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The YARRA Preamplifier/HPA for Melbourne DB Group Buy

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R

redjr

Member
Joined 2011
xrk971 said:
Hi YOB,
Glad you found this in your perusals.

The Melbourne is indeed similar to Aksa Lender Preamp but dual rail, more importantly, is DC coupled, if you wish. It also has a topology tweak on the output - it has a mu-follower which enables it to drive lower impedance loads at lower distortion. This was needed since the 600ohm Edcor on M2x was quite a difficult load for the regular Aksa Lender. Maybe the HPA version would have faired better - but I needed dual rail to be compatible with M2X.

You can indeed use same awesome PSU from the ppm distortion HPA project. However that’s a 18v supply and the Melbourne likes 24v to 30v dual rail.

It’s got a lot of SMT though so the YARRA is pretty much all TH, which works well for a lot of folks. The use of linear trafos and cap multipliers also makes this PSU one of the best around. It can handle loads in excess of 1A depending on your trafo and diodes.

Jump on in if you want. Get the Melbournes at least and play with them.
Click to expand...
Thanks X for this explanation. I've joined the party late and was wondering the same thing. I will look on Esty to see if there are Mel DBs still available to purchase. I received the Korg 6P1 kit PCBs last week, along with the PCA DBs as a courtesy from you. Thanks! I just sent an order off to Mouser and Digi-key for parts.

Looking forward to the build.
 
R

redjr

Member
Joined 2011
2.2mfd 63v 5mm WIMA Film Cap

Anyone know of a ready source for these caps. Having a difficult time finding any of them at the big parts houses. (Mouser, Digi-key). They are out of stock at Mouser and won't be back in until, "will advise" :(

MKS2C042201K00JO00
2.2 uF 63 VDC 5%
WIMA Film Capacitors

In the meantime I've ordered some from China, but they likely won't show up until Christmas, and may not be authentic! Urgh. It's been my experience, that WIMAs are hard to find caps with 5MM lead spacing.

Is there an equally as good substitute brand for this preamp?
 
Mark Johnson

Mark Johnson

Member
Joined 2011
Paid Member
An octopart.com search found only two distributors for those caps, one of whom has a minimum order quantity greater than 1000 pieces. It might be a good idea to widen your search to include different voltage ratings and/or different tolerances and/or different capacitance values and/or different lead spacings and/or different manufacturers.
 
R

redjr

Member
Joined 2011
Mark Johnson said:
An octopart.com search found only two distributors for those caps, one of whom has a minimum order quantity greater than 1000 pieces. It might be a good idea to widen your search to include different voltage ratings and/or different tolerances and/or different capacitance values and/or different lead spacings and/or different manufacturers.
Click to expand...

Well, the value itself must have been chosen for a reason based on the designer. Also, the daughter boards are fairly well compact with parts, so a different lead spacing and/or voltage rating may not fit properly. I like to use what is specifically called out for in the BOM - within reason. I know, I know my OCB at play here! :)

As I mentioned... If there are just as suitable other brands and lines that can compete with the WIMAs, I will make appropriate substitutions.
 
H

Hicoco

Member
Joined 2018
Paid Member
redjr said:
Anyone know of a ready source for these caps. Having a difficult time finding any of them at the big parts houses. (Mouser, Digi-key). They are out of stock at Mouser and won't be back in until, "will advise" :(

MKS2C042201K00JO00
2.2 uF 63 VDC 5%
WIMA Film Capacitors

In the meantime I've ordered some from China, but they likely won't show up until Christmas, and may not be authentic! Urgh. It's been my experience, that WIMAs are hard to find caps with 5MM lead spacing.

Is there an equally as good substitute brand for this preamp?
Click to expand...
Min. amount:1050 for MKS2C042201K00JO00 now for 5 you can try Here but 10%
 
R

redjr

Member
Joined 2011
Here is the Mouser shopping cart (revised to include Schurter EIC) and other miscellaneous parts as provided by Vunce:
Project & Cart Sharing | Mouser
Click to expand...

X, Would you please re-link the Mouser project BOM for Yarra. The link above doesn't seem to work for me. Is it still active? Is there an access ID required? I'm assuming it's a shared project?
 
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