The YARRA Preamplifier/HPA for Melbourne DB Group Buy

[Mark Johnson]

You're a nonconformist radical, a dangerous freethinker shockingly lacking in reverence for the conventional. A maverick who cares not what other people do.

Perhaps you might consider tracing backwards from your right ear. Start at the right headphone driver, then through the TRS plug on its cord (which does have an industry wide standard for "this one is Left, that one is Right"), through the headphone jack, through the amplifier itself, to the RCA input. Does the right headphone driver get fed from the Left RCA input, or the Right RCA input? Do you care (you are a maverick after all)?

 

[jwjarch]

Throwing my hat in the ring for the custom case. Looking great JPS!

Interest List for Custom Machined Preamp Enclosure:

xrk971 - 1 case - USA
JPS64 - 1 case - USA
gary s - 1 case - Australia
Vunce - 1 case - USA
windwardmt - 1 case - USA
TungstenAudio - 1 case - USA
Meanie - 1 case - Singapore
Roundtoit - 1 case - USA
mordikai - 1 case - USA
afoor - 1 case - USA
Big E - 1 case - Canada
TboneAK - 1 case - USA
Sampsonite - 1 case - USA
jwjarch - 1 case - USA

 

[xrk971]

Good thing the pneumonic of R is right for TRS (tip ring sleeve) so that leaves T for left as S for common. We have all mixed it up once before if not more, but yes, that is a world wide standard. Just as white and red RCA are left and right, respectively. Left as top is probably not important as they are labeled redundantly with red for Right and white for Left.

 

[Mark Johnson]

Why does everybody do it the same way, if it truly doesn't matter? Maybe there is no easy answer.

 

[BRN]

I think for my next build I will configure the power button so it turns off when you push it in. I will take the path less traveled.

 

[JPS64]

I´ve to do two corrections on PCB (silkscreen and verifying switch Eagle definition).


I´ll send tonight the enclosure datas for inquiry to HIFI2000.


Finishing iso exploded view with part list.


Well, seems to end.


JP

 

[xrk971]

Looks great JP!

Is there a provision for a set of ready-to-enlarge pilot holes on the backside of the front panel for a HPA using the Neutrik locking black plastic jack with red release button? I think this requires a central large hole and two diagonal small M3 threaded holes? Where does this go for least chance of mechanical interference and clean aesthetic?

Perhaps between the SOURCE and the "ON" LED holes?, should LED hole be moved over a bit in that case?

Thanks,
X

Neutrik NJ3FP6F-P 1/4" Locking Chassis Jack Plastic Housing

An externally hosted image should be here but it was not working when we last tested it.

I was thinking of something like this - so blind pilot holes would need to be pre-drilled on back side.

 

[JPS64]

Hi X,


as I know two version should be build, one preamplifier and one HPA, after all, two different version?



So I´ll propose two different front plate and the second HPA one will have the NEUTRIK JACK XLR mounting holes.


JP

 

[batty]

I know it is a long shot but has anyone got a BOM with Mouser part numbers, I find it difficult choosing parts.

Also is there a rough price for the Yarra Pre chassis.

 

[batty]

I just swapped out R118 on Melbourne for 1k (5k6 default) and now gain is 30.6dB. Actually a nice setting for my Bluetooth source to drive my MOAMOFO. Can play very nice and loud now. Sounds great.

The removable Melbourne max changing the resistor a snap. Nice ease of use / servicing.

Do you know what gain (and value of R118) would best suit the M2X on the Melbourne boards, I plan to build 2 sets, 1 set for buffers for the M2x and 1 set in the Yarra Pre. My current pre is unity gain (B1 mesmerize).

 

[batty]

Interested in the Yarra case.

xrk971 - 1 case - USA
JPS64 - 1 case - USA
gary s - 1 case - Australia
Vunce - 1 case - USA
windwardmt - 1 case - USA
TungstenAudio - 1 case - USA
Meanie - 1 case - Singapore
Roundtoit - 1 case - USA
mordikai - 1 case - USA
afoor - 1 case - USA
Big E - 1 case - Canada
TboneAK - 1 case - USA
Sampsonite - 1 case - USA
jwjarch - 1 case - USA
batty - 1 case - Australia

 

[md_Stryker]

Interested in the Yarra case.

xrk971 - 1 case - USA
JPS64 - 1 case - USA
gary s - 1 case - Australia
Vunce - 1 case - USA
windwardmt - 1 case - USA
TungstenAudio - 1 case - USA
Meanie - 1 case - Singapore
Roundtoit - 1 case - USA
mordikai - 1 case - USA
afoor - 1 case - USA
Big E - 1 case - Canada
TboneAK - 1 case - USA
Sampsonite - 1 case - USA
jwjarch - 1 case - USA
batty - 1 case - Australia
MD_Stryker - 1 case - USA

 

[xrk971]

This is an excellent level of interest thatnwebhave on the custom case. I hope we can make this happen with a reasonable price.

 

[xrk971]

This is going to be a sweet preamplifier. Can't wait to see the case in real life. JPS64 made this look probably as good or better than many big name professional products. Vunce tells me the populated PSU board alone weighs 3.1 lbs. Still waiting to hear from JPS64 regarding manufacturer's quote.

I have made SW assemblies before, but never anything with this many parts - it is an incredible amount of work to see that it all fits a-priori. I think we also have JPS64's significant other to thank for the SW model. What a lucky guy. I do not know another guy on DIYA whose spouse does audio with him on the same projects! 😀

 

[jhofland]

add me to the interest in the JP's excellent case

xrk971 - 1 case - USA
JPS64 - 1 case - USA
gary s - 1 case - Australia
Vunce - 1 case - USA
windwardmt - 1 case - USA
TungstenAudio - 1 case - USA
Meanie - 1 case - Singapore
Roundtoit - 1 case - USA
mordikai - 1 case - USA
afoor - 1 case - USA
Big E - 1 case - Canada
TboneAK - 1 case - USA
Sampsonite - 1 case - USA
jwjarch - 1 case - USA
batty - 1 case - Australia
MD_Stryker - 1 case - USA
jhofland - 1 case - USA

 

[TboneAK]

What value volume pot is recommended? I'm starting to source non mouser components.

Arrow has the Fischer Heatsinks that JP specs out for the Melb boards.

https://www.arrow.com/en/products/sk...her-elektronik

 

[bk856er]

That's good. Anyone have the full PN for the PS board heatsinks JPS designed for?

BK

 

[Oracle1]

SK 95 25 TO 220 - Heat Sink, TO-220, 36 °C/W, TO-220, 25 mm, 25 mm, 6.5 mm


4621554 farnell

 

[bk856er]

Thanks, Oracle1, but I was referring the the larger heatsinks on the PS board, which seem to be SK104 category.

BK

 

[Oracle1]

SK 104 25,4 LS - Heat Sink, TO-220, 14 °C/W, SOT-32, TO-3P, TO-220, 34.9 mm, 12.7 mm, 25.4 mm


1892326 farnell