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

[frequencycentral]

Oh I just read Ton's post, it amused me - but no offence meant, I apologise. I knew you were oldgravity over there anyway. Conductive flux will FUBAR for sure. BTW, is your diode a UF4004 fast recovery type? Is your MOSFET an IRF740? And what layout are you using?

[Taylor]

Well, it's no problem, I didn't choose a different name there because I was trying to pretend I wasn't me, I just happened to be feeling that my real first name was kind of dumb the day I signed up for FSB. Since I (like you) have made duplicate posts here and there, the connection's obvious. The problem only arises when some guy wants to make me feel bad, so he digs up my old posts to make it clear how much more he knows about electronics than I. I have much older, much stupider posts here...   I also realized that I had used the name oldgravity for things involving my personal life, which I'd prefer to keep separate from here.

Anyway, yes I'm using a UF4004 and an IRF740, and the layout from page 3 of this thread:

http://www.diystompboxes.com/smfforum/index.php?topic=78302.msg651912#msg651912

[frequencycentral]

Yeah, that place can be a sharkpit. I try to steer clear of the controversy and just use the information (and sell a few amps!). I post stuff to put stuff back in.

I've done a quick check of the PCB vs my perf, they seem identical except the pinout of the IRF740 that you identified. Would be worth your while checking the PCB against the schematic though. This is frustrating isn't it? Have you tried running it at say 100 - 150 volts? The more voltage from the SMPS the lower the current, therefore hum or whine is more likely at very high voltage.

[Cliff Schecht]

Yeah, that place can be a sharkpit. I try to steer clear of the controversy and just use the information (and sell a few amps!). I post stuff to put stuff back in.

I've done a quick check of the PCB vs my perf, they seem identical except the pinout of the IRF740 that you identified. Would be worth your while checking the PCB against the schematic though. This is frustrating isn't it? Have you tried running it at say 100 - 150 volts? The more voltage from the SMPS the lower the current, therefore hum or whine is more likely at very high voltage.

Man no joke about these supplies being frustrating.. Both of the SMPS's I'm working work great until I start trying to draw about 80% or more of that max power, then the output voltages droop significantly. I can tell on the boost supply (175V one) that the inductors are saturating, they're the only part getting hot, but on the flyback supply I'm working on everything stays just warm to the touch at full-rated power (diodes get some heat but they're fine) even though the output voltage is sagging. I'm really thinking that adding 10-20% to the max power handling of these supplies will fix my problems. Still, what a frustrating couple of designs!

[punkin]

Not to derail but in my quest to gather parts for this project I found a couple nifty looking tube sockets for sub-mini tubes.


http://pacifictv.ca/socket.htm#submin

This one looks particularly interesting for a horizontal mount. http://members.shaw.ca/Ceceg/b8dierc1.jpg

[calico]

I'm looking for this SMPS for almost a year, I plant to build Headphone Amp using tubes that draw 10mA each.
How much Load (mA) this SMPS can handle ? 100mA ? sure ?

I know anyone have not tried to use as Headphone amp PSU before, how can I "Filter" this SMPS ?
I know you have no problem with Guitar Amp but this Headphone amp is more sensitive ... right ?

which Schematic I should try ? I gotta try.


Cal

[therecordingart]

Two questions on this:

-Has the PCB layout been verified?
-Where do you get those "U" shaped bars for the top of your enclosures?

[frequencycentral]

I sold my Superfly prototype - I was made an offer I couldn't refuse, (I just started building another) and never used it with headphones, but I'd guess it could run them ok without any modification. A guy over at AX84 made a purpose built submini stereo amp: http://www.ax84.com/bbs/index.php?id=405677

Not sure of the maximum capabilities of the SMPS, I'd guess 50ma but have never tested for that. The max load is also linked to the type of inductor you use and the voltage you run it at.

The PCB layout (not my layout) is closely based my perf layout (which is verified), although the IRF740 on the PCB may be incorrectly oriented - worth checking. I don't know if Taylor ever debugged his build? I'm not aware of any other builds, my prototype may be the only one, until my new one is finished.

The handles are from a DIY home store in the UK called B&Q.

[dimi3]

Im in plannig phase for this great amp, I have the tubes, and gethering other parts also for MO amp, also plan to use PCB since its easyer to do, im checking the "99%" correct PCB posted on forum.

Maybe I should wait till another superfly is born

Are any changes planned for second one?

Did you concidered to offer PCB's for your amps or maybee a kit. I think most of the people here enoy DIY stuff, becouse its more fun than buy finished product, at least for me 

[Taylor]

I don't know if Taylor ever debugged his build?

Never did, I think it's botched because of this weird solder I used. I set this aside for a while, but was thinking of trying it again. I think the PCB layout is fine, but just double check the pinout on the IRF740 against the schematic.

[max30]

I hope Rick wount mind posting this, I redraw the superfly schematic without the SMPS, I used IC sockets for tube mounting, that way tubes are not soldered to the board, and could be changed realy easy.

I plan to use already available SMPS supply from here http://www.desmith.net/NMdS/Electronics/NixiePSU.html, since eagle files are already available and just attach it to the amp board, and it should be able to handle more than 100mA current.

Since I'm not really an expert in eagle I'm still struggling with the routing of the amp board.

If someone is willing to help please let me know, I can share the files no problem, I also plan to make a small batch of PCB for out of this (10 boards), this is the smallest batch that PCB makers are willing to do here, so if someone is willing to join with the desing please let me know.

[Taylor]

It's cool of you to do boards for people that want them, but if you just want a single board fabbed as cheaply as possible, check out BatchPCB. You can get one board this size for around $30.

[max30]

true, but the problem is since SMPS is so small and have SMD components on it, I cant make double sided board at home. And the price is the same for 1 PCB or 10 since the PCB shop charges the whole pannel and i can put arround 10 PCB's per pannel, I dont want to sell them to people, it would be "gift" for those who help to make it happen.

[frequencycentral]

I hope Rick wount mind posting this..................

Feel free, it's not really mine to give anyway, as Doug H already gave Firefly to the world. I just made it smaller.

Here's my second one:

[Taylor]

true, but the problem is since SMPS is so small and have SMD components on it, I cant make double sided board at home. And the price is the same for 1 PCB or 10 since the PCB shop charges the whole pannel and i can put arround 10 PCB's per pannel, I dont want to sell them to people, it would be "gift" for those who help to make it happen.

What I was saying about BatchPCB is they will take Gerber files and produce a pro, double-sided, silkscreened, soldermasked board with through plating for $30. It's the best deal I've found for this. If your 10 boards are cheaper than $30, I'd love to know where you get them. 

But  I applaud you wanting to give the boards away, very kind of you.

[max30]

Here is the redrawn schematic of the amp section. If someone is good at Eagle routing please give it a go

I had no luck with with it yet.


I uploaded the Eagle file here, I hope it works.

//http://www.2shared.com/file/12022710/c6522fed/Superfly-EAGLE.html

[frequencycentral]

I was getting some squealing with my second Superfly at high volumes. The cure was to remove that 470pF cap. Squeals went away totally.

[prnet]

Hi freq, There's something strange I cannot understand in the schematic in the first page..

The OT impedance on the schematic is 22500:8ohm referred to the pins 2 and 5 (as I see from the pics of your build too)
But my 125a connection chart uses the pins 2 and 4 to obtain 22500:8.

the pins 2-5 are for 8200:8ohm in the chart of the transformer label.

So.. Am I right?

[frequencycentral]

I noticed that too, but as this is virtually a straight copy of Doug H's Firefly I stuck to the Firefly schematic. I *suspect* the ohmage figure on the Firefly schematic refers to the maximum available from that transformer as opposed to the taps used. Maybe Doug could shed some light on it? The plate resistance of a 12AU7 is 6500 - 7700 ohms, so 8200 is pretty close. The plate resistance of a 6111WA is 4000 - 5000 ohm. So maybe there's a slighly better combination available. I did try different combinations including 2 and 4, with little difference THB. I'm currently building a Superfly with the addition of a tonestack and a master volume.  

[prnet]

I ordered a raytheon 6112 for the pre, and a general electric 6021 for the power section from Audiograde,
because I want to try this nice build. I've already soldered all the components in the night.
I used an unlabeled induttance that I grabbed from other stuff. For the truth I have a 100h induttance too, but is  a toroidal one and it's  a little bigger, and it's a bit difficult to fit in the box.

Yes, I think that I'll mod it with a 1M volume pot too..