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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.

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

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

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!!

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.

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

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.

Dang now I'll have to find one.

Sure I saw some on Ebay yesterday.

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!

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.

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!

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

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?

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!

Here's the perf layout:

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.

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: