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

[MetalUpYerEye]

zambo I haven't had any trouble with my power supply yet.. I remember reading somewhere in this thread that people were having problems with the irf740 heating up and heatsinking it and etc... I have run the crap out of mine and it doesn't even get warm to the touch. 

I'm really jonesing to meddle with the bias a bit but I took the amp over to my pops on poker night last weekend and it hasn't made it back.. Must sound ok huh! 

I think my next project might be a full sized Firefly though i'm excited to try something with more volume. 5 watts seems to be about the standard for a first build tube amp with a power transformer, etc. so i'll probably go that route.

[zambo]

ax84 has some great 5 watts on the forum. lots of different ones. Its a great place to start. Firefly is good to , but you already have a low watt amp so yeah.. 5 is great. I have done plenty of gigs with a 5 watt se amp ! as long as your dealing with the voltage issues of a first build though, may as well spend a few extra bucks and build a single ended 10 watt with a6l6/ el34 . same build but louder. it keeps up with heavier drummers etc. worth a look anyway.

[MetalUpYerEye]

zambo i'm a CA state licensed electrician specializing in residential solar power. So I deal with split phase 240 volt AC (125-225 amp) and 350-550 volt DC (6-50+ amp) electrical systems every day. Highly trained in the art of safety, so thats slightly less of a problem for me than cost and volume requirement!

Still, it would be nice to have something louder than my HT5 to jam with friends, etc. Even cranked the HT5 is saying "cmon dude, we could use a little more!"

I'm just really taken with the Blackstar sound. If I can get somewhere near that with more volume (10-15 watts) without murdering my wallet then i'll be all set! 

[zambo]

Ahh welll voltage is not an issue for you! I was ( and am ) slightly scared of it . much respect for the lightning juice! A single ended 6l6 is a loud beast. If its just about money and tone a push pull 6v6 amp is a beautiful thing. About 20 watts of lovin right there. the iron for that is cheaper too depending how you go. I use blues jr replacement iron and its cheap and effective. ends up around 18 watts and i am never too quiet. I dare say the se 6l6 is as loud somehow. they are just more in your face but not as  "metal" sounding. anyway, good luck!

[Brymus]

The HT5 does sound nice but it is mostly a solid state amp with some tubes in it,just listened and then looked at the schematic.Lots of non tube sound shaping going on in it,but it does have a nice Metal sound.The ISF is just a fancy sweep control using a dual ganged pot still kinda of cool and neat approach to an old idea.
If you are good with building pedals you could build the HT5 not sure how cost effective it would be once its boxed up though.
Probably cheaper to buy a used one and tweak it.

[MetalUpYerEye]

The HT5 is a great mix of tube and solid technologies. I'd never considered an HT5 pedal but that would really be pretty cool. The HT5 preamp is pretty extensive for a pedal though.. And I already have an HT5.. 

Would be great to get up to 15 or 18 watts with the HT5 preamp.. Guess I could build a preamp based off the HT5 and hack on a bigger power amp. 

[zambo]

or run the ht5 preamp out into a 20 watt tube power amp. It does have a preamp out right?
Oh yeah btw we totally hijacked this thread..

[mrsmash23]

Hello!

Firstly thanks to Rick for this awesome project! I finally managed to finish this project(with 6021 + 6112 tubes). I made second one using russian variants of these tubes (according to seller's description), 6N16B-V + 6N17B-V, with respecting different pinout of these tubes.
Amp works, but it is ultra clean, no distortion even if Volume pot is at max(or both Volume and Master Volume pots). Rest of parts I used are same as shown on Rick's layout at page 9. Made it with Master Volume and Bias mod, no Tone Stack. Can anybody help me which parts to replace to get that nice crunch distortion as on samples? Thank you in advance!

Links to datasheet of both russian tubes:
1) 6N16B-V
http://www.goldenmiddle.com/files/6N16B.pdf

2) 6N17B-V
http://pdf.datasheetarchive.com/indexerfiles/Scans-026/ScansUX8555.pdf

[frequencycentral]

Hello!

Firstly thanks to Rick for this awesome project! I finally managed to finish this project(with 6021 + 6112 tubes). I made second one using russian variants of these tubes (according to seller's description), 6N16B-V + 6N17B-V, with respecting different pinout of these tubes.
Amp works, but it is ultra clean, no distortion even if Volume pot is at max(or both Volume and Master Volume pots). Rest of parts I used are same as shown on Rick's layout at page 9. Made it with Master Volume and Bias mod, no Tone Stack. Can anybody help me which parts to replace to get that nice crunch distortion as on samples? Thank you in advance!

Links to datasheet of both russian tubes:
1) 6N16B-V
http://www.goldenmiddle.com/files/6N16B.pdf

2) 6N17B-V
http://pdf.datasheetarchive.com/indexerfiles/Scans-026/ScansUX8555.pdf

That sounds really interesting! I stopped building Superfly to sell largely because sourcing significant batches of the tubes at a decent price is a hassle. Recently I've been thinking about doing exactly what you've done, as Russian tube seem more plentiful, and cheap too! I've been thinking of having some fabbed PCBs made up with on board pots to speed up the build time. Interesting that the Russian tubes are a cleaner sound...is it as loud as your 6021/6112 version?

[mrsmash23]

Hello!
Subjectively they both sounds equally loud, but russian one without the crunch. First I made russian one with 2x 6N16B-V, than 6N16B-V + 6N17B-V and 2x6N17B-V. All combination and no crunch :-) Last combo felt louder, but sorry I have no numbers to back it up
I tried Mustachio's (Thanks M. for help you provided me!) suggestion about swapping some caps for different tone, but it has no effect on missing distortion. I guess it would take changing some resistors... Any advice from tube experienced folk would be appreciated! 

Recently I made PCB sharing (99%)same layout with traces changed according to different pinout of russian tubes. I can send it to you in PM after I can safely confirm it is working. 

[frequencycentral]

Recently I made PCB sharing (99%)same layout with traces changed according to different pinout of russian tubes. I can send it to you in PM after I can safely confirm it is working. 

I'd love it please. Actually you should post it here for others to try too.

[Brymus]

Recently I made PCB sharing (99%)same layout with traces changed according to different pinout of russian tubes. I can send it to you in PM after I can safely confirm it is working. 

I'd love it please. Actually you should post it here for others to try too.

+1
I have about 2 dozen russian sub mini tubes.I bought them cheap about 5 years ago to build some of Rick's stuff but never got around to it.
And have since forget what the pins are/lost the hand written english pin outs ,and I can't read the data sheet that was sent with them.

I would love to hear some sound clips of your Russian sub mini amp.

[Perrow]

The Russian tubes I used had only two legs different from 6111/6112/6021, and they were next to each other so I just twisted those legs (insulated one of them) and used the standard layout.

[mrsmash23]

BRYMUS:
can't A/B them simultaneously, got only 1 transformer at the moment  I guess they're both similar only the missing distortion with russian tubes
I made "quick comparison guide" between western and eastern tubes and draw modified pcb, but not tested it at the moment. Please check it for errors by yourself before making it.

img5.rajce.idnes.cz/d0508/5/5681/5681993_a5168db5901a45267b327b0141ad31a4/images/SuperflyRU_guide.jpg

PCB in PDF file:
http://www.sendspace.com/file/adie02

[Brymus]

BRYMUS:
can't A/B them simultaneously, got only 1 transformer at the moment  I guess they're both similar only the missing distortion with russian tubes
I made "quick comparison guide" between western and eastern tubes and draw modified pcb, but not tested it at the moment. Please check it for errors by yourself before making it.

img5.rajce.idnes.cz/d0508/5/5681/5681993_a5168db5901a45267b327b0141ad31a4/images/SuperflyRU_guide.jpg

PCB in PDF file:
http://www.sendspace.com/file/adie02

Wow !! Thank You 
That is a really awesome chart you made.IMHO it deserves it's own thread.

As far as getting more "crunch" from your Russian tubes Have you tried decreasing the plate resistors and increasing the cathode resistors.
Looking at a version of the "Superfly" w/o the cascode input,I would say raise the first cathode's R to something around 2K7 or higher,and lower the next stage's cathode R to 680R or 470R.While lowering both plate resistors to 47K.That should give it some nice crunch if those tubes behave anything like 12ax7 triodes.Which is what it looks like they are modeled after in the schematic.
(It's been a few years since I reviewed the sub mini stuff)

[GiulioGratz]

The russian version of SuperFly could become the BASS GUITAR outdoor jam tube amp!!!! Can anyone try it with bass? I was just looking for something cheap, tubey and CLEAN to use with my acoustic irish folk band, this could be my holy grail!

[mrsmash23]

Hello guys!
I dismantled original superfly to get transformer, but now I can confirm that the modified PCB for russian tubes is working. Using sockets for tubes is amazing time saver!

BRYMUS: Thank you for your input! I tried to follow your advices of changing resistor, but not sure if I identified the resistors correctly:
"raise the first cathode's R to something around 2K7 or higher" -> R2 =  2,7k (from 1,8k)
"lower the next stage's cathode R to 680R or 470R" -> R3= 560R (from 820R)
"While lowering both plate resistors to 47K" -> R12, R13 = 50k (from 100k)
I did those changes, but still the amp got not crunch. I try higher value for R2 and lower one for R3 later...(in case I got confirmation I swapped right resistors )



GiulioGratz: I think you can give it a try. With russian tubes it is not expensive ( it works fine with 2x 6N16B-V ). As I mentioned with original parts your sound will be very clean even at high settings... Maybe also skip the BIAS mode, but use R17 value instead of R3 to be sure its "cleaner sounding than already clean"

Another thing I noticed, happens with both versions of amp, the voltage is slowly dropping after 10 mins of running by 8-10V (from 183V). Then it settles (jumping +/- 0.1V). If I turn it off for and on again (after a few seconds), voltage drop is still there. If I wait few minutes, the voltage is at original setting, 183V, and it is slowly dropping again...

[Scruffie]

I'm no tube expert... but all those mods sounds like they'd do the opposite of what you want and make it cleaner.

Edit: looking at the datasheet, it seems it has much lower gain than the 6112 too, 25 vs 70, you want the 6N17 in the preamp... or i'm just wrong 

[Brymus]

I'm no tube expert... but all those mods sounds like they'd do the opposite of what you want and make it cleaner.

Yeah the Plate resistors need to be higher, I am very sorry I was very tired.

The plate resistors should be INCREASED to something like 120-180K,as high as 220K,the higher the value the more gain the stage should have.
The lower cathode resistor biases the stage warmer,the higher cathode biases the stage colder.By biasing the stage out of its center area you get clipping much easier,especially when the gain is increased.(raising the plate R's)
By biasing the stages cold then hot a clean booster at the input can really make it sing.

One thing I read today to keep in mind, is to make sure you don't exceed the tubes dissipation.
The voltage drop may be from lowering the second stages cathode R as that value lowers you dissipate more.

Again I am sorry about the mis information on the plate resistors.

I would start by raising the input stages plate resistor to 180-220K ,with the original 1k8 cathode resistor set on a 10KL pot (so you can find your sweet spot) bypassed by a .68 - 1 uf cap.
The goal at the input is to get as much gain as possible to overdrive the second stage.
Then you can raise the second stage's plate R to get more gain too,but bias it hotter by lowering the cathode R (a 2-5KL pot should suffice to find best value)bypass the second stage cathode with around a 10uf cap.
Two stages are hard to get more than mild OD with, most 2 stage amps rely on the power stage for saturated distortion.
If you could add a cathode follower at the end of the pre amp feeding a tonestack/or not that would add some compression of the signal.
Not more gain but you would squash the signal/sine so as to cause distortion at the top and bottom of the voltage swing.

I should have asked what type of distortion you were after,
Before giving my input and drafted a rough schematic to check my suggestion(lesson learned)
I will draw up what I am describing and post it so it is clear.

[Scruffie]

I think the second point I made is the most important, the preamp tube is more like an AU7 than AX7, if you can get the 6N17 there, that should get it back to sounding how it should with the standard values.

Lowering the plate resistors will also have increases current draw and perhaps the SMPS isn't liking that regards the voltage drop.