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AudioSector-chip amp kits, dacs, chassis

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I finally got to setting up a proper website. It's been created by Vikash, and I have to admit that I'm very happy with the overall appearance:


So far, the main items are chip amp kits that I have been developing together with Brian. I will be producing boards and sourcing components completely independent now, so you might expect some diversity in the offerings.

I'm bringing back the Premium kit. The board revision is marked SE (Special Edition). It will be gold plated on all copper areas, and the layout and components placement is improved. Especially the mounting of the feedback resistor is more appropriate now (on the board, but directly between the pins of the chip; the previously used location is still available as well). The power supply will accept snubber setup (the snubber parts with exception of big caps are included free of charge). Though the boards sizes didn't change, the direct mounting of 35mm electrolytis is possible as well (underneath). The more compact assembly is possible too, with mounting holes and power point connections matching and the 2 boards connected with standoffs. I also added LED output on PS board.

The next offering is LM47890 kit; I have the boards presently in stock, so if someone wants them quickly, they ship immediately. I will revise next version, with possibility of operating both halves of the chip separately (for stereo). The PS will be also modified for snubber implementation. The snubber placement doesn't change anything in the boards layout, it just the spot for additional components that can be used or not. Snubber circuit application for GC was developed and introduced by CarlosFM.

I will go with new color for the boards, and they will be dark blue with yellow silkscreen.

The next offering will be TDA1543 based DAC. Preliminary tests indicate very good performance. The layout is practically finished and I will be ordering boards early next week. I spent close to a year optimizing that circuit, and it compares (if not excels) very favourable to both TDA1541S2 and TDA1545 DACs.

There is currently one complete amp being offered, but more will come, including Patek.

Below, the SE version of LM3875 board.


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Looks good, Peter! I saw the 6moons review of the integrated amp and DAC too. One thing I was wondering though. For selling amps in a complete kit (like the integrated amp), do you need to worry about having it electrically certified, or do you just have to be sure that you conform to standards?

Here's the finalized SE LM3875 board. I further changed the rectifiers board layout. My recent experiments indicate that placing 100u BG N cap on the amp board gives best results in overall tonality, resolution and musicality. Those caps are fine by itself (and I'm not using any other caps presently when powering from AC supply). On the rectifiers board there are pads for additional filter caps, and one can use anything between 1000u and 10,000u (up to 35mm dia.). There is a space for snubber components as well, and also a bypass cap (200, 300, 400 mill spacing). The LED output is available. The size of the board has not been changed, as I'm implementing them in many different projects and actualy the size does matter.

The board went into production this week, and expected delivery is Tuesday. I decided on gold plating, with clear solder mask and black silkscreen. As it is a limited edition, I ordered only 50 pcs, which will be numbered (just jocking) ;)


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Re: DAC details?

sanjeev said:
I am waiting for your DAC kit. When do you expect to start taking orders, and how much will it be?

Here's the current DAC layout. I'm pretty much ready for fabrication and will probably go with dark blue mask and yellow silk.

The DAC has been optimized through many versions and parts substitutions. It is quite simplified circuit, but as simplicity allows, the sonic presentation is very distinct, direct and clear, with wonderful sound free of the electronic veil imposed by more complex circuits. Those who like well implemented chip amps, should definitely enjoy this DAC as well.

I decided to keep things simple with regards to assembly, so the whole DAC is contained on a single board. With 48VA Hammond trafo, dual raw supplies, common mode chokes and resistors for CLRC filtering, the PS is less simple, but it compares very favourable against batteries, and most people actually prefered direct AC connection. I decided not to use any additional bypasses besides low value electrolytics mounted directly at the chips pins. A lot of care went into optimizing the input circuit, with minimum signal length, careful trace routing and proper grounding. BNC input and RCA outputs are also directly board mounted.

A follow up to an earlier review of a similar DAC can be found here: http://www.6moons.com/audioreviews/audiozone3/dac.html


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