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

frequencycentral · Post by **frequencycentral** » 15 Aug 2009, 18:04

I've been looking for another submini amp build, I've breadboarded a few of my own ideas, but nothing satisfied. Today I breadboarded a submini version of Doug H's Firefly using a 6112 and a 7327. I really like it. Very crunchy at maximum volume, and pretty clean with the volume rolled back. The 7327 tube I used is a rare beast indeed, it's a mil-spec replacement for 6111/6021 and capable of handling up to 300 volts on the plates. A 6021WA could be used as a suitable replacement, the WA suffix having higher volatge rating than the standard 6021. At a push I guess a standard 6111/6021 could be used in place of th 7327, though it would be operating outside of it's spec. The subminis are tough little @#$%ers though! If they can be shot out of missiles at 80,000 feet they can handle a few more volts!

I'm using the nixie SMPS to power the amp, which has been posted elsewhere a few times and is based on this design: http://www.ledsales.com.au/kits/nixie_supply.pdf I'm running it with a better inductor than the one listed in the diagram, kindly handmade for me by a friend. My B+ is currently 185 volts.

I'll be building this up into a tiny enclosure over the next week or two, at the moment it's nestling happily on my breadboard! Many, many thanks to Doug H for allowing me to re-draw and post his great design.

frequencycentral · Post by **frequencycentral** » 19 Aug 2009, 18:04

Here's some soundclips featuring my now almost legendary lousy but highly sought after guitar style:

Signal path:

Squier Telecaster Custom (bridge humbucker) >>> Superfly >>> Shure SM58 >>> >>> Event Gina 24 Soundcard >>> Wavelab

Volume at 12 o'clock:

http://dl.getdropbox.com/u/967492/Super ... volume.mp3

Volume at maximum:

http://dl.getdropbox.com/u/967492/Super ... volume.mp3

Volume at maximum, with a Big Muff driving the amp (and some genuine submini low voltage feedback):

http://dl.getdropbox.com/u/967492/Super ... 20Muff.mp3

lochy · Post by **lochy** » 19 Aug 2009, 22:33

now thats nice !!!!
I would love to have one of those.

lochy · Post by **lochy** » 21 Aug 2009, 09:46

hi there I've been listening to both the Submin and the FFsub now how does you SM compare when the gains at 12.
I do notice that at higher gain there is more bite. could the SM be modded to give this bite?
As I do think that the FF sounds more like a jcm800.

I'm gona build a TMB SM version. I want the mini marshall look and the 800 sound.

by the way I love'm both. Great work!!

frequencycentral · Post by **frequencycentral** » 21 Aug 2009, 11:46

I'm a little confused - too many acronyms! Which amps are we comparing? Murder One, Sub Zero, Superfly?

Assuming we're comparing Sub Zero and Superfly, there are a couple of differences. Superfly has the biggest bang for the buck for two reasons. First, I used a 6112 pre amp, the 6112 being hi mu versus the 6111 medium mu of Sub Zero. Secondly, Superfly's output section is self-split, therefore there is no cathodyne phase inverter stage; Sub Zero has a cathodyne phase inverter stage at the expense of only one preamp triode.

So yeah, Superfly has more bite, more gain and more volume.

lochy · Post by **lochy** » 21 Aug 2009, 21:15

yes the SF has more bite.
could the MO be made to have more bite? or even a switch for both more and less?

frequencycentral · Post by **frequencycentral** » 21 Aug 2009, 23:37

I think the 6111 in the MO could be replaced with a 6112 which would certainly give it more bite. 6111 = gain of 20, 6112 = gain of 70.

lochy · Post by **lochy** » 22 Aug 2009, 00:12

Dang now I'll have to find one.

frequencycentral · Post by **frequencycentral** » 22 Aug 2009, 00:15

Sure I saw some on Ebay yesterday.

frequencycentral · Post by **frequencycentral** » 22 Aug 2009, 15:50

briggs · Post by **briggs** » 22 Aug 2009, 16:01

Layout layout layout layout!

Another question - which mini-amp is your favourite? Murder One, Sub Zero or SuperFly? I tempted to say the Superfly sounds best to me - loudest and crunchiest!

frequencycentral · Post by **frequencycentral** » 22 Aug 2009, 16:32

Oh sure I'll post the layout later. I've tweaked it a little as I've built it, so I need to update the DIYLC file. I'll do a PCB layout too if that helps people.

I prefer Superfly, for the reasons you stated - loudest and crunchiest. I never did build a Sub Zero, though I breadboarded it again recently to compare it to Superfly. Superfly can do just about the same clean as Sub Zero, but Sub Zero can't do loud 'n' dirty. Murder One I still like a lot, such and easy build, and the power supply is way easier, less hassle and safer than a SMPS. I still have to try a charge pump up to 180 volts - yeah it would be a lot of caps/diodes, but then again an SMPS needs quite a bit of space for the heatsink and that HUGE 400v cap.

Curiously, one guy on 'another forum' had this to say about the Superfly soundclips: "i wont lie, but the sound clips quality are awful .
you must find an other way to record yourself"

I cried myself to sleep that night.

briggs · Post by **briggs** » 22 Aug 2009, 16:42

I'll build one up when you post the layout. I'll stick an Omega (runoffgroove) booster in there as a switchable front-end so that can substitute for the cascade mode in the full size firefly - I imagine it'll sound killer!

Only problem is finding the god damn tubes!

frequencycentral · Post by **frequencycentral** » 22 Aug 2009, 17:51

These guys in the UK sell what you need, just do a search of their site. Minimum order £50 though. If you need someone to chip in to make your order up to £50 give me a shout: https://secure25.securewebsession.com/b ... ed43ba0219

GJonesy · Post by **GJonesy** » 22 Aug 2009, 23:50

frequencycentral wrote:These guys in the UK sell what you need, just do a search of their site. Minimum order £50 though. If you need someone to chip in to make your order up to £50 give me a shout: https://secure25.securewebsession.com/b ... ed43ba0219

Try langrex.co.uk. you'll need to phone for a quote but Ive used them and theyre pretty reasonable. Loads of stock even of the 7327 tubes. Loving what youre doing with the subminis, I made the Murder1 but didnt do anything after that. Currently trying a JCM800 pre into 18watt backend. I wonder what this would sound like as a submini version? Anybody willing to give it a go?

frequencycentral · Post by **frequencycentral** » 23 Aug 2009, 13:13

GJonesy wrote:Loving what youre doing with the subminis, I made the Murder1 but didnt do anything after that.

Cool that you've made a MO, I knew you were looking into it. Have you got photos for us? Soundclips? How are you finding it?

That tube supplier you linked to looks cool - and nice that you can see how many of each tube they have in stock - 100's in some cases!

frequencycentral · Post by **frequencycentral** » 26 Aug 2009, 19:18

frequencycentral · Post by **frequencycentral** » 27 Aug 2009, 19:04

Here's the perf layout:

Draal · Post by **Draal** » 31 Aug 2009, 22:54

Freq,

I thought your Murder One rocked; but DAY-UM! That Superfly IS superfly! After I get done modding my Valve JR. I'm gonna do this build. Great work as usual dude.

frequencycentral · Post by **frequencycentral** » 06 Sep 2009, 11:10

Someone asked by PM for some idea of how big it is, so here's a photo for scale, together with some internationally recognised household items: