Kestral 2s love tubes and either choice will probably be just fine. On my experience with the Kestrals, I'd opt for the KT88-based Prologue 2. The speakers will appreciate that extra bit of power, and the added "bottom" provided by KT88s will be most welcome, especially if you're listening to rock or big symphonic works. Plus I recall that the Prologue 2 will also take EL34 tubes should you ever want it to (but not vice versa, I believe).
The Prologue 2 will allow you to use different tube types: KT88s (supplied), as well as 6550, EL-34, 6CA7, 6L6GC, KT66, or 7581. The Prologue 1 can only be used with EL-34.
Each tube type does sound somewhat different. You may find yourself experimenting (or wanting to experiment). You probably know yourself better in this regard and how prone you are to tweak things.
KT88's will give you more punch in the bass, EL34's highlight the midrange, the 6550's (to my ears anyway) seem to bridge both the bass and midrange spectrums the best.
I have had the Prologue 2 for about a year and a half now. I wanted the flexibility of tube swapping, am driving "old school" Acoustic Research 3 way speakers, and wanted the extra oomph in the bass that KT88's provide. I am still very happy with the purchase and have no desire to upgrade.
Craig, I'm not familar with your system or what in reproduced music is important to you, however I am quite familar with the Primaluna. Its simple - if your into audio because you want to hear every thing crisp and defined so you can listen to all of the nuances of audiophilia you need the 2 as it provides more resolution and detail than the 1, as well as flexibility. If you are into music more and just want to relax and listen to a tune without worrying about what your system is doing the 1 is ideal. IMHO it is the more balanced, tonally speaking, of the two units but you will find the bass a bit less resolved and the highs are a tad softer. Good luck with your choice.
IMHO [the Prologue 1] is the more balanced, tonally speaking, of the two units but you will find the bass a bit less resolved and the highs are a tad softer. Good luck with your choice.
Newbee (System | Threads | Answers)
Do you suppose this is because of the circuit, or the EL34 tubes? And, if it's the tubes, wouldn't swapping EL34 tubes into the Prologue 2 result in a tad softer top and and less resolved bass?
The circuit I expect. I have other amps which use EL34's from which to form my opinions apart from the Primaluna, and my experience with the 1 and those amps with the EL34's is similar except that my other amps have big trannies and produce a tighter bass, but not necessarily deeper bass.
Surprisingly the bass response in the 1 w/EL34's sounds fuller (some might say warmer/looser) throughout the bass frequencies than using the 2 (or in my case the 5) with even the KT88's or 6550's. With these two tube types the bass takes on a different texture, becomes more taut, drum whacks more percussive, its still very capable, and certainly more audiophile approved, etc, but when you plug EL34's (or 6L6's) into the 2 the deep bass become enemic when compared to the 1 or the 2 w/KT88's/6550's.
An important consideration is selecting tube type in the 2 would be the bass capabilities of the speakers. If they don't do deep bass and you want a more crisp tone the 2 would be great, and its really responsive to tailoring with different tube types and brands.
But I'm really sincere in my comments about the 1. I love it for what it is, a great little unit with which you can listen to tunes and forget audiophilia. :-)
I appreciate everyone's comments and suggestions. If anyone wants to take this further (since Newbee raised the issue and it's a valid one), let me add that the characteristics I've always valued in my (and others') systems' performance are: a wide and deep soundstage with solid imaging, accurate instrumental timbre and a sense of air around individual instruments/voices. That's all kind of retro, I know, but I got into this hobby back in the late 70s and then sat out for a few decades just listening to the music. My system chronology includes many fewer component upgrades than most who, like me, have been at this for 30 years. My 20-year-old B&K ST-140 is only my second power amp, for example (the first was a GAS Son of Ampzilla - that *really* dates me).
When I did get active again, I suddenly found reviewers and others talking about equipment having rhythm and pacing and the kind of timing qualities that seemed to me to either be there in the recorded performance or not, not something that a component could add to or detract from. Consequently I'm not sure if I've ever even experienced those types of qualities, or how to even listen for them. I suspect on some level they're at the heart of the "musicality" issue, and whether you get lost in the music vs listening to the hifi. But I have to say I don't know that for sure. I remember when the debate was about whether everyone meant the same thing when they described a sound as "dark," or "dry," or "grainy." It seems much more difficult now. How do I know what a "sense of pace" sounds like?
Before this gets too far off the PrimaLuna topic, let me say that I guess the long and short is I want something that sounds as life-like as possible for the money, and that doesn't cause fatigue from being overly analytical and detailed beyond the detail you get in real sound in a real hall (using a symphony orchestra as a reference). I guess that's one way of saying I want to simply get involved in the music. My current system gets me almost all the way there, but I know it has some weak links, one of which is the preamp. And if I'm going to look into a replacement for it, I thought tubes might be a good approach, and a cost-effective way to do that might be through one of the PrimaLuna integrateds, i.e., maximize the tube effect by having both pre and power. And here we are.
What are your speakers' sensitivity and impedance specs?
Points well made, though if I follow your dates correctly I may still be older (damm).
So, I own the Prologue 2 integrated and Prologue 5 power amps. With either unit, I have never found myself obsessing about 3/4 of the stuff that I read reviewers write about. What struck me about both the 2 and the 5 is that the music had very much a 3D quality to it. The music seem suspended in the air, so to speak. I have recently shuffled all my components around and in the system I use the Prologue 5, the monitors are placed inside of a bookcase, on their sides, about 4 feet up in the air. The system sounds fantastic ... clear, clean, and musical with excellent rendering of the recording ... like what else could I want? My room size is about the same as yours, the speakers have a sensitivity of 86 db, and assuming I don't want ear bleed ... it plays plenty loud.
I use the Prima Lunas as follows:
Prologue 2 integrated amp, Rega Apollo CD player, SONY SCD 555ES SACD player, Acoustic Research 302 speakers.
Prologue 5 power amp, Musical Fidelity CD PRE 24 CD player/preamp combo, Rega Ara monitors.
For both systems, the interconnects are Signal Cable and the power cords are Naim.
Without knowing how your current equipment set-up sounds, I think that you would be happy with either the Prologue 1 or 2. I think that the 2 gives you a little more, but I don't think that it distracts from the music. Question though, if you suspect that the preamp is the problem, have you considered picking up the Prologue 3 preamp instead?
Tvad - the published specs on the Kestrel 2s are pretty skimpy - with no other parameters given it simply says impedance is 8 ohms (it doesn't even say it's nominal) and sensitivity is listed as 89dB (with nothing said about input or distance).
Rich - thanks for the thoughtful comments. I *have* considered just upgrading the preamp alone, but as I was trying to suggest toward the end of my last post (I could have been clearer, but figured I'd gone on long enough as it was), I thought if there was going to be a sonic benefit to introducing tubes into the mix, the best way to be sure of getting that benefit would be to go with tubes for both power and pre. But your question begs this next one - leaving aside issues such as the relative quality differences between my current power amp and preamp, and assuming I'd have the money to replace both with separates (which may or may not be the case), which approach is likely to have the greater effect on the sound of the system - switching out the power amp or the preamp?
I know a *whole* lot of it has to do with the actual equipment being evaluated, but with the nearest opportunity to hear any PrimaLunas in person being a drive of, well, however far it is from Indy to Kansas City, we've got to talk in hypothetical terms for now. Unless I get an unusually strong craving for BBQ in the next few weeks.
Anyone have any thoughts on that?
Provided you don't listen to rock at floor shaking levels, your Kestrels should be happy with low powered tubes. There are many good options for low powered tube integrateds these days...PrimaLuna Prologue 1 or 2, Rogue Cronus and Eastern Electric M520 (M stands for the classic Mullard design on which the M520 is based), among others.
I also understand George Wright has a cool 15w Class A EL34 integrated with USB input coming out soon.
Between the power and preamp, I would say the biggest sonic benefit is in switching out the preamp. But then you are getting into a hybrid situation (tube preamp/solid state power amp) and you may or may not want to do that. Supposedly that hybrid combination gives you the best of both worlds ... more analog sounding front end with solid state power for control and volume. I do the reverse (tube power amp/solid state preamp), because it worked out that way and I like the combination quite a bit.
At the time that I purchased my Prologue 2, I had an email exchange with Kevin Deal as to whether to go with the 1 or the 2. The price difference was about $200 or so. Kevin wrote back that the P2 would give me more "oomph in the bass" and "the parts were slightly better." That was as technical as it got, but it helped me make my decision. I was planning to run the P2 with full range speakers that went down to 35hz and figured that the P2 would support those speakers better. I did not know from tube swapping then and that a quartet of KT88's accounted for at least 40% of the price difference.
In the end, I think that you are correct in saying that a tube integrated will give you the most sonic benefit bang for the buck. I would still go with the P2 because it gives me the tube swapping options, which may become valuable to you later down the line. I would also go with Prima Luna, in general, because of the auto biasing and soft start features, which just make ownership so much simpler.
Craig, Your question to Rarl re power v pre, is sort of a chicken/egg question and you'll get many folks taking up both positions. For folks just coming to 'tubes' the pre-amp is usually the best choice if only for the reason that its easier to maintain and integrate into your system. Tube amps are a whole different ball of wax, they do require some maintanence and if poorly chosen can be a PITA. But if you buy a tube pre and like it, you'll eventually get a tube amp. Then your hooked!
Apart from the principal benefit of tubes sonically, a liquidity, air, and dimensionality, not usually available in SS stuff, in my budget anyway, you can if you wish alter the tone by changing tubes. For example you buy a new CDP - it has a bit of brightness, but otherwise you like it. With SS stuff you're kind of stuck, but with tubes you can usually accomodate the new CDP by just changing a tube or two somewhetre in your system.
From a pratical point of view, at least IMHO, the principal benefit in having a pre/power seperates is the flexibility it offers in being able to use different amps in the future, but also gives you far more alternatives when it comes to system tuning. For someone anal about getting that last iota of tone, seperates are a must, if for no other reason that sooner or later you're going there. Just go in the first place. But, by the way you have described your needs, I would think that a good tube integrated would be a great choice. While it might minimize your options it will also minimize your angst and let you enjoy the music.
Tvad has mentioned some other integrateds that could work for you - there are others as well, however if you decide to research these units pay careful attention to the tone issues. Your BK amp has a warm signature (I used to own one) if you get an integrated today which is described by reviewers as neutral, compared to your BK you might well find it bright, not neutral. A unit described as warm, you might consider neutral. There has been a substantial change in usage of these terms in the past 30 years. The emphasis today seems to be placed on detail retrieval. Personally, I'm very wary of any review of equipment which dwells on this - i.e. "I heard sounds on my favorite record I've never heard before". Usually all this means is that the unit has either an up-tilted high end or the amp is over damped and the normal decay time is shortened and you hear the highs more clearly, but artificially.
FWIW, I have not heard the other amps mentioned by Tvad. But, the PL's err on the warm side of neutral. The sound of the 1 would be far more of the sound of a tube amp from the 70's and 80's and the 2 would have more of the crispness found in todays tube amps, albeit still having a warm signature compared to a lot of the competitors.
JMHO, Hope this diatribe helps a bit.
Rich, Newbee, et al -
Again, thanks for the further thoughts and clarifications. At this point it looks like I'll be shopping for a used PL2, especially since a nice-looking unit has just come up here on Audiogon. I'd probably jump on it immediately if it weren't for some fantasizing about popping for a pair of PL7s that have also just come up at what appears to be a pretty nice price for essentially brand new equipment. Of course that alone would be a bigger budget stretch than I'd planned, and would still leave me with an additional expenditure to get a preamp. Easy enough to discard the idea except there's a good-looking used PL3 out there right now, too. >sigh<
Craig, Unless you spring for the PL3 and PL7 go with the the PL2, at least based on my experience with the PL5 that's what I would do. Read the review of 6moons. I think he's pretty spot on on the combo. I've had conversations with Kevin Deal about the differences between the 5 6 and 7. All I've ever been able to get out of him is the curcuit differences between the unit's. No comments whatsever about the sound. For myself, if I was so inclined, I'd wait to read some independent reviews and user reviews on the 7's. I read the review on the PL6 in TAS and learned nothing useful.
Your comments on the relatively skimpy info regarding actual audible differences is well taken. I've been assuming that the differences I've read about between the EL34-based 1 and its brother, the KT88-based 2, are pretty similar across the board with the others (i.e., PL4/5 and PL6/7) and that may not necessarily be the case.
At any rate, it was a bit of a fantasy anyway. When I saw the 7s it was one of those "how can you *not* afford to do this?" kind of moments. With a little reflection, I can think of any number of ways I can not afford to do it. ;) If I like what I hear with the 2 but feel it just isn't "enough" I can always save my money until I have enough for the separates (monoblocks or otherwise).
Thanks for helping to give me that moment of reflection. It looks like the 2 is it.
Thanks again to everyone who participated in the thread. After considering everything that was said, I decided on a Prologue 2, and found a nice-looking used unit at what I believe is a decent price from a reputable source here on Audiogon. With a little luck it should arrive before the week is out.
Thanks once more to everyone for their invaluable help!
Congratulations on going with the Prima Luna product. I think that you will enjoy the Prologue 2. I have done well the SED Winged C 6550's and KT88's tubes that Upscale also sells. The stock tubes are pretty decent to get you started.
As for power cords, I have had great luck with the Naim $25 power cord that is sold by Gene Rubin Audio
. I had read a few threads both here and in Audio Asylum and splurged for $150 for 6 power cords. I am using Signal Cable Classic Speaker Cables
. For interconnects, I have used IXOS Silver Gamma 1001 (silver/copper hybrid) and the Signal Cable Silver Resolution also with success.
Let's us know how you make out with your new amp.