A short article describing the Genesic GA10JT12 transistor in a Zen type
amplifier circuit has been posted in the FW articles section.
FIRST WATT
😎
amplifier circuit has been posted in the FW articles section.
FIRST WATT
😎
Best regards
I was wondering how foolproof the biasing circuit is.
Particularly, if anything happens to the opto while ageing, what is going to happen to the power Mosfet ?
Wouldn't the addition of a resistor in parallel with the biasing transistor (the one in blue below) provide some safety in case the opto fails (imagine the gate would be at +Vcc voltage). Something around 500 Ohm to provide a gate voltage of 1V or so
What do you think ?
Particularly, if anything happens to the opto while ageing, what is going to happen to the power Mosfet ?
Wouldn't the addition of a resistor in parallel with the biasing transistor (the one in blue below) provide some safety in case the opto fails (imagine the gate would be at +Vcc voltage). Something around 500 Ohm to provide a gate voltage of 1V or so
What do you think ?
OK, I'm also trying to confirm that I understood the design properly.... could this at least be a good safety measure to take ?
TBH the idea came to me as I was contemplating putting the opto on an IC socket, (so as to try what various opto types would do to the sound) and wondered what would happened if the contact was not properly done
I guess my question should have been: is the opto critical to the sound ?
From my LTSpice simulations, R7 and R5 values are very critical to the biasing depending on what opto you use 😛 ...
Fred
Last edited:
opto is governing element of CCS , not some Voodoo approved part
so , CCS is either working properly , at current intended ....... or is intended current altered using some other opto , so you need to alter resistors to go back to intended current
so , to conclude , when working properly - opto is invisible soundwise
also - putting resistor in parallel with bjt opto-part , whichever reason you have , will alter function of opto itself
so , speaker is pretty much safe due to existence of coupling cap
put appropriately sized sloblo fuse in rail and you done everything needed
that opto will outlive you too , most probably
so , CCS is either working properly , at current intended ....... or is intended current altered using some other opto , so you need to alter resistors to go back to intended current
so , to conclude , when working properly - opto is invisible soundwise
also - putting resistor in parallel with bjt opto-part , whichever reason you have , will alter function of opto itself
so , speaker is pretty much safe due to existence of coupling cap
put appropriately sized sloblo fuse in rail and you done everything needed
that opto will outlive you too , most probably
This thread has went to sleep. Any players? It appears to me that the voltages can be achieved with a typical FW PS with a slight reduction. The device has nice curves. I stumbled upon this thread doing some research on the F3, Zen 9 builds. I read NP article when it came out but diverted to another path. Q3 = 4N35 as in M2?
Last edited:
Main interest these days seems to be PP with hockey pucks. Wish I was younger and could use learn spice sim's.
Last edited:
Me wait patiently for announced articles about DEF with his kit
and Tokin 2SK180, single-ended 2sj28 that is Papa much more exciting games.
Btw always interesting to see different ZEN game players
Attachments
I am with you on the SE 2SJ28. We wait patiently on the guru for crumbs. I welcome any bone he throws my way. As far as I am concerned he does not need to build and test the circuit himself.
What sort of SE amplifier would you like to see made with the 2SJ28?
*Sorry, just realized this is a thread about the GeneSiC, so I'm off-topic.
*Sorry, just realized this is a thread about the GeneSiC, so I'm off-topic.
Last edited:
Yes projects with hockey puck's are fantastic....Diyers who want try other technology silicon carbide transistors
GeneSic GA10JT12 can do the job.
Rare Semisouth's become "unicorns" and prices was skyrocketed.
http://www.mouser.com/ds/2/169/GA10JT12-247-553277.pdf
http://www.mouser.fr/ProductDetail/GeneSiC-Semiconductor/GA10JT12-247/?qs=rJ%2bziJWpyswlGCmHhheLLA==
Ooouh no one actually in stock....but can be in command
Smart Minimalism amplifiers sort with extraordinary linearity and transparency
Hi Mike, I have seen your SE schematics using these V-fets and have seriously considered building it using my extra J28's. About that time NP said he would see what he could work up using the V-fets in SE not that it would be better but.....
You are right we should not stray any further away from topic.
- Status
- Not open for further replies.