Zvex - Nano Head

Tube or solid-state, this section goes to eleven!
User avatar
qnup
Information
Posts: 2
Joined: 23 Jan 2013, 01:44
Has thanked: 1 time

Post by qnup »

Hey Guys,

i have some Question to this Circuit Image

I found it on this Website http://revolutiondeux.blogspot.de/2009/ ... matic.html :

I dont know where the Input is, can you say it to me?
And is the Hammond 269EX the Power Supply or what is it? And how to connect ?

Also i have to know where i have to connect R17 / R18 / R19 / R20.
What means "To 602/Wheaters C6.3VAC" ?

I hope you can help me

User avatar
~arph
Cap Cooler
Information
Posts: 607
Joined: 20 Sep 2007, 10:35
Has thanked: 60 times
Been thanked: 163 times

Post by ~arph »

Yes, the input is in the green circle.

Hammond 269EX is the power supply transformer. It connects to mains voltage on the left (I think it needs a fuse too)
The ""To 602/Wheaters C6.3VAC" ?" means that this output of the transformer is used as the supply voltage for the heaters of the tubes. The output is taken at the wo little white circles between the resistors. (this is an AC connection). So that is where those resistors connect.

EDIT: Oh and you probably know this, but WATCH OUT WITH MAINS VOLTAGE! :shock: :D
In the quiet words of the virgin Mary: "Come again?"

User avatar
qnup
Information
Posts: 2
Joined: 23 Jan 2013, 01:44
Has thanked: 1 time

Post by qnup »

The ""To 602/Wheaters C6.3VAC" ?" means that this output of the transformer is used as the supply voltage for the heaters of the tubes. The output is taken at the wo little white circles between the resistors. (this is an AC connection). So that is where those resistors connect.
Okay first thanks for the Help, and the next Question :D

When i take the Output at the two little White Circles between the Resistors where i have to connect them at the tubes?
I have there Connectors from 1 to 9 , and 3,6 and 9 are free.

User avatar
frequencycentral
Cap Cooler
Information
Posts: 696
Joined: 30 Mar 2009, 09:37
Location: United Kingdom
Has thanked: 28 times
Been thanked: 61 times

Post by frequencycentral »

6021W heaters.

User avatar
robotekmania
Information
Posts: 2
Joined: 25 Jul 2013, 16:09
Been thanked: 2 times

Post by robotekmania »

Image

1 - Transformador 24V 1A
1 - Transformador 6V 300mA
1 - Caja aluminio (tipo Hammond 1590N1)
2 - Válvulas 12ax7
2 - Bases para válvulas 9 pines (para chasis)
1 - interruptor
1 - Led

3 - Condensador 47nF 50V
1 - Condensador 1uF 50V
1 - Condensador 10nF 50V
5 - Condensador 10uF 50V
1 - Condensador 100uF 160V
1 - Condensador 47uF 160V

1 - Potenciometro B50K
2 - Potenciometro A100K

2 - Resistencia 1K
1 - Resistencia 4,7K
1 - Resistencia 100K
1 - Resistencia 220K
2 - Resistencia 470K
1 - Resistencia 1M

5 - Diodos 1N4007

Image
Image
Image
Image
Image
Image
Image
Image






User avatar
ppluis0
Diode Debunker
Information
Posts: 915
Joined: 14 Jul 2010, 18:33
Location: Argentina
Has thanked: 127 times
Been thanked: 299 times

Post by ppluis0 »

Good job !!!

Try to replace the second valve with an 12AU7 (or ECC82) tube due the 12AX7 even paralleled both sections isn't capable to drive an audio output transformer adequately.

Cheers,
Jose

------------------------------

Buen trabajo !!

Tratà de cambiar la segunda válvula por una 12AU7 (o ECC82) ya que las 12AX7 aun con las dos secciones en paralelo no es capaz de manejar un transformador de salida como corresponde.
Saludos,
Jose

User avatar
frequencycentral
Cap Cooler
Information
Posts: 696
Joined: 30 Mar 2009, 09:37
Location: United Kingdom
Has thanked: 28 times
Been thanked: 61 times

Post by frequencycentral »

@ robotekmania: L.O.V.E. it!! :applause:

User avatar
richiewichie
Information
Posts: 1
Joined: 28 Nov 2010, 19:43

Post by richiewichie »

Hi Guys,

For those who want to build a Nano head in Europe...would be Hammond 369EX PT the better choice as equivalent for 269EX??

Thanks!

User avatar
delaystomper
Information
Posts: 16
Joined: 21 Sep 2009, 22:30

Post by delaystomper »

Hi so did anyone ever build an imp clone or something like it ?
Im looking to bulld a bookshelf speaker amp just like the imp .
I know for sure i have most the parts needed just need to know how is put togeather
In the drawing.
Anyone help ??
Thanks

User avatar
Thomas_H
Information
Posts: 46
Joined: 05 Mar 2013, 12:37
Has thanked: 3 times
Been thanked: 18 times

Post by Thomas_H »

Hi,

I saw that project some time ago, don't think there is a layout or schematic available, but in the videos and pictures it's possible to identify that there are two 6021wa in PP. The pictures are from the Zvex photobucket.
Image
The preamp and PI are the IC that on the bottom of the amp.

I think the blue transformers are from 110V to 12V, so you will have the first one for the heaters in series, and the second one to have the B+. It could be that the ratio of the second one is different to achieve a lower or higher voltages.

Have you seen this:
Image
Image
Image

all tube, but everything is in japanese. It's probably Parallel SE, I recognize that transformers from my builds.
It also uses a Max1771 SMPS to boost the 12v to 200V.
http://blogs.yahoo.co.jp/matsu_kat/56212415.html
http://blogs.yahoo.co.jp/matsu_kat/57994244.html

I also found this one:
http://www.roehrentechnik.de/html/kolibri.html

The imp has the advantage of using transformers, so you won't have problems with the SMPS, but I would add a pair of tubes to make it all tube.
If you don't mind building a PSE version 3 tubes would be enough to amplify each channel.

cheers,
Thomas

User avatar
delaystomper
Information
Posts: 16
Joined: 21 Sep 2009, 22:30

Post by delaystomper »

Wow that japanese website tube amp looks killer i wonder if there is a schematic ? It looks like he has a
Factory printed pcb i wonder if it is from a tube amp kit it also seems like a low count parts. A project like thats Is what im looking for because i do feel i have most of the parts for the imp amp including the transformes from a previous bass preamp that i was building. In know there some other parts on the other pcb of the imp amp
I wonder if anyone can post a schematic ? What videos did you look at i saw one but it only shows so fast and little piece
Of the schematic ?

User avatar
Thomas_H
Information
Posts: 46
Joined: 05 Mar 2013, 12:37
Has thanked: 3 times
Been thanked: 18 times

Post by Thomas_H »

About the japanese one,
there are not that much components, and the values are written on the board. I found the original guy or girl that designed it.
He, or she, was selling the board in 2009/2010.
http://lucythesoloist.blog33.fc2.com/bl ... 00902.html
Image
Image
Image
I guess we could identify the circuit, or even design one to our needs (PP or SE, PSE), the layout picture above shows the top and botton layers overlapping, but it's possible to see that this amp is PSE, with 4 triodes per channel, without a preamp.
Just 4 triodes in PSE for each transformer. That explains the low component count.
That could be associated with the fact that the designer assumes that the correct impedance for the tubes is 80K, and putting 4 in parallel reduces that to 20k I guess.

There is a guitar amp, from a french forum : http://techniguitare.com/forum/lampes-h ... 12161.html
Image
Open the image in another page to see the whole schematic.
that has 1 gain stage, cathodyne and PP output stage. With 4 tubes it would be possible to build a stereo one.
I'm not sure if you really need the gain stage for audio.

About the Imp AMp, I found some internal pictures some time ago and saved, but can't find the source.
It uses two OP275 as gain stages and PI. Similar to the guitar amp above.
https://www.dropbox.com/s/s0nwit1v1v6xj ... 1.jpg?dl=0

User avatar
Thomas_H
Information
Posts: 46
Joined: 05 Mar 2013, 12:37
Has thanked: 3 times
Been thanked: 18 times

Post by Thomas_H »

Ok, found the source of the pictures:
http://www.diyaudio.com/forums/tubes-va ... mpamp.html

and a schematic for the PI

Image

User avatar
delaystomper
Information
Posts: 16
Joined: 21 Sep 2009, 22:30

Post by delaystomper »

Hey Thomas i tried looking for the pcb for sale from that japanese web site but no luck i dont think he sales them anymore
And cant find anywere he could have posted a schematic. Its a nice looking little amp i would like to build if i cant build the imp amp . Yoh think there migh be website translator on his site . The amp from the french site seem cool too but ment for guitar correct ? In that diyaudio site they mention the op275 so , how would that be placed on the signal flow ? It would have to be the input driver correct

User avatar
Thomas_H
Information
Posts: 46
Joined: 05 Mar 2013, 12:37
Has thanked: 3 times
Been thanked: 18 times

Post by Thomas_H »

delaystomper wrote: It would have to be the input driver correct
yes, it comes right before the tubes, each output goes to one triode grid.
There are two op275, one for each channel, as you can see at the pictures.

What I found interesting about this is that the Imp amp uses both opamps in one IC for the Phase Inverter.
It would be possible to use another double triode for this function, in a long tail pair configuration.

The amp in the french forum is for guitar, but the output stage and the PI could be used in something like the imp amp.
I don't know exactly what are you looking for, but I guess it won't need a preamp stage right?

The japanese site has no schematic, but you can identify it by the layout I posted. It is a simple design, with all the triodes in parallel, using only a cathode resistor for each channel and the grid leak resistor. The components on the left side are for the SMPS, that is based on the MAx1771.

User avatar
delaystomper
Information
Posts: 16
Joined: 21 Sep 2009, 22:30

Post by delaystomper »

Hey thomas can you explain abiy about the phase inverter so if for say im building one channel to start
How does the phase inverter functions ?
Or is it when you have two channels at the same time ?

User avatar
Thomas_H
Information
Posts: 46
Joined: 05 Mar 2013, 12:37
Has thanked: 3 times
Been thanked: 18 times

Post by Thomas_H »

The phase inverter is used when you have a push-pull output stage, like in the imp amp, it inverts the signal that goes to the second output tube.
So, while one tube is amplifying in one phase the signal at the other is perfectly mirrowed .

http://www.valvewizard.co.uk/pp.html
here you have some basic information of how a pp stage works, and why you need the PI,

and here you have a text about a tube PI.
http://www.valvewizard.co.uk/dcltp.html

You said you had some parts, what kind of transformers do you have, are they for push-pull or single ended output stages.
If they are for single ended stages, then you won't need the phase inverter.

User avatar
delaystomper
Information
Posts: 16
Joined: 21 Sep 2009, 22:30

Post by delaystomper »

Hi thomas thanks for the response it makes perfect since
I will read up about on the links you sent me i been on his site before and he has
Some lots of interesting topics
The tranformers ate excatly the same that mr vezx used .
Wil everything then be layout as such ? On thaat diy audio sire he mention a TI rails slpitter for the grounds
Any ideas ?

User avatar
Thomas_H
Information
Posts: 46
Joined: 05 Mar 2013, 12:37
Has thanked: 3 times
Been thanked: 18 times

Post by Thomas_H »

no idea about that, i know it is quite common in stereo amplifiers, and has something to do with the fact that the opamp requires a symmetric power supply.

As I mostly build things for guitar, it's always mono, and runs on 9v.
I once tried a cmoy build, that had something to split the 9v, and instead of using the battery negative side as ground it also had a this kind of virtual ground. Problem is that it was never as good as a real symmetric supply because the virtual ground was changing with volume, making one channel clip.

Not sure how zvex made it, but most of the reliable solutions included an active circuit with transistor or another opamp.

It's not necessary if you adapt the circuit to a single supply.
About the transformers I don't know which one he used in this build, I thought initially it was the same transformer used on the nano head, but the transformer of the nano head is single ended, and in the video he shows a Push pull transformer on the schematic. You know the part name or code? So I can check the impedance ratio and size?

I think I'll do a 3 tubes version and instead of the long tail pair just use a cathodyne.Probably the hammond 125a would be a good bet as OT, just wanted to know where zvex got his with the metal bells.

User avatar
delaystomper
Information
Posts: 16
Joined: 21 Sep 2009, 22:30

Post by delaystomper »

Check it out thomas , this the same transformer i have
-The TI spliter im still clueless
-the chips is op275 for phase inversion for sure


Amplifier topology is a single stage push-pull using 6021W sub-mini tube. That tube has 0.7W anode dissipation rating, which means that it runs in Class B to get 1W output. Bias for PP pair is done with a single blue LED. External 12V/1A PSU feeds two 6021 heaters in series, and HT is stepped up inside by a pair of AMVECO 70000K 1.6W toroids connected in reverse. Rectifier is obviously solid state. The only thing which is not quite clear is how phase splitting is done in a front-end...

Post Reply