Aksa Lender P-MOS Hybrid Aleph (ALPHA) Amplifier

FYI - I got a quote from Tortech to produce an appropriate toroidal transformer for ABB:


Item: 2x 500VA 240/30/30V Open Toroidal Transformer (500VA Transformer with Dual 30V Output Windings and ES.).

Total price for both units: $490 including GST, plus $35 freight. ($245 per unit including GST, plus freight).

Availability: 1-2 Weeks.​

Unfortunately price was too high for this particular situation.

It's also worth considering SMPS (Meanwell from Mouser) as cost effective options for us Aussies depending on requirements (i.e. if no off the shelf toroidal is available).
 
Can we ask what trafo's you ended up getting?

Zman01 has some experience getting 500VA (?) Toroidy's shipped to AUS then hand-carried (I feel sorry for his friend's back lugging these around) to Dhaka - LOL :)

Yah I got these as shown in the previous build photo: 0500P1-2-030K | 2 Output Toroidal Transformer, 500VA, 2 x 30V ac | RS Components

The RSPRO branded version of the same unit is: 2 Output Toroidal Transformer, 500VA, 2 x 30V ac | RS Components

There's also non-potted versions available at RS.

Quite affordable compared to other options in Australia :)
 
Here's an updated list of the usual suspects,
they're ordered by package and transconductance.

I've found some combinations with low rdson and matching transconductance:
TO-247 IXFH110N10P + IXTH90P10P
TO-247 IXFH74N20P + IXTH90P10P

TO-264 IXTK120N20P + IXTK170P10P
TO-264 IXTK102N30P/IXFK102N30P + IXTK170P10P

What would be a good combination for an Alpha4R 2A from the following candidates?


N-Channel
Code:
[SIZE="3"]
                                               Gfs  Ciss    Crss   RdsOn   Rthjc Rthcs C/W              
Fairchild FQA28N15  TO3PN  N  227W  33A  150V  20S  1250pF   50pF  90mOhm  0.66  0.24
Fairchild FQA32N20C TO3PN  N  204W  32A  200V  20S  1700pF  185pF  82mOhm  0.61  0.24
Fairchild FDA69N25  TO3PN  N  480W  69A  250V  25S  3570pF   84pF  41mOhm  0.26  0.24
Fairchild FQA40N25  TO3PN  N  280W  40A  250V  29S  3100pF   70pF  70mOhm  0.45  0.24
Fairchild FQA46N15  TO3PN  N  250W  50A  150V  36S  2500pF  100pF  42mOhm  0.60  0.24
Fairchild FQA70N15  TO3PN  N  330W  70A  150V  48S  4150pF  135pF  28mOhm  0.45  0.24
Fairchild FQH90N15  TO3PN  N  375W  90A  150V  68S  6700pF  200pF  18mOhm  0.40  0.24
IXYS IXTH64N10L2    TO247  N  357W  64A  100V  27S  3620pF  235pF  32mOhm  0.35  0.21 
IXYS IXFH70N20Q3    TO247  N  690W  70A  200V  32S  3150pF  100pF  40mOhm  0.18  0.21  
IXYS IXFH110N10P    TO247  N  480W 110A  100V  40S  3550pF  440pF  15mOhm  0.31  0.21    
IXYS IXFH74N20P     TO247  N  480W  74A  200V  44S  3300pF  190pF  34mOhm  0.31  0.25 
IXYS IXTH75N10L2    TO247  N  400W  75A  100V  44S  8100pF  350pF  21mOhm  0.31  0.21   
IXYS IXTH80N20L     TO247  N  520W  80A  200V  45S  6160pF  520pF  32mOhm  0.24  0.21 
IXYS IXFH96N20P     TO247  N  690W  96A  200V  52S  4800pF  270pF  24mOhm  0.25  0.21  
IXYS IXTH96N20P     TO247  N  600W  96A  200V  52S  4800pF  270pF  24mOhm  0.25  0.21
IXYS IXFH100N25P    TO247  N  600W 100A  250V  56S  6300pF  240pF  27mOhm  0.25  0.21
IXYS IXFH120N15P    TO247  N  600W 120A  150V  60S  4900pF  330pF  16mOhm  0.25  0.21    
IXYS IXFH72N30X3    TO247  N  390W  72A  300V  60S  5400pF    2pF  15mOhm  0.32  0.25  
IXYS IXFH80N25X3    TO247  N  390W  80A  250V  64S  5430pF    2pF  13mOhm  0.32  0.25  
IXYS IXFH140N10P    TO247  N  600W 140A  100V  65S  4700pF  600pF  11mOhm  0.25  0.21    
IXYS IXFH94N30P3    TO247  N 1040W  94A  300V  68S  5510pF   25pF  36mOhm  0.12  0.25 
IXYS IXFH140N20X3   TO247  N  480W 140A  200V  94S  7660pF    5pF  10mOhm  0.26  0.25   
IXYS IXFK90N20Q     TO264  N  500W  90A  200V  50S  6800pF  480pF  22mOhm  0.26  0.15  
IXYS IXTK82N25P     TO264  N  500W  82A  250V  52S  4800pF  210pF  38mOhm  0.25  0.15  
IXYS IXTK102N30P    TO264  N  700W 102A  300V  57S  7500pF  230pF  33mOhm  0.18  0.15  
IXYS IXFK102N30P    TO264  N  700W 102A  300V  57S  7500pF  230pF  33mOhm  0.18  0.15  
IXYS IXTK88N30P     TO264  N  600W  88A  300V  60S  6300pF  190pF  40mOhm  0.21  0.15 
IXYS IXTK120N20P    TO264  N  710W 120A  200V  63S  6000pF  265pF  22mOhm  0.21  0.15  
IXYS IXFK140N20P    TO264  N  830W 140A  200V  84S  7500pF  280pF  14mOhm  0.18  0.15  
IXYS IXFK120N30P3   TO264  N 1130W 120A  300V  90S  8630pF   20pF  27mOhm  0.11  0.15  
 [/SIZE]

P-Channel
Code:
[SIZE="3"]
                                               Gfs  Ciss    Crss   RdsOn   Rthjc Rthcs C/W              
Fairchild FQA36P15  TO3PN  P  294W  36A  150V  19S  2550pF  110pF  90mOhm  0.51  0.24
IXYS IXTH52P10P     TO247  P  300W  52A  100V  20S  2845pF  275pF  50mOhm  0.42  0.21
IXYS IXTH50P10      TO247  P  300W  50A  100V  22S  4350pF  733pF  55mOhm  0.42  0.25
IXYS IXTH48P20P     TO247  P  462W  48A  200V  32S  5400pF  170pF  85mOhm  0.27  0.21  
IXYS IXTH90P10P     TO247  P  462W  90A  100V  37S  5800pF  510pF  25mOhm  0.27  0.21 
IXYS IXTX170P10P    TO247  P  890W 170A  100V  58S 12600pF  930pF  14mOhm  0.14  0.15
IXYS IXTK90P20P     TO264  P  890W  90A  200V  51S 12000pF  250pF  44mOhm  0.14  0.15
IXYS IXTK170P10P    TO264  P  890W 170A  100V  58S 12600pF  930pF  14mOhm  0.14  0.15  [/SIZE]

Regards,
Danny
 
Hi Danny,
Thank you for your wonderful list of suspects! Seeing them still, not moving, makes it much easier to identity the crime choices.......
The 4R ALPHA needs >200W devices with lowish transconductance and max voltage.
The ones I like are FQA32N20C nmos and FQA36P15 pmos. These have less than Ciss of 2.6nF and will cope with the 50W dissipation with ease.

The big amp, the BB, needs much bigger mosfets. I like IXFH74N20P nmos + IXTH48P20P pmos because they are TO247 - good thermal capacity - and low Ciss for high dissipation and current.

Again, Danny, thank you!

Hugh
 
She's alive!

Took much longer than necessary because I stupidly blew one channel and associated SLB by incorrectly swapping the output FETs! :( Fortunately both boards were salvageable.

Sounds gorgeous :) Thanks to all involved in its design.

IMG_0445.jpg