Zvex - Nano Head

SirElwood · Post by **SirElwood** » 16 Mar 2009, 01:15

soulsonic wrote: But it's a crap design that outputs a bunch of RF noise.

Yeah. Atleast in europe we have very strict guidelines for RF noise. I've been wondering will "this amp thing" pass if someone would test it.

soulsonic wrote: Why not a new design that gets similar sounds?

Or similar thing with better sounds.

DougH · Post by **DougH** » 16 Mar 2009, 13:27

This has been around a lot longer than the nano head:

http://ax84.com/index.php/oldprojects.h ... id=firefly

Not as tiny but a lot of people like the sound of it. You can get pcb artwork or buy a pcb for a cookbook build of it here:

http://web.mac.com/calhoun/PCB/Firefly_PCB.html

Don't have my Firefly anymore but have been playing with ECC99's for 2W/4W amps:

http://www.aronnelson.com/gallery/main. ... onfly+Amp/

http://www.aronnelson.com/gallery/main. ... amp/chime/

These are class a/b push-pull with a PI and I like them better than 12au7 self-split stuff. They have the right balance of "big sound/low volume" for me although they can be quite loud through a 4x12. With a 1x12 though they are the perfect volume for me.

Ripthorn · Post by **Ripthorn** » 16 Mar 2009, 14:44

I am working on an amp that uses two 6021's and one 6111 for the preamp and PI and then two 5672's for one power amp section and two 5902's for a second power amp section. It will put out about 125 mW/2W, respectively, so hopefully the pentode power tube distortion will help get that big amp sound at bedroom levels. The preamp sounds really great, so it is now just a matter of getting the power amp section breadboarded.

I was interested by the nano and that is what got me into this, but i decided I wanted a full-blown tube amp but at lower voltages (~100V on plates). We'll see how it works.

DougH · Post by **DougH** » 16 Mar 2009, 15:17

IME pentodes won't make much of a difference and in fact I prefer triodes for a lot of this low power stuff. They are smoother sounding and easier to deal with. I think part of the secret of "big sound" is to get enough air moving with the speaker. In general, a speaker is the one component that will have the biggest impact on the sound of an amp anyway. This contradicts the idea of a "low volume" amp somewhat, but in the end I think it's a balance- getting "enough" power to make the speaker sound right and sound "big" without requiring so much that it causes hearing damage.

I have never heard a nano clip that I thought sounded good. But I will reserve judgement on the nano because that could be due to the clips and I have not heard one in person. But IMO it is easy to build something that buzzes and has enough power to drive a speaker. Does it sound "big" or "good" or whatever, though, that's a different story.

To be honest, I think a dummy load, line out, speaker sim, mixer and headphones can sound better than some small amps I've heard. If you are interested in low volume apartment level don't wake the baby stuff, I think that approach can be more effective- even a POD or something (perish the thought

).

I just don't hear "big sound" through a speaker below a certain threshold of minimal volume, but that's just my experience. YMMV...

culturejam · Post by **culturejam** » 16 Mar 2009, 15:45

soulsonic wrote:
culturejam wrote:
JiM wrote:Seriously, there's absolutely no reason for more than 2 layers here, all we need is a solder-side gutshot and components values ...
I would LOVE if this was the next Tracer's Fund purchase.
But it's a crap design that outputs a bunch of RF noise.
Why not a new design that gets similar sounds?

Fine with me. I just want something like it. And if it's better, then all the better.

JiM · Post by **JiM** » 16 Mar 2009, 20:01

There's definitely something to do in the FireFly /Blackheart Killer Ant area.

Personnaly i think i'll prefer "full size" preamp tubes, or go all the way to nuvistor if i can get some.

If properly done (i know, it's not easy), a switching mode power supply is a must for compactness and efficiency.

About speakers, isn't there some smaller ones (in size and in power rating) tuned for guitar ? Or using guitar speaker simulation with garden-variety hifi speaker ?
Maybe it would be simpler to use a dummy load (it's easier with small power) and speaker sim into LM386-headphones or hifi.

By the way it reminds me the tube cricket (which just lacks a (low)power amp stage) : http://www.beavisaudio.com/projects/TubeCricket/

Ripthorn · Post by **Ripthorn** » 17 Mar 2009, 01:24

DougH wrote: To be honest, I think a dummy load, line out, speaker sim, mixer and headphones can sound better than some small amps I've heard. If you are interested in low volume apartment level don't wake the baby stuff, I think that approach can be more effective- even a POD or something (perish the thought ).

I just don't hear "big sound" through a speaker below a certain threshold of minimal volume, but that's just my experience. YMMV...

I have a POD (before I got into this DIY thing) and the amp I am building will have a line out and a cab sim built in, I just thought the pentodes might be nice after hearing a lot of Rick Holt's stuff with the 5672. More than anything, it is an experiment (I'm a physicist, so it is only natural for me to follow through on the "I wonder what happens if..." line of thought). If the triodes work out better for a power amp, then it's a good thing I've got a few spare.

Good point on the speakers and moving air. I used to always stand in front of my speaker cab with the volume cranked, but I am a little more sensible and a lot more married now.

I haven't heard the Nano, but the whole idea of submini amps is fascinating.

DougH · Post by **DougH** » 17 Mar 2009, 01:48

Ripthorn wrote: I have a POD (before I got into this DIY thing) and the amp I am building will have a line out and a cab sim built in, I just thought the pentodes might be nice after hearing a lot of Rick Holt's stuff with the 5672. More than anything, it is an experiment (I'm a physicist, so it is only natural for me to follow through on the "I wonder what happens if..." line of thought). If the triodes work out better for a power amp, then it's a good thing I've got a few spare.

Good point on the speakers and moving air. I used to always stand in front of my speaker cab with the volume cranked, but I am a little more sensible and a lot more married now.

I haven't heard the Nano, but the whole idea of submini amps is fascinating.

Well good luck and I hope your experiment is successful!

That's exactly how I come up with a lot of ideas- trying things and asking "what if?"

Have you ever tried re-amping? I forgot about that. I used a dummy load on an amp, and ran a line level signal from it to another amp and that sounded very good. It might be a good way of getting some decent sounding attenuation as well.

Ripthorn · Post by **Ripthorn** » 17 Mar 2009, 04:10

I've heard of reamping, though never done it, though that was mostly because I only really thought of it before I had anything worth reamping through.

But I think the real fun of DIY is that we have the power to follow through on the "what happens if" moments.

soulsonic · Post by **soulsonic** » 17 Mar 2009, 07:54

Have you seen the Firefly-style that Igor Shaev did with 6SN7? It looks sweet, and the big plates of the 6SN7 should be able to carry some nice current. I've got to try it sometime because I have a whole box of mostly good blackplate 6SN7s I pulled out of a defunct organ.

DougH · Post by **DougH** » 17 Mar 2009, 12:32

One thing I meant to mention in my earlier post but completely forgot-

Check ax84.com. They have restructured their projects such that the preamps and poweramps are interchangeable. One of the power amps is a 2W push-pull utilizing the 6sn7 (they like that tube a lot over there). There are a lot of people building 2 watt Octobers (plexi style) and 4-4-0's (a trainwreck kind of deal) and they really love them.

DougH · Post by **DougH** » 17 Mar 2009, 12:44

Ripthorn wrote:I've heard of reamping, though never done it, though that was mostly because I only really thought of it before I had anything worth reamping through.

My main interest in it was to be able to implement an fx loop with my little 2w power-amp distorters. I added a line-out to my attenuator and used the atten. as a load box. It worked really well for that. I tried a wet/dry setup first (attenuated speaker on one side, line-out->fx->another amp on the other) and a wet/wet with just the line-out split to a stereo fx buss to 2 amps. It sounded great but it was hardware-intensive.

There's a popular product out called the "ultimate attenuator", and from what I've read I believe it's a reamp-in-a-box. I think it's a resistive load, line-level divider, and an amp to provide a low impedance drive to the speaker. (Probably the reason it sounds good. I suspect it's the high-Z drive of the speaker that makes passive attenuators sound bad below a certain threshold.) I think it's a good idea, if for nothing else because it takes the sprawling hardware, cable, etc and packs into a compact box for a mono reamp setup. You could probably build this kind of thing pretty easily and use a chip amp for the amplifier part. 100W chip amp kits are pretty inexpensive. You could even use this as a slave for a low power amp if you needed more power. You could add an fx loop, etc. All kinds of things you could do with this sort of setup.

Ripthorn wrote:But I think the real fun of DIY is that we have the power to follow through on the "what happens if" moments.

I agree!

deeleyer · Post by **deeleyer** » 29 Mar 2009, 01:15

bajaman wrote:As a side note - The Blackstar Dual HT pedal uses a very elegant switching power supply system - I have reversed it and will put it up in a new DIY ready to build project thread very soon for all those folks that would like to get 300v DC from a 15v DC supply rail. But be careful - 300v DC can give you more than a little "tingle"
stay tuned
bajaman

Very interesting

I will wait that thread.

briggs · Post by **briggs** » 07 Apr 2009, 15:11

Here is the Zvex NANO HEAD schematic. Note that this is not the original power supply, this is a different power supply that was opted for in place of the switching type included in the original. I have produced this schematic by reversing a working layout build that was used to build a 1:1 clone, minus power supply.

I MUST SAY THAT I DID NOT DO THE ORIGINAL REVERSE, I JUST DREW THE SCHEMATIC UP FROM A LAYOUT PROVIDED BY ANOTHER FSB MEMBER.

culturejam · Post by **culturejam** » 07 Apr 2009, 16:03

That cat's out of the bag, now.

Nice work, Briggs.

briggs · Post by **briggs** » 07 Apr 2009, 16:20

Many thanks to all involved!

frequencycentral · Post by **frequencycentral** » 07 Apr 2009, 16:39

The Fender part number for the transformer is either 125A20B or 022921 (the second can be clearly seen on the Nano top view).

The Hammond equivalent is the 1750A

briggs · Post by **briggs** » 08 Apr 2009, 11:08

I just updated the power supply section of the build, I also moved the position of C8 from behind the bright switch to in front of it, just to keep consistency with the original.

Here are some picture of the clone. Again, not my work.

AL · Post by AL » 08 Apr 2009, 19:29

Nice !! Thank you

AL

flood · Post by **flood** » 10 Apr 2009, 05:50

The monkey's out of the bottle now! That Pandora, he doesn't go back in the box!

Thanks for the great effort!