Output cap replacement
Remove the output PCB board. Start by de-soldering the green points shown, then unscrew the four screws in each corner. I used these caps -
Vishay MKP1839 (10uf) x 8,
Vishay MKP1839 (.1uf) x 8
De-solder and clean up the board, remove the stock orange caps by what way you wish. I also removed the two blue block .47uf output caps as this unit has the preamp output removed. It will give you more room to work with. The cleaner the board is, the easier the install.
I also chose to relocate the resistors to the bottom of the PCB so my caps could sit more flush.
Measurements for cap replacement buying, you have some extra overhang room on the rear and sides, just be aware of the leads and insulate, etc. Don't let anything touch the case or another lead.
Okay, get your caps ready, I chose to match my L and R channels. I tried fitting ten but could only safely fit eight due to the outer edge lip of the case being too close to the capacitor which made installing the board next to impossible. I added a 1% bypass cap, piggybacking the greens for ease of installation.
Add the caps, carefully enlarge any pad hole if needed with a Dremel and diamond bit, careful.. slow and easy does it, go up in bit sizes gradually. This PCB board is quite robust though. If you study the PCB, you will notice there are traces on the top and bottom of the PCB. Because of this, I felt it was necessary to carefully solder the top and bottom of every pad to ensure good solid connection. These caps are so long that they cover the rear lead connection, so I wrapped them around the board and went up through the bottom. Because this PCB is mounted on metal posts, you have some clearance to do so. My process was: Solder the rear lead on the top, pull the cap down and then solder the other 3 pads (bottom rear, front top and front bottom)
Ensure everything is fairly flush and clean. The tape was added to the rear of the cap wall as a safety measure before installation.
Now it's time to place it in the case.. the toughest part here is getting the wires from the transformer to line up, but it really was much less of a problem that I thought it would be, it pretty much fit for me first try, use a flashlight/headlamp to see where the wires are in relation to the PCB holes. Don't forget to screw it down.
Re-solder all of your connections. Be conscious of the leads, do not push them so far into the hole that they are touching or anywhere close to the case below.
Enjoy a beer.
Also I should mention that my amp has the current mods:
dim red LED cathode bias,
ALPS Blue 50k, 47k shunt, Preamp output removal, rhodium plated
RCA input jacks, micalex sockets, replaced wiring and some other minor or cosmetic things like panel led, switch and jack replacements. see sig for phones used etc.
I will do my best to describe the sonic differences.. I think the overall resolution has improved slightly, not a dramatic change. The low end is more articulate and tight, I noticed a slight decrease in bass boom, this is a good thing (I used to run a -2db in low end due to my phones/pads but now it's set to 0), it doesn't get so low to the point of wanting to break up. The high frequency range improved and is overall more crisp, less chance of becoming harsh too. I don't immediately notice much of a change in the soundstage, ie: there isn't some grand 3D airy sound now. It's hard to compare without an A/B, separation may have slightly improved. However, we have tubes for some of these changes. Overall these caps have a warmer sound than the stock oranges but not in a veil sort of way. Mid emphasis but still have decent frequency extension that bests the stock orange caps.
I will come back and edit this post if I notice any sonic changes to mention after 100+ hours of use. I have no idea if cap burn in is real or not. Some claim certain caps give you more low end and or less grain, etc after some listening.
Feel free to DM me for questions.
@bcowen is installing a single 47uf
Mundorf per channel soon and that is possibly another cap option for the Darkvoice but we will see if those beasts fit soon. Then once he sends me his amp to demo, I will let you know which caps I prefer.
Capacitor reviews: Capacitor Musings By Jon L.,
Part One,
Part Two
