Zvex - Nano Head

Tube or solid-state, this section goes to eleven!
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Goop_buster
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Post by Goop_buster »

Papa_lazerous wrote:I really need to get into SPICE :!:

I had a look at it a while ago and couldnt get into it, I dont know what the best version to try is.... I should definately give ti a try though.

I was the same with Eagle I didnt like th elook of it and went away and now I am into it and love it

Any spice advice apreciated certainly makes things safer and cheaper to try
This is just from the top of my head so do not take it as the truth :lol: . Think a bit for yourself to be sure :D .
The current draw from the first three triode stages should be low..probably below 1.5mA each. The power stage triode half has a max anode dissipation of 1.1W or something. At 200V you should therefore get away with 5.5mA. (gives total 10mA) . Perhapsthat was the reason I settled on 15k when testing the supply.
In reality my memory say that current consumtion with signal present was much higher than that in this amp despite it is class A from in to out.
The power stage cathode bias resistor is probably not telling the hole truth about how much anode current there is because my memory tells me that there was some serious grid current flowing when hard pushed.

I am not on the right computer now but at least found this model with google

*Vacuum Tube submini 6021
.SUBCKT X6021 A G K

* ANODE MODEL

BLIM LI 0 V=(URAMP((V(A)-V(K))))* 0.0037
BGG GG 0 V=((V(G)-V(K))*0.61)--0.14
BRP1 RP1 0 V=URAMP(-V(GG)* 0.09869 )
BRP2 RP2 0 V=V(RP1)-URAMP(V(RP1)-0.999)
BRPF RP 0 V=(1-V(RP2)^ 1 )+URAMP(V(GG))* 0.1
BGR GR 0 V=URAMP(V(GG))-URAMP(-(V(GG)*(1+V(GG)* 0.012937 )))
BEM EM 0 V=URAMP(V(A)-V(K)+V(GR)* 50.093 )
BEP EP 0 V=(V(EM)^ 1.53 )*V(RP)* 0.00001063
BEL1 EL1 0 V=URAMP(V(EP))
BEL EL 0 V=V(EL1)-URAMP(V(EL1)-V(LI))
BLD LD 0 V=URAMP(V(EP)-V(LI))
BAK A K I=V(EL)

* GRID MODEL

BGF GF 0 V=(URAMP(V(G)-V(K)--0.5 )^1.4)* 0.00012
BG G K I=V(GF)+V(LD)

* CAPS

CAK A K 0.00000000000028
CGK G K 0.0000000000007
CGA G A 0.0000000000015

.ENDS X6021

Should work in circuitmaker for instance (or any 3f4 spice). May not be the best spice software there is out there but should be available for free in a limited version and very easy to use without to much learning threshold .
Just open the triode.sub file with triode models and paste the text and it should show up when opening the software.

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Post by Papa_lazerous »

thanks for that, I will download circuit maker in the morning when I get home from work. I havent got admin rights here so cant install software :(

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Post by Goop_buster »

Papa_lazerous wrote:thanks for that, I will download circuit maker in the morning when I get home from work. I havent got admin rights here so cant install software :(
If I remember right there is no working output transfomer models in circuit maker ( at least not the free version) so you can mainly play with the preamp stages.
Perhaps there is some other free software that have this though. I am not exactly up to date of what is out there :lol:

Btw...To be able to have also simple "bode plots" (frequency responses etc) in CM you have to alter parameters in analysis setup. For instance click AC to increase up to 100kHz or more and increase number of test points and change sweep to decade etc...well you will probably find out quickly :)

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Papa_lazerous
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Post by Papa_lazerous »

somethign tells me its not going to be easy to play with.... steep learning curve alert :wink:

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Post by Goop_buster »

Papa_lazerous wrote:somethign tells me its not going to be easy to play with.... steep learning curve alert :wink:
:lol:
8)

Well at least it is very handy to use to sometimes. You can often rule out the bad ideas before you solder them.

Do not trust it to much though. As soon as you get into non linear behaviour and clipping of tubes the models will be less accurate
The ears are always the most important tool in the end :)

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Post by radred »

If you want to have a bash at modeling tube circuits I can heartily recommend visiting "beigebag-DOT-com" and download B2 Spice. You get a 45-day free period.

Easiest to use simulator I've ever seen (seems aimed at audio guys) and the tube portion were written by John Broskie of "tubecad-DOT-com".

Look at the "resources" link and see a slew of how-to's for various audio dilemmas - many including tubes....

I'm radred and I like zach vex.

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Post by culturejam »

I'm resurrecting this old thread.

Anybody come up with a working schematic yet?

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Post by bestegw »

Hi everybody,

Just like lots of people I'm also interested in building one of those way too cuddly Nano Head amps. Not just to please the wife :lol: :lol:, but also because I'd simply love to try a project that involves tubes.

I came across this guy: http://jjs.at/electronic/class_a_subminiature.html

Seems like he got this puppy working and decided to add a Class AB to the line as well. Now, what do the more techy types of this website think of this design?

BESTEGW

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Post by culturejam »

I'm certainly no expert, but that looks like a nice little amp. And the with schem and layout graphic at the bottom, it shouldn't be too hard (for *somebody*) to create a full, reproducible project.

The Class A/B unit looks nice as well (sound clips):

http://jjs.at/electronic/class_ab_subminiature.html

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Post by Tube2stomp »

Don't expect any of those small amps (including Zak's Nano) to sound anything like a big amp distortion @bedroom level.
It's not a metter of power, it's the design.
These baby amps are usualy single ended (SE) or parallel SE, using triods as power tubes and by design Class A.
The big amps are ALWAYS push pull, 2 to 4 PENTODE power tubes, 99% of them are Class AB, employing NFB (negative feedback), active tone control @power amp (presence), PI (phase inverter) tube that distort like crazy etc.

You see, not even apples vs oranges :secret:
Even when in rare cases you will find a baby amp with PP power stage, it will be a "self split" twist, meaning no PI tube, and still triodes, no NFB etc.
Build/Buy one and enjoy iy for what it is, but don't Build/Buy one and expect EVH marshall sounds a 2AM :mrgreen:

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Post by eddieod »

Hi all,

I don't really totaly agree on behalf of the sound of the baby-amps in getting great power tube-distorted sounds with these kind of amps. I developed one myself and yes it operates with triodes in push pull as opposed to penthodes and yes, without using a pi but I guess you'd have to judge this one by just using your ears...

http://www.edscustomshop.com/sounds/Pic ... downII.mp3

have fun!

Ed's Custom Shop
Edwin Thoen
Maarssen
The Netherlands
http://www.edscustomshop.com

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Post by earthtonesaudio »

According to Zach, in a long-ago post I couldn't hope to find again, the coolest thing about the Nano is the power supply. It's supposedly a super-compact switching power supply involving very few components. I think he said he used a negistor circuit as the oscillator. Crude but very compact.

Also I think the pc board is a 6-layer affair. Props to anyone who takes the time to trace that thing. Probably full of buried/blind vias. :roll:
rocklander wrote:hairsplitting and semantics aren't exactly the same thing though.. we may need two contests for that.

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Post by nelson »

earthtonesaudio wrote:According to Zach, in a long-ago post I couldn't hope to find again, the coolest thing about the Nano is the power supply. It's supposedly a super-compact switching power supply involving very few components. I think he said he used a negistor circuit as the oscillator. Crude but very compact.

Also I think the pc board is a 6-layer affair. Props to anyone who takes the time to trace that thing. Probably full of buried/blind vias. :roll:

So, negistor, mosfet, Inductor, some HF diodes and another transistor to switch the oscillator off when voltage gets to a threshold, ie regulation.


Could probably do it with 11-12 components.

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Post by soulsonic »

"Crude" + "Switching Power Supply" = "Soon-To-Be-Burned-Up Switching Power Supply"

I have trouble believing his story about it using a negistor. I wouldn't be surprised if the power supply is something slick Cusack did for him that's actually a professional design and not the quirky mad scientist thing he's trying to pass it off as. That whole "Quirky Mad Scientist" thing is just his gimmick anyway.
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Post by IggY »

More information at the mother of DIY forum:
https://www.diystompboxes.com/smfforum/ ... #msg364280

and new from Tone God found by beavis:
https://www.diystompboxes.com/smfforum/ ... ic=69484.0

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Post by Silent Fly »

IggY wrote:More information at the mother of DIY forum:
https://www.diystompboxes.com/smfforum/ ... #msg364280

and new from Tone God found by beavis:
https://www.diystompboxes.com/smfforum/ ... ic=69484.0
I stopped reading when Zvex compared himself to Edison.

The arrogance of that man really have no boundaries. It makes me physically sick.
"Remember - all I am offering is the truth, nothing more". Morpheus

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Post by soulsonic »

Seeing that up-close photo shows the 2N2222 clearly; so I guess it is a negister. But why? When I was playing around with one, I found the frequency to be very unstable; why would anyone want to deal with the headache of using that for something so critical? Whatever. His reasoning seems to be logical, but I don't think the end result is a solid design. I guess that can be said of the majority of his products. Like the majority of boutique builders, he doesn't seem to have an understanding of designing for reliability; that's something that constantly distresses me when I see how many of these products are designed/built.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

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Post by earthtonesaudio »

+1 on negistors being unstable. You can make a more efficient and stable oscillator with fewer parts. Seems like the negistor was chosen for bragging rights more than anything else. Maybe no one's ever used it in a commercial product before because it doesn't work very well. Hm...
rocklander wrote:hairsplitting and semantics aren't exactly the same thing though.. we may need two contests for that.

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Post by earthtonesaudio »

http://www.thegearpage.net/board/showth ... p?t=451737

Apparently, it's cheaper and easier to just tell people to only plug into a guitar cabinet than it is to remove the switching spikes from the output signal... Or not have switching spikes on the output in the first place.

Lesson: only plug the Nano into Zvex-approved speaker cabinets.
rocklander wrote:hairsplitting and semantics aren't exactly the same thing though.. we may need two contests for that.

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Post by analogguru »

zachary vex wrote:The switching power supply that's external could be a car battery or whatever you want (even 8 D-Cell batteries!) that supplies 12VDC at 1.5A. The internal high-voltage power supply is what I was talking about.

The Nano is designed to drive a 16 ohm speaker cabinet. It's not designed for DI use. It needs a proper load for safe operation, and the ultrasonic output from the unit's power supply could easily damage a solid-state amp which likely would be able to reproduce it and send it to the tweeters.

You can't hear the ultrasonic frequency using a guitar speaker cabinet. It's far above the response of a guitar cab. You wouldn't be able to hear it through a solid-state amp either, but it would certainly be hammering on your tweeters!

Part of the magic of any tube amp is the amazing interaction between the speaker's reactance reflecting through the transformer to the tube's plate and cathode. It's really where the magic is in the sound... if you take a tube amp and drive a non-reactive resisitive load like an attenuator typically uses, your tone will fall much more flat and lifeless. You can hear this happening when you attach an attenuator to a speaker cab and turn it down more than 12dB... the speaker sounds sterile and lifeless. The Nano is very low wattage (1/2 watt peak, much less RMS), so you can achieve the lively tone of the speaker's reactive relationship with the tubes and output transformer at a very moderate volume. THAT's what I designed it for!
Under this circumstances I wonder how this kitchen-table-designer could get a FCC-approval or CE-certification for his junk-products.

analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

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