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COVID-19 took a real toll on postage time but I eventually received all of the components from various sources and started my build of a Stereo Coffee within the last week or so.

 

Chris Daly (@stereo coffee) is an amazingly responsive and knowledgeable designer and I could always rely on him replying to my emails with extreme rapidity and clarity; he's a pleasure to deal with.


I believe that I could have ordered a built up unit from Chris for the ongoing cost of everything I have amassed, however I enjoyed this voyage of discovery, having never before built any electronics, except for a pair of monitor style speakers from a kit some 20 years ago.

 

I took things very slowly, measuring up clearances between the boards and the Jaycar toroidal transformer that I wanted to use in place of the Jaycar SMPS. Despite that I realised I would have to drill a replacement hole for the transformer as it needed more clearance from the back of the IEC socket than the one I did initially.

 

Build Summary:

Stereo Coffee LDR pre-amp boards, May-June 2020 build spec. ($264 incl. GST from Chris Daly's eBay store)

Brushed aluminium pre-amp case from eBay (China, $120 delivered). Pre-drilled with 8 RCA holes, knobs, and IEC socket supplied (upgraded to Furutech).

Furutech fused IEC socket, with a 500mA slow-burn fuse bought from another SNAer.

1 pair Audio Note silver-plated RCAs for the Stereo Coffee outputs

1 pair Connex solderless rhodium-plated eutectic copper RCAs as  I/P 1

Aliexpress gold-plated copper RCAs for I/Ps 2 and 3.  Pic 2 shows the RCAs wired (messily) and the LDR board.

20 VA Jaycar toroidal transformer (MT2084)

Wire from PartsConnexion (Canada: partsconnexion.com) bargain basement -

1. Duelund 26 awg tinned copper with oiled-cotton insulation. Used for signal wiring from RCAs to board.

2. Duelund 20 awg solid-copper with oiled-cotton. Used from switch to main board I/P 1 , switch pole, and start-circuit between main and LDR boards.

3. Connex 24 awg tinned copper, from switch I/P 2 and 3 to main board.

My biggest build challenge was trying to solder the ground leads to the Aliexpress gold-plated (copper signal pin) RCAs because I was using such fine wire.

I splashed out on a second-hand Groot soldering station that made life much nicer than if I had used a cheap Jaycar iron or similar.

 

28 June:

I finally finished my Stereo Coffee (SC) build today, after some other interruptions, and a very steep learning curve when it comes to to soldering 26 awg wire in confined quarters.

 

I connected it first to my simple head-fi setup: desktop Mac playing Tidal, to Schiit Modi 3, then SC, then Cavalli Tube Hybrid amp and Massdrop Sennheiser HD6XX. Having proven that nothing untoward happened, I then proceeded to connect it to my main system.
 
I need to mark some volume references and I have further work to do, to deepen the switch knob/shorten the shaft, and better secure the volume knob (hole-deepening may have obscured the securing stud inner thread area).

 

Performance:

I'm still inside five hours of listening time, however with it hooked up to my main system (pic 1), the first few bars revealed a richer bass than I am used to. I have a great pre- in the Bryston BP25, however the Stereo Coffee is even more revealing than the high level I was already used to.  A favourite well-recorded album is Holly Cole's 'Temptation' and one that I know well. The SC makes that album even more involving and relaxing than ever. 

 

Separation between instruments, spatially and tonally is heightened, drums and cymbals have more resolution and the sound-stage is deeper. I haven't noticed any widening of the sound-stage in what I've listened to so far although I'm sure the relatively constrained positioning of my speakers is a factor, although I don't lack  great imaging from them.

 

The overall performance I'm hearing mixes clarity, and resolution with a relaxing, analogue (in the best sense) reproduction. I'm listening exclusively to 44.1 kHz/ 16 bit FLACs, either from CD rips or from Tidal. I sold off my CDP (Naim CDS) because my Auralic Aries streamer enables me to play CDs from a computer USB drive, and rip on-the-fly if so desired. Combining that with my Gieseler Klein III DAC with Enhanced Gold Tune Kraftwerk LPSU gives me sound quality that now negates my need for a traditional CDP.

 

Some test music:

 

1. Holly Cole, 'Temptation', 'Frank's Theme' opening piano notes are amazing

 

2. Pat Metheny/Lyle Mays, 'As Falls Wichita, So Falls Wichita Falls'. This title track is a great test of the atmosphere that purports to be in a large stadium (though a friend told me it was studio recorded!). I use this track to compare pre-amps ...the SC is winning!

 

3. Sara K, 'Hell or High Water' , Fabulously recorded... sounding wonderful (it usually does!)

 

4. Ben Harper, 'Welcome to the Cruel World'. Just more resolution and presence and I was already very happy with my previous setup.

 

5. Jordi Savall, 'The Celtic Viol II', Comments as per #4!

 

 

System comprises:

 

Stereo Coffee LDR pre-amp boards, May-June 2020 build spec.

Shunyata Research Hydra power conditioner and power cables.

NAS-files, or Tidal, serving up 44.1 / 16 FLACs over wi-fi to

Auralic Aries streamer (Femto clock and LPSU model).

iFi iUSB Nano 3.0 and Curious USB cable between streamer and DAC.

Gieseler Klein III DAC  (USB) with Enhanced Gold Tune Kraftwerk LPSU.

Bryston Cable+ ICs from DAC to Stereo Coffee.

Rega P3, with Exact cart and iFi iPhono2 phono stage. Ikea bamboo chopping board! 

Bill's Covid-busting cable #2, from iPhono2 to Stereo Coffee

Morrow Audio MA-1 baseline unbalanced ICs from SC to Gamut D200 Mk 3 dual mono poweramp*.

Morrow Audio SP-4 speaker cables. Sonus Faber Concerto Home speakers.

 

 

* My Bryston BP25 pre- uses Shunyata (Aries) balanced ICs to the Gamut, so the relatively cheap Morrow MA-1 unbalanced ICs aren't in the same league, yet the SC is delivering higher performance. Later I added short silver RCA-XLR ICs to those Morrow MA-1 ICs using female-female couplings, so that my Gamut now uses its XLR inputs. I can notice a difference, as did the family, when I unpaused Tidal and the extra volume hit with a blast (different I/P sensitivity on the amp).

I have now ordered an RCA-XLR hybrid cable from @Bill125812 as I want to continue to feed the Gamut through its XLR sockets.


I am very, very happy with my Stereo Coffee performance and also pleased that the challenges I found building it have added to my enjoyment of the product.

 

I'm now thinking what else can I build  ... perhaps another Stereo Coffee and something like a Goldclone amp?

 

 

 

20200629_hi-fi_w_SC.jpg

SC-int-plan.jpeg

Edited by lenticularis
improved structure
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Nice work!

 

I tried the Dueland 16AWG on my StereoCoffee board inputs and outputs but found it actually muddied the transparency slightly and enhanced bass, as they tend to do when used as speaker wiring.

 

The muddiness was especially noticeable with my DIY 505 Mini ESL panels.

 

Over the last few weeks I have built simulated litz cable using four strands of Teflon insulated 30AWG Kynar tinned copper wrapping wire from Jaycar which is twisted tightly. Its a bugger to trying to strip off the teflon so you will probably break a few before you get the hang of it. You can get 30 metres for under $18 so you will never run out. Make one lead about 80mm for each LDR board input and output.

 

For consistent results I found its best to have the thinner wire touching the silver edge of the input/output lead holes on the LDR board when you solder it.

 

The result is even better transparency than silver but a tighter sound with precise width and depth. I find that bass texture has improved too. I'm getting wall to wall width and precise positioning on appropriate tracks.

 

If you want to fatten up the sound try eight strands instead of four.

 

Recently, I wound a double strand of insulated silver wire around the four strand leads to add a bit more warmth. Strangely, I found that two strands to the output RCA improved musicality.

 

Of course, you might have different tastes and the rest of your system mightn't sound right but it's worth a shot and doesn't cost much.

 

The great thing with StereoCoffee is that you can tweak inputs and output to get the exact sound you want in a few minutes.

 

Have fun!

 

Cheers, Rob

 

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Thanks Rob, I'll investigate that wire, it sounds great value and worth a try, although soldering those RCAs is not something I want regularly do!

 

Currently I have no problems with transparency...if anything some of the stuff I'm playing might do with some more warmth. Some tracks have plenty of bass, but I suspect it's also a case of the SC accurately reflecting the quality of recording/mastering.

 

I'm changing a solid silver RCA interconnect order with @Bill125812, on his advice, to be an RCA-XLR hybrid, also using a mix of solid copper and solid silver. Bill is an amazing SNA contributor.

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Thats great David.

 

I have some Taiwanese versions of similar RCA sockets and i really had to pump up the temperature of my iron and ended up folding the wire ends to make them thicker.

 

I have just purchased some Aurealis interconnects and speaker cables that us litz silver and copper. Very nice balance, so yours should be excellent.

 

Cheers, Rob

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