Zen -> Cen -> Sen, evolution of a minimalistic IV Converter

[mandalore]

I forgot to mention, these 2SK146 are BL grade (8-16 mA Idss according to datasheet).

 

[EUVL]

If you make your own PCB, yes.
The pinout of the 2SK146 would have a real hard time fitting onto my PCB.




Patrick

 

[mandalore]

Well, with so little parts, I might as well do it without PCB.

Thanks for replies.

 

[mandalore]

Well, I've built it. The actual SEN is only one tenth of the PCB , the rest are two shunt regulators. I used two separate transformers, and I was having trouble with large amounts of hum, buzz, distorsion, etc., but that was solved after adding of 100R resistors on gates going to the ground (thanks for the tip )

I still have some "buzz" on higher volume levels, but I thing that the problem is with close proximity of transformers, I will rearrange them. It is sounding good so far, the voltage on regulators is 17.5 V, I will experiment with higher voltages, for with these transformers I can go as high as 21 V regulated.

Thanks again for everything

 

[mandalore]

Ah, once again I forgot to write something.
This is off course only one SEN PCB made for personal use. I do not intend to "manufacture" it or anything like it. It's not even a "real" PCB actualy, I just drilled some more holes in spare space of the shunt PCB and connected the JFETs with wires

 

[EUVL]

Yes, for such a simple circuit it is really totally viable to do P2P without a PCB.
And I would encourage anyone to try this even on a breadboard.

Suggest you now try to play with passive components, especially R_iv and C_iv.
Don't waste those FETs.




P.

 

[EUVL]

BTW your SEN circuit is too close to the regulator for my liking.
If you were to do another PCB again, try to separate the two with 5~10mm space.

Just gut feeling, no scientific proof.


Patrick

 

[qusp]

really? is it simply because its low level analogue? because normally the closer the better, as you well know.

 

[EUVL]

It's because everything including the power supply is floating.


Patrick

 

[Dr.H]

Starting to look at this project again.
Please remind me: Do the SK170's need mathcing of both IDSS and VGS or just IDSS?

Thanks
Ryan

 

[EUVL]

Idss.

Patrick

 

[Dr.H]

Thanks Patrick.

 

[Dr.H]

Patrick, you recommend K170BL for the 8mA IDSS, but I can only source GR at much lower IDSS (3-5mA?). Any ideas on how I can compensate for the lower IDSS?

 

[qusp]

i'm sure someone can help you find some BL, if nobody closer can, i can probably help you out. is it the standard or sabre version you are building? in other words how many do you need?

 

[EUVL]

http://www.diyaudio.com/forums/swap-meet/131284-toshiba-2sk170bl-sales-12.html#post2847443


Patrick

 

[Dr.H]

Thanks guys

 

[Tham]

Hi Patrick,

Will the standard SEN circuit on page 1 works with TDA1545A DAC?

 

[EUVL]

Not as is.

Someone has used it successfully for the TDA1541.
Maybe you should ask him.

I have no on-hand experience with those old Philips DACs.


Patrick

 

[Tham]

Thanks for the quick reply....

 

[EUVL]

You're welcome.

Patrick