcb marker so last night I gave it a shot.

Start process


After etched and tinned



Its not perfect but I'm happy with it I think it should work just fine I usually use the positive photo method to make boards but this was a lot of fun !

I think I have all the parts on hand now So gonna start building it this week!

[Perrow]

Well I've been planing on making a superfly , for my first sub mini amp project. gonna make a standard one first from the superfly special layout(thanks Rick!). Now that the turkey day contest is over I can start working on this.

Early in the turkey day contest I seen some one making a pcb by hand drawing the traces and I thought I'd like to give it a try. I had some black pcb material on hand and a pcb marker so last night I gave it a shot.

You do know there's a 1590A layout for this one

[Mustachio]

Hah yeah I seen your tinny 1590a build of this! Its pretty awesome! And I have a 1590a sitting here I haven't used. But I was planing on an orange squeezer for it as my first 1590a build. Doing a superfly in a 1590a for my first tinny box seems daunting but maybe in the future I have enough tubes to make 10 of these!

Been using your wiki for reference to this its great thanks for that!

[Perrow]

Always nice to hear that someone uses it

Good luck and keep your fingers clear of the high voltage, it stings, trust me, I know.

[Mustachio]

I've had a lot to do lately and have had the board all soldered up. I realized it was flipped the wrong way when putting in components but I didnt think Id have problems untill I went to pop the ne555 into the socket haha all the pins would be wrong.

No biggie I figure I'll mount the IC and the tube sockets on the backside of the pcb and foam insulate the board so it doesn't touch the top of the box. gonna give it a try later tonight maybe if I have time. The other thing was the transistor couldnt be bent the right way since it was flipped but I just grabed a smaller heatsink off my valve caster and it fits fine now.

The only thing I have to look into is the wiring of the output of the transformer. I noticed everyone is using the center lugs top and bottom. I just gotta see how they connect to the output jack.

[Perrow]

Either wire from the OT to either of the connections on the out jack. As it is a transformer they're isolated

For the 555 I believe you could have bent the pins "up" and flipped it on it's back and the pins would have been "correct", I sort of remember reading about others that done so on mirrored layouts. Haven't had to use that trick myself (yet) but it's a neat trick.