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Linestage types versus soundstage

A little background. I have been cynical about powered linestages in a digital system. If the impedance ratios are okay, what needs any gain or amplification? Isn’t “straight wire with attenuation” the goal? What’s all those components doing in there if it all ends up going through an attenuator anyway? Would such linestages exist if CD’s had been invented before vinyl? As I watched these products climb to $10K, $20K and beyond, it just seemed stranger—likened to a product that makes water wetter. Cynical, rational me.

But I still felt audio was an experiential endeavor, and had a tube integrated because I enjoy music played through it. I got the upgrade bug and bought the newer, bigger, better tube amp from the same great company, thinking I’d stay in budget by running my Benchmark DAC2 HGC straight into it.

So I did. Things are clearer and more extended…and the soundstage moved to the wall behind the rack and went flat. Let me say here that I have complete belief and trust that Benchmark products are at the top of their class. I respect their recommendation to place nothing between their DAC’s with HGC and the amp. Nevertheless, I borrowed back my old Pass Aleph P linestage. This line stage allows me to optionally add gain to each single-Mosfet channel that fronts a high-quality attenuator. I did that and the soundstage seems taller, but not back to the voice hovering-in-space of the tube integrated.

To summarize, I’ve gone from a tube integrated to tube amp driven from a very good DAC, and gone from EL34’s to KT88’s, and gone from single-ended to balanced, but the DAC and speakers are the same. Perhaps I’ve screwed up something else in the signal path. I wasn’t planning on adding another device, but it looks like I’ve crossed the Rubicon on tube-powered linestages, which I’ll judge on experience rather than thought. Still, some questions hover:

1) What creates soundstage and is there something about tubes that gives them this ability?
2) How is the signal leaving a powered linestage better than the incoming signal? I can answer that question for amps, phono stages and MC step-ups, but beyond "attenuated" I'm still conflicted on powered linestages.
3) Is there an argument that a lot of energy behind the signal going into the linestage attenuator can produce better results? If not, why does BAT have all that energy storage?
4) What new or used tubed preamp less than 4k will give me back that compelling 3D soundstage that extends in front of speakers without added bloat and syrup? New Backert, ZOTL or Van Alstine or a used BAT or AR?  I'd like one that doesn't create a lot of heat.
6) Should I leave things as they are and look to speakers to address the soundstage issue?

I’m going to AXPONA to see what’s out there.
Thanks for any advice or education.
electroslacker
1markr
594 posts
 
I can without doubt tell you that the Backert will give you the 3D soundstage and musical bloom you are looking for, but that assumes the rest of your components are up for the task as well. It’s not just preamp / linestage related, but contributions from your front end components, amps, and all your cables will affect a holographic soundstage, and lets not forget the room either! 
charles1dad's avatar
charles1dad
10,248 posts
 
Electroslacker,
In addition to the Backert I’d look into these given the stated price range 4K or less.
Don Sachs Line Stage
Aric Audio to custom build one for you
A used Coincident Statement Line Stage
A used TRL Dude
A used Shindo Aurieges
A used Atma-sphere MP-3
Different topologies, circuits and tube choice but all high quality options.
Compare them to Your Benchmark DAC running direct and just "listen" this is the key point,  trust your ears. 
georgehifi's avatar
georgehifi
10,312 posts
 
Isn’t “straight wire with attenuation” the goal?

Yes I firmly believe this, "if" impedance matching is good and you have enough volume, direct source to amp is the closest to that you’ll find to the above statement, giving the most transparent, dynamic, accurate staging and depth of sound possible from the source.
Anything active in the path can only add noise, distortion/s, and reduce the dynamic range (unless it has a dynamic range enhancer circuit which sound like c**p)

Cheers George
kalali's avatar
kalali
1,977 posts
 
This topic has been discussed ad nuseam and the debate goes on.
My advice is trust your ears and ignore the rest. I have yet to hear a passive linestage that could approach the soundstage and overall musicality that an active linestage, particularly a tube design, could deliver. Call it inaccurate, too tubey, or whatever, but clearly more enjoyable. And that's the ultimate goal.   
atmasphere's avatar
atmasphere
11,740 posts
 
1) What creates soundstage and is there something about tubes that gives them this ability?
2) How is the signal leaving a powered linestage better than the incoming signal? I can answer that question for amps, phono stages and MC step-ups, but beyond "attenuated" I'm still conflicted on powered linestages.
3) Is there an argument that a lot of energy behind the signal going into the linestage attenuator can produce better results? If not, why does BAT have all that energy storage?
4) What new or used tubed preamp less than 4k will give me back that compelling 3D soundstage that extends in front of speakers without added bloat and syrup? New Backert, ZOTL or Van Alstine or a used BAT or AR? I'd like one that doesn't create a lot of heat.
6) Should I leave things as they are and look to speakers to address the soundstage issue?
1) proper phase relationships and bandwidth
2) It isn't. The thing is, what you are not including here is the effect of the interconnect cable. The fact is most cables editorialize- the have colorations of their own. One thing a decent line stage can do is minimize those colorations and so it can appear to sound better, because it does. But there is no question that it degrades the signal! Funny, huh? With regards to cables, it is easier to reduce cable colorations by going balanced. However there is a balanced standard that is not well supported in high end audio, so you will still be auditioning cables if your gear is balanced but doesn't support the standard.
3) No. But you are confusing (or the post is mis-worded) the energy going into the volume control (attenuator) with the energy used to power the circuit. They are not the same. The energy in the power supply of the preamp simply has to be as clean as possible so that the active circuits are not influenced by the power supply. Brute force is one way to do it, good regulation of the supplies is another.
4) If you want to avoid 'syrup', that is an aspect of single-ended operation. But a preamp can be single-ended and have very low distortion, in which case it will not be 'syruppy'. Auditions are important. We avoid syrup (2nd harmonic) by employing differential balanced circuits throughout our balanced preamps.

BTW, tubes don't have to have syrup, even though they are often know for a lot of 2nd ordered harmonics (example.: SET amplifiers). The harmonic distortions generated by any circuit dictate how that circuit 'sounds', since the are converts all forms of distortion into tonality of some form. So the 2nd contributes to richness and syrup while the higher orders (5th and above) contribute to brightness and harshness (in particular, the 7th contributes to a metallic quality). The reason some circuits have certain distortions and not others is very dependent on the topology of the circuit- for example whether tube or transistor, single-ended circuits will have more 2nd harmonic than a circuit that is fully differential.

Unfortunately the industry does not recognize how the various harmonics influence sound (even though we've known this since the 1930s). So the spec sheets will continue to not be all that helpful- you'll still have to audition the gear to see what works for you.
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