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
...a bit of a caveat......most changes (subtle, grand, good, bad) are perceived as a "Wow". Live with this new one for a few weeks and discover ITS warts...you just might want to go back to your old one.
I don't think so Stringreen. I've been in this hobby 40 years and have been a reviewer for over 15 years so I have a lot of experience with such things.

All I know is that as my Mojo Audio power cords continue to break in, the sound is getting incrementally better and better. In fact, I have never heard digital high frequencies sound so much like the real thing!

I'm not sure I understand what you mean about going back to my "old one." My old one of what? If you mean the tube pre it's easily switched in and out. And incidentally, the tube pre usually works better with my turntable source because the highs are a bit more extended with the vinyl source and the tube pre knocks that down just a touch. But I need to try it again because I haven't played the turntable since I installed the new W4S XLR interconnects on Friday.

BTW, I'm from Tucson so if you ever get the urge to take a day trip it might be worth your while...

Frank ;-)
I respect plato`s opinion and he`s right YMMV.I`ve found the complete opposite result.High quality tube components(preamp and power amplifiers) are more resolving,honest,realistic and nuanced.They seem to be purer with audio signal propagation. They are capable of preserving the musical signal and allow that vital emotional connection and expression of music.Thus far in my personal experience SS/digital amplified signals just are incomplete and stripped of the inner detail subtle information,just does`nt sound as real life as high quality tube electronics.For some reason this observation does`nt hold up with source components(CD and DACs so far, gube vs SS),I don`t no why.
Just another man`s point of view. I know preference can go in either direction.I hear less masking and superior resolution with the tube gear.This is why they sound more natural and less HiFi character compared to SS/digital amplifying the signal,at least to my ears.The good thing is we all eventually find our own audio direction and solution. Johnnyb53`s revelation makes sense to me. I don`t believe he`d have quite this same reaction without 'good' tube components.There`ll always be two sides to this story.
Regards,
If the OP actually listed his system it would give a better context to understand his recent aural discoveries.

I also think Stringreen makes a good point.
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.