I still have to get the Yarra verification PCB from the factory (probably another 5 days), then build it (another week). If no errors, order final set of production boards. Another week maybe 10 days, then send out. Looks like 3 more weeks until I ship final board.
The case, I have no idea - we are lucky that JPS64 and his wife are doing the professional mechanical design for us for free, so we can't rush that. Once the design is done, then we need to get quotes from vendor. Probably 3-6 weeks more?
The case, I have no idea - we are lucky that JPS64 and his wife are doing the professional mechanical design for us for free, so we can't rush that. Once the design is done, then we need to get quotes from vendor. Probably 3-6 weeks more?
YARRA enclosure - weekend progress
Hello,
IO and PSU PCB placed and rear plate drilled (silkscreen or digital printing later).
We´ll place tomorrow the preamplifier with Melbournes and check the different spacer for the different potentiometer variants.
Finishing with engraving.
Hoping finishing middle of next week so we would inquire and get an offer till end of coming week.
P.S.: someone who can/will share (Google Drive) 3D PDF (1.39MB) so I´ll send him file with email.
JP
Hello,
IO and PSU PCB placed and rear plate drilled (silkscreen or digital printing later).
We´ll place tomorrow the preamplifier with Melbournes and check the different spacer for the different potentiometer variants.
Finishing with engraving.
Hoping finishing middle of next week so we would inquire and get an offer till end of coming week.
P.S.: someone who can/will share (Google Drive) 3D PDF (1.39MB) so I´ll send him file with email.
JP
Attachments
The version 1 verification build boards are here. They are 1.6mm but with 2oz copper and ENIG. These are perhaps the largest amplifier boards I have ever seen - about the size of a PC motherboard before you break apart the small sub panels. Here are some photos plus detailed closeups to show the master strokes of JPS64 at work. This is true art. Thank you JP for an superb layout and design!
Top:
Bottom:
Detail of Cap Mx PSU (thanks to design inspired by Prasi):
Left and Right ground planes split down the middle of a 4-pin JST jack:
Detail of the 3 different volume pot boards for connecting the wires with less strain:
Detail of the nice curved AC primary traces from the IEC to the transformers:
Top:
Bottom:
Detail of Cap Mx PSU (thanks to design inspired by Prasi):
Left and Right ground planes split down the middle of a 4-pin JST jack:
Detail of the 3 different volume pot boards for connecting the wires with less strain:
Detail of the nice curved AC primary traces from the IEC to the transformers:
Attachments
Last edited:
Since we are going with a 2U case, I will be going with the 25VA Talema’s with 22v output.
https://www.digikey.com/products/en?keywords=Talema 70065k
With a circa 3v drop across the cap Mx we should easily get 27v rails out of this preamp. Enough to drive 50w 6.8ohm load with an amp stage that has 0dB gain. Also works to drive 40Vpp 8ohm loads with amps like F4. The gain resistor will have to be adjusted to hit these higher output voltages though from a normal RCA level line input.
https://www.digikey.com/products/en?keywords=Talema 70065k
With a circa 3v drop across the cap Mx we should easily get 27v rails out of this preamp. Enough to drive 50w 6.8ohm load with an amp stage that has 0dB gain. Also works to drive 40Vpp 8ohm loads with amps like F4. The gain resistor will have to be adjusted to hit these higher output voltages though from a normal RCA level line input.
Last edited:
Unfortunately will have to break the PSU board off and fold it over. Or else it is measures 12in x 9in, larger than a regular large envelope. It pains me to break the panel. If you really want it whole - it will cost more to ship but can be done.
Hi JP,
Can we also get a partially drilled through rebate and pilot hole from the back for anyone wishing to add a headphone connector? Not sure where it would go but perhaps on right side? Maybe for Neutrik black plastic locking jack with red push button and two screws?
Thanks!
X
For example:
Neutrik NJ3FP6C-BAG Locking 1/4" TRS Stereo Jack (Black)
Can we also get a partially drilled through rebate and pilot hole from the back for anyone wishing to add a headphone connector? Not sure where it would go but perhaps on right side? Maybe for Neutrik black plastic locking jack with red push button and two screws?
Thanks!
X
For example:
Neutrik NJ3FP6C-BAG Locking 1/4" TRS Stereo Jack (Black)
Progress on verification build: PSU is populated mostly. That’s a lot of caps! Quite heavy now with all those Panasonic FCs and Nichicon KWs. Will use a temporary external trafo to apply power while waiting for Talema to arrive.
Attachments
Neat work X on the power supply, looks impressive.
Another question for you X, I assume you will be posting a BOM in association with JPS as to what parts the enclosure has been designed around. I am talking about things like the mains IEC entry socket, RCA female connectors, input select switch and extension shafts, volume and input knobs etc.... Taking that to another level, have you thought about offering these parts together with the enclosure to offer a complete enclosure kit?
Also an up to date BOM on all parts used (where there might have been a change or 2) for the items on all PCB's to do with the Yarra preamp board set, will be available once the boards are ready to go?
Another question for you X, I assume you will be posting a BOM in association with JPS as to what parts the enclosure has been designed around. I am talking about things like the mains IEC entry socket, RCA female connectors, input select switch and extension shafts, volume and input knobs etc.... Taking that to another level, have you thought about offering these parts together with the enclosure to offer a complete enclosure kit?
Also an up to date BOM on all parts used (where there might have been a change or 2) for the items on all PCB's to do with the Yarra preamp board set, will be available once the boards are ready to go?