Read at couple of places regarding BF862 some say its even better than 2sk170. Just to know if anybody compared B1 or any Pass amps which as 2sk170 replaced with BF862 and did a audition?
I have switched from using the 2SK170 to the BF862 in all my projects. The sound is more neutral and authoritative - no added warmness. The BF862 is an SMD SOT-23 which is a PITA, but worth the extra effort to me. I have a bunch of 2SK170's left if anyone wants to buy them from me cheap.
How would one implement the BF862 in existing through hole pcbs? There are surely many ways but what would be the best?
Regards
Regards
I bought some just to look at with my last order from Mouser. About half the size of a grain of rice with 3 connections to solder. Looks like a ball of fun soldering them! You cannot beat the price and I am glad we have alternatives to the Toshiba and LSK's though.
"You cannot beat the price and I am glad we have alternatives to the Toshiba and LSK's though"...
+1 - just need the best way of implementing to though hole pcb's 🙂. Might be wires as you wrote wdecho🙂
Have anyone made readings on these with appropriate instruments?
Regards
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Be mindful of 2 things using the BF862
1) you must use gate stopper resistor OR ferrite bead on the gate lead. The intended purpose of the BF862 was RF.
2) Idss runs high and the devices run warm. A TO92 transistor will dissipate heat through its legs, for the BF862 the PCB trace thickness should be mindful of the added purpose of dissipating heat.
If you are using an SMT adapter, use a 100R resistor instead of wire for the gate lead.
1) you must use gate stopper resistor OR ferrite bead on the gate lead. The intended purpose of the BF862 was RF.
2) Idss runs high and the devices run warm. A TO92 transistor will dissipate heat through its legs, for the BF862 the PCB trace thickness should be mindful of the added purpose of dissipating heat.
If you are using an SMT adapter, use a 100R resistor instead of wire for the gate lead.
agreed the fact as its a RF Jfet but adding 100ohm at the gate doesnt swamp out the noise advantage of the jfet?
Is it compulsory to use 100ohm resistor at gate?
Drain only dissipate Heat!
Is there a real demand so it will be a good idea to Brain about a replacement tiny PBA
Is there a real demand so it will be a good idea to Brain about a replacement tiny PBA
Drain only dissipate Heat!
Is there a real demand so it will be a good idea to Brain about a replacement tiny PBA
Is there a real demand so it will be a good idea to Brain about a replacement tiny PBA
Do you have any opportunity to measure the noise in the audio band? The datasheet says 0.7 nV at 100 kHz.
then why many don`t use BF862? If we put a small heatsink as much as for the TO 220 package heatsink wouldnt that suffice?
but I see it can be used even for the shunt regs aswell. But why BF862 is being used?
but I see it can be used even for the shunt regs aswell. But why BF862 is being used?
There is a SOT-23 to pin adapter available.
Here's a Digikey link.
http://www.digikey.com/product-detail/en/33205/33205CA-ND/272914
They are for SOT23-5, so you can just ignore the extra pads when you use them for SOT23-3.
I've built fast low noise photoamp stages with the BF862 on these adapter.. They are great to work with!
Here's a Digikey link.
http://www.digikey.com/product-detail/en/33205/33205CA-ND/272914
They are for SOT23-5, so you can just ignore the extra pads when you use them for SOT23-3.
I've built fast low noise photoamp stages with the BF862 on these adapter.. They are great to work with!
To get the heat out you need to thermally connect directly to the substrate, which is glued onto the gate pin.
Then you need a decent surface area, like 4x5mm, in order to provide enough surface area for heat transfer to the heat sink.
That means an adaptor PCB with a large gate pad.
Then probably a special sink 4x 5mm, to make it into a TO92 compatible device.
Can be done, won't be less than 1 USD, plus soldering and gluing.
Work costs money.
Patrick
Then you need a decent surface area, like 4x5mm, in order to provide enough surface area for heat transfer to the heat sink.
That means an adaptor PCB with a large gate pad.
Then probably a special sink 4x 5mm, to make it into a TO92 compatible device.
Can be done, won't be less than 1 USD, plus soldering and gluing.
Work costs money.
Patrick
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