• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

tube preamp...opinions

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fscarpa58 said:
Guys

download a free copy of Micro Cap 7 demo at
http://www.spectrum-soft.com/demodown.shtm

you will able to draw circuits as well as to
simulate them ( max 50 components)
very user frendly, recommended.

Tube models on the web or ask in the forum.

Federico


great prog, but probably is someone here who already knows better how to use it.. I will try to recalculate CF with +/- 50V, but I am not fell sure to my work..

please, I need just a moment of your time...


thanks
 
I can only see the 12AX7 triode and all others are greyed out. Is this what you mean by tube models? If I'll be using 6922 or 6DJ8, what do I do? Sorry for the questions.

Yes JojoD818,
they are greyed because it is a demo.But , really, the model is
actually there, in the tube.lib file. You can see it in the library
folder. Then
1) run Mcap
2) go under windows menu... select and click component editor.
On the right click on Analog Library
3) click on tubes then on triodes
4) click on 12AX7 and carefully look at top left under >definition>
You will see Subckt. While in the simbol( left bottom) you will
see the node name A,G,K.
Well now clik on 6DJ8. definition will became <null>. Change it
to subckt. Moreover A,G,K disappear. click near the node
and input the right letter.
5) switch between 12ax7 and 6DJ8 the have to appear equal.
( apart from the name , naturally)
6) close by clicking on the top right cross.
7) save

If all it right now, if you go under
component/analog. lib/etc./triodes
6DJ8 is no longer greyed.

Tell me if it works

note: there are other ways to make your model
working. This is the long way.
Note also that those are the duncan models
I do not know if they work well.
Certainly the best ( as for me )are Koren models.


Federico
 
fscarpa58 said:


Yes JojoD818,
they are greyed because it is a demo.But , really, the model is
actually there, in the tube.lib file. You can see it in the library
folder. Then
1) run Mcap
2) go under windows menu... select and click component editor.
On the right click on Analog Library
3) click on tubes then on triodes
4) click on 12AX7 and carefully look at top left under >definition>
You will see Subckt. While in the simbol( left bottom) you will
see the node name A,G,K.
Well now clik on 6DJ8. definition will became <null>. Change it
to subckt. Moreover A,G,K disappear. click near the node
and input the right letter.
5) switch between 12ax7 and 6DJ8 the have to appear equal.
( apart from the name , naturally)
6) close by clicking on the top right cross.
7) save

If all it right now, if you go under
component/analog. lib/etc./triodes
6DJ8 is no longer greyed.

Tell me if it works

note: there are other ways to make your model
working. This is the long way.
Note also that those are the duncan models
I do not know if they work well.
Certainly the best ( as for me )are Koren models.


Federico


IT WORKS!!! Thank you thank you! 6DJ8 is no longer greyed!

Where do I get Koren models? How do I use it in Mcap?

You're instructions are the best btw!

Thanks,
JojoD
 
Hi JojoD818

You can find a lot on the web.
for instance go to

http://www.normankoren.com/Audio/Tubemodelinstr.HTM

download the file tubemods.zip (it is at the 3rd line)

1) in it there are a lot of file but you are
interested in those with .lib ext.
for istance tube.lib.
Decomp it, save it as koren.lib and put it in the library
folder of microcap.
( I advice you to open the file and add a k (koren) to
all tube names to avoid later confusion, that is
where you find 6DJ8, for instance, write k6DJ8.
for every tube) note that some are pentodes.
Change at least one name(e.g. k6dj8) you can change
the other in the future.

2)open the file named nom.lib (library folder)
and add at the bottom the string
.lib "koren.lib" like the other you can see
( this tells Mcap where to look for)

3)save it

4) start microcap
5) as before in the windows menu click on component editor
6) on the right select analog library
7) on the top left push the button <add group> (9th from left, double plus)
8) put the name of the new group, e.g. Koren Tubes, enter
9) the group will appear and it is selected.
10) press again new group and write Triodes, enter
11) press <add part > ( right before the previous) and fill
the form at top left
/name: k6Dj8
/Shape: triode
/definition: subckt
12) This time you will not use the letter A,G,K
but the number 1,2,3 because in the koren library the
reference to the pins is made in such a way.

13) top right cross to close and you are ready.

Obviously you can add the other names present in
the library when you wont


good luck

Federico
 
)....also I dont understand quite about adding a diode between the grid and cathode of the cathode follower, to make a soft start....

Hi trancy.

no it does not make a soft start.

If you have a normal start the grid of the second tube
will go at 165V ( or 280V) since the heaters are cool and
the tubes initially do not conduct.
This is very dangerous since when the heater become
hot and start to conduct that is the risk of too great current.

so the diode in such a place is to avoid this and to protect the tube.

I am newbie and I have a lot of problem to recalculate elements values for CF

I again advice you to download a free copy of Micro Cap 7 demo at

http://www.spectrum-soft.com/demodown.shtm

bye

Federico
 
HI!
Is it possible to use this preamp for a ZEN amp or for what is it good for, except for nice background illumination? :))
Thanks!
Tyimo
 

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fscarpa58 said:
Hi JojoD818

You can find a lot on the web.
for instance go to

http://www.normankoren.com/Audio/Tubemodelinstr.HTM

download the file tubemods.zip (it is at the 3rd line)

1) in it there are a lot of file but you are
interested in those with .lib ext.
for istance tube.lib.
Decomp it, save it as koren.lib and put it in the library
folder of microcap.
( I advice you to open the file and add a k (koren) to
all tube names to avoid later confusion, that is
where you find 6DJ8, for instance, write k6DJ8.
for every tube) note that some are pentodes.
Change at least one name(e.g. k6dj8) you can change
the other in the future.

2)open the file named nom.lib (library folder)
and add at the bottom the string
.lib "koren.lib" like the other you can see
( this tells Mcap where to look for)

3)save it

4) start microcap
5) as before in the windows menu click on component editor
6) on the right select analog library
7) on the top left push the button <add group> (9th from left, double plus)
8) put the name of the new group, e.g. Koren Tubes, enter
9) the group will appear and it is selected.
10) press again new group and write Triodes, enter
11) press <add part > ( right before the previous) and fill
the form at top left
/name: k6Dj8
/Shape: triode
/definition: subckt
12) This time you will not use the letter A,G,K
but the number 1,2,3 because in the koren library the
reference to the pins is made in such a way.

13) top right cross to close and you are ready.

Obviously you can add the other names present in
the library when you wont


good luck

Federico


It did it! Thanks! You are the man!

JojoD
 
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