Component Impact

I've been an "audiophile" for 20 years and my experience has taught me that speakers have the most impact on sound. Well that was my experience until one week ago. Over the years I've changed speakers, amps, source, and cables...sometimes I could hear differences and sometimes I couldn't. I recently decided to upgrade my Densen B-250 preamp to the Densen B-250+. My ears still can't believe what I'm hearing...better separation,detail, soundstage. I'm totally shocked by the improvements. Has anyone else experienced significant improvements by changing/upgrading their preamp?
Yes. And speakers should always make a noticeable difference....

I could not believe the difference when I changed my preamp, quality of sound improved by a large margin in every department, but I believe that speakers make the biggest difference.
I agree speakers can make a big difference, but not always the biggest improvement. The speakers are reproducing what they are being fed.
Try eliminating the preamp. That's even better, a lot better.

There are two ways you can do this:

1) use a good quality DAC volume and drive amps directly

2) use a transformer passive linestage (TVC) instead of an active preamp

The impact I have discovered from most important to least is:

1) source quality and digital jitter
2) speaker crossover quality - mod it or eliminate it
3) speaker quality
4) volume control technology
5) digital filtering
6) amplifier quality, particularly output impedance and speed

It just makes sense that source quality is first on the list. If the source is poor, there is nothing you can do later in the chain to fix that. Even $100K speakers will not do it.

Digital filtering in the DAC is very important, even though it is low on the list. The less of that the better.

Steve N.
Empirical Audio
I have had some spectacular SQ improvements with better preamps in the past, culminating in the elimination of the preamp altogether as suggested by Steve.

Just for kicks I reinserted a preamp into my multi channel system recently. It took me all of 15 seconds to hear I was inserting an active circuit and some cables in the chain that subtracted from the quality of the signal, and the device was back on audiogon where I bought it.
Has anyone else experienced significant improvements by changing/upgrading their preamp?

Absolutely, in fact I've found that it is harder for me to find a preamp that I can live happily with than it is to find speakers that I can live happily with.
IMHO, the preamp is THE most difficult component to choose.
Steve N.,

I would love to eliminate my preamp. What DAC with volume control do you recommend?
Sure.....the system operates at the ability of the weakest link in the chain
In one of my older systems, I was sure I needed to change the amplifier until my dealer, who sold both, proved to me that the sound I was looking for was actually achieved by upgrading the preamp. The system had more solidity, tonal accuracy and more pitch-accurate bass. All the things I previously believed were attributable to the amp were accomplished by the preamp. Quite an eye-opener.
Ricred1, what pricerange DAC with VC are you looking at? Steve manufactures/sells one himself, so may be he refrains from answering to avoid perception of conflict of interest. I personally have been researching and playing with DAC + VC with and without preamps for quite some time so I can give you a pretty good lay of the land and guidance if I better understand your parametes. What digital source(s) are you planning to use?
"I would love to eliminate my preamp. What DAC with volume control do you recommend?"

There are only a few choices that enable actually eliminating the effects of the preamp:

1) Overdrive SE
2) older Bidat with external volume option
3) Weiss 202 because it has gain settings that can be used in conjunction with a little bit of digital volume reduction - only works with computer audio

The sound of these varies all over the map, so I recommend auditioning.

Another thing that helps significantly and even improves on the "no-preamp" system is to add a high-quality transformer buffer betwen DAC and amps. This has numerous advantages and improves SQ:

Steve N.
Empirical Audio

What do you recommend under 5K? I will use the Apollo R as the transport for now, until funds permit me to upgrade.
Depends on what school of volume control thought you subscribe to.

School 1 says all digital attenuation over say 6dB degrades the signal and is to be avoided (Steve N. is a proponent of this school).

School 2 says unless you are doing more than say 30dB attenuation you are absolutely fine with digital VC, and in fact, it is better than analog, because you avoid an analog circuit (advocates of are PS audio and Bel Canto).

My personal experience is consistent with school 2. I am not claiming school 2 is right and 1 is wrong. I'm just reporting my personal observations.

So first, if you need significant amount of attenuation (over 30dB) you probably need an analog VC, whether you're school 1 or 2.

There are three contenders in the $5K price range with analog (or hybrid) VC:

Empirical Audio Overdrive SE
Weiss 202 (Hybrid)
Aesthetix Pandora (Tube - MSRP 6K / street price 5K)

Note that the Overdrive has no remote control. With PC audio you can do coarse setting analog on the DAC, and do fine grain setting digital in your music server (say amarra or JRiver). With a CD player as source, this is a problem.

If you subscribe to school 2, and don't need more than 30dB attenuation, your options increase. Three highly regarded contenders with digital VC are:

PS audio Perfectwave DAC MKII
Berkely Alpha II
Bel Canto VB3.5

There are other threads on this subject you can read up on. I'm sure I missed a few.

Fully support Steve's suggestion to listen to a few DACs and make up your mind.

Have fun!