Decided: Plan to build my F5 Turbo Monoblocks 50WPC

[recepky]

2SK170BL Front End Board 4x 2 matched pair (old stock - ebay)
2SJ74BL 4x 2 matched pair (old stock - ebay)
2SC4793 2x 1 matched pair (not found)
2SA1837 2x 1 matched pair (not found)
IRFP9240 P Channel 2x 1 matched pair (found at mouser)
FQA12P20 2x 1 matched pair (not found)
IRFP240 N Channel 2x 1 matched pair (found at mouser)
FQA19N20 2x 1 matched pair (not found)
MUR3020W 8X 4 matched pair (found at mouser)

where can I find these parts?
actually I prefer not to use old stock items, what is the equvalent of these parts that I can easily find as mathced pairs?

 

[Bfpca]

2SK170BL Front End Board 4x 2 matched pair (old stock - ebay)
2SJ74BL 4x 2 matched pair (old stock - ebay)
2SC4793 2x 1 matched pair (not found)
2SA1837 2x 1 matched pair (not found)
IRFP9240 P Channel 2x 1 matched pair (founmouser)
FQA12P20 2x 1 matched pair (not found)
IRFP240 N Channel 2x 1 matched pair (found at mouser)
FQA19N20 2x 1 matched pair (not found)
MUR3020W 8X 4 matched pair (found at mouser)

where can I find these parts?
actually I prefer not to use old stock items, what is the equvalent of these parts that I can easily find as mathced pairs?

I recently completed a F5 turbo V3 monoblock build. I used 2sa1593, 2sc4135 for the cascode transistors. They are smaller than to220, I think to251 surface mount. I used solder on heatsinks from Mouser part no 532-573100D00000G. You may not need the heatsinks depending on the supply voltage and the current in the front end. I used IR 240 / 9240 for outputs with no issues.

 

[recepky]

hi bfpca
thanks for the reply, what did you use instead of FQA12P20 and FQA12N20?

 

[recepky]

I want to guarantee 50 watts, so I want to set the amp for 60 watts,
for this:
how much rail voltage shuuld I need?
how much trafo VA that I need (per monoblock)
which capacitor voltage should I select (50V still enough?) 8x10000uF capacitance?
Which bias should I set?

Sorry my idiotic questions but I still didnt understand the calculations on the article read them very quick please help

 

[Dennis Hui]

Hi recepky,

The original output devices are the Fairchild FQA19n20c/FQA12p20 devices. As those
have been discontinued, many have used IRFP240/IRFP9240 instead.

Cheers,
Dennis

 

[2 picoDumbs]

I want to guarantee 50 watts, so I want to set the amp for 60 watts,
for this:
how much rail voltage shuuld I need?
how much trafo VA that I need (per monoblock)
which capacitor voltage should I select (50V still enough?) 8x10000uF capacitance?
Which bias should I set?

Sorry my idiotic questions but I still didnt understand the calculations on the article read them very quick please help

You would be better off keeping rail voltages below 35V and getting the biggest 35Volt caps you can fit eg 33,000uF caps. 32V rails is enough.


If you absolutely want to go more than 50W, I would probably go the balanced route with 23V rails.

 

[2 picoDumbs]

Assuming you limit rails to 32V
2 x 400VA transformers with 24V secondaries. Antek AS series are quite good and reasonably priced.
Biased at 2A.

 

[Bfpca]

hi bfpca
thanks for the reply, what did you use instead of FQA12P20 and FQA12N20?

I used IRFP240/9240. Those should still be readily available.

 

[Marra]

I would recommend buying your jfets from Spencer at Fet Audio.

FET Audio | Hi-End Audio Projects

h_a[Hannes] of this parish still supplies well matched mosfets I think.

 

[recepky]

I would recommend buying your jfets from Spencer at Fet Audio.

FET Audio | Hi-End Audio Projects

h_a[Hannes] of this parish still supplies well matched mosfets I think.

I ordered some of the fets from Spencer already.
I will buy the power mosfets from ebay, a guy sells matched quad IRFP240 and 9240 on ebay.

 

[recepky]

hi,

I will use;

2x 400VA, 240V to +24/-24V transformer (one for each mnoblock)

8x 10 000 uF, 50 V capacitor for each universal PSU board from diyaudio store (one for each monoblock = 16x capacitor in total)

SO;

which diode should I use for D1-D8 (D1=TO-247/TO-3P or D1X=TO-220 Diodes) ?
The BOM file says you should use diodes match with your transformers seconadary voltage. is this part ok: https://www.digikey.com/product-det...ision/FEP30DP-E3-45/FEP30DP-E3-45GI-ND/604818 (Voltage - DC Reverse (Vr) (Max) 200V)

which input snubber resistor should I use for RS1 ans RS2 in the BOM

which input snubber capacitor should I use for CX1 CX2 CS1 CS2 ?

thanks

 

[recepky]

Hi everybody

A few things just arrived, 2 x chassis, heatsinks and PCBs, now waitin for the electronic parts. Here is the pics:









I hope I will finish the project before the summer ends.

 

[recepky]

hi friends

I stuffed FE boards in my spare time following 6L6's perfect build guide.
I could not set P3 trimmers to exact value (which is 100 ohm), one of them set as 101.2 ohm and the other is 108.2 ohm (from leg 1 to 2 and 2 to 3)
is it okey?

I also used dale resistors everywhere, the black ones are military grade resistors.

 

[btesize]

hi friends

I stuffed FE boards in my spare time following 6L6's perfect build guide.
I could not set P3 trimmers to exact value (which is 100 ohm), one of them set as 101.2 ohm and the other is 108.2 ohm (from leg 1 to 2 and 2 to 3)
is it okey?

I also used dale resistors everywhere, the black ones are military grade resistors.

Great looking Recep [emoji122][emoji122][emoji122]

 

[recepky]

hi everybody

I also stuffed but not soldered n channel and p channel boards, I have some missing items which are C1x and C2x, I need 4 10uF electrolytic cap, but I have 2.
They are strictly necessary or should I leave them empty?

because according to 6L6's built guide, they seem empty on some photos.

Please see the attached pics.

 

[recepky]

Great looking Recep [emoji122][emoji122][emoji122]

thanks my friend

 

[Horses]

Old thread; any updates/pics, recepky?