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

himister · Post by **himister** » 06 Sep 2009, 11:49

Wonderful build Rick.

I really hope that in the future I could acquire some subs to build this beauty.

Well done.

Cheers

briggs · Post by **briggs** » 08 Sep 2009, 20:25

Have you ever calculated the wattage output of this beaut? It would be interesting to find out!

frequencycentral · Post by **frequencycentral** » 08 Sep 2009, 23:14

Fred it never occurred to me to even measure the wattage. I wouldn't know how to anyway. Loud enough I'd say, I haven't really felt the need to use it at full volume. Generally I have the volume control at about 11 o'clock. Pretty clean and clear just there. Too loud says my GF - that's my seal of approval!

briggs · Post by **briggs** » 09 Sep 2009, 13:15

Soulsonic once described it to me ->

You need a good dummy load (big ass wattage resistor the same resistance as the speaker you usually plug into (4, 8 or 16 ohms I'm presuming), I used a 50W resistor bolted to a metal heat sink for my valve junior), a multimeter and a signal generator.

Hook the amp up to the dummy load instead of the speaker and use the signal generator to produce a sine wave at a determined freq (400Hz ~ 1000Hz, whatever you like!) for the input instead of your guitar. Measure the voltage across the dummy load and then stick it into the ohm's law formula -> you got your output wattage at that specific freq

rasta_maleek · Post by **rasta_maleek** » 09 Sep 2009, 23:22

wonderfull proyect, i´ll go to build it

, thanks a lot for your job frecuency, only one thing, i have twice 6021, can i use it for the proyect?
and what is those valves voltage?

thanks again and bye

frequencycentral · Post by **frequencycentral** » 10 Sep 2009, 17:04

rasta_maleek wrote:wonderfull proyect, i´ll go to build it , thanks a lot for your job frecuency, only one thing, i have twice 6021, can i use it for the proyect?
and what is those valves voltage?

thanks again and bye

6021 should work fine in this circuit, though in the preamp position will give less gain than the 6112 I used.

6021 = gain of 35
6112 = gain of 70

IIR the voltage rating of a standard 6021 is 150v, the voltage rating of a 6021WA is 300v. I personally feel that I'd happily 'overvolt' a standard 6021 if I didn't have a 6021WA available. It may shorten the tubes' life a little, it may not. Basically, pretty much all subminis are mil-spec and were designed to be tough as hell.

rasta_maleek · Post by **rasta_maleek** » 11 Sep 2009, 10:01

then, i can put a standart 6021 in power section, and other 6021 w in preamp section, one of this tubes are 6021w.
or buying a 7327 sub mini for power and 6021w that i have for preamp, isn´t it?

DougH · Post by **DougH** » 11 Sep 2009, 10:59

frequencycentral wrote:Fred it never occurred to me to even measure the wattage. I wouldn't know how to anyway. Loud enough I'd say, I haven't really felt the need to use it at full volume. Generally I have the volume control at about 11 o'clock. Pretty clean and clear just there. Too loud says my GF - that's my seal of approval!

http://www.aikenamps.com/TI_Aiken_Q&A.html

Scroll down a little more than halfway.

briggs · Post by **briggs** » 11 Sep 2009, 11:30

^^ That is a great page Doug. I have that saved in my bookmarks

To simplify; P = (V^2/R) [where P is your output wattage, V is your AC voltage across the dummy load resistor and R is the resistance in ohms of your dummy load] Use this formula while ramming the input with a 400Hz sine wave and the output loaded across a 8 ohm 10/20w resistor that should give you an indication of the output power

frequencycentral · Post by **frequencycentral** » 11 Sep 2009, 16:58

rasta_maleek wrote:then, i can put a standart 6021 in power section, and other 6021 w in preamp section, one of this tubes are 6021w.
or buying a 7327 sub mini for power and 6021w that i have for preamp, isn´t it?

Use the standard 6021 in the preamp and the 6021W in the power section. The anode resistors in the preamp section reduce the voltage down below the standard 6021 maximum voltage.

rasta_maleek · Post by **rasta_maleek** » 12 Sep 2009, 08:36

thank, frecuency, i´m nuilding the vero version. When i finish i will come to revise with you.
Over the anode resistor, to reduce to 165v for the 6021 standard, did you know this resistor value?
which voltage is if i will not change this resistor, in the same point?
thnks

frequencycentral · Post by **frequencycentral** » 12 Sep 2009, 11:21

rasta_maleek wrote:thank, frecuency, i´m nuilding the vero version. When i finish i will come to revise with you.
Over the anode resistor, to reduce to 165v for the 6021 standard, did you know this resistor value?
which voltage is if i will not change this resistor, in the same point?
thnks

Don't worry, the resistors in the schematic already do reduce the voltage to down below what the standard 6021 can handle. You don't have to change the value.

rasta_maleek · Post by **rasta_maleek** » 13 Sep 2009, 19:36

i was trying to do this circuit in vero but it seem to me very dificult, then i do the pcb drawing, tomorrow i will go to do some transfer copies and then i will do the super fly to my own, i´m a freak

rasta_maleek · Post by **rasta_maleek** » 13 Sep 2009, 19:43

can i use this inductor, its 3300uH 1.5A, looks like zvex use in his nanoamp

frequencycentral · Post by **frequencycentral** » 14 Sep 2009, 16:14

rasta_maleek wrote:can i use this inductor, its 3300uH 1.5A, looks like zvex use in his nanoamp

I'm not sure. I don't know what difference it would make. Worth a try though I guess.

charlietheunicorn · Post by **charlietheunicorn** » 14 Sep 2009, 19:44

for a boost power supply it's pretty the same inductor i have used and it works very well

.

oldgravity · Post by **oldgravity** » 15 Sep 2009, 06:41

rasta_maleek wrote:i was trying to do this circuit in vero but it seem to me very dificult, then i do the pcb drawing, tomorrow i will go to do some transfer copies and then i will do the super fly to my own, i´m a freak

Cool, thanks for that. Would you mind posting the .diy file or a render of the traces?

rasta_maleek · Post by **rasta_maleek** » 15 Sep 2009, 16:29

here comes the diy file.

oldgravity · Post by **oldgravity** » 11 Oct 2009, 02:55

Hey Rasta Maleek, the IRF740 is backwards in your layout. I realized this just as I was about to connect the power to my build. No fires yet.

I was going to fix it myself and upload the new file, but for some reason, my DIYLC won't open your file (maybe because I use the Mac version?) so I can't.

rasta_maleek · Post by **rasta_maleek** » 13 Oct 2009, 17:31

no matter with this, post it revised archive, i fix it when i do the initial proves, the power supply works well but only take 165vdc with the trimmer turned at max, i think i may change some resistor next to the trimmer,
frecuency, i have some transformer for two 6v6(fender blackface), did this transformers works well with the two triodes of the 6021w??
thanks.