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
This a really good thread. I hope a lot of people take the time to read it. A good preamp makes a huge difference. Unfortunately, most people overlook the preamp and go for the more "exciting" components like amps and speakers. Thats a huge mistake. When you get the right preamp, its like a window opens up in your system.
There are simply too many variables to be able to make definitive generalizations about tubes and solid state or analog and digital. No doubt a lot of it has to do with implementation, cabling, vibration isolation and other tweaks, especially those addressing room acoustics. And whether CDs are just off the shelf and untreated, for example.
I have always said that a tube preamp is the most important component in a system. I realize that is a controversial statement; a good source is very important too. I found I need the gain and dynamics of an active pre for listening satisfaction. I have two Joule Electras btw, which have replaced much higher priced preamps; just more musical in my system and for my tastes.
I agree with Plato in my experience of 47 yrs. Tubes are fantastic and have their place. But when I want to get more of the music- the rhythm, flow, needed dynamics, timbre, the picture of the whole package. A more natural balance of what I would remember as the real thing as being there, as reasonably best as we can produce it via our sound systems. The ss stuff I have more often does that for me.To me there is music and there is sound. You can walk down a street and here live music coming from a closed up home. I can't explain it but it definitely is different than reproduced sound/music. To me it is easy to tell and for me I get it most, most of the time from my ss stuff. I have not had but only a few high quality tube amps, pre amps and I have been around a few more. They were all more expensive than my ss stuff. I know I haven't tried every option we have a audiophiles. I have only optimized them for about 10 of my 47 years so it might not be a perfect comparison. But that is my reasonable conclusion for me.
ClioO9, okay, fair enough, but ALL the tweaks I've mentioned (cables, chassis diffusion, and AC conditioning) make positive improvements in EVERY system and on nearly every product I've experimented with. But I can agree that most product offerings have room for improvement.

I suggest you go over to PS Audio's website and read Paul McGowan's blogs on the new PowerBase product he's developing. To me this makes a lot of sense... based on my own trials and tribulations. Mike VanEvers used to offer a wood-block resonance tuning kit that I've found quite useful and instructive in my own experiments.

Frank