About possible Babelfish J interest

Official Court Jester
Joined 2003
Paid Member
IRFP150 - standard rail (22V5dc , resulting from 18Vac secondary) , will work with Iq of 2A for eons , if properly cooled

higher rails , for more power , demands more output pairs (thus Daughter boards) and decrease of Iq per vertical pair , to limit max sane dissipation per device at max 45W

base pcb is shown with dimensions in post #1

it is slightly changed later in development , but nothing substantial

that board you can get if you contact me , first reading Trade thread , link of which is also in post #1
 
IRFP150 - standard rail (22V5dc , resulting from 18Vac secondary) , will work with Iq of 2A for eons , if properly cooled

Sounds good to me. Should the transistors pairs go to the same heatsink (for thermal tracking), or can they each have their own heatsink? I am thinking of doing a Pass Aleph style build with four heatsinks on each side of the chassis. Then I'd have 2 x 2 IRFP150 for a stereo amplifier, so each IRFP150 could go to it's own heatsink.
 
Official Court Jester
Joined 2003
Paid Member
ref. to enclosed sch. just value of R7 , decreasing or shortie

also , you can make life little easier - put shortie instead of TP2 , change R10 to 68R

548516d1462973257-babelfish-base-pcb-sch-jpg
 
ref. to enclosed sch. just value of R7 , decreasing or shortie

Thanks! What would be a good value for the bias voltage at the gate of the SJEP120R100?

also , you can make life little easier - put shortie instead of TP2 , change R10 to 68R

Ok -- but is this related to the SJEP120R100 idea, or just to make things easier in general?
 
final schematic for just base pcb iteration and parts placement pictures

Sorry for nagging, but the boards I received seem to be from a later revision. They have additional resistors R33, R34, R35 and R36. As far as I can tell, there are not other changes, but I am not sure.

I believe all I have to do is to leave R33, R34, R35 and R36 empty and not worry about anything else. However, I am not sure if I missed anything, so it would be cool if someone could confirm.
 
Official Court Jester
Joined 2003
Paid Member
read and observe schematic little more

goal is to understand it

if you have , say, one 0R27 per output mosfet source, and you have 2 output mosfets, then you have 2pcs of 0R27 paralleled in output current sense series group

if you have 2 pairs of output mosfet , then there are 4pcs of 0R27 paralleled in output current sense series group

if you have 3 pairs of output mosfet , then there are 6pcs of 0R27 paralleled in output current sense series group

what's there , one can't understand?

:clown:
 
if you have , say, one 0R27 per output mosfet ... if you have 2 pairs ... if you have 3 pairs ... what's there , one can't understand?

Hi ZM, sure, I understand the purpose of those additional resistors. But the core of my question was something else:

...the boards I received seem to be from a later revision. They have additional resistors R33, R34, R35 and R36. As far as I can tell, there are not other changes, but I am not sure.

You indicated that post #138 has the final schematic. That's obviously not the case, and I wondered if the changes in the board I received are only related to R33, R34, R35 and R36, or if there are any other changes. Can you confirm? Maybe you could simply post the correct schematic?