SS Preamp with Tube Amp?

Raquel raises an interesting point about the problems associated with both types of pre-amps and power amps when frequent electrical storms, i.e., outages as well as possible strikes by lightning, occur in your location. Is that reason enough to choose tubes vs SS? Is it true that tubes come up to an optimal operating status quicker than SS devices after power is turned off and then back on? With more power problems, especially in summer peak demand periods, as happens with increasing frequency in the D.C. suburbs here in the Mid-Atlantic region, should this consideration be given more weight in choosing tubes vs SS? I do not have hours to wait before I can listen to an optimal sound after a long day at work.

I share the same opinion as 6550c in that a preamp should be as neutral as possible. This is why I prefer using passive preamps. While I have had some nice active preamps in my system, and have sat and listened to many others, I always seem to gravitate back towards a passive design.

"Truly good sounding solid-state preamps....bla bla "

I thought the whole idea was "strait wire with gain" ?
Shouldn't a "really good" preamp shoot for nutrality and thus have no "sound"?

Put Klyne on the list for consideration;Stan's pre amps are highly regarded and build quality is first class;only I think you need to get off the couch,no remote as I recall
unless he has one in the works;been a while.

As noted by others, there have been a lot of threads on this subject and you should research them.

Truly good sounding solid-state preamps, which is to say, the ones that do not sound "solid-state", tend to be very expensive, and I agree with the above poster that it is a lot easier to get a good sounding tube preamp at a given price point than solid-state. Most importantly, tube preamps layer space better than most solid-state preamps.

That said, the very best solid-state preamps layer space just as well as tube preamps. They are also quieter, and this to me is crucial - tube pre's obscure detail compared to the better solid-state preamps because of the greater noise levels generated by small-signal tubes. A preamp sends a signal that is amplified many times by the amplifier - if the signal received from the preamp at an amp's inputs is noisy to begin with, noise levels become quickly audible. In a high-resolution system, a solid-state preamp allows a listener to hear deeper, and with the best SS pre's, a lot deeper, into recordings.

Except for those that are output transformer coupled (most are not), tube preamps have high-ish output impedances and often have bass rolloff problems with amps having low input impedances, compromising compatibility. They also tend to have trouble driving long (>2 M.) interconnects, again limiting compatibility. The only inconvenience I have encountered with SS pre's concerns powering them down for electrical storms - tube preamps come back to life within a few hours, while a solid-state pre's need a lot longer.

Turning to your specific question, the issue with running a solid-state preamp with a tube preamp again comes back to cost. Just as it takes a very good (and thus very $$$) solid-state preamp to get past solid-state preamp problems, it likewise takes a lot of money to get into a tube amp that does not have typical tube amp problems, specifically, an inability to control woofers and non-linear frequency response due to impedance issues with dynamic (cone) loudspeakers - the amp has to have massive power supplies and most importantly, really good output transformers, which are really expensive. In the alternative, you can get a hell of a lot of performance from a relatively moderate-cost combo like an Audible Illusions 3A tube preamp with a Bryston or McCormack SS amp.

At the top end of the market, however, a solid-state pre is the way to go in my opinion. I run a very quiet solid-state preamp (battery powered, fully differential balanced Rowland Coherence II) with either solid-state (darTZeel) or triode tube (VAC Renaissance 70/70) amplifiers. The Rowland's output impedance is a really low 50 Ohms, which can even drive the darTZeel through its 50 Ohm input. My backup preamp is a solid-state ARC LS-3. I've owned some pretty decent tube preamps (Jadis, Hovland, CAT), I've heard many others, and love what they do well, but believe that, generally speaking, very high-end solid-state is best at the preamplification stage with either tube or solid-state amplification.

Mapman, you understood I was talking about phono preamps right? With regular preamps, tube rolling generally doesn't seem to have much effect on sonics, compared to tube rolling in amps, so I tend to lean toward SS for those. Now of course if someone allowed me to audition a Nick Doshi, or perhaps the new CAT, or a Calypso, I might give in ;--)

"But you can't "roll" transistors; so if you want to tailor the sonics, why you're just SOL ;-)"

An undeniable benefit of tubes. Getting it right is all about tailoring sonics somehow more so than which piece is better than others, although some undeniably are better.

Like baking a cake. You need a good recipe to tell you how to properly combine the ingredients, but quality ingredients are needed for best results.

The reason I would still choose a SS pre over a tube pre (even assuming the highest quality of either) is because to me, transistors are the device of choice for handling very small/weak signals. There are a number of different reason I feel this way including:

>> transistors don't change their behavior over time
>> transistors don't require large power supplies (compared to a similar tube unit)
>> transistors (except power output transistors) don't generate much heat (which can affect other electronic parts)
>> transistors don't produce electron "rush" (tube noise) which in a low level device like a preamp is bound to be amplified. Tube noise and tape hiss is why Dolby Laboratories was born ;-)

Preamps don't generally amplify the signal. They just select it, balance it, and attenuate it (reduce it's strength) when you don't want to play the music loud.

One kind of preamp that DOES amplify is a phono preamp. And in most cases, it also provides RIAA equalization to reduce record surface noise and strengthen the high frequencies. Frankly, I'm divided on this one. On one hand, I like tube PHONO preamps because you can mess with the tubes ;-) On the other hand, they DO make noise, and what I really dislike is the fact that if you want enough gain for MC cartridges, you almost always have to use a step-up transformer before the preamp; and I really dislike those! Transistor phono preamps can deliver plenty of noise-free gain, even for the lowest output MC cartridges. But you can't "roll" transistors; so if you want to tailor the sonics, why you're just SOL ;-)
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Odd. . . I do seem to enjoy perfectly well my SS rig.

Guido -- there's this marvelous website called Google http://www.google.com where you can not only find out stuff like "waht's a nonosecond?" but you can also look up the correct spelling for common words like what? ;-)

Nanosecond definition here: http://searchcio-midmarket.techtarget.com/sDefinition/0,,sid183_gci212620,00.html
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Every once in a while I try various combinations of tube/ss electronics, and enjoy whatever benefit it brings to the table. I always gravitate back to all tubes. There's a reason you almost never hear of a tube lover going back to ss, for sonic reasons alone. It's almost always for some other reason(heat, trouble, compactness, whatever.) Once you have heard the difference, it is hard to go back.

"Semi suggests that a tube pre and amp is the ultimate."

I believe this has the biggest upside in regards to realistic sound reproduction with tube amplification and with most speakers out there today, particularly in larger rooms. Juice (current) is key. I've been extremely pleased with the results of this in my rig. For modest cost, I think my rig is at least competitive with the best I have heard which also happen to cost many times more.

With more efficient, higher impedance speakers (less common today in that SS still rules), then I think tube amps can also achieve the highest levels as well. You will pay a premium for good tube amplification though.

Fascinating. . . waht's a nonosecond?

The reason for my "pronouncement" ;-) about the 85% contribution of the amp/speaker/speakercable "group" as it affects system sonic character is as follows:

A. The amp is where the signal gets processed the most -- multiplied many many times its original strength and therefore subject to all manner of (possible) modification by the amplifier's electronics: harmonic and intermodulation distortion, variations in frequency distribution, timing changes, noise components and many others. If you ever heard the effects of a microphonic tube for instance, you have some idea what can happen on a less obvious level. All equally true for SS amps as well.

B. Loudspeakers have their own sonic signature(s) as we all know, but that's not the end of it. When an amplifier of one kind or another "looks into" the load characteristics presented by a given speaker (particularly the speaker's crossover network,) bad things can happen (or not) depending on the electrical compatibility of the two devices.

C. Ditto for the electrical characteristics of the speaker cable in use. Example: electrostats require low capacitance speaker cable, which is why it's advisable to stay away from high capacitance cable (almost all Cardas for instance) if you're driving electostats.

Then there's the issue of quality, no matter what kind of gear you want to use -- there are certainly some VERY quiet (and VERY expensive) tube preamps as there are SS preamps. My point was that using a great tube preamp (instead of a great SS preamp) will not get you "tube sound".

So how is it a tube amp produces "tube sound"? And why can't (most) SS amps produce "tube sound"? The answer is quite simple really. but first I need to define what, for me anyway, constitutes "tube sound". To me "tube sound" means that every molecule of signal detail is PRESERVED as the signal is amplified, and then it is sent on to the speakers "whole". In other words, to me it doesn't necessarily mean a "warm" sound, or a "mellow" sound. "Tube sound" is most noticable in an extremely lifelike midrange -- a quality that is less important to rockers for instance, than dynamic range, power, and tight bass.

To understand why tubes 'preserve' the signal better than transistors, you need remember just one thing: "switching speed." Power output devices (tubes OR transistors) are actually valves that normally operate in pairs, often referred to as "push-pull". One valve (tube or transistor) turns on and lets a powerful voltage through that represents a half-wave of the signal. Then it turns off and it's partner opens and lets the other half of the wave through.

OK, here it comes:

Tubes don't turn on/off instantly. They heat up, they cool down. And so there is some overlap between when one of the pair stops operating and the other one starts. There's a bit of -- let's call it lingering -- in handing off the signal; and so "the ball can never get dropped", so to speak. But if the "lingering" goes on too long, the waveform is distorted at the critical inflection point and you get muddy sound. (Some call it warm ;-)

Now transistors are just the opposite. They can turn on and off INSTANTLY. No lingering ;-) But what happens if when one valve turns off, the other one turns on just a nanosecond later? Sound (actually 'signal') was happening (or supposed to be happening) during that nonosecond. Where did it go? Well, it fell through the (nanosecond) crack! Lost! The result can be sound that feels 'hard' or 'etched', but in reality, the signal has simply lost some of it's original microdetail. It's a bit like when you throw away every hundreth pixel of a digital image, the picture seems to 'sharpen', but no longer looks completely "natural".

Very VERY expensive SS amps, like darTZeel, don't have cracks between their pairs of power output transistors ;-) However, it takes incredibly complex circuit design, and component matching, to reduce that nonosecond to a MILLIONTH of a nonosecond ;-)
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Very helpful comments...thanks very much.

Turns out, I have two tube preamps, a Blue Circle and a Dodd (both 6922's). So I plan to do some A/B tests with the different preamps.

My interest in a SS pre like the JRDG Capri is a full service remote (yes I've gotten lazy), little or no tube noise, and the attributes of a good SS pre (speed, broadband, drive, etc.)

Semi suggests that a tube pre and amp is the ultimate. I hope to investigate this difference in next few months.

If your tube preamp is dominating the sound of your system then you have a very colored preamp. The classic test of a preamp is to run a signal from a source that does not require a preamp to your amps and listen to it. Then put your preamp in the circuit, if you can tell a big difference then you have a bad preamp. I have a friend who wants his preamp to bring the midrange forward because he likes the sound that way, he knows it is not neutral but doesn't care.

I agree with Nsgarch, tube amp has much more influence on the sound than tube pre amp.

I also started with tube pre and solid state power 20 years ago, only when I changed to a tube amp I discovered "tube pre + SS power" is for the wannabe. Same goes for hybrid amp, they only do half of the trick or less.

From impedance perspective, it should not be an issue for most tube amp to preceeded by SS pre amp, but not the other way around. Best option like many suggest is to use tube pre, it will take your system to a whole new level.

I basically agree with what Nsgarch said.

I run my hybrid Lamm M2.1 amplifiers with my solid state Ayre K-1xe preamp and I love the sound. It is very quiet, and yet exhibits a nice touch of that tube sound.

By the way, this has been discussed many, many times here and on Audio Ayslum, so you might want to do a search of both sites and read the lengthy threads and posts, rather than base your decision on just this thread.

FYI, one thing I have come to the conclusion about though, is that it takes a really good solid state preamp, to equal a really good tube preamp. (i.e. Entry level tube preamps seem to be better than entry level solid state amps. At least that is my opinion.)

Good Luck in your search!

I doubt it matters in general.

If you want to bask in tubelike sound, this can probably accomplish that depending on the details but more tubes in the signal path will probably be merrier.

I'm still a bit befuddled by the whole fascination with tubes, though I do appreciate their allure as I am a sufferer as well to some extent.

I've heard very good tube amplification that sounds a lot like SS, but I have yet to hear very good SS amplification that sounds like tubes.

Also, I do not hear a tube-like sound at most good live performances I attend, so my current conclusion is that good sound does not sound like tubes.

My current mindset is perhaps also that tubes are better off being seen but not heard.

I believe that Glenn is especially interested in real experiences -- positive or negative as they may be -- that match a Capri pre with tube amps, and with his tube amp in particular.

Unfortunately I have not tried Capri on a tube amp myself, but only on JRDG 7M and JRDG 312, so my comments are partially non helpful.

Sonically, if we make a scale from 0 to 100 for the extreme harsh solid-statish versus clawingly warm tubish sound, the Capri seems to me to fall on the very slightly warm side of neutral at about 53 or 54.

From a compatibility point of view, the Capri presents an output impedance of 40 Ohms single ended and 80 Ohms balanced. This should, at least in principle, make it compatible with most any amps, including most tube devices.

As its gain has a resolution of 0.5dB, there should be no issue ina very gradual volume increase in most situations.

In the end though, there may be no substitution for trhying things out by oneself. . . My experience is that one audiophile's poison tends to be an other one's ambrosia, and viceversa.

G.

I ran a Klyne 6LX3p pre amp with vtl 225's,manley ref 440/200 and cary slam 100's with excellant results;unless there is a gross mismatch of preamp to amp mating I don't see why your plan would not work;also Buconero117 idea of a loaner from a dealer is not a bad idea.

Nsgarch IMO your wrong..Ive never know anyone that thinks "85% or more" of the system is the amp/speaker and the remaining 15% or less is the source/ pre-amp/cable/room treatment/power,thats just silly..My tube pre is the heart of my system..

No, you miss the point of tubes. Best way to tell is get a dealer to loan you a tube pre, any make, and give it a try.

My Capri with VAC Auricle Musicblocs is a nice combination. Prior to getting the VAC amps the RM-10 was on my short list to use with the Capri.

FWIW I also like, and to a degree prefer, a passive preamp in front of tube amps. I'm using a couple different ones in my system right now. The Lightspeed attenuator and the Slagleman Autoformer Volume Control.

If you can understand why the sonic charcter of any system is determined 85% or more by the amp/speaker (and speaker cable) combo, then you'll understand that if you want "tube sound" then you need a tube amp -- i.e., a tube preamp and a ss amp won't do it (contrary to what many people think ;-) Also, tube preamps make tube noise which is amplified by the amplifier. Tube amplifiers by themselves (genreally speaking) make no noise.

I drive my McIntosh MC275 with a Mark Levinson 26s preamp and the system is quiet, fast, and beautifully balanced sonically speaking. The main attributes of a preamp should be accuracy and blackest background. Since preamps do not process (amplify) the signal, but rather simply select sources and attenuate their output (volume control ;-) there's not much they can do to adulterate the signal, so may as well have a quiet preamp and go SS IMO.

After that, the amp and speakers will determine what your system actually sounds like.

IMO you typically loose that tube sound running a ss pre, thats my experience ..try it the other way around,,, ss amp w/tube pre.....

can a SS preamp do the tube amp justice to maintain the tube amp's liquidity, sweetness, wonderful midrange, etc.

Yes, certainly, if the two components match up well.

The 6Moons review of your amplifier describes its sound as follows:

Extrapolating from that, we can characterize the RM 10 as slightly on the lean, fast, accurate and linear side of the common tube fence. Comparing that assessment against what I sense are Roger Modjeski's sensibilities as a designer, it seems fitting, factual and deliberate.

Given that, what would probably be the best matchup would be a solid state preamp that leans (or errs) in the direction of emulating a tube-like sound, rather than one that tends to be toward the analytical/resolving part of the spectrum, or even at the neutral center.

I can't comment on the Capri, but I would suggest that several of the 1990's Classe preamps fall into that category (solid state preamps with tube-like sonic characteristics), including the DR5, DR6, CP50, CP60, and possibly the CP35. I currently use a CP60 with a Chinese-made Paxthon 8 x EL34 (not 84) 80 wpc amplifier, and I've been very pleased with the combination. Most notable, I would say, is that the soundstage produced by this combination is enormous, although I attribute that more to the power amp than the preamp.

I've also had very good results previously with a vintage Mark Levinson ML1 solid state preamp driving various hi-end vintage tube amps, including Marantz 2's and 9's (which I no longer have, in case anyone reading this is tempted to ask).

Regards,
-- Al