My_Ref Fremen Edition - Beta build/Fine tuning

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Are you wanting builders with sophisticated test equipment or just ears and a DMM? If the later, I would be in for a pair.

The goal is to reach 20 partecipants so that cost will be around 30€ (circa 39US$) per PCB pair (2mm, 70um, chemical gold) plus shipping.

So any type of builder is welcome. ;)

So far:

  1. ClaveFremen
  2. Suburra
  3. SoIL4x4
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Boards will be made in Italy in 15 working days from the order.


The boards can be populated entirely with Mouser parts.


Later I'll post the exact cost of Mouser BOM.
 
Later I'll post the exact cost of Mouser BOM.

A full Mouser BOM, that includes mounting hardware, (for both PCBs) will cost 206.64US$ / 157,78€.

The BOM includes premium industrial parts like Caddocks, Susumus, Nichicon FGs, Wima and ERO film/foil caps.

Fancy but effective parts like Mundorf Zn/Audyn True Copper and Mundorf MLythic AG can replace the input cap and big smoothing caps and will cost more 130US$/100€ (for both PCBs).

To complete the amp the necessary is:

  • 2x 160VA 2x25V transformers (higher VA rating is better, 300VA is ideal)
  • 4x binding posts
  • 2x rca sockets
  • case
  • wire/solder/etc.
I've made a Release Candidate Google Docs folder with BOM and schematic.
 
A full Mouser BOM, that includes mounting hardware, (for both PCBs) will cost 206.64US$ / 157,78€.

Maybe BOM's price point could scare someone... ;)

It must be taken in account that it can be lowered without sacrificing too much quality:


  • -19$ if you already have hardware and don't want connectors
  • -30$ if you replace Caddock MP930 with MP915, MP915 with KOA SPR and MK132 with carbon films.
  • -4$ if you buy Tawain Semi MUR820
This more budget oriented BOM would cost 153US$
 
Is Kiwame and KOA Speer the same company ?

A lot of people, including me, trust that Kiwame are rebranded KOA SPR.

In fact they look (and sound) identical.

Will C102-C202 be omited from this PCB run ?

There is still the position but they're optional, to be mounted only if needed.

One application where they could be needed is a Rev A with a different opamp.

What is the output of the LED header ?

19.5V (+ on the right)

I modified the slip-on heatsinks I bought for IC101 (LM317) to work on R3. My boards are now populated so I just need to attach heatsinks and hook up Trafos.

Well done!

I can't wait to read your comments. :)
 
A little Show & Tell

Here are the FEs with the new giant Antek 300VA toroids. Listening now to a live Reno Big Band album and the sound is simply gorgeous, powerful, unrestrained in any way.

Tomorrow hopefully, some more Caddocks and a trial without C102/202 will happen. Still comparing ZNs and Sonicaps with sockets.

That's the Mini2496 DAC with Dario's up bump in the background.:D
 

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Here are the FEs with the new giant 300VA toroids. Listening now to a live Reno Big Band album and the sound is simply gorgeous, powerful, unrestrained in any way.

So the bigger toroids are a worthwile improvement, right?

Tomorrow hopefully, some more Caddocks and a trial without C102/202 will happen. Still comparing ZNs and Sonicaps with sockets.

I'll read your comments with interest. :)

If you have at hand some FKP2 swap the FKS2 with FKP2, after last tests I feel those are the best available ones for those positions (best are the out of production ERO KP1834 I've sent you for C7).
 
Yes, the bigger toroids add a tad more power but most remarkable is just the solidity and the feeling / impression of a relaxed effort to produce big dynamic changes. A 200 might well have been enough, but no way am I sorry I got these.

As soon as I get the sockets (prob late afternoon tomorrow) I'll be back in swap city.:whazzat:
 
Thanks, The 200 (in my integrated amp) and the 300 have about the same diameter but the later is about 1/2" taller.

Like SoIL4x4 I'm also considering mono blocks. They could be placed near or on the speakers like Sunflower builder Jason did with his crossovers. My XOs will go back inside after tweaking, leaving a sopt for the FEs.

(speaker wires comming out of the wall on floor are for using the SFs as fronts for the 7.1 HT system.)
 

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