Jump to content

A Krell of a Push-Pull


Deang

Recommended Posts

I am going to avoid superfluousness. I could easily ramble on for several pages, but I no longer believe it is beneficial in the context of helping others decide what a piece, or pieces together might do in their system. Besides, with the RF-7's, and my total addiction to anything that pounds, grinds, and splits atoms -- generating countless keystrokes is pretty much a waste of time.

The Companion IIc

The Companion IIc is in the middle of the Bruce Moore preamp product line. I do not know much about the circuit except that it shares some things in common with the line stage of the original Audible Illusions Modulas which Bruce Moore also designed. However, I was told by Bob Bergner that it is a weak comparison, as the Companion IIc "is on a completely different level". A schematic is not forthcoming as Bruce Moore simply does not want them floating around until he has the patent. I would imagine the patent is related to his use of using "tubes", or one of the triode sections in each tube for "power supply decoupling and/or voltage stabilization". Speaking of tubes, there are only two sad and pitiful 6922's. Seriously, if you have a problem with this tube then just stay away from it. As for me, I like it -- and think it's a great sounding tube as part of a hard hitting setup. Between the Companion and the Dual 70 -- I'm running six of them.

The sound?

I really couldn't pin down the sound until the 6SN7 preamp from Hong Kong showed up. I simply couldn't tell what was preamp and what was amp. Once I got the other preamp into the system -- it was much easier.

Unlike any combination of preamp and amp I have had in the house to this point, where I strongly felt the preamp was responsible for most of the systems attributes, it is clear that in this instance -- the Dual 70 is calling all the shots. Whether I'm running the Companion or the Lam unit, there is a characteristic crystalline quality that has more in common with very good solid state than with tubes.

There, I said it.

Of course, it's not solid state, and so is completely devoid of the hashy and somewhat filmly background quality even good solid state sometimes brings with it.

The mystery here are the preamps, as they should really shift things around some, and surprisingly -- don't seem to sound all that different. The only thing I can say is that the Lam unit seems a little more open at lower volume levels, and the Moore unit is cleaner at the higher volume levels. I sense a bit of glare with the Lam unit above 95 db. However, it still has less than 100 hours on it. As far as warmth, and dimensionality in the soundstage -- they are dead even. Needless to say, the Lam unit is one hell of a bargain, and I don't think anyone needs more preamp than this. At this point, I don't think I can give one the nod over the other, and if I had to pick just one -- I would keep the Moore unit simply because it looks better with the amp. Yes, I know -- pathetic logic. The interesting thing here is how to interpret this: Do we say the Moore unit is outstanding because it sounds as good, and very similiar to a tube rectified, tube regulated, 6SN7 SRPP unit? Or do we say the Lam unit is outstanding because it sounds as good as a $2200 preamp? Maybe the Companion is suspect since it can't move past a $300 unit from eBay? I suppose in fairness, it should be noted that I have over $250 of quality NOS tubes sticking out of the top of that Lam unit, yet am still running a pair of lousy JAN Philips 6922's in the Companion. With a used price of $1200 for the Companion, and almost $600 for the Lam unit with the tubes -- things are a bit closer (at least it's not on the order of almost 10x).

This setup is not a "tubey" sound, and actually does much better in the 80 to 90 db arena than the Quicksilvers and the Cary. That combo was so warm, that at lower volume levels things just seemed to collapse in on themselves. It lacked some detail that could only be recovered by jacking up the attenuator. At a certain point, the sound would explode into the room, and it was very impressive -- and enjoyable. The Quicksilvers always wanted me to turn them up.

This setup, regardless of which preamp I am using -- is the complete antithesis of the Quicksilver/Cary setup. Very clean and detailed at even the lowest volume levels, yet rich enough to let you know you have tubes in the system. However, there is no real projection, or three dimensional sense to the soundstage until you get past 85 db -- and better yet at 90db. There seems to be more resolving power with the Bruce Moore gear, as I don't ever really feel the need to go past 90db.

The bass is Bryston-like in quality. This is both good and bad. The Dual 70 with the EI Kt-88's don't excite the room nodes in the same way the Quicksilvers did. I don't really understand what's going on here. I could rearrange the furniture with the Quicksilvers, yet still maintain a nice punchy quality. In comparison, the Dual 70 just turns the whole room into a boom box. I had to move the RF-7's around a bit before I could get the room to calm down. Getting them out of the corners, and off the side walls brought me lightning fast bass transients while still maintaining some appreciable warmth. However, like the Bryston, the notes appear and decay so fast I barely have time to enjoy them. I'm sure part of this if from having become acclimated to the fat lush sound of the EL-34. However, my ears are finally settling in to this new sound, and I'm now able to hear some the advantages of the KT-88. Speed and dynamics are at the top of the list.

As with the Quickies, the smoothest and most natural sound comes on the 4 ohm taps while running the 15 ohm resistors in parallel with the amps outputs.

Link to comment
Share on other sites

I love the Amperex 7308, they are very powerful and extended. I haven't tried the CCa's yet but I'm using the Telefunken E88CC's which are way better than the same type Mullard.

Don't be tempted to buy the European Amperex it is inferior to the US one. From what I've read, not all CCa's are equal and the best ones are early 60's prodction.

Here's some info from the HK tube audio http://www.hktubeaudio.homestead.com/files/6DJ8.html

Don't get scared by the tubes prices, they're in HK$ and not USD.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...