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My_Ref Fremen Edition GB (seventh run)

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ClaveFremen

ClaveFremen

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Joined 2005
inserra.it
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#1
Preface

From the requests I'm receiveing via PM it's time to start a new GB...

This run's boards will have a revision on the power supply section and some parts will change so please don't buy the BOM until I will release the updated one.

There will be, for whom is afraid of SMD soldering, the option for boards with SMD parts already soldered for 40€ more per kit, including SMD parts (price to be confirmed after new BOM will be released).

Now the usual (updated) opener:

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

KSTR's measurements on beta boards:

287973d1340049095-my_ref-fremen-edition-beta-build-fine-tuning-thd_imd.gif


On my Google Drive you'll find:

Schematic
Schematic PS
BOM
Build Tutorial
And a YouTube video on SMD soldering of FE modules.

Mouser shared projects (order 2, each project is for a SINGLE board):
Industrial BOM
Industrial BOM without SMD parts
Industrial BOM + Evo A Mod
Industrial BOM + Evo A Mod without SMD parts

Actual price will depend on number of partecipants/kits, the Group Buy is about PCBs only, with an option for SMD populated ones (option price will be confirmed later).

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

10-14 kits 42€
15-19 kits 33€
20-24 kits 28€
25-29 kits 25€
30-39 kits 23€
40-50 kits 21€
100 or more 19€

Shipping prices will be (up to 2 kits, more than 2 will be calculated):

Italy 8€
Europe 12€
Rest of the world apart Oceania 14€
Oceania 16€

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 67€ per board (premium industrial BOM) which can be lowered to 53€ (On a budget BOM).

Build a complete amp (premium industrial BOM with case, connectors, cabling, transformers etc.) 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)

October, 24 price will be fixed and I'll start sending PayPal Invoices, all payments are due by October, 31.

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

Boards will be ordered by November, 1 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:
#17
Opinions wanted

At the end the PCB revion lead to the Fremen Edition 2.0:

attachment.php


I feel it is a much improved design but at the same time it's untested.

What partecipants would prefer?

Try the brand new version with supposed improved distortion and noise immunity or a slightly modified version of the proven design?
 

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#18
ClaveFremen said:
I feel it is a much improved design but at the same time it's untested.

What partecipants would prefer?

Try the brand new version with supposed improved distortion and noise immunity or a slightly modified version of the proven design?
Click to expand...

Regarding my order, i can wait further testing without problems, so you can check the new design taking as long as you need, then send me this new design if everything is OK, or proven old design if anything should go wrong.
 
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