Category Archives: Audio/Video Hardware

Articles about audio and video hardware.

Digital audio reboot

It costs a bit, but it takes a heck of a DAC to get me to like digital music.  I admired some of its attributes, but there were others I could never get around.  After using typical mass market CD players, I bought the Pioneer Elite DV-45A due to its ability to play back DVD-Audio and SACD; I bought a DV-578A as a backup.  “This is OK, but…” was one of those phrases that ran through my mind.  Higher resolution recordings did sound somewhat better, but again, digititis would set in and I’d be turning the volume way down or shutting the system off.

The Oppo BDP-105 was a big improvement–it has a wide and deep soundstage in comparison to the abysmal DV-45A, and lost some of that harsh digital edge and having a more full-bodied sound.  I lived with its sound for a few years with very few sonic issues, except that I was using it primarily as a network player to access FLAC files on my server.  It worked, but here were issues with the playback.  No gapless.  No way to stream DSD from the server over the network.  And JRiver was (and still does) crash often regardless of which computer it runs on, making the experience less than satisfactory.  Oppo’s own Media Control app was adequate.

I considered adding a streamer like the microRendu or ultraRendu, but I still wouldn’t be able to access the 300+ ripped SACDs on my server.

I upped my game and have a PS Audio DirectStream Jr. in house. I bought it shortly before they killed Junior, due to supply issues.  It uses the same basic concept as the big brother DirectStream, so it provides pretty much the same sound quality with that last little bit of refinement that I likely wouldn’t hear anyways.

I won’t go into the architecture, other than to say that unlike other DACs, the PS Audio DS DACs do not use a DAC chip.  They use FPGAs to process a digital signal which is upsampled to 20X DSD; for the output, this is downsampled to 2X DSD and output as analog, using only transformers to filter the output (so it avoids all the brickwall filtering of PCM-based DACs).  One additional advantage is that the unit is upgradeable.  If a new sampling rate or bit rate comes along, or another feature of some sort, it gets written into the next firmware.  I’m currently running Snowmass on the DSJ.

The improvement is noticeable.  The digital glare is pretty much gone. Anything remaining is probably on the original recording.  I hate to repeat marketing lingo, but there are times while listening to CDs that I did indeed here parts of the music that I have been missing.  It is a very nice, smooth sound that is also incredibly detailed.

One draw for me with the DSJ was the built-in Bridge II.  This is the network component which lets you use the DSJ as a player/streamer. (It also has the usual DAC inputs, and an I2S input for a compatible disc player.)  JRiver could use it, but I discovered the setup was still clumsy, and given JRiver’s multitudes of settings, there was no guarantee I was getting a bit perfect stream to the DAC.  Not only that, I was using the Qobuz beta program at the Studio level (which offers up to 24-bit/192kHz streaming), and I had no way to play it on the DSJ without using some kludge on a smartphone to make it happen.

The more I read about it, the more I started leaning towards Roon.  It has a reputation of getting a clean, lossless, bit-perfect audio to whatever device it streams to, up to its maximum resolution.  (So it can cast 24/96 to a Chromecast Audio, for instance.)  It also integrates Qobuz and Tidal, so you can not only browse your own library, you get access to millions of tracks that are only a few clicks or taps away.

There are two drawbacks to Roon.  First, it is expensive.  The cost is about $120/year or $500/lifetime.  But it is well supported, even if support of new features can be somewhat glacial.  It also requires some computing horsepower to make it work ideally.  They recommend a good quad core processor, plenty of memory and a SSD so that browsing the library is seamless.  In other words, unless you have a pricey NAS with a lot of computing power, you are going to have to run it on a separate computer.  This server component is called Roon Core.

To that end, I put together one of those Intel NUC mini-computers. These offer full-powered processors (i3, i5 or i7), two memory slots (load ’em up), and room for both a 3.5″ SSD and one of the smaller M.2 SSDs.  There are also numerous ports–plenty of USB ports, an HDMI port, you name it.  I went with an i3, processor, 8GB of memory (to start), and a Crucial M.2 SSD.  The size is no bigger than a stack of maybe four or five CD jewel cases.

It not only runs Roon Core, I decided to start using Mezzmo again, since now I had a silent, low-powered computer to run it on.  (Mezzmo runs only on Windows, but has features none of the other video servers have.)  I have a couple of other processes I can now offload from my NAS, which makes it run more efficiently.  I can tuck it in the basement on my network rack and run it headless, but decided to connect it to the 4K TV for now.

So far, this combination works mostly well enough, yet I am having a few glitches playing back DSD files (stored as .dsf files) over the network, as it is a bug in the Bridge II.  So I will wait another update or so before deciding if I might want to add a streamer of some sort.

I haven’t introduced the rest of the household to Roon yet, but I’m sure it’s simple enough to use. I may still use Pandora in many instances, but it is easy to direct music to any device, or group of devices, and each user can have their own profile.

So I’ve mostly got this nailed down.  I just need to refine things a bit, but in its current state, it’s certainly livable and working well.

Distributed bass array, Part 1

I read about a distributed bass array (DBA) a couple of years ago, and the concept was intriguing and made a lot of sense.  Bass in a listening room is affected by standing waves/room modes.  The distributed bass array alleviates this by strategically placing as many as four (!) subwoofers in a room to even out the bass response.  The volume of each subwoofer is set to a very low level, so it is not a matter of overpowering a room with too much bass.

Martin Logan 700W. ‘Tis wireless!

There is at least one complete DBA system available, comprised of a single 1,000 watt amplifier and four subwoofer modules.  Given my room layout, this would be somewhat inconvenient, primarily for all the wiring it would require.

Enter wireless subwoofers.

A Martin Logan Dynamo 700W sub came up on the local Craigslist dirt cheap and in excellent condition, so it followed me home. These subs are not very big at all–with the feet or spikes on, they are a hair less than the cubed size of an album jacket. Yet they can dip down into the 25Hz range. With class D amps on board, they offer up to 300w continuous and 900w peak. It can be changed from downward firing to front firing.

My Vandersteen 2ce pair dips down to about 28Hz for a -3dB point, thanks to the “bass coupler” which is a 10″ driver at the bottom rear of the speaker that pretty much acts as its own subwoofer. But that nasty bass suckout in my room bothered me. The DBA has been at the back of my mind as a means to minimize that suckout.

The 700W is wireless (the “W” in the model), and comes with the transmitter that hooks to a preamp output. I used Audioquest RCA cable splitters at the preamp, and ran the spare interconnects to the wireless transmitter. It paired up easily, and it works. (As an aside, my ML soundbar can also act as a transmitter for the 700W and 1000W subwoofers.)

I’ve tried the 700W in the corner by my desk in the back of the room, but found it a little too boomy. I moved it in front of the CD rack, by the opening to the kitchen at the rear of the room, and it’s a bit better. The key is to set the frequency low enough to cover the missing bass notes, and the volume low enough so the sub isn’t noticed. Setting the phase (0°, 90°, 180°) is another option.

OK, so far with dialing it in roughly, and having only one sub, the distributed bass array concept mostly works. I can sit in my preferred spot and the bass is now much more even, and I can hear just about all bass notes now. A clear improvement.

Here’s where it gets tricky. A DBA calls for as many as four subwoofers. And placement is somewhat critical, in that I would need to find the four spots in the room, along the walls, where the bass sounds the most even. (The fourth sub is run 180° out of phase.)

So, I’m three subwoofers short.

For the time being, I would live with the Vandersteens up front, and two rear subwoofers. But there is still a catch I hinted at above. I can still localize the bass in the rear, very slightly, even when I have the volume as low as I can logically set it. I believe this is partly due to time alignment. The bass from that rear sub is maybe a couple of feet closer to the listening position. Adding another 700W back near the desk is the plan, which should even it out just a little more–the bass feels slightly weighted towards one side of the room.

But what can I do with the time alignment? I am looking at a MiniDSP box with the right software plugin, where I could program in the distances for the rear subwoofers so they are delayed enough to match the perceived distance as the front speakers. In effect, pushing the virtual dimensions of the room so the subs appear to be further away.  I am not fond of digital processing (my amplification chain is, and shall remain, completely analog), but since this affects only the bass and is split out from the main signal path, it won’t make a difference in the grand scheme of things.

So for the time being, I will keep an eye out for another bargain 700W. They are plentiful.

Note that I still have the forlorn Sequel IIs to finish refurbishing (who has the time?), so if I put those into service, I will need to rethink the positioning since their response is not as low. Especially if I replaced the original woofers with the recommended aluminum woofers–the bass would not be nearly deep enough for me. Long term, I’m looking at the Martin Logan Summit, which has its own powered twin woofers that reach down as low as the 700W subwoofers, and that would be a natural for the two added rear subwoofers.

One subwoofer is only a small start on a DBA. Stay tuned as I work with this concept further.  Two subs may be enough if the front two speakers are responding well enough.  Or I may eventually need to take it up to four.  But my single 700W is more like a proof-of-concept trial and I can report that the basic premise is sound (no pun intended).

TubeCube Gone Bad…

I can’t say I was entirely surprised, but the TubeCube started acting up. I normally have it turn on with the rest of my desk–I have a remote switch which turns on the lights, TubeCube and DAC. I noticed the tubes would not light up until maybe 10-15 minutes later.  As the next couple of weeks went on, it would take an hour or two for the tubes to light up.  Finally, it quit turning on altogether.

Crap. The audio circuitry is dead simple, but the power supply? Forget it. It is a switching power supply which utilizes all sorts of SMDs (surface mount devices) that are impossible for me to work on.

I did notice that the capacitors in this unit were all off-brand chinese capacitors. Some were labeled Chong, and I couldn’t help but think of them going “up in smoke.” At any rate, I had read elsewhere that there were two pairs of capacitors in the audio circuit that could stand improvement by changing the values–the cathode capacitor, and the coupling capacitor.

Armed with that idea, and a set of calipers, I went to examining all of the electrolytic caps in this amp. I figured that I wanted to upgrade those two pairs of audio caps, but with the problem I was having, for not much additional money, I could replace all of them with quality Nichicon caps.

Mouser order. Nichicon Muse caps in the upper right, and the eraser-colored caps are the WIMA film caps.

I built up my order at Mouser, had it shipped, and went about replacing the caps. Upon closer inspection as I began removing the old caps, I noticed that I missed one!! A tiny cap tucked behind two large ones, against the side of the case.  And I figured that with my luck, that one might be the capacitor causing the problem.  I tested it in place, and got a reading close enough to its nominal value.  Crisis averted.

Upon removing the original caps, I took to measuring them with the multimeter.  Every one of them was at the very low end of the ±20% tolerance range…just barely within tolerance.  One cap in particular, though, was far out of range, and was (if I recall) about 25%-27% out of range on the low side.  And, that was a cap that was located right next to the IC that is essentially the “brains” of the switching power supply, which is mounted to a heatsink.

So, I soldered in all the new caps.  All Nichicons, except that one pair in the audio circuit were Nichicon Muse caps (their audiophile series), and the other pair was WIMA film caps.  Reassembled the case.  Plugged everything in.

It worked.

Small electrolytic cap just to the left of the heatsink was way out of spec!

My only issue now is that one of my reissue Mullards is getting a little noisy–the left channel occasionally makes a rustling sound, which stops when I tap on the left EL84.  Ah well.  At least it’s working, and if/when that tube gets annoyingly worse, I’ll pick up a new pair.

I also want to pick up a different 12AX7.  This amp ships with a rolled off high end.  The capacitors unfortunately did not change the severe rolloff in the highs, and I noticed almost no change in the sound after replacing all the capacitors. I am writing this off as a design flaw.

Project completed, though. It’s doing nightly duties for anywhere from 4-6 hours.  And it still looks cool up on the desk…

Speaker upgrade: Vandersteen 2Ce

I keep an eye on a handful of web sites that list audio equipment for sale.  Mostly it is casual browsing, watching pricing trends on certain items I am interested in.  Every so often, I will hear of a component that has good value for the money, and tell myself I might pounce on a “too good to be true” deal should it come along.

Thanks to a local seller who was moving out of state within a few days, I scored a really inexpensive pair of Vandersteen 2Ces.  I was watching prices on these for several months.  When these came up, I emailed, paid a visit, and drove away with a bargain.

Cosmetically the “socks” (the speaker cloth that surrounds the 2Ces on all four sides) have a few tiny holes, and some dust/dirt I cannot remove.  So I might want to replace that. The wooden end caps could also stand some refinishing but really, they are not all that bad.  The speakers did not come with stands, although I may see about getting some used Sound Anchor stands so that I might properly spike these to the floor.

So, what is the Vandersteen 2Ce all about?

It is a floorstanding speaker (some might call it a “tower,” which it really is not).  The drivers are time- and phase-aligned, so the sound from all three front-facing drivers (tweeter, midrange, 8″ mid-woofer) arrives at your ears coherently.  In the rear at the bottom of the cabinet is a 10-inch “acoustic coupler” that adds the very lowest octave of bass.  The drivers are arranged on minimally-sized baffles, so that sound can easily disperse into the room. This enhances the soundstaging and imaging.  (As such, it is recommended they be placed away from the walls in the room.)  They are designed to be aimed straight into the room, not “toed in” unless there is an issue with room acoustics and you cannot achieve a solid phantom center image.

My initial impression upon first hooking them up was that they were a bit dull, and lacking highs.  It didn’t take but 15-20 minutes to realize that the highs are there, but just not falsely accentuated (or just a bit bright, as the Dahlquist speakers were).  In other words, once I threw more of a variety of music at them, I realized it just sounded right.  They do throw a nice soundstage, but if you are off-axis or in another room, they can tend to sound less bright than when you sit at or near the sweet spot.

Since I only listened briefly that first day, I decided to bi-wire the speakers, per Vandersteen’s recommendation.  So, just about all listening has been done with the bi-wiring in place.  (And that means I had no way to do a direct comparison using just a single run of wire to the speaker.)

I am still playing with the positioning of the speakers in the room.  For now I have settled on having them only slightly toed in, with the acoustical centers just over 22 inches from the back wall.  The saddest part of this room is that due to the size and the furnishings, the sweet spot happens to be in an area that has a low level of bass.  I would prefer sitting further back, but it is not possible.  I may rearrange the room if I get a chance.

So despite the positioning, these speakers do have a strong, deep bass response.  I suppose one could use a subwoofer with these, but I would find it unnecessary–they cover all of the important octaves of the music.

And the soundstage is just as advertised–it can be wider than the speakers themselves.  I have yet to hear much in the way of front-to-back imaging, but I am still dialing in their positioning in the room.  Once I lock that in, possibly adding some room treatments, that will fall into place.

Given the cost, these were quite a deal.  The Martin Logan project of mine is still on the sidelines.  It will be interesting to compare the two different types of speakers once I get those completed.  At least these Vandersteens are enough of a step upward to hear what my other components are capable of.


The phono stage dilemma

While searching for my ideal preamp, one of my criteria was for this new preamp to have a built-in phono stage.  That turned out to be more difficult, as the only way I could find them was in older preamps, or in new preamps that were way beyond my budget.  I finally caved in to the idea of getting a phono stage.

Yet, which one?  I really wanted tubes.  I still do, to an extent.  But my choices in tubed phono stages was limited within my budget.  And when pressed for a choice, tubes might not be my solution after all.

My first candidate was a Jolida JD9 Mk II.  While build quality seemed acceptable, a few Internet forums mentioned that there were additional upgrades that could take the JD9 up to a higher level.  Upgrades include swapping in premium op amps, better output coupling capacitors, and HEXFRED rectifiers in the power supply.  Not to mention swapping in premium tubes.  I also would have installed my own mono switch on the rear panel.

While I like getting into the innards of electronics with soldering iron and voltmeter, the idea of hacking up a brand new phono stage (and voiding the warranty) did not sit well with me.  Once I did the math, I realized the Jolida would not have been a good investment.

The other candidate in valve land was the Pro-Ject Tube Box DS, which has the unique loading adjustment on the front panel.  It is nicely built, sure.  Yet like the JD9, I could not find any mainstream reviews of this model.  I found a killer deal on it, but decided to pass.  I do not put 100% weight in reviews, of course, but they are a helpful second opinion.

My luck came about by way of a lightly used Phonomena II+ by Musical Surroundings.  Mainstream press?  Yep, Absolute Sound had picked it as an Editor’s Choice.  Other reviews thought highly of it, and especially praised the depth and control in the bass.  Perfect.  It arrived within a week of purchasing it, and looked essentially unused.  The sound is, as you’d expect, phonomenal (sorry).

Loading is quite easy on the Phonomena.  A series of DIP switches on the rear can be set in many combinations to get LOMC loading where you need it to be.  For my Dynavector, I am currently at 59 ohms, but feel that I could probably nudge it down to 50 ohms to really smooth it out.

Running a MM cartridge, though, I have the option of two different resistive loads, and capacitive loads.  The only drawback is that MM loads are limited to 47k or 100k ohms; ear bleeders like the Audio Technica MM carts are happier with different loading, maybe in the 22k range.  The next available setting is 2k ohms.

For gain, there are 13 steps available from 40 to 60dB.

I did notice a bit of “rush” (faint white noise) when turning the volume way up.  I am going to inquire whether this is normal or not, and if a better power supply (than the small wall wart) would help that.  This phono stage uses so little power that a battery power supply may be an option too.

Overall, I have not had much chance to listen to it yet, but the sound is very clean and full-bodied.  If the soundstage was improved with the C-J preamp, this really locks it in further when playing vinyl.  I do want to tweak loads a little more, but it is really sounding nice at 59 ohms.

I will have more impressions over the coming week as I evaluate some high-quality vinyl.