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Second Omicron Group Buy

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alexcp

alexcp

Member
Joined 2009
HiFiOcean.com
Paid Member
#1
UPDATE: This GB is now closed. The boards were ordered, manufactured and are being shipped to GB participants.

After the first Omicron group buy closed in March this year, there has been a number of requests for more boards. Let's see if there is enough unmet demand to warrant another manufacturing run. This GB will close at the and of the day on Saturday, September 30. If you're interested, be sure to sign up before then.

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What it is
  • Omicron is a compact, inexpensive and easy to build headphone amplifier with uniquely low distortion, very musical, pure, clean, liquid sound and perfect clarity even in the most harmonically complex pieces. As one of the first GB participants put it, "The clarity is surreal."
  • Designed to work with 32 to 600 ohm headphones and tested with a range of over-the-ear and on-the-ear cans from AKG, Beyerdynamic, Grado, Klipsch, and Sennheiser as well as with lower impedance 16 and 8 ohm headphones, such as AKG's K3003 3-way in-ear monitors; even white Apple EarPods (tethered ones, both 1st and 2nd generation) sound great with Omicron, too!
Features and benefits
  • Ultra low distortion; at -140dBc, Omicron is an order or two more linear than other "high-performance" and "ultra-high performance" headamps. Omicron adds neither dirt nor fairy dust, offering exceptional clarity and fluidity of sound. With Omicron and a good pair of cans, music just carries you away. And if you want to look at the measurements, we have them, too.
  • Simple and inexpensive to build. One channel of Omicron is built with just one dual opamp, two transistors, ans a bunch of resistors and capacitors. The circuit allows broad opamp substitution and has been tested to work well with many modern (e.g. OPA1642) and not-so-modern (NE5532) opamps. At the time of the first GB, the total cost of parts to build one Omicron board (two channels) was just $42.
  • Built-in fast (10ms) and sensitive (80mV DC) headphone protection.
  • Built-in optional cross-feed circuit, helping to create a more realistic soundstage.
  • Compact and easy to build, with the choice of two PCBs. Each PCB carries two amplifier channels with crossfeed, protection, and output filters.
    • PCB option 1: a 80x110mm, two-sided, all through-hole PCB, regular sized parts, super easy to build. The output stage is heatsinked, so the amp can be run at higher quiescent current if needed.
    • PCB option 2: a 60x90mm, mostly SMT, two-sided board, with no parts smaller than 1206 or SOT-23, reasonably easy to solder by hand. No heatsinks (the board itself server as a heatsink), but two additional functions: a separate line output and the cross-feed switchable by a relay.
  • Power supply board is available, too. A 130x80mm PSU PCB carries an AC mains filter, a power transformer, a pair of regulators, and an quick-turn-off circuit that works together with Omicron's protection. (And yes, I added the bleeder resistor that was missing on the boards from the initial batch).
Pricing
  • $15 per any one board (one Omicron board carries two channels, protection, cross-feed and output filters) plus shipping.
  • Shipping is flat $5 for the continental U.S. (USPS Ground Advantage) and $15 elsewhere (USPS First Class International Package). Should you want to buy something else from me, I of course can combine shipping.
  • If there is interest, I will also offer fully assembled with high quality components and tested SMT boards for $150 apiece.
Technical details
  • The main thread has lots of details, including full schematics, part lists, board outlines, assembly instructions, and more. The first post in the main thread includes a list if links to most useful posts. I will review the thread in the coming days and update it as needed.
  • Part lists aka BOMs has been published for each board. I will update the BOMs over the next couple of weeks making sure all parts are available and any errors and omissions discovered so far are corrected.
  • We support Omicron builders mostly in the main thread.
If interested in purchasing any of these boards, please reply to this thread. Copy this sentence along with everything below into your post and add your own line as follows:

(1) Your name here on diyAudio -- (2) TH board, pieces -- (3) SMT bare board, pieces -- (4) PSU board, pieces -- (5) Assembled and tested SMT boards, pieces, -- (6) Country to ship the board(s).

Try to preserve formatting.

Running List for Subscription :

alexcp -- 1 -- 1 -- 1 -- 0 -- USA

This group buy will close on Saturday, September 30. Be sure to sign up before then.
 
Last edited:
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#9
Resistorius --1--1--2--0--Germany
Antsav - -1- -0- -1- - 0- -Finland
emuffler - - 1 - - 0 - - 1 - - 0 - - USA
comicrcc -- 1 -- 0 -- 1 -- 0 -- USA
Wirewiggler - -0- -1- -1- -0- - USA
roh1018 -- 1 -- 1 -- 0 -- 0 -- Australia
 
#11
Thank you! Here is the consolidated list so far:

Resistorius --1--1--2--0--Germany
Antsav - -1- -0- -1- - 0- -Finland
emuffler - - 1 - - 0 - - 1 - - 0 - - USA
comicrcc -- 1 -- 0 -- 1 -- 0 -- USA
Wirewiggler - -0- -1- -1- -0- - USA
roh1018 -- 1 -- 1 -- 0 -- 0 -- Australia
Will2226--1--0--1--0--USA

I started posting updated reference information on these boards in the main thread and edited the first post of the main thread for easier access to most useful posts.

As a reminder, this GB will close in two days. If you're still on the fence, now is the time.
 
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Reactions: Will2226
#12
Resistorius --1--1--2--0--Germany
Antsav - -1- -0- -1- - 0- -Finland
emuffler - - 1 - - 0 - - 1 - - 0 - - USA
comicrcc -- 1 -- 0 -- 1 -- 0 -- USA
Wirewiggler - -0- -1- -1- -0- - USA
roh1018 -- 1 -- 1 -- 0 -- 0 -- Australia
Will2226--1--0--1--0--USA
bloqhed--0--3--3--0--USA
 
  • Like
Reactions: alexcp
#14
Resistorius --1--1--2--0--Germany
Antsav - -1- -0- -1- - 0- -Finland
emuffler - - 1 - - 0 - - 1 - - 0 - - USA
comicrcc -- 1 -- 0 -- 1 -- 0 -- USA
Wirewiggler - -0- -1- -1- -0- - USA
roh1018 -- 1 -- 1 -- 0 -- 0 -- Australia
Will2226--1--0--1--0--USA
bloqhed--0--3--3--0--USA
mulburg- -1- -0- -1- - 0- -USA
 
#15
pinnocchio said:
could you supply stencils
Click to expand...
Stencils make sense if you are going to assemble more than a couple of boards. I could order some for you at OSH Stencils - I have been using them for many years, they are quick and helpful. One polyimide film stencil for Omicron's SMT board at OSH Stencils would cost $22 plus shipping. Alternatively, I could share the "top paste" gerber file, which is all you need to have the stencil manufactured elsewhere. Note the bottom of the board only has two diodes, so the bottom stencil would not be particularly useful.
 
#19
Resistorius --1--1--2--0--Germany
Antsav - -1- -0- -1- - 0- -Finland
emuffler - - 1 - - 0 - - 1 - - 0 - - USA
comicrcc -- 1 -- 0 -- 1 -- 0 -- USA
Wirewiggler - -0- -1- -1- -0- - USA
roh1018 -- 1 -- 1 -- 0 -- 0 -- Australia
Will2226--1--0--1--0--USA
bloqhed--0--3--3--0--USA
mulburg- -1- -0- -1- - 0- -USA
CaféNoir --1--2--1--0-- France
 
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