Okay,
I now have well over 200 hours on my Woo 6 modified with Mundorf silver oils. The oils were used for everything that the Blackgates were used for, on the original modified versions of Woo 6... bypass, decoupling, etc. From the beginning, the sound of the Woo 6 was noticeably better in every way: Detail, low end, presence. The midrange is so good that everything is balanced, all the the time. As of now...well...it is something of a dream acheived for me....it is that good. To clarify, I use Senn 650's to listen and I listen to mostly pop and rock.
The Mundorfs sound fantastic. There is a liquidity to the sound that plays well with the sound signature of the Woo 6. I've burnt in now for about 215 hours or so, so I'm sure the sound will continue to improve, but I'd be happy with it either way...it sounds incredible. The sound does remind me very much of the Vcap sound signature, with the addition of liquidity...I can't tell if it is the caps or the tubes giving off the vibe, but I suspect it is a combination. Out of the box, I was disappointed in the Woo 6. I was used to the slam and fullness of the imod/vcap dock/Stepdance. The Woo lacked presence...or guts. Everything was too subdued. Now, running the imod/vcap dock into the Woo 6, it is a huge improvement over the Stepdance (as it should be). The detail and slam are present (Much more detail than I had with Stepdance), along with the soft glow and flowing quality of tube sound. The low end is balanced but never shy. Just like the guys with the early modded Woo's said, a Woo tube amp really is the best of both worlds when modified: Tubey without taking anything away from the presence of solid state. It sounds so great that I daydream of it while I'm at work. So far, knock on wood, there doesn't seem to be any issue with heat effecting the caps. In fact, feeling the top when it has been on for a while, the temp doesn't seem to be higher than merely warm. I highly recommend this upgrade. One word: the guy who did this for me has been doing work like this for twenty years, and he said it was hard to get the caps in...a very tight squeeze. Just FYI. He was expecting the whole thing to be a one hour job, but it took him over two.
Now as to the tubes...Naturally, the tube are what really show (or DON'T show) the best qualities of the Mundorf Silver oil upgrade....Had the best luck so far with the combo of Sophia Princess rectifier with Brimar CV1988 type of 6SN7 drivers (Note: You must buy a converter to get 6SN7 to fit). At first, wanting the upfront quality and fullness of each instrument, I liked the RCA 6FD7. For the same reason, the 1957 Mullard Holland GZ34 metal base rectifier was good. But as the sound of the caps improved, I noticed that there was so much "push" in the modified sound of the Woo 6 that it was getting congested during busy passages...there would be instants of distortion, although few and far between...and the overall darkness and up-frontness, although these are qualities I normally like, drove me to nausea...it was that sharp of a coloring in the sound, and it struck me as unnatural. Short answer...the problem was not the caps but the tubes. The story: Thinking the problem was in the pairing, I tried Princess with 6FD7 and Mullard Holland with 6SN7. I tried the rectifiers individually also with the 6EW7s. I discovered that Princess will never distort unless the original recording is distorted, and the low end and high end were as good as the GZ34. Also, the Princess has the most distinction in staging...You can hear for instance if a tamborine is being played distant right side, or closer right side. In addition, you can tell if the tamborine is being played below the microphone, above, or centered...and every instrument and voice is that way. The GZ34 can't do that, to nearly as great of an extent...not with this set -up, anyway. Does the Princess sound distant for pop/rock? No...I discovered that, on recordings that were intended to sound up-close, it was true to the recording. As for drivers...even with the Princess, the 6FD7s still didn't sound right...the up-frontness clipped or phased-out any of the fun staging...so no tamborine playing distant/low/right...and although I love thickness, the sound was too much so...and no fun anymore. 6EW7 didn't clip or color much, but all the balls were zapped from the music: the drums may as well have been played with brushes instead of sticks. So if adding too much taint to the original sound bothers you, go for the Princess with this mod, and use your play time trying out 6SN7s... then you will be avoided over-coloration and distortion. Try looking at the 6SN7 threads, to save time and find good brands...some of them kinda stink. Also, word of note: The casing won't get as hot using the converters with 6SN7s...the tube is lifted up above it. Since overheat is bad for Mundorf Silver Oils, this is worth noting. As a lover of the V-cap dock, I can tell you the Mundorf silver oils sound spectacular as Woo 6 modifiers...guts, yes, presence...hell, yes. Detail...Mmmm. More than I've ever heard before...but they don't bug me. The sound is very natural. I was worried that I wouldn't be able to achieve greatness without blackgates...NNNGGGG!! Wrong answer.
