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The YARRA Preamplifier/HPA for Melbourne DB Group Buy
The YARRA Preamplifier/HPA for Melbourne DB Group Buy
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Old 25th February 2019, 01:46 AM   #1
xrk971 is offline xrk971  United States
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The YARRA Preamplifier/HPA for Melbourne DB Group Buy
Default The YARRA Preamplifier/HPA for Melbourne DB Group Buy

Edit June 12, 2019 - due to the huge logistical and time commitment issues of providing large GB’s via my old PayPal invoice method, I will be switching to using Etsy for handling GB orders. Yarra is now available here:
Yarra Class A modular preamplifier PCB | Etsy


This is the integrated preampflifier/headphone amplifier based on the Melbourne daughterboard which uses the Aksa-Lender topology. More on the Melbourne here. The Yarra river runs through Melbourne, so it seemed like a fitting name for the daughterboard the resides on it. The Yarra will provide a power supply based on a BJT capacitance multiplier fed by a linear toroidal transformer. The output of the capacitance multiplier is further smoothed by the built-in CRCRC aboard each Melbourne DB. The Yarra also provides for extra room for boutique coupling capacitors, your choice of volume pots (4 different formats), an input selector switch and double RCA outputs plus a HPA jack output. The nice thing about the Yarra is that you can switch out the Melbourne modules easily if you want to try different gains, or even different bias currents etc. They are easy to make and cost effective little core units that are available on a separate GB here. the Yarra is a dual monoblock design with separate power transformers and separate capacitance multipliers for the lowest noise, and highest channel separation, and it helps to eliminate ground loops.

Thanks so much to JPS64 for yet another masterpiece in layout design!
And of course, thank so much to Aksa for the Aksa-Lender core circuit!
And thanks to Prasi for the design of the BJT capacitance multiplier which was the inspiration for the one used here!

Here is the 3d render of the Melbourne DB (v2):
Click the image to open in full size.

Here is the schematic for the Yarra:
Click the image to open in full size.

Here is the 3d render with the components mounted:
Click the image to open in full size.

Here is the render of the PCB showing JPS64's trademark via stitching:
Click the image to open in full size.

Here are how the parts are placed on the board. The toroidal transformers are 20W Talema's.
Click the image to open in full size.

So i am trying to determine interest in this project. The boards will probably be 1.6mm thick and 1oz copper but with ENIG finish and blue color solder mask. These are rather large boards at 299mm x 227mm so will probably end up being about $40ea.

Edit Mar 2, 2019 - changes to shipping costs:
If you are interested, please add your name, qnty of boards desired, and country to ship to below. Shipping will be $8 in CONUS, $18 CAN, and $23 everywhere else for up to 1 board plus up to 4 Melbourne DB's should you order those in this GB, and additional boards will be extra (TBD).

Edit Feb 25, 2019: If you want to get the Melbourne DB that is goes with the Yarra, you can add it to your order here at $10ea with no extra charge for shipping.

Thanks,
X

Example of sign-up list:
Quote:
DIYA_Johndoe - 1 Yarra - USA
DIYA_Janedoe - 2 Yarra, 4 Melbourne - UK
etc...

Edit Mar 2 2019, Yarra BOM here:
https://www.diyaudio.com/forums/atta...om_v1c_raw-zip

Edit Mar 5, 2019: What parts on Melbourne can be left off if using on Yarra?
Click the image to open in full size.

Edit March 24, 2019: HPA centric schematic for driving low impedance headphones.
Click the image to open in full size.

Edit April 14, 2019: Final Production Layout Schematic and Placement Guide:
The YARRA Preamplifier/HPA for Melbourne DB Group Buy

Here is the Mouser shopping cart (revised to include Schurter EIC) and other miscellaneous parts as provided by Vunce:
https://www.mouser.com/ProjectManage...9-285a2544070b

Edit May 3, 2019 - pricing on Yarra custom case is 101Euro ea for minimum order of 20.
Please sign up for GB in list here (and beyond):
The YARRA Preamplifier/HPA for Melbourne DB Group Buy

Edit July 12, 2019: Schematic for PCA daughterboard:
Click the image to open in full size.
Attached Images
File Type: png Melbourner-MB-3d-01.png (929.2 KB, 2530 views)
File Type: jpg Melbourner-MB-3d-02.jpg (453.7 KB, 2502 views)
File Type: png Melbourne-top-parts-placement.png (182.5 KB, 2574 views)
File Type: png Melbourne-schematic-v1-image.png (547.8 KB, 2721 views)
Attached Files
File Type: pdf YARRA_SCH_001a.pdf (81.7 KB, 141 views)
File Type: pdf YARRA_PBA-TOP_001a.pdf (62.7 KB, 78 views)
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Last edited by xrk971; 13th July 2019 at 02:52 AM.
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Old 25th February 2019, 02:17 AM   #2
Vunce is offline Vunce  United States
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The YARRA Preamplifier/HPA for Melbourne DB Group Buy
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Old 25th February 2019, 02:19 AM   #3
zman01 is offline zman01  Bangladesh
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Old 25th February 2019, 02:29 AM   #4
xrk971 is offline xrk971  United States
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The YARRA Preamplifier/HPA for Melbourne DB Group Buy
Haha, the Aksa fan club returns!
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Old 25th February 2019, 02:37 AM   #5
Vunce is offline Vunce  United States
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The YARRA Preamplifier/HPA for Melbourne DB Group Buy
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I’ll keep going back!
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Old 25th February 2019, 03:06 AM   #6
twitchie is offline twitchie  Canada
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The YARRA Preamplifier/HPA for Melbourne DB Group Buy
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twitchie- 1 board set - Canada
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Old 25th February 2019, 03:37 AM   #7
BRN is offline BRN  United States
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Old 25th February 2019, 03:59 AM   #8
Roundtoit is offline Roundtoit  United States
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Old 25th February 2019, 04:35 AM   #9
Russellc is offline Russellc  United States
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The YARRA Preamplifier/HPA for Melbourne DB Group Buy
I'm in for a set!

Vunce - 1 board set - USA
zman01- 1 board set - USA
twitchie- 1 board set - Canada
BRN - 1 board set - USA
Roundtoit - 1 board set - USA
Russellc- one board set. USA
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Old 25th February 2019, 06:29 AM   #10
maty tinman is offline maty tinman  Spain
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I upload an image so that everyone can see it without having to be registered in the forums. And for image searchers too.

YARRA Preamplifier with HPA

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[IMG, link] http://maty.galeon.com/WP-imagenes/h...rne-design.png
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