Well, as with every SMD device if you can solder resistors I think you can get away with it. It's tiny, but not impossible. If you have some experience with basic SMD, then yes.
I get nervous around SMD, too, but these look pretty easy compared to a 0603 resistor!
Cheap enough so that when the inevitable misstep occurs it will not be very painful.
Does this FET need any kind of selection?
Cheap enough so that when the inevitable misstep occurs it will not be very painful.
Does this FET need any kind of selection?
Hi Ale, rediscovered this in my archive, totally forgotten. Excellent as source follower with Gm ~1S at 2A. Interesting Crss and Coss for lower gyrator transistor use at >20mA.
Hi Ale.
I have one question about R7 on your PCB.
In your 01A preamp value for R7 is 1K5 and on other schematics for 4P1L that value is from 150R to 1K.
What is the purpose of that resistor and do we need to change that if I want to convert 01A preamp to 4P1L (besides lower fet in CCS cascode)?
I have one question about R7 on your PCB.
In your 01A preamp value for R7 is 1K5 and on other schematics for 4P1L that value is from 150R to 1K.
What is the purpose of that resistor and do we need to change that if I want to convert 01A preamp to 4P1L (besides lower fet in CCS cascode)?
At some point we'll all have to deal with SMD components. One way I can imagine constructing these kind of active loads with BF862 etc is to use tag boards, where you solder wires to the legs of the SMD components and then solder those wires to the tags on each side of the board. I've never tried it, but I imagine it could work.
Attachments
Searching of lower gyrator transistor the most critical point of view is the Vds: 1.2-1.5V.
Anything else parameter is depends on this Vds.
Forgive me for being late to the party, but is there a thread or group buy for mogliaas gyrator PCBs? Curious to try them in place of the regular cascode CCS loads i'm using.
There are many types of adapter boards available to help you work with SMD's. For example, this one converts a SOT-23 like the BF862 to a 3-leaded device similar a TO-92:
<http://www.digikey.com/product-detail/en/6103/6103CA-ND/151941>
This makes it easy to install a SMD into a through-hole board. Similar adapter boards are available for most any SMD package from a variety of sources.
John
<http://www.digikey.com/product-detail/en/6103/6103CA-ND/151941>
This makes it easy to install a SMD into a through-hole board. Similar adapter boards are available for most any SMD package from a variety of sources.
John
Hello
Hope someone will tell me a little about the Resistor who is mounted after the output cap to ground...in the 4P1L (across the rca )
what is the best value for this ?
my Poweramp has 10k input
Best Bjarne
Hope someone will tell me a little about the Resistor who is mounted after the output cap to ground...in the 4P1L (across the rca )
what is the best value for this ?
my Poweramp has 10k input
Best Bjarne
Hi Bjarne,
Use 1M ohm. It is used simply to keep the output-end of the cap at ground if the preamp is disconnected, then plugged into a power-amp.
Lower values load the preamp for no reason.
Still, it takes a little time for the output to stabilise - so it is always best to have both amps powered OFF before connecting.
Use 1M ohm. It is used simply to keep the output-end of the cap at ground if the preamp is disconnected, then plugged into a power-amp.
Lower values load the preamp for no reason.
Still, it takes a little time for the output to stabilise - so it is always best to have both amps powered OFF before connecting.
Thanks Rod
it is some big difference to the 83k i use now...once again i must order some new parts.
this is all what diy is about...learn new things,,and the joy when it succeed
just now my 4P1L play with soft and friendly sound,,my 1965 tube plays more soft than my 1980 tube---comes to a matter off taste
i must also say that the Rod Coleman upgrade to ver 7,,is a must have..better sound an more easy to get right DC value..
have also ordered 2 more Rike Qcaps to the output,,,so i will have 3,77uf...
those Rike Qcaps play so well ,,i compare to my Mundorf silver in oil..but The Rike beat them
Best Bjarne
it is some big difference to the 83k i use now...once again i must order some new parts.
this is all what diy is about...learn new things,,and the joy when it succeed
just now my 4P1L play with soft and friendly sound,,my 1965 tube plays more soft than my 1980 tube---comes to a matter off taste
i must also say that the Rod Coleman upgrade to ver 7,,is a must have..better sound an more easy to get right DC value..
have also ordered 2 more Rike Qcaps to the output,,,so i will have 3,77uf...
those Rike Qcaps play so well ,,i compare to my Mundorf silver in oil..but The Rike beat them
Best Bjarne
If you take care to leave the preamp connected at all times, you can disconnect the 82K and see if it sounds/works better! When the power amp input resistance is present, it will keep the input at ground.
One more thing to try,,first i will disconnect ,,and then 1M resistor..
by me i must start the Pre first...my Gryphon amp do not like the DC from the Pre
by me i must start the Pre first...my Gryphon amp do not like the DC from the Pre
Yesterday i removed the 82k from the output
funny funny,,the sound got more clear and clean..easy to hear on female voice,,but i think it make a difference overall on the sound..
the resistor will not come back,,
it once again tell me that the 4P1l pre is a top pre ,everything you do to it can be heard
Best Bjarne
funny funny,,the sound got more clear and clean..easy to hear on female voice,,but i think it make a difference overall on the sound..
the resistor will not come back,,
it once again tell me that the 4P1l pre is a top pre ,everything you do to it can be heard
Best Bjarne
Hello
At last i get rid off my high freqent noise...it comes from the main 230v net
the solution for me was split bobbin trafo from JMS transformer
2 pieces 150va to the Rod Coleman supply
now no noise and absolute no hum..perfekt
next is the Rike Qcaps to output,,comes in a week
Best Bjarne
At last i get rid off my high freqent noise...it comes from the main 230v net
the solution for me was split bobbin trafo from JMS transformer
2 pieces 150va to the Rod Coleman supply
now no noise and absolute no hum..perfekt
next is the Rike Qcaps to output,,comes in a week
Best Bjarne