My_Ref Fremen Edition RC - Build thread

[bcmbob]

Spares are a good idea. However, if you use the end of the wick instead of the side, and trim the wick after about 1/4" has absorbed solder, you can draw a lot out with minimum heat. Two - four passes may be required. I heat the wick and then move the iron/wick combo into the solder on the board/chip. Liberal liquid flux on both the board and the wick.

Don't use a lot of downward pressure as the wick can be very abrasive.

[bcmbob]

CORRECTION!!

Here is a correction on my post #883.

"The LF03c is a dual DIP8 discrete opamp, so it won't electrically replace the LF01 .......... The LF03c is meant for DAC, CDP I/V, line stages, etc. which use dual opamps, and provides greater transparency than existing monolithics."

Sorry if I misled anyone. In any case, if it performs at a level matching the LFO1 it will be a valuable addition to the component/s in which it is installed.

[SoIL4x4]

Well I finally have the majority of both of the boards populated with the exception of a few locations. I am expecting an order from mouser any day now with some replacement smd parts and the 220uf caps for c14 that I somehow omitted from my original order. Having said that I am going to replace most of the smd parts just to be on the safe side. It seems a few builders have had issues with that part of the process and now I feel like I have the hang of them I also have to decide what orientation I want to use for c9 and r10. Has there been a consensus reached on the ideal configuration?

I am also a little confused by the different values recommended for c10 22pf or 33pf. I did a quick search but I didn't find much info about this location and the values; any explanation would be great, I am sure I missed it along the way.

Ps. You can see in the photo that I absent mindedly installed a resister in one of the possible r10 locations

[ClaveFremen]

Originally Posted by SoIL4x4

I also have to decide what orientation I want to use for c9 and r10. Has there been a consensus reached on the ideal configuration?

From what I can remember everyone liked best the alternate config:

Originally Posted by SoIL4x4

I am also a little confused by the different values recommended for c10 22pf or 33pf. I did a quick search but I didn't find much info about this location and the values; any explanation would be great, I am sure I missed it along the way.

Pay attention, C10 and C34 are linked and both have alternate values.

C10 and C34 are compensation caps.

The first one (C) is the MyRef Rev C original compensation by Mauro Penasa (the My_Ref designer), well tested and absolutely safe.

The second one (FE) is an alternate compensation, the official (but somewhat experimental) one for the Fremen Edition, and was determined by a trial and listen method by me with Siva's help (simulation and listening).

The (FE) compensation has proved to be stable and safe so far and sounds (much) better according my (and Bob's and others) ears.

Just for clarity:

Rev C compensation

C10 22pF
C34 10pF

Fremen Edition compensation

C10 33pF
C34 27pF

Originally Posted by SoIL4x4

Ps. You can see in the photo that I absent mindedly installed a resister in one of the possible r10 locations

You'll probably desolder it...

[Pandpliers]

Originally Posted by ClaveFremen

Hi John,

yes, it sound better



Sadly no, maybe you could ask if one of the Release Candidate partecipants that buyed spare boards wants to sell them.

In the next months, though, there will probably be a group buy.

Hi This is last information I could find on the group buy . Dou you have any more plans for a group buy in the near future? I would like to buy the pcb's. Please keep us who are eagerly awaiting a chance to build your amplifier posted of any progress. Thanks for all the hard work you have done. I bet it sounds great!

[svon]

This is my design of this amplifier

[voxxonline]

It doesn't look too difficult to populate , right ? I do not have experience with smd, but those look like not the smallest- so hopefully I ll become happy owner of this beauty

[ClaveFremen]

Originally Posted by Pandpliers

Dou you have any more plans for a group buy in the near future? I would like to buy the pcb's. Please keep us who are eagerly awaiting a chance to build your amplifier posted of any progress.

The Group Buy for the final version will probably start this February.

The final PCBs are quite identical to RC ones with the following differences:

• some holes are larger
• no more alternatives for C9/R10 arrangement
• some DMM readings are indicated on PCB

Originally Posted by Pandpliers

Thanks for all the hard work you have done. I bet it sounds great!

You're welcome.

Sure it sounds great!

Originally Posted by svon

This is my design of this amplifier

Hi Svon,

interesting work but it seems a standard My_Ref, isn't it?

Originally Posted by voxxonline

hopefully I ll become happy owner of this beauty

Are you referrring to the Fremen Edition or Svon's work?

[voxxonline]

Oh, I see
Never mind- February is soon

[voxxonline]

Guys, how do you think will FE match well with passive buffer or it needs active pre ?