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

11-04-12: Peter_s
Maybe you can figure out a way to add a motorized volume control to it?
To my surprise the lack of remote became a non-issue.So far, with this unit I don't miss the remote control. With all my previous SS preamps and integrated amps I constantly fiddled with the remote's volume--turning it up to hear loud passages and down when crescendos might wake the house or simply irritate me.

However, the noise floor on this preamp is so low that I can hear soft passages just fine and the crescendos, while loud, don't get hard or bright. From this new experience, I'm theorizing that if you constantly fiddle with your volume control, it *may* indicate that your line stage lacks low amplitude resolution. With the new preamp, I keep the volume knob at one position and just let the music play on. This is a complete paradigm shift for me and it profoundly enhances my listening experience.
Johhnyb53 I know just what you mean. Good for you. I just put a Joule Electra LA100 mkII preamp in my system a few days ago. It's not my first quality tube preamp; I once had the top of the line Cary preamp in a different system. The JE preamp has made everything in my system sound more like real instruments and music. It has brought dimension, depth and realism. It is a "game changer" that has brought the "high end" experience to my system. As a jazz lover, I'm very happy with what this tube line stage brings to the music.
Jhonnyb53,
Congratulations!Getting rid of OP-Amps and their associated negative feedback was a wise move. This new found realism,life- like flesh and blood presence and emotional connection is an eye(ear) opener once discovered.Well implemented simple circuits with tube amplication seem to do this the best.Passive and solid state have`nt been able to match this realism and involvement you describe in my experiences(so far, maybe one day). I certaintainly can understand your increased joy and happiness.
Regards,