My_Ref Fremen Edition GB (fifth run)

[ClaveFremen]

Preface

From the last run I've had several requests for boards, it's possibly time for a fifth run.

This run boards will have a position for a film bypass for C9.

Now the usual 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

On my Google Drive you'll find:

Schematic
BOM
Build Tutorial

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).

Build a complete amp (premium industrial BOM with case, connectors, cabling. 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, 27 price will be fixed and I'll start sending PayPal Invoices, all payments are due by November, 2.

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

Boards will be ordered by November,3 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:

 

[ClaveFremen]

5 kits so far.

Please, after filling in the Google Docs spreadsheet and sending PP info, post also here.

 

[sontero]

excellent initiative.
Are there any changes?

 

[zenit70]

Fantastic! this time I do not lose the opportunity

 

[ClaveFremen]

Are there any changes?

The only one is already in the opening post

This run boards will have a position for a film bypass for C9.

 

[sontero]

The only one is already in the opening post

My God .... it's true. I'm sorry.
I could adopt the same solution on my PCB. You advice this intervention?
I want to inform you but I'm buying for a capacitor C9 a Black Gate, and perhaps, therefore, would not need the bypass.
I also purchased the two ERO 1834 (10 nF and 150 pF) and the Riken for R10.
Many Thanks Dario

 

[ClaveFremen]

My God .... it's true. I'm sorry.

Nothing to be sorry of

I could adopt the same solution on my PCB. You advice this intervention?
I want to inform you but I'm buying for a capacitor C9 a Black Gate, and perhaps, therefore, would not need the bypass.

You can bypass easily C9, simply solder the bypass on C9 pads, on the bottom side of the PCB.

I've added the bypass position to overcome the scarcity of BGs.

Buy the BG only if price is reasonable, prices on eBay are mostly absurd.

When using a BG a bypass is not necessary, sometimes even detrimental.

I also purchased the two ERO 1834 (10 nF and 150 pF) and the Riken for R10.

Good choice, let us know (on the build thread) if and how sound changes.

Many Thanks Dario

You're welcome

 

[macholino]

5 kits so far.

Please, after filling in the Google Docs spreadsheet and sending PP info, post also here.

Hi Dario,
here I am
Thank you so much!

Marco

 

[lehmanhill]

I'm in. again.

I've got a few of the earlier boards to build yet, but I think I want to play around with R10 and the added pads for the Caddocks will help. Besides, I eventually want to be using FE's for each stage of an active crossover. That means I'll need several boards.

For all of you who haven't built one of these yet, jump on board. This is a great amp with lots of helpful people behind it.

Jac

 

[jacorius]

Hi, Time to try this little amp.

 

[ClaveFremen]

with actual numbers (less than 10 kits) each kit will cost 39€ + shipping.

If someone else is interested jump in, even 5 more kits would lead to a price drop to 30€.

 

[lehmanhill]

If we get to 14, I'll make it 15 complete the price drop. I'm not sure what I will do with the extra pair, but these amps are so cool, I will put them to use.

Jac

 

[macholino]

If we get to 14, I'll make it 15 complete the price drop. I'm not sure what I will do with the extra pair, but these amps are so cool, I will put them to use.

Jac

I agree....and I offer my willingness to purchase another kit for reach 15.

Marco


P.S. for me will be ok if we move the closure of the GB at 27

 

[zenit70]

Sono d'accordo sul rinvio della chiusura del GB

 

[Mooly]

Sono d'accordo sul rinvio della chiusura del GB

English only please. RULES

I agree about the postponement of the closure of the GB

 

[mindo]

5 kits so far.

Please, after filling in the Google Docs spreadsheet and sending PP info, post also here.

Hello Dario,

Count me in, Thank You!

 

[ClaveFremen]

The GB is already open until October, 27.

What will be fixed today is the price for invoices I'll send later.

Like I did for the previous GBs, if numbers will allow a price drop the difference will be remboursed.

If by the end of the week partecipants still feels useful to postpone the order date to achieve bigger numbers for me it's not a problem to do it.

 

[zenit70]

English only please. RULES

I agree about the postponement of the closure of the GB

please forgive me

 

[olivosunlight]

Maybe, someone is late to join, just waiting for a couple days.

 

[DrizztDo]

IS this a good project to get in DIY ? I've already soldered components, including smd.

If it is then count me in for 1 kit