Those are the ones I was searching for! Thanks for the part # Jim.
I'm pretty lame when sourcing parts. I don't know how I pulled the trigger on what I got. I guess I was in too much of a hurry to pay attention to details!
I hope you are both doing well under the current situation! Stay safe & healthy!!!
I'm pretty lame when sourcing parts. I don't know how I pulled the trigger on what I got. I guess I was in too much of a hurry to pay attention to details!
I hope you are both doing well under the current situation! Stay safe & healthy!!!
Permission granted.
The PCBs just arrived. JPS64 did a nice job on the layout.
Thank you, Mr. Pass.
In these dreary home quarantine corona virus times, I am hoping many of you get to do some extra DIY.
Please note that Mark Johnson has cautioned that the max output of the H2 circuit is 2Vrms per measurements provide by Mr Pass. The M2X requries 3Vrms to hit maximum signal. So you may want to use it more as a preamp in the Yarra format mainboard. There miught be a circuit tweak possible to allow it to run to 3Vrms output - but that will be up to you to figure out. Also, the board is given freely as-is and I have not tested it yet.
I have 20 of these H2 boards that I will be giving away, you just need to pay for postage, PayPal fees, and packaging costs. Limit one pair per person. Shipping (no tracking) is $4 in US and $6 CAN, $7 everywhere else. Please put your name and country in the list below. First come first serve.
Stay well and safe!
Cheers,
X
####################
Name Country
JohnDoe USA
Please note that Mark Johnson has cautioned that the max output of the H2 circuit is 2Vrms per measurements provide by Mr Pass. The M2X requries 3Vrms to hit maximum signal. So you may want to use it more as a preamp in the Yarra format mainboard. There miught be a circuit tweak possible to allow it to run to 3Vrms output - but that will be up to you to figure out. Also, the board is given freely as-is and I have not tested it yet.
I have 20 of these H2 boards that I will be giving away, you just need to pay for postage, PayPal fees, and packaging costs. Limit one pair per person. Shipping (no tracking) is $4 in US and $6 CAN, $7 everywhere else. Please put your name and country in the list below. First come first serve.
Stay well and safe!
Cheers,
X
####################
Name Country
JohnDoe USA
Last edited:
I had one spare board (number 21) so populated it just to make sure it works. I followed the schematic diagram and used basic cheap no-name metal thin film 1% resistors, a 10uF 35v Silmic II for the output cap (+ve facing the JFET), and a set of paralleled J113 JFETs to get enough bias current per the schematic as designed for J112. I did not have a TO92 LM317, but a TO220 fits just fine in the same pads. I stuck the second J113 underneath the PCB poking up throught the same hole. I happened to have a Hakuin preamp on a plank handy and pulled off the right channel fot he Hakuin and put the Pass H2 in. After reading the H2 article, I see that an input cap is actually not needed since the JFET gate is referenced to ground via the 33k resistor. So with a 24.5v power supply rail, I measured 27mA (close to the 30mA specified for the design) bias current through the parallel J113's. That was a kluge that happened to work out very well. Anyhow, listeming to it through my Alpha Nirvana 40w SE Class A amp, and my B80/RS225 Transient Perfect FAST speaker - it sounds great! Vert musical. Very quiet. So the circuit is now verified to work. Very easy to build and quite exciting to listen to. You guys will have fun.
Here is the B80/RS225 FAST speaker and the Alpha Nirvana amp setup:
Here is the Pass H2 mounted on the Hakuin amp on a plank (right channel):
Closeup (2nd J113 not visible as it is underneath):
Here is the B80/RS225 FAST speaker and the Alpha Nirvana amp setup:
Here is the Pass H2 mounted on the Hakuin amp on a plank (right channel):
Closeup (2nd J113 not visible as it is underneath):
Attachments
Last edited: