Stereo Analog Bypass

So I've owned my 950 since 2002, but for some reason I'm just now realizing that the 5.1 analog input bass mgmt is different from the analog bypass bass mgmt. (And I know this is the 990 forum, but since I'm in the market for an upgrade I figured it was still pertinent.)

I'm at the point where I want to incorporate a high end 2-channel preamp into my HT. I really like my 950 for movies, but it's become the weak link in terms of music. So my question is this: What improvements are there to be had by picking up a really nice DAC and running it through the stereo analog bypass? I don't expect that to sound as good as if I had a great preamp to go with it, but for now I'm wondering how much of an upgrade the DAC alone would be.

I was wondering if any of you guys are running high quality sources with your Outlaw pre/pros vs. just using the DACs in the 950/990/etc for music. Do you guys think the analog bypass is good enough in the 950 that improving the source (for Redbook CDs) would make a nice upgrade?

Thanks!

I'll take a stab at this by presenting the architecture recommended for audiophiles. It is as follows:

1. A high end stereo preamplifier with home theater pass-through capability is added to the system. It will receive all analog inputs (phono, DACs, CDP). Its outputs will feed the Left and Right channels of the power amp. Preferably this power amp is a high end stereo one driving full range speakers, but the two channels of a good multi channel amp will do as well.
2. The HT processor will receive all digital inputs and will have its left and right outputs connected to the pass-through inputs of the stereo preamp. This will assure that the left and right channels of the power amp are used by both the surround processor and the stereo preamp.

This architecture assumes large front speakers and gives the best of both worlds. It is, in fact, two separate systems which share the power amp and speakers for the two main channels.

If you don't yet have purchased the stereo preamp and have large main speakers, this might help.

Just the two cents of a fellow outlaw...

There's a related thread on the 970 board that may be of interest to you: http://ubb.outlawaudio.com/cgi-bin/ubb/ultimatebb.cgi?/ubb/get_topic/f/6/t/000930.html

AJZepp,

If your 950's bypass mode is similar to the 990's bypass mode, then you should realize a sound improvement gain using a higher quality digital source. I used to own a Channel Islands Audio external DAC which uses the top-line Burr-Brown (TI) DAC that I really liked and it made my ten year old Sony megachanger sing! Currently, I am using a Marantz DV-9600 which uses the top-line Cirrus Logic DAC and it also sings in two-channel. If I use my old Sony in stock form, it sounds life-less without some help. Even the built-in upsampler in the 990 helps my Sony tremendously. So I think whether you go external DAC or replace your digital source, you should hear a positive gain with your 950. What is your digital source that you are using currently for 2-channel redbook CDs?

Slbenz

Alex: Thanks, that's exactly what I'm planning to do. I'm just trying to get some feedback on how good the analog bypass is on the Outlaw pre/pros so I can decide whether to buy an outboard DAC or a preamp first.

Videodrome: Thanks for the link!

Slbenz: That's exactly what I was getting at, thanks. I'm looking at either a Lite Audio 60 or possibly a Monarchy NM24. The interesting thing about the Monarchy piece is that it has a built in preamp section (it's a very well-reviewed piece) along with a top notch tube DAC. Supposedly the weak link is the volume control on the preamp, though, so even if I played around with the preamp feature I'm not sure it would be as good of a presentation as if I ran the DAC into a better preamp. But your experience with the CI DAC is exactly what I was looking for. Right now I have a Denon 2900 Uni player, but I usually just run a dig cable into the Outlaw so as to avoid issues with bass mgmt. But now that I know that I can still adjust the bass trim on stereo bypass sources, I'll play around with things a bit more with the Denon.

Thanks, guys!

AJZepp,

Glad to be of some help. As you probably know, the two DACs you are looking at use variations of the the PCM1704 DAC but the Monarchy is supposed to use the best of the bunch. Your Denon uses a custom TI DSD1790 DAC that is supposed to be slightly less spec-wise than the DSD1792 which is a better spec'd DAC than is found in the Denon 3910 or current 3930. I've heard good things with both external DACs you've selected and suspect either one can help your Denon. Having those tubes in either DAC will help tame the edginess of your CDs, that is why I have the tube buffers in my system. Good luck with your search to better two-channel sound.

Slbenz

Dang, Slbenz, you know your DACs! lol Thanks for that info!

And "taming the edginess of my CDs" is exactly what I'm trying to achieve here. I want detail and transparency, but at the same time I want to avoid "clinical" and "sterile". I listen to a wide range of music, and I don't want one entire portion of my collection ostracized because I've assembled a system that is way too analytical. I have a tube hybrid amp that I love, and I expect (based on what I've read from multiple sources, including yourself, about certain tube DACs) that I'll achieve exactly what I'm going after as a result of the research I'm doing and the questions I'm asking.

I thought at first that I'd have to get rid of my 950, but then I realized that it's done everything I've ever asked it to do in terms of HT...so why not just keep it around? I'll incorporate the necessary gear to take my 2-channel to the next level and still have my trusty Outlaw pre/pro to handle movies.

By the way, nice speakers! I had MMGs for almost two years and loved every minute. Maggies are probably the only speaker I'd give up my current DeVores for...I bet your system sounds awesome!

Thanks again!

slbenz,

you say you have the tubed buffer amps in you system. Do they really work? I was always thinking that, in analog domain, once harm is done it cannot be undone, thus if the CDP produces edgy sound, no stage coming after it could undo that.

But, apparently, my thinking is contradicted by real live (this wouldn't be the first time ).

My CDP is a Music Hall MMF CD-25 to which I replaced the op amps with the Burr Brown OPA-627, the rectifiers with HEXFRED ones and the stock output jacks with high quality ones.

The sound is pretty nice, but I wouldn't mind a smoother one. The amp is a Cambridge Audio Azur 640A.

Do you think a Musical Fidelity buffer amp would be worth the investment? I saw them on eBay numerous times, only I coudln't convince myself to bid on them...

Alex,

The MF X10v3 tube buffer acts like a tube DAC that AJZepp is currently thinking about using with his Denon. I was quite surprised at the difference when I first installed the MF into my system. Warm mids and clearer highs while reducing or eliminating all edginess to the CD. Others will say using the MF is system dependent and if it doesn't work in your system you could easily sell the unit off for probably the same price your paid. I have mine installed between my Outlaw and Parasound so all sources benefit including AM/FM which sounds richer with the MF installed if that is any help.

Slbenz

Thank you, Slbenz, I'll give one of these a shot next time around.

If Santa heard my request for the Yaqin tube buffer someone praised in another thread here, I'll report on the effects on the sound after Christmas.

Just make sure to get the Yaqin with the single twin-triode tube and not the dual 6J1 tube. Much easier to tube roll with the twin-triode by Pacific Valve and Electric Company. You can use either the 6DJ8 or 6922 tube which are a very popular size. I use the green label JAN Phillips 6922 tube with great results.

Slbenz

P.S. Hope Santa rewards you with one!

Where could the Yagin be purchased from?

Thanks

Alex,

Right here: http://www.pacificvalve.us/YaqinTB.html
This is where I bought mine and they have a 30 day return policy less 8% restocking fee.

Slbenz

Slbenz (or anyone else): Do you have any experience with the TADAC from Tube Audio Design? Seems like he's got quite a loyal following and a very highly regarded product. I had a few email exchanges with him today and I'm very interested in giving the TADAC a try, but like the Monarchy piece, it's a DAC and preamp in one chassis. But unlike the Monarchy, you apparently can't choose a line out for the tube DAC...in the TADAC, the signal passes through the volume control and on to the L and R analog outs. Paul of TAD said if I wanted to use another preamp and just run the TADAC as an outboard DAC, I'd just keep the volume (on the TADAC) set to one level, run the L and R outputs into the preamp, and then use the preamps volume control from there.

Is there an issue with running the signal through two volume controls? Or do you think this would be fine?

AJZepp,

Haven't heard the TADAC but judging on the components used from their web site they don't use the latest generation CS8416 chip but the CS8414 chip. Also, the DAC they use is an inexpensive Burr-Brown 1793 which specs less than your current DAC in your Denon. If you are really interested in an external DAC, you should try the Channel Islands ext. DAC which uses the CS8416 chip and the latest Burr-Brown 1794 DAC which equals or exceeds the 1792. I can tell you from experience the CIA ext. DAC will give your Denon extra detail with warmth. You may want to check out the modified Lite Audio DAC 60 from Pacific Valve and Electric Company. It sells for the same as the CIA.

Slbenz

Thanks, man...I'll definitely add the CI piece to my list!

I'll second products from Pacific Valve and Electric. I bought my Musiland MD10 from them. They are also very willing to talk to you if you have any questions or need guidance on what DAC to buy.

Thank you, slbenz.
I am currently bidding on eBay on a Musical Fidelity unit.

If I lose there, I'll go with the Yagin. Do you think Yagin is superior? My bid is not that high, I'll definitely lose if I don't go higher, thus I might let it die if Yagin is better.

What would you do?

Thanks

Alex,

I knew you were going to ask this question of me. Here is a review I did of the Yaqin tube buffer that I own comparing it to the Musical Fidelity that I own as well:http://www1.epinions.com/content_312424107652

Bottom line: if you lose the eBay bid, I would go with the Yaqin. More flexibility, better sound via tube rolling to customize the buffer to your system vs. the MF which forces you to only use the 6112 mil-spec tubes that are soldered in onto the board. Oops! Just realized that the one you are bidding on is original MF tube buffer and not the the one with the mil-spec tube. The one you are bidding on is supposed to be a lesser sounding one than the X10v3 that I own. So I would definitely go with the Yaqin instead.

Slbenz