pyjaman
Well-known member
ORIGINAL TOPIC:
http://www.groupdiy.com/index.php?topic=5866.0
Hi, I allways wanted to give a try to this little DOA, while I never did until now.
Since Tamas, nor Fabio seem to appear on the forum anymore, I have sketched my own layout for it based on this schematic of the big fet bloak:
http://twin-x.com/groupdiy/displayimage.php?pos=-4692
here is the layout :
http://twin-x.com/groupdiy/displayimage.php?pos=-4691
and the traces for home-etching (single-sided):
http://twin-x.com/groupdiy/displayimage.php?pos=-4690
after several readings of the entire topic during the past years, I tried to make it so the biasing diodes are barely thermaly coupled to the power devices (read: close), and there is room behind the output transistors to mount these on a shared "heatsink" (I plan to use a 1.5mm thickness plate or L shapped piece of aluminium for it).
Feel free to : analyse, criticise, and use this layout.
I plan tu use it in a classic 312-like circuit and I need your advices for this, because the "recommended circuit" drawn by Tamas is no longer aviable and some infos are still unclear to me.
I will use 10k for feedback R and a 10k C pot in serie with 100 ohms for Rgain. I'll try 10pf in parallele with Rf.
First question: what minimum value would you recommend for Cgain (cap in serie with Rgain to ground), and what minimum voltage rating.
Second one: do I NEED an output coupling capacitor from DOA out to 600:600 output transformer ?
and if so, what value would you recommend ?
Third one : for +/- 24v supply, what current per channel should the PSU be able to safely provide ?
and fourth : I have a bunch of 1:10 input tx's, do you think they'll be too high a ratio in this circuit ?
(I remember Tamas recommended 1:3 to 1:7 for the task )
Thanks a lot for your comments and help.
Laurent.
http://www.groupdiy.com/index.php?topic=5866.0
Hi, I allways wanted to give a try to this little DOA, while I never did until now.
Since Tamas, nor Fabio seem to appear on the forum anymore, I have sketched my own layout for it based on this schematic of the big fet bloak:
http://twin-x.com/groupdiy/displayimage.php?pos=-4692
here is the layout :
http://twin-x.com/groupdiy/displayimage.php?pos=-4691
and the traces for home-etching (single-sided):
http://twin-x.com/groupdiy/displayimage.php?pos=-4690
after several readings of the entire topic during the past years, I tried to make it so the biasing diodes are barely thermaly coupled to the power devices (read: close), and there is room behind the output transistors to mount these on a shared "heatsink" (I plan to use a 1.5mm thickness plate or L shapped piece of aluminium for it).
Feel free to : analyse, criticise, and use this layout.
I plan tu use it in a classic 312-like circuit and I need your advices for this, because the "recommended circuit" drawn by Tamas is no longer aviable and some infos are still unclear to me.
I will use 10k for feedback R and a 10k C pot in serie with 100 ohms for Rgain. I'll try 10pf in parallele with Rf.
First question: what minimum value would you recommend for Cgain (cap in serie with Rgain to ground), and what minimum voltage rating.
Second one: do I NEED an output coupling capacitor from DOA out to 600:600 output transformer ?
and if so, what value would you recommend ?
Third one : for +/- 24v supply, what current per channel should the PSU be able to safely provide ?
and fourth : I have a bunch of 1:10 input tx's, do you think they'll be too high a ratio in this circuit ?
(I remember Tamas recommended 1:3 to 1:7 for the task )
Thanks a lot for your comments and help.
Laurent.