The YARRA Preamplifier/HPA for Melbourne DB Group Buy

[Vunce]

WBA 2018 preamp DB List:

JPS64 - 2 boards
xrk971 - 2 boards
Vunce - 2 boards
Roundtoit - 2 boards
Carl Huff - 2 boards
Gary S - 2 boards
Meanie - 2 boards
Big E - 2 boards
Kokanee - 2 boards + 1 Yarra MB
MD_Stryker - 2 boards
arthur - 6 boards,if possible, 3 Yarra boards
afoor - 2 boards
Russellc - 2 boards
jhofland - 2 boards
Oracle1 - 2 boards
skunark - 4 boards, 1 yarra board
TungstenAudio - 2 boards
bologna1 - 2 boards
windwardmt - 2 boards
ZUM911 - 2 boards
Batty - 2 boards
bk856er - 2 boards (+ interest in a surface mount version)
Modman - 2 boards
sampsonite - 2 boards
TboneAK - 2 boards - 1 Yarra board set
BEYoung - 4 boards
mordikai - 2 boards
Asuslover- 2 Melbourne boards+ 1 Yarra board

Thank you

 

[vvs07]

WBA 2018 preamp DB List:

JPS64 - 2 boards
xrk971 - 2 boards
Vunce - 2 boards
Roundtoit - 2 boards
Carl Huff - 2 boards
Gary S - 2 boards
Meanie - 2 boards
Big E - 2 boards
Kokanee - 2 boards + 1 Yarra MB
MD_Stryker - 2 boards
arthur - 6 boards,if possible, 3 Yarra boards
afoor - 2 boards
Russellc - 2 boards
jhofland - 2 boards
Oracle1 - 2 boards
skunark - 4 boards, 1 yarra board
TungstenAudio - 2 boards
bologna1 - 2 boards
windwardmt - 2 boards
ZUM911 - 2 boards
Batty - 2 boards
bk856er - 2 boards (+ interest in a surface mount version)
Modman - 2 boards
sampsonite - 2 boards
TboneAK - 2 boards - 1 Yarra board set
BEYoung - 4 boards
mordikai - 2 boards
Asuslover- 2 Melbourne boards+ 1 Yarra board
vvs07- 4 boards + 2 Yarra boards


Thank you!

 

[xrk971]

Looks like I ha e enough interest for a Yarra GB2.

 

[BDP]

WBA 2018 preamp DB List:

JPS64 - 2 boards
xrk971 - 2 boards
Vunce - 2 boards
Roundtoit - 2 boards
Carl Huff - 2 boards
Gary S - 2 boards
Meanie - 2 boards
Big E - 2 boards
Kokanee - 2 boards + 1 Yarra MB
MD_Stryker - 2 boards
arthur - 6 boards,if possible, 3 Yarra boards
afoor - 2 boards
Russellc - 2 boards
jhofland - 2 boards
Oracle1 - 2 boards
skunark - 4 boards, 1 yarra board
TungstenAudio - 2 boards
bologna1 - 2 boards
windwardmt - 2 boards
ZUM911 - 2 boards
Batty - 2 boards
bk856er - 2 boards (+ interest in a surface mount version)
Modman - 2 boards
sampsonite - 2 boards
TboneAK - 2 boards - 1 Yarra board set
BEYoung - 4 boards
mordikai - 2 boards
Asuslover- 2 Melbourne boards+ 1 Yarra board
vvs07- 4 boards + 2 Yarra boards
BDP - 2 boards - 1 Yarra board


Thank you!

 

[BRN]

WBA 2018 preamp DB List:

JPS64 - 2 boards
xrk971 - 2 boards
Vunce - 2 boards
Roundtoit - 2 boards
Carl Huff - 2 boards
Gary S - 2 boards
Meanie - 2 boards
Big E - 2 boards
Kokanee - 2 boards + 1 Yarra MB
MD_Stryker - 2 boards
arthur - 6 boards,if possible, 3 Yarra boards
afoor - 2 boards
Russellc - 2 boards
jhofland - 2 boards
Oracle1 - 2 boards
skunark - 4 boards, 1 yarra board
TungstenAudio - 2 boards
bologna1 - 2 boards
windwardmt - 2 boards
ZUM911 - 2 boards
Batty - 2 boards
bk856er - 2 boards (+ interest in a surface mount version)
Modman - 2 boards
sampsonite - 2 boards
TboneAK - 2 boards - 1 Yarra board set
BEYoung - 4 boards
mordikai - 2 boards
Asuslover- 2 Melbourne boards+ 1 Yarra board
vvs07- 4 boards + 2 Yarra boards
BDP - 2 boards - 1 Yarra board
BRN - 2 boards

Thank you

 

[gary s]

I make that total up to 70 now for Wayne's BA18 Yarra daughter board line stage.

 

[xrk971]

Wow, that BA18 is going fast. You guys are giving me no rest with the whole stuffing envelopes. I am wondering if there is an easier format for doing the boards. Maybe I can just have you guys order via my Etsy shop? That way, the whole tracking and logistics is a lot easier.

Btw, here is the first measurement of the Yarra/Melbourne. Looks like it's working very well with only 0.00088% THD at 2.0Vpp.

I just got a 2ppm 1kHz oscillator and had to try it out.

 

[gary s]

Impressive specs X, perhaps you need a PA to help with all the logistics.

 

[JPS64]

last ADD-ON: HPA...

 

[xrk971]

Hi JP,
What circuit are you using to drive the headphones? The Melbourne can actually drive phones directly if one increases bias current to 70mA and reduces voltage.

 

[xrk971]

The verification build WBA18 PCBs arrived today, along with another batch of Melbournes. I am still waiting for the BOM from Mouser to arrive. If I had ordered it from Arrow it would have been here 4 days ago.

 

[gary s]

That PCB looks as "busy" as the Melbourne DB's.

Looking forward to getting hold of these as well.

 

[gary s]

One question I have for you X, do you have a BOM or parts list that lines up with the parts as shown screen printed on the two daughter boards for the Melbourne and BA18. It looks like the screen printed parts are shown abbreviated - probably due to very tight space restrictions.

If you could point us to post numbers for this or list them again that would help members who will be assembling these PCB's in the near future, anything to help so mistakes will not be made is very helpful.

 

[xrk971]

Hi Gary,
The WBA18 is still the verification build PCB - I haven't released the BOM or placement guide yet because I want to make sure they are good.

I guess there is probably no harm in releasing the BOM early if you want to do some shopping for parts first...

So these are still preliminary, please use the latest version once I verify the board works and order the final production boards.

Below are the BOM (in zipped CSV format), the stuffing guide and the schematic.

 

[gary s]

Hi X, I have the parts already for a BA18 build with Wayne's original purple PCB, but will use these together with any differences you might have with your verification build, to put together these for the Yarra.

Can you point me to the BOM and placement guide for the Melbourne DB, thanks.

 

[xrk971]

Please see bottom of post 1 of the Melbourne GB thread:

Melbourne Daughterboard for M2X

 

[gary s]

Thanks for the answers X, and the BA18 info, will keep an eye out for any changes after you build it up and test.

 

[jwjarch]

X, what kind of gain and voltage will you get out of the WBA18 boards with the Yarra? The original Wayne’s boards get about 12db gain. I have those as a Preamp driving an ACA with 4ohm speakers and it’s barely had enough gain to keep up. And i'm using 18v rails as well.

 

[xrk971]

Hi Jwjarch,
The standard WBA18 design, per Wayne is to have R121 at 10k and R122 at 27k. Gain is set by G=(R121+R122)/(R121), currently gives 3.7x or 11.4dB (not much).

For a little more oomph, you could use R121=3k and R122=27k for 20db gain.

 

[jwjarch]

Thanks for the tip X. Does this affect the heat at the outputs? I only have TO-92 transistors with no sinks. They already get noticeably warm/hot. Planing to swap to TTA004 and TTC004's eventually.