LKS MODIFICATIONS
I have done a significantly more amount of work than most people would do. However, it all adds up in the end. With all the upgrades, this DAC no longer resembles stock. The resolution and attack are amazing. High frequency detail is significantly improved and much more realistic. Bass is significantly stronger (think “punch you in the chest” type of bass). This DAC is now absolutely beautiful to listen to.
This is the work I have done:
A/C input
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- Furutech gold IEC => Upgraded to Furutech Rhodium IEC
- Fuse => Upgraded to Furutech Rhodium 3.15A (not available anymore)
- Transformer Secondary wires => twisted like everyone else
- Rectifier Diodes => All 24 diodes upgraded to 8A Vishay Schottky Diodes (VS-8TQ100-M3)
Digital Power Supply
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- 4x6800uf Gold Tune caps => Initially I upgraded these to 4x10,000uf Nichicon KW. I can’t remember where I read this, but I’ve read that Gold Tune are not as tight sounding and somewhat laid back. Anyways, I wanted to boost the capacitance, so I used KW caps. Later, I decided to go and upgrade to all Mundorf. I used a Mundorf 22,000uf 25V for the left most largest cap. I used Mundorf 10,000uf 25V for the 3 remaining. I did some measurements and these caps are only seeing 9V DC after the rectifier diodes, so the 25V Mundorf caps are totally safe and provide much larger capacitance. They are also 125 degree caps. I soldered Vishay 0.1uf MKP film caps to the leads underneath the board because they wouldn’t fit in the spaces between these large caps.
- 390uf post-regulator caps => Upgraded to 470uf Nichicon FG.
- 0.1uf MKP post-regulator => Upgraded to Vishay 0.1uf MKP (BFC241641004) except for one spot where I had to use a smaller WIMA 0.1uf MKP.
- LM317 regulators => I thought about upgrading these to the Sparkos SS1117 discrete regulators, but the Sparkos are internally limited at 1A. The LM317 allow up to 1.5A of current, and we know the DAC chips love the current. I don’t think I’m getting any less of performance at this point. Upgrading to Sparkos would require tweaking of the SMD resistors in front of the regulators.
Digital Circuits
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- Replaced the input coupling caps (big 0.1uf WIMA) on the S/PDIF inputs with straight wire (Ric Shultz trick). I used Neotech 20awg solid-core OCC copper that has been stripped.
- 270uf Polymer caps => All these were upgraded to Nichicon 330uf polymer. It’s not much, but every little bit helps! The stock 270uf caps are actually very good, so you can skip this part if you want. Make sure you re-solder those film caps on the bottom leads.
- 100uf Polymer caps => I left these alone because the stock Panasonic SEPC had such a great ESR (8 mohm). I couldn’t beat that.
- 0.1uf film caps => replaced these with Vishay 0.1uf MKP
- Crystek 575 => I did several clock tests before I decided on the Accusilicon AS318-B-100 (clock comments are in following post). I soldered a small 0.01uf film cap across the GRND/POWER pins on the bottom side of the board. For testing purposes, Mil-Max has a nice 14-pin socket with only 4 pins loaded so that you don’t have to melt out those other pins (digikey ED90428-ND). For final clock, I remove this socket and soldered the clock directly in.
Analog Power Supply
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- 2x4700uf Mundorf => Upgraded these to 2x10,000uf 40V Mundorf
- 2x1000uf post regulator => Upgraded to 2x1000uf Nichicon FG
- 220pf regulator MKP => Upgraded to 220pf Kemet PFR film-on-foil caps
- 0.1uf film caps => Upgraded to 0.1uf Vishay MKP
Analog I/V section
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- 22uf MUSE caps => Upgraded to 22uf + 47uf Nichicon FG. The 47uf caps used the hole for 0.1uf film caps. I soldered WIMA 0.1uf MKP to the leads underneath the board. For many years, I thought Nichicon MUSE were the best caps to use. However, about a year ago I did some critical comparisons for the heck of it and found that FG (Fine Gold) actually sounded better. The MUSE caps are nice and very high resolution, but they have a little bit of glare in the upper mids/highs. The FG caps actually sound much more natural and realistic and they have excellent high frequency response! I increase the capacitance for each discrete section. I found that having a bit more capacitance here helps with bass/midbass punch and strength. You definitely do not want to starve these discrete Class A circuits!
- 220pf MKP caps => Upgraded to 220pf Kemet PFR film-on-foil caps. These are the 3 caps in the middle if the discrete circuit (on earlier models, these are the silver-mica caps) I have found that these film-on-foil are superior to any MKP. However, they are only available in small values (up to 2200pf picofarad).
- 2200pf film caps => Upgraded to 2200pf Kemet PFR. These are the two inline rows of polyester caps above the circuit.
- 61.8 ohm resistors => Upgraded to Vishay CPF3 3-watt 61.9 ohm resistors. Like many have recommended, I could have gotten the TX2575-3 z-Foil resistors, but I didn’t want to deal with the lead time and $70 per resistor. In past projects, I have found that a higher wattage resistor actually is more transparent and provide better response. I learned this when comparing a .5w resistor to a 1w resistor in a op amp negative feedback circuit. The CPF3 are only $3.25 each (mouser 71-CPF361R900BEE14). I think they give excellent results! They are long and have to be soldered into the extended holes. These resistors have excellent specs at 0.1% tolerance and Temperature Coefficient of 25PPM/C (we all know this section likes to heat up). There are resistors that have lower PPM specs, but they are generally a much higher resistance. This was the best resistor I found between Digikey/Mouser for this application.