A custom made transformer from Toroidy for the DAO.
There are 4 secondaries (+/-Vs for 2 channels).
2 of them were wound between from o'clock, via 12 o'clock to 3 o'clock.
The other 2 from 3 o'clock, via 6 o'clock to 9 o'clock.
There is also a electrostatic shield between primary and secondary.
This is an attempt to minimise cross talk between two channels.
But the Tx was rather expensive.
Patrick
There are 4 secondaries (+/-Vs for 2 channels).
2 of them were wound between from o'clock, via 12 o'clock to 3 o'clock.
The other 2 from 3 o'clock, via 6 o'clock to 9 o'clock.
There is also a electrostatic shield between primary and secondary.
This is an attempt to minimise cross talk between two channels.
But the Tx was rather expensive.
Patrick
Attachments
Patrick,
I know you have not finished the build description of this beauty yet, but as I have plenty of 2SK2013, and a fellow admirer of the DAO has plenty LU1014D, we would very much appreciate your opinion on the optimal type and values of matching to aim for with this build.
Any comments would be greatly appreciated
Nic
I know you have not finished the build description of this beauty yet, but as I have plenty of 2SK2013, and a fellow admirer of the DAO has plenty LU1014D, we would very much appreciate your opinion on the optimal type and values of matching to aim for with this build.
Any comments would be greatly appreciated
Nic
All the modules are working. I am just waiting for mechanical some parts before final integration.
For devices, I don't aim for a specific value of 2SK2013, as long as they are matched to each other at bias.
As long as you take close-to-average Vgs values (from a large batch), you should be fine.
LU1014D is more complex, as we curve trace in the real triode-cell circuit.
Suggest you build up a triode cell and do some measurements first.
If you can repeat the triode curves as in the publications, you are on track.
ALL but 50 of our own LU1014Ds were pre-matched for Vgs.
So we are only dealing with minute differences.
If you have random devices, you might need to change the cascode voltage and/or degeneration individually to get the right responses.
And then things becomes very complicated.
No short cut I am afraid.
Patrick
For devices, I don't aim for a specific value of 2SK2013, as long as they are matched to each other at bias.
As long as you take close-to-average Vgs values (from a large batch), you should be fine.
LU1014D is more complex, as we curve trace in the real triode-cell circuit.
Suggest you build up a triode cell and do some measurements first.
If you can repeat the triode curves as in the publications, you are on track.
ALL but 50 of our own LU1014Ds were pre-matched for Vgs.
So we are only dealing with minute differences.
If you have random devices, you might need to change the cascode voltage and/or degeneration individually to get the right responses.
And then things becomes very complicated.
No short cut I am afraid.
Patrick
Thanks for your kind clarifications Patrick,
>For devices, I don't aim for a specific value of 2SK2013, as long as they are matched to each other at bias.
For what bias did you settle?
> LU1014D is more complex, as we curve trace in the real triode-cell circuit.
Suggest you build up a triode cell and do some measurements first.
If you can repeat the triode curves as in the publications, you are on track.
Ok - I guess I will have to study and see if I can find out how to build and use such triode cell.
>For devices, I don't aim for a specific value of 2SK2013, as long as they are matched to each other at bias.
For what bias did you settle?
> LU1014D is more complex, as we curve trace in the real triode-cell circuit.
Suggest you build up a triode cell and do some measurements first.
If you can repeat the triode curves as in the publications, you are on track.
Ok - I guess I will have to study and see if I can find out how to build and use such triode cell.
I have a few PMs asking me about availabilities of devices, mechanics and PCBs etc.
As you can see, we have not even finish outr own examples.
And until we have, the design is just that, a design, not yet verified.
We shall of course let you know when it is fully finished.
And then (and only then) if there would be sufficient interest, we'll make a project available for subscription.
I cannot promise a deadline, but it is more likely to be after September than before.
Thank you for your interest and patience,
Patrick
As you can see, we have not even finish outr own examples.
And until we have, the design is just that, a design, not yet verified.
We shall of course let you know when it is fully finished.
And then (and only then) if there would be sufficient interest, we'll make a project available for subscription.
I cannot promise a deadline, but it is more likely to be after September than before.
Thank you for your interest and patience,
Patrick
I am so terribly sorry to have kept you waiting.
All my electronics are tested and ready to wire.
But after more than 6 months I still have no mechanical parts.
I am as disappointed as you are, but the factory is there to make a living, not hobbies.
And business is exceptionally good this year, which means hobbies has STILL a long wait.
Patrick
All my electronics are tested and ready to wire.
But after more than 6 months I still have no mechanical parts.
I am as disappointed as you are, but the factory is there to make a living, not hobbies.
And business is exceptionally good this year, which means hobbies has STILL a long wait.
Patrick
You can get them from here :
LU1014D JFET's
But they are not matched at temperature and under the bias we are using.
Instead they are matched by the Nelson Pass method for his Zen V9 (I think 1.3A if I am not wrong).
What we did was to purchase a few hundred pieces from them pre-matched their way.
Then we re-matched them again in the DAO triode circuit, at heat sink temperature.
When we are ready to offer this as a public project, you will be able to get properly matched devices from us.
Of course you are always welcome to buy from them and then fine match your own.
Patrick
LU1014D JFET's
But they are not matched at temperature and under the bias we are using.
Instead they are matched by the Nelson Pass method for his Zen V9 (I think 1.3A if I am not wrong).
What we did was to purchase a few hundred pieces from them pre-matched their way.
Then we re-matched them again in the DAO triode circuit, at heat sink temperature.
When we are ready to offer this as a public project, you will be able to get properly matched devices from us.
Of course you are always welcome to buy from them and then fine match your own.
Patrick
