OT ZVEX PRAISE.

[Ansil]

k i finaly understand a few things.  i got to see a nano head at a recording session. i am completely blown AWAY!!!.  it is one thing to see the pictures it is another to listen to it in person through a 5150 cabinet and realize this is some serious stuff..   it is another to look at the pics Z generously posts on his site of the guts of this little masterpiece but is is another to see it for yourself.  i truely understand why everyone has so much respect for his builds.  there is too much time and effort in just the packaging alone  let alone the actual circuitry.  Kudos to you my friend this is an invention that should be placed with the telephone and the beer cooler.  

Hats Off

[Marcus Dahl]

Mmmmmmmm, beeeeerrrrrr!!!!!!!!!  :roll:

[idlefaction]

ahhhhh tis 3pm friday soon - beer o'clock!

:twisted:  :roll:  :twisted:  :roll:  :twisted:  :roll:

[Paul Perry (Frostwave)]

ahhhhh tis 3pm friday soon - beer o'clock!

:twisted:  :roll:  :twisted:  :roll:  :twisted:  :roll:

Here in Australia it is "Poets Day"..
Piss Off Early, Tomorrow's Saturday!
(this was actually said to a friend who turned up to get parts at midday on Fri at a factory & only the caretaker was there

Oh, and good wor Zach

[jimmy]

i agree, the nano head is one of the greatest things ive ever seen. definately up there with the telephone.

cheers
Jim

[Ansil]

i agree, the nano head is one of the greatest things ive ever seen. definately up there with the telephone.

cheers
Jim

and the BEER  COOLER  never forget the BEER COOLER..  LOL :twisted:  :twisted:  :twisted:  :twisted:  :twisted:

[MarkB]

Couldn't agree more..
I got to see/touch/play one when they first came out - at a local music store (the local Zvex dealer) and the thing is awesome.  Really a great tone  - regardless of the size, but that just adds to the 'cool factor'.

If anyone wonders why we hold Z in high regard around here - other than the fact that he's a nice guy  - go play a NanoHead and you'll get it.  
"-)

[Kilby]

I am on the lookout for a decent amp (I am currently sharing my room with an Line 6 spider 112).

What sort of volume can the nano amp produce (I think I read it's 1/2 watt), could I get away with one as an 'bedroom' amp ?

I liked the sound demos but there is no Z-Vex dealers where I live (Ireland).

[manulonch]

Does someone can maybe trace the schematic of the Nano-Head ?
Not to copy this one but to see the technical solutions.
( for the power supply... I think I frequency step-up voltage )

[Peter Snowberg]

From the pics on his site, it looks like a very straight forward device. It looks like a boost coverter is used to get B+. It has two dual triodes and the transformer is a reverb transformer which is a single coil. Given that transformer wants two sections of 12AT7, I'm guessing he uses two triodes in parallel to drive the output and two gain stages. I'll bet it's technically similar to a Fender Champ in some respects; even if remotely.

Rather than even copy the architecture, look out there at all the good low power amp schematics. Doug Hammond's FireFly is one of the best examples IMHO thanks to the use of an ancient and almost forgotten output topology that halves the grid drive required while reducing parts count.

If you want to see how DC/DC converters work, visit sites like www.linear.com and www.maxim.com as both of them produce ICs for the task. It takes some work to get a power suppy like this in that small of a space. Please respect his work by not posting anything specific about the internals.

-Peter

[zachary vex]

k i finaly understand a few things.  i got to see a nano head at a recording session. i am completely blown AWAY!!!.  it is one thing to see the pictures it is another to listen to it in person through a 5150 cabinet and realize this is some serious stuff..   it is another to look at the pics Z generously posts on his site of the guts of this little masterpiece but is is another to see it for yourself.  i truely understand why everyone has so much respect for his builds.  there is too much time and effort in just the packaging alone  let alone the actual circuitry.  Kudos to you my friend this is an invention that should be placed with the telephone and the beer cooler.  

Hats Off

thanks so much, ansil, and everyone else.  i appreciate it.  8^)

[manulonch]

# Please respect his work by not posting anything specific about the internals. #

I already say I'm not interested to copy, but to see the tech solutions.

[Ansil]

From the pics on his site, it looks like a very straight forward device. It looks like a boost coverter is used to get B+. It has two dual triodes and the transformer is a reverb transformer which is a single coil. Given that transformer wants two sections of 12AT7, I'm guessing he uses two triodes in parallel to drive the output and two gain stages. I'll bet it's technically similar to a Fender Champ in some respects; even if remotely.

Rather than even copy the architecture, look out there at all the good low power amp schematics. Doug Hammond's FireFly is one of the best examples IMHO thanks to the use of an ancient and almost forgotten output topology that halves the grid drive required while reducing parts count.

If you want to see how DC/DC converters work, visit sites like www.linear.com and www.maxim.com as both of them produce ICs for the task. It takes some work to get a power suppy like this in that small of a space. Please respect his work by not posting anything specific about the internals.

-Peter

if you read on z's site, he says that it is a tripple stage  and the the last stage of the tube is the poweramp section in class A mode.
but i have to agree it would be better to attempt to do somehting this on your own and not try to copy his work.. also  i dn't think anyone else could squeaze all that in there.

[Prive]

Hi, i remember Zach told me in the old forum that the power supply on the nanohead is built around a negistor.

[The Tone God]

IIRC the negistor is a simplified oscillator that he uses to clock the switching supply. I belive he once posted a link to a site that had a bunch of different switching supply circuits saying that he used one of them to get the 12V input up to 230V (?) then stripped the circuit down. It should be in the archives somewhere. Gosh darn I miss those archives. I might have the link bookmarked somewhere but I have to do some hunting.

Andrew

[Peter Snowberg]

Aron has 2/3 of the archives reloaded. They should be back very soon.

I can give you this out of the archives....

Constantin Necrasov
Guest
Posted: 11 Jun 2003 03:08 am    Post subject: Negistor again    
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Since I don't have an osccilloscope and havent yet built a negistor to check myself, can anyone tell me what is the waveshape of the oscillation?

Brett Clark (the other Br
Guest
Posted: 11 Jun 2003 02:43 pm    Post subject: Re: Negistor again    
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It's sawtooth - ramp up, near-instant drop down. The shape of the ramp varies a bit with the cap value and supply voltage.

Tim Escobedo
Guest
Posted: 11 Jun 2003 04:09 pm    Post subject: Re: Negistor again    
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IIRC, it's a rather non linear saw wave. Really needs a buffer to get the best ramp. Unbuffered, it starts to look more like a spikey pulse.

zachary vex
Guest
Posted: 13 Jun 2003 02:31 am    Post subject: Re: Negistor again    
-------------------------------------------------------------------------------
when followed by a high-impedance buffer, it's one of the most pure sawtooths you can make. the supply voltage usually has to be higher than 9 volts, so it's best to use two for an 18V supply. just follow it with a source follower and don't load it down...








zachary vex
Guest
Posted: 27 Jun 2003 08:00 am    Post subject: Re: Interesting stuff in the new Guitar Player    
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mike asked:
"If you're reading this, Zach, I'm curious about how you ever stumbled onto the tubes in question and what sorts of industry mags one has to keep in touch with to stumble onto such things. My guess is that it was one of those "This-will-come-in-handy-one-of-these-days" bits of trivia knowledge that you hang onto."

i don't subscribe to any industry rags. i called one of my suppliers to order some jacks about a year and 8 months ago, and my salesguy there, bruce, told me about these small tubes they had for sale and asked if i wanted a couple samples. i got them, looked at them, and thought they were really cute, but decided i was not going to get sidetracked into something ultimately silly. i was thinking along the lines of tube effects at the time, but i decided to stick with low-current battery circuits. i put the tubes on an eye-level shelf with some other high-voltage stuff i've accumulated over the years... other tubes, a fender reverb transformer, stuff like that. about a year later, after releasing the super-duper and lo-fi loop junky, i was staring at nothing, really, at my bench, and the fender reverb transformer and those tiny tubes caught my eye. i suddenly was curious what tube usually drives a fender reverb transformer, because i remembered seeing a spec sheet on a replacement reverb tranny and the output impedance being 4 ohms, very close to typical speaker impedances. i looked up some fender schematics in my groove tubes book, and i saw that the driver was a 12AT7. i compared the plate resistance with that of my 6021W subminiatures, and sure enough, they were reasonably close. that night i built up an output section, just one triode in the duotriode envelope and tested it by driving an ac-30 cab using my trusty tascam oscillator... and it was LOUD and sounded great. within 36 hours, the basic design was completely done, with all the controls and all values selected, including the 18 component dc-dc 12V/230V power supply that uses negistor technology for regulation that i'd previously developed for another project.

that was the end of the fun part... stuffing it into the box and gearing up for production took 3 months of searching for parts and solving weird problems.





zachary vex
Guest
Posted: 27 Jun 2003 05:43 pm    Post subject: Re: Interesting stuff in the new Guitar Player *LINK* *PIC*    
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i started with a very complex design that i found on the net that someone labeled "not for commercial use." it was chip-based and used pulse-width control for regulation. i adapted it, bit by bit, chopping out parts that i didn't need and removing the chip-based oscillator and replacing it with the negistor oscillator circuit, which changes frequency based on source voltage, and adapted the zener diode feedback circuit for output regulation by varying pulsewidth of a rectangular wave generated by distorting the output of the negistor. yes, it's quite proprietary! 8^) i should have patented it, perhaps, although it's a few percent less efficient than other switching-type circuits (74%), and the only advantage it has is that it's discrete and has a small parts count. in the picture, the power supply is most of the stuff to the left of the gap where the fat red and blue wires connect to the board, and most of the stuff below the two grey switches at the top. now that i count out the parts carefully, i remeber that i added a couple extra layers of filtering and protection parts, so it's higher than the original 18 part design... i think it's now 21 parts not counting the filter caps and filter inductor (seen as the green thing at the very bottom of the circuit board.)

the starting point circuit that i was inspired by is found here:
http://members.aol.com/sbench101/PowerSupplies/lvps.gif

you can navigate his site a bit to find more info about how to wire it up.


==============================================
Straight from ZVex himself.

There are 15 threads with negistor in th archives. Sit tight.

[puretube]

IMMSMW, ZVex mentioned somewhere, the PCB is a 4-layer (or even 6?).
Seen the fact, that tracing down single-sided PCBs has caused problems in the near past, I don`t think Z`s amp will be cloned soon...



//www.puretube.com