Denon 2900 "Dutch Mod"

I am naming this mod procedure the Denon Dutch Mod as I got the idea through this Dutch modding website and through assistance from diyaudio forum member D.A.R.R.Y.L. who happens to live in Holland.
These are the steps:

1. Months ago I replaced the two opamps (IC216 and IC21?) on the top of the audio board and the one underneath the board marked "IC213"with AD8620's. You can also use BB OPA627's on browndogs. It all depends on your ears, your system, and your budget. (Note: I have found the AD8620 midrange is too light for my ears, so over the weekend, I am going to try AD8066's which some say provide the detail of the AD8620's and warmth of the BB opa627's.)



2. I removed all the two-channel output caps from the top of the audio board using a hot iron and soderwick. They would be
C369 and C360 (Blue film caps)
C366, C355, C367, and C357 (4- 2.2uf/50V caps)
C421 and it's mate (2- 220uf/50V caps)

3. I replaced all these caps with 2 - 10uf/200V Auricaps (Actually I used OEM Auricaps from RTI). I am sure Solens, Audyncaps, Multicaps, Sonicaps, etc... are good and cheaper equivalents. I soldered the negative leads to the negative pads of C357 and C355. I soldered the postive leads to now shorted C369 and C360 (where the Blue film caps used to be).

4. I secured the rather big Auricaps to the board with Silicone.



Experience shows that Auricaps take a number of hours to break-in but I noticed immediate positive results from this upgrade. More micro detail, less harsh highs, bouncy bass, slightly warmer midrange.

The RTI Audio Film Caps (a.k.a Auricaps) have been in the 2900 for three days now and it appears that the auricap midrange bloom is in process! At least for now, they have managed to compensate for the AD8620's light midrange presentation. This could lead to two rather scandalous conclusions:

1. Auricaps are not neutral.
2. AD8620's provide nice midrange with the right caps.

Over the weekend, I replaced every electrolytic cap in the power supply with Panasonic FC's, increasing the capacitance by 20% over stock except the large cap after the diodes which I increased by 100%. I also replaced the 5 stock diodes with FRED's. In a few weeks I intend to replace the two X-rated caps with Auricaps. It still is breaking in but the results are very good. Darker background, tighter bass, and cleaner highs.

This morning I replaced the two AD8260's (IC216 and IC21?) with two AD8066's each coupled at V+ to V- with .47uf/50V BG PK's. I also replaced the Marinco Cryo'd AC plug I had removed. Of course, it is still breaking in but the results are gorgeous. With the Auricap output mod and the AD8066's the Denon 2900 sounds stunning! I highly recommend it.

I am going to let things burn in over the next week and than I will replace IC213 with an AD8066.