I'm going to build a Pass XOno.

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Gyuri

Gyuri

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Joined 2003
It is live!

Before anyone would think I have miraculous properties,
I must say, I do not have.
Just S1-8 off position available this favorable situation.
It doesn't matter, this is singing for me now. (Without caps.)
We will be good friends, I think.
There is some hum, perhaps because it is on the desk only.
I have made some error during wakeup CH2.
But only a 10K trimmer was the victim of this.
 
sakellogg

sakellogg

Member
Joined 2008
you do to have magic! you make me smile when you post, that is magic!

you just need practice with magic on the cats. that magic not your strong suit yet i hear.

enjoy my freind. it is a sweet phono stage! i have a very low hum when its cranked up no music.

i forgot to ajust the regulators before i fired it up.....i cooked allkinds of stuff. i learned, but the hard way.
 
Gyuri

Gyuri

Member
Joined 2003
If that's the case, I welcome this.
That is my intention.:)
A half-smile is a half recovery.
Even if you give it, even if you got it.

As for the cats, my bad.
Because I know them.
I saw in Huncutka's crazy eyes, glassy gaze, "coup d'oeil", the fore standing whiskers, in his chameleon-like crawling, so I knew what he is going to do. But too late I have spoken on him.

I'm still learning XOno.
That hum evidently assigned with cables at the inputs.
At this moment, it dissapeared almost completly.
The dc offset is like chorea.
If I blowing some air on the panel, it is growing rapidly like chorea Sancti Viti.
Perhaps I still will have to build in those capacitors.
 
sakellogg

sakellogg

Member
Joined 2008
it took a few days of tweeking to get mine tuned in right. i have it in a almost sealed case to keep it at a constant temp. and i dont turn it off very often. but all that said, ive got the caps in the cir.

i couldnt tell the diffrence. but its nice to know i can take them out if i want to.
 
G

GaryB

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Joined 2002
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I built an XOno phono stage quite a few years ago and found it easy to eliminate the output caps. I only built the single ended version but the concept would translate to the balanced version as well.

In terms of thermal stability, using dual transistors such as the 2SK389 for the MM input, one gets good matching of the temperature of the critical FETs and temperature drift shouldn't be an issue. If you can't get the 2SK389, then put the transistors on a common heatshink or put them in a little "house" like a matchbox so that they aren't exposed to air flow. They will quickly settle to a common temperature.
To get down to a very low offset voltages, once can then substitute the drain resistor R4 for a 10 turn pot (5K) and dial the offset down to zero. Once set, it has been very stable for me.
---Gary
 

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Gyuri

Gyuri

Member
Joined 2003
I have some questions about XOno.
Am I right, that MC input fets are running at about 4mA?
Ideal voltages accross R45,46,47,48 88mV?
Mine voltages are between 84-91 mV

And what about Q15?
Mine is there now a 2SK170BL, running at about 3,6mA 200mV/56Ohm.

And how about D5?
Accross legs I can measure about 1.74V, 1.72 on the other side.
I get voltages 1.13V and 1.11V on R67, 1.14 and 1.12 on R53.
Is it good, or I must search better LEDs?
I don't want to change resistors.
The 0.35V on R33 present, a little bit changing on the timeline.
DC offsets are somehow bouncing histerical as I wrote earlier, but I don't get bigger than say +- 0.1V.

The whole thing very quiet, dynamical, airy with good bass, middle and treble.
What can I say?
It's a perfect amp.

What can I do to make it better?
Maybe I should put it into the boxes.
Only that poor finger.

Wacky
 
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