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Importance of line stage pre--Who Knew?

Well, I'm sure a lot of you knew, or there would be no $5K and up market for line stages.

As for me... This month marks the 40th anniversary of buying my first stereo with my own money. In all that time I've only had solid state in the signal chain except for a Jolida phono preamp and matching line stage I picked up a couple of years ago. It turns out that the tubes in those units were for a buffer stage to warm up the sound, while the gain was handled by op amps. Well, recently an audio buddy came by to spin some vinyl and show me a tube-driven line stage preamp he wanted to sell.

See it here.

This is just a simple, modest line stage preamp with 5-input rotary selection knob, balance, and volume. Five pairs of inputs, one fixed and two volume-controlled pairs of outputs on the back. However, it's a PTP hand-wired design with tube rectifier and large transformer. I didn't want to like it as it had a couple of deal-killers: 1) no remote control and 2) too tall to fit on my audio rack thanks to that outsize transformer. It would have to be a game-changer for me to consider getting it.

We tried it out in the humblest of circumstances. I set it on a Rubbermaid step stool in front of my rack and patched it into the signal path, bypassing the Jolida op amp/tube buffer line stage.

HOLY MOLY!

Game changer? Sh'yeah! After just a few seconds of hearing it you know it's not leaving the house. So what did it do?

It simply sounded more real and less electronic. It heightened the illusion of performers in real space making music. It took my system a big step away from a tune player to a sonic virtual reality device. Sonically the difference might be considered subtle, but in the realm of emotional response to the music, it was a big step. There was more separation between the various elements of the mix, and if you sat in the sweet spot between the speakers, you heard a 3-dimensional image of performers spread out before you. That physical separation also separates into audible separation. It was easier to hear how the musicians interact with each other to make music together--just like in a live performance. Instead of an amorphous left-to-right smear there was a sonic hologram of where the performers stood in the mix. However, this did not desconstruct the performance, but rather showed how the elements worked together to form ensemble music.

Timbres sounded more real: Brass had more blat when called for, more sense of air flowing through metal, of lungs full of air providing the energy for the resulting sound. Strings sounded pluckier, voices more human, acoustic instruments woodier... you get the picture. It made LPs sound enveloping with a nicely laid-out soundstage, and it elevated computer-based digital music from tolerable to involving and enjoyable, again with the 3-D imaging and wider-than-the-speakers sound stage.

Before picking up this piece, I was thinking of upgrading amplifiers yet another time. But I experienced a valuable lesson I had previously known more in theory--that for fine gradations of amplitude, tubes rule, and it's the low level--preamp and component level--signals that are most fragile; if part of the signal drops out at that stage, no amplifier will bring it back regardless of the amp's bandwidth, rise time, signal-to-noise ratio, or resolving power. The preamp has to caress and amplify those low level signals and pass them on to the amplifier so you can groove to them when they exit the speakers. Since all my sources--LP, CD, FM, iPod, and computer--run through this unit, everything sounds better,

In fact, one of the things I learned from this experience is that my $220 used 1981 Heathkit amplifier is even better than I thought. Paired with this preamp, it is still superb. Sure there are better and much better. But for now and some time to come, it'll do nicely.

Since picking it up I swapped in a set of Sylvania NOS tubes--a JAN (mil-spec) 6X5WGT rectifier (smoother delivery and better voltage regulation) and a matched set of '50s-era Sylvania 6SN7GTB triodes (even more liquidity, less grain, more 3-D imaging). I'm a happy man. Next up--sell off some electronics and get a tube phono stage from this maker.
johnnyb53
plato
1,543 posts
 
With all due respect, Charles1dad from your reply my feeling is that you've just never heard digital or solid-state done right.

But here is a possible explanation. With solid-state gear those who don't like it normally feel this way because of its sins of commission... This means that since ss amps and preamps are generally lower-noise and more linear through the audible range that you can hear more of what is going wrong in the treble if you don't use proper cabling, chassis diffusion, or AC conditioning/regeneration products.

With tubes, the sins are mainly of omission meaning that they generally roll treble, round fast transients, and muddle things a bit in even the best designs. This makes the sound more "musical" at the expense of removing musical information, nuance and detail.

And honestly, I've done these experiments enough times to be confident in my position. The outcome is always the same.

I absolutely love both my digital and my tube systems. They are both glorious. But I know the digital system is more nuanced and revealing while at the same time seeming more like a live musical experience.

By contrast, the tube system sounds extremely smooth and euphonic. It has a huge holographic sound stage and the music is so sweet and soothing it can literally lull me to sleep. But ultimately I don't think it's as musically correct.

As I said, both systems sound great in their own right. I just think the digital format has more potential to take me closer to a "Live" performance. But everything has to be right and optimized for this to happen and I've taken pains to do this right.

With tube gear it's easy because as I said the sins are of omission rather than commission and you gain more by the tubes removing high-frequency nasties and rounding transients than you lose in bass control, proper transient reproduction and lower noise.

Obviously many tube fanatics won't agree with me but it's mostly because they haven't had the same success getting their solid-state or digital gear to sound right... because it's more difficult to achieve and you need to really understand the things that work and the things that don't.
clio09
3,354 posts
 
With tubes, the sins are mainly of omission meaning that they generally roll treble, round fast transients, and muddle things a bit in even the best designs. This makes the sound more "musical" at the expense of removing musical information, nuance and detail.

Having had both solid state and tube systems I just cannot agree with this as it pertains to the best designs, which regardless of price point, I will say are few and far between. I especially find this comment erroneous as it pertains to direct coupled and OTL designs that have been properly executed.

As for your statement on solid state, the part pertaining to chassis diffusion, cabling, and AC/power regeneration says it all...and I say that with all kindness because I just can't stop shaking my head. If that is what it takes to get solid state to sound its best, then maybe those designs should not be considered "the best" and need to be revisited.
charles1dad's avatar
charles1dad
10,250 posts
 
I feel the same as Clio09.Plato I respect your opinion but realize we`re just not going to agree and that`s okay.
Don`t make an assumption on what me and other posters here have heard or experienced just because our conclusions differ from yours. You have two systems and find the digital one more correct, I can`t argue with what you hear,that`s personal.I stated my reasons for preferring tube amplification you don`t have to share the same opinion. Don`t comment on my exposure(or lack of), you have no idea what it consisted of.

Over the years I`ve listened to many tube and SS based systems(and digital) and have formed my own conclusions also.It`s pointless to turn this into a which is ultimately better. Both approaches will have plenty of supporters. Let us just agree we`ve both found our respective paths to satisfying systems.
Regards,
plato
1,543 posts
 
Okay, ClioO9, You're right, we are not going to agree. But I want to make a couple of points. First, yes, perhaps direct-coupled OTL amps are a little less muddled than other types (I have owned the Atma-sphere M60 Mk3.1's btw as well as highly-modified AHT/Acoustat direct-drive OTL amps), but conventional OTL's like the Atma-sphere's throw an amazing amount of heat which is not great in AZ in the Summer. But beyond that, they are a crap-shoot as far as their bass-performance goes because of the usual bass impedance peak at some audible low frequency. I had a problem with that.

Second, my idea of using chassis diffusing feet on my gear applies equally (if not more) to tube gear, not just digital and solid-state. I take it from your remarks about power regeneration that you are poo-pooing it, which I find very suspect in view of the sonic improvements regeneration provides. But I won't argue further with you because I see no point in it due to your close-minded attitude.

Charles1dad, you're right, I don't know the full scope of your experience but without me tooting my own horn I would just say that the odds are (being a past president of the NJ Audio Society, a veteran Senior Reviewer and 40-year audiophile) that I have more experience tweaking different types of products and systems than you do. Without a resume of your experience I haven't a clue.

I'll also allow that you and others may take the "tubes are great" view, and I basically agree, I just think there are other approaches that can equal or exceed the limits of tube technology based on my own first-hand experience (not other's opinions or hearsay). Sorry to be a progressive thinker, I guess.
clio09
3,354 posts
 
Plato, not necessarily poo-pooing power regeneration (I tried these products in my system so I do not consider myself close minded on the subject) but just your comment and the idea that this, along with cabling and chassis diffusion, is what is required to get the most from solid state. If you need all that then IMO something is wrong elsewhere in the system.

As for the Atma-Sphere your point on the heat and AZ is well taken. However I live in Las Vegas and have managed to tolerate the situation. In may case I look at it as an opportunity to have a built in sauna. Martini and iPad in hand, some good music, and sweat off a couple pounds in the process :)
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