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My_Ref Fremen Edition GB (fourth run)

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ClaveFremen

ClaveFremen

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Joined 2005
inserra.it
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#1
********** GB is closed and all extra boards are gone **********

Preface:

Third run My_Ref Fremen Edition PCBs were still shipping and I've been requested to organize a fourth run...

Until today people has 'booked' for it, now the fourth run is officially open with already 29 booked kits.

Now 'bookers' are invited to PM me their PP associated email address and new partecipants are invited to sign up on the Google Spreadsheet and PM the PP account.

Now the usual opener with complete GB conditions:

The My_Ref Fremen Edition is a variation of Mauro Penasa's My_Ref with this goals:

  • a more stable and performing amp using SMD parts
  • raise LM318's PS voltage thanks to a voltage limiter
  • better PS for LM318
I've designed a brand new PCB with these features:

  • bigger caps (16mm diameter with both 7 and 5 mm pads) for C1, C2, C9
  • large use of SMD components
  • quite all small caps and some critical resistors are still through-hole
  • very small paths thanks to SMD
  • ground planes design
  • zener limiter based on schematic 5b from this link (which seems pretty similar to My_Evo one)
  • CCS shunt PS for the LM318
  • An alternate C9/R10 arrangement
  • Different grounding
  • Different compensation
  • a double diode bridge like in most gainclones
Both PCB and schematic have been tested organizing beta and release candidate mini group buys

I've been authorized by Mauro Penasa to proceed with this My_Ref derivate amp.





You can find references on development, beta and release candidate here:

My_Ref Fremen Edition - need help on PCB evaluation - diyAudio
My_Ref Fremen Edition - Beta build/Fine tuning - diyAudio
My_Ref Fremen Edition RC - Build thread - diyAudio
My_Ref Fremen Edition - Build Thread

On my Google Drive you'll find:

Schematic
 BOM
Build Tutorial
There's also a shared Mouser BOM to order parts.

And a YouTube video on SMD soldering of FE modules.

Actual price will depend on number of partecipants/kits, the Group Buy is about PCBs only

Approximate prices (one kit = 2 PCBs, PayPal fees and 1€/kit donation to DIY audio included):

10-14 kits 38€
15-19 kits 30€
20-24 kits 26€
25-29 kits 24€
30-39 kits 22€
40-50 kits 20€
100 or more 16€

Shipping prices will be (for each kit, for 2 kits add 1€, more than 2 will be calculated):

Italy 7€
Europe 10€
Rest of the world apart Oceania 13€
Oceania 14€

PCBs (circa 12 x 10.5 cm) will be blue, 2mm tick, 2 Oz/70um copper, gold plated, made in Italy.

One transformer 160VA-300VA will be needed for each board (monoblock design)

BOM cost is around 76€ per board (premium industrial BOM) which can be lowered to 52€ (On a budget BOM).

A complete amp (premium industrial BOM) will cost around 450€ and up.

If interested please PM me your PayPal associated email address and fill your nickname, country (2 letter code) and number of kits on the Google Spreadsheet (please leave blank the 'PP account sent' column, I'll fill it so you have a feedbakc that I've received your data)

December, 22 price will be fixed and I'll start sending PayPal Invoices, all payments are due by January, 5.

Until order is done it will be possible to partecipate to the GB

Boards will be ordered by January,7 and should be in my hands in 15-20 days, then packaged and shipped in a week or so.

Greetings:
Mauro Penasa for his great design and kind permission
LinuxGuru for his help on new compensation
Luka for the LM318 PS initial design
KSTR for the new C9, R10 arrangement.
Soongsc, Marce, Sebaastian, KSTR and Metal for help on PCB design
BMCBob for all support, tests and reviews

Images of boards from the first GB:



 
Last edited:
#5
A lot of PP addresses missing...

A not small number of PP associated addresses are missing... so I must fix the price on the number of confirmed kit (26).

So price will be 24€ per kit (2 PCBs).

If all of the missing confirm before December,31 I'll try to update price and rembourse the difference.

Turbon said:
Any changes in schematic, BOM or PCB from the third run?
Click to expand...

None but maybe someone may have missed that the suggested 'audiophile' cap for C13 is now a Mundorf Supreme instead of Audyn True Copper.
 
#18
still4given said:
I'm sorry, I should have looked more closely. I didn't realize this is a chip amp. I will be removing my name form the list for boards.
Click to expand...

Hi Terry,

the My_Ref it's not exactly a chipamp... the LM3886 is used only as a current pump driven by the LM318, the latter determine sound performance.

It has it's roots on Musical Fidelity A-370 and it's somewhat similar to Quad 405 in concept.

The fact that it uses a power opamp does not make it a 'real' chipamp...and it outperforms a lot of discrete designs, too. 😉

BTW no problem 🙂
 
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