Proper outputs for F-5 V3.0

[saabracer23]

Several years back I bought the F-5 V3.0 boards and now I’m finally getting around to work on them. I’m sure this comes up, but couldn’t find anything. What are the proper outputs for the V3.0? The FQA19N20 and it’s complement seem to be obsolete. I’m guessing there is a reason they swapped from the IRFP240 and it’s complement. I’m placing an order now, but not sure what to purchase. Any other parts that might be obsolete and need a replacement? I can’t seem to find a BOM for the V3.0.

Thank you,
Dan

 

[Dennis Hui]

For the jfets Q1 and Q2, you need idss-matched pairs. If you don't have the
original Toshibas, you can use the LS parts:

Linear Systems Matched JFETs – diyAudio Store

For the output devices I suggest sticking with IRFP240/IRFP9240.

All other parts are readily available.

Cheers,
Dennis

 

[saabracer23]

For the jfets Q1 and Q2, you need idss-matched pairs. If you don't have the
original Toshibas, you can use the LS parts:

Linear Systems Matched JFETs – diyAudio Store

For the output devices I suggest sticking with IRFP240/IRFP9240.

All other parts are readily available.

Cheers,
Dennis

Thank you, I’ll stick with the 240 and 9240s. I have several of the 2SK170BLs. Do you have a clue where I can purchase just the 2SJ74BL?

I’m also building the B1 Mezmerize and it also calls for two pair of matched 2SK170BL as well. Is that something I’m able to do at home with a Peak Atlas DCA 75?

Here in the pics is the info it provides for n fets and j fets. I apologize, just not well versed in matching fets.

Dan

 

[Zen Mod]

you can use 9V battery as voltage source

match them to 0.5mA and you're good

 

[Dennis Hui]

Hi Dan,

I suggest measuring using the setup ZM posted above.

According to the dca pro user guide (p.26):
https://www.peakelec.co.uk/downloads/dca-pro-user-guide-en.pdf

it will measure idss at Vds<3V, which is rather low and non-standard.

The 2sj74BL will be a bit tricky if you are looking for ones to match
your existing 2sk170. Best to measure your 2sk170 first and see
what Idss you need for the 2sj74.

There are some sellers mentioned in this thread:

Replacement For Toshiba 2SK170/2SJ74

but you might also try a want ad once you know what you need.

Cheers,
Dennis

 

[saabracer23]

you can use 9V battery as voltage source

match them to 0.5mA and you're good

Wow, beautiful! Thank you so much. Would I get more accurate results if I used my bench top power supply to give me 12v or is 9 more than good enough?

Hi Dan,

I suggest measuring using the setup ZM posted above.

According to the dca pro user guide (p.26):
https://www.peakelec.co.uk/downloads/dca-pro-user-guide-en.pdf

it will measure idss at Vds<3V, which is rather low and non-standard.

The 2sj74BL will be a bit tricky if you are looking for ones to match
your existing 2sk170. Best to measure your 2sk170 first and see
what Idss you need for the 2sj74.

There are some sellers mentioned in this thread:

Replacement For Toshiba 2SK170/2SJ74

but you might also try a want ad once you know what you need.

Cheers,
Dennis

Awesome, I really appreciate the assistance! Once I get the testing device built and I can measure what I’ve got I’ll go from there.

Dan

 

[jackinnj]

Here in the pics is the info it provides for n fets and j fets. I apologize, just not well versed in matching fets.

Dan

The DCA75 can draw curves and drop the data into Excel as CSV file for better matching.

 

[takitaj]

You should keep/match your 2Sk170's for the B1 build. Buying enough 2Sj74's to match your 2Sk170's could get expensive.

You could just purchase the already matched quad of LSk170/LSj74 BL from the DIYAudio store here - Linear Systems Matched JFETs – diyAudio Store.

Cheap in the long run, IMO.

TJ