السبت، 3 أبريل 2010

Dared VP-20 Valve Amplifier Review

Before I get to the review, I'd like to give a bit of background to clarify my level of experience and explain my situation. If you don't want to read it, you can skip straight to the actual review, labeled in red down below. Also, gratuitous tube pr0n is down at the bottom of the post. ;-)

My piece of crap solid-state, Sony 5.1 receiver has finally died after nine years of service and, rather than replace it with an equally crappy updated model, I decided to take the plunge and drop a few hundred more bucks on my first tube amplifier. I have read quite a bit on audiophile forums and, while I have never really bought into their pseudoscientific bullshit, I was intrigued by their insistence that tube amps (also known as valve amps) are in a whole different category from their transistor-based cousins.

I am no stranger to a hot soldering iron, so I looked at a number of DIY kits, including a remake of the venerable Dynaco ST-70, which ranged in price from approximately $250 to $700. While the DIY route would have certainly been a great learning experience, one has to weigh the benefits (education, fun, cost-savings) with the potential risks (added costs due to the inevitable mistakes, frustration, potential failure). In the end, I decided it was more likely to actually cost more to go DIY, so I started exploring alternatives.

Overall, new valve amps from well-respected brands start at approximately $1,500, which is much greater than my budget of roughly $600. Within this price range, I basically had two options: buy a used entry-level amp from a well-known, reputable company or take a risk on one of the ultra-low-cost Chinese-built amplifiers that can be found online (e.g., Music Angel and Yaqin).

Side note: For anyone who is taking their first steps into high-end audio, the best places to look online appear to be eBay and AudiogoN. Out of the two, I think AudiogoN is a better place to find good deals on solid equipment. The crowd there is highly knowledgeable and I think you are less likely to get stuck with non-functional equipment than if you purchase from eBay.

I kept my eye on both eBay and AudiogoN looking for anything that fit my criteria. On eBay, I was drawn to the Yaqin MC-100B, which utilizes 6sn7 preamp tubes and the very popular KT-88 output tubes. This amp was available from two sellers, one from Hong Kong for approximately $700 after shipping and one from Canada for approximately $800 after shipping. The one from Canada also does quality assurance testing, which is apparently the main concern with the Chinese amps, so anyone looking into this amplifier should strongly consider spending the extra hundred bucks just for peace of mind and ease of support should the need for repairs arise.

Just when I was ready to take the plunge on the MC-100B, I came across an interesting alternative: a seller on AudiogoN was offering a demo unit of the Dared VP-20 for $590 (the official retail price is $1,300, but I suspect this price is inflated to make the actual selling prices seem extra-low; I have seen brand new units for only ~$100 more). This amplifier, which uses both the 12AX7 and 12AU7 preamp tubes and 6L6G output tubes, is a strange beast in that it sits somewhere between the traditional integrated and monoblock options. The two channels are separated from one another but they are tethered to and share a single power supply, which is intended to reduce interference while saving on the cost of additional power supply components.

I only found one review of this amp online and it seemed a little overly effusive for its supposed objectivity, so I didn't place too much trust in it. This left me with essentially no prior guidance on the amp's quality, regarding either sound or craftsmanship. I was encouraged, though, by Dared's use of audiophile-quality capacitors, gold-plated jacks and gold-printed circuit boards. Furthermore, the amp is built with an auto-biasing circuit, which apparently makes tube rolling as easy as plugging in a toaster (i.e., no mucking around with multimeters and tiny screwdrivers).

Now for the review

I decided to go for it and the seller, who is apparently(?) Dared's North American distributor based out of Illinois, was very helpful and patient when dealing with my many questions. He accepted my offer and three days later, the amp was delivered to my door via FedEx. It was double-boxed and then packed into a fitted foam block:


The tubes were not separately packed, which was a bit of a disappointment, but overall, the packing was very secure and it was clear that nothing had moved around during transit.

In addition to the amp, the box came with several of the usual goodies, including a pair of white gloves, a microfiber cleaning cloth and a cleaning brush, along with a run-of-the-mill power cord, two meaty cables to connect the quasi-monoblocks to the shared power supply and--inexplicably--a USB-A to USB-A cable (I'm still not sure why this was included, but I suspect my unit was mistaken for another one from the same seller that comes with a simple USB DAC):


The first thing I noticed upon pulling the actual amp units out of the foam was its mass and solidity. The pieces felt very sturdy in my hands, and I have absolutely zero complaints about build quality. Where I had expected plastic and/or cheap metal, I found polished stainless steel and gorgeous, natural wood. There were quite a few fingerprints on the units, but I didn't mind since it was a former demo unit and they were easily polished out with the included cloth.


On the back of the blocks, you can see the gold-plated RCA and speaker jacks:

This amplifier will push either 8 ohm or 16 ohm speakers, depending on which speaker jacks you plug into. Unfortunately, the speaker jacks do not appear to be labeled, unlike most every other opening on the amps, so I just *guessed* that the signal jacks to the left of the ground jack was the 8 ohm on both sides... Everything appears okay so far, so it looks like I guessed correctly.

Another puzzling oversight is that the back of the power supply unit has both output power jacks labeled with the identical "To Right Amplifier":


Once I got everything plugged up and connected to my speakers (Phase Technology Teatro 7.5s; now discontinued, but you can find out more about them here), I flipped the switch on the front of the power supply and watched the tubes spring to life:


Before attaching any signal to the amp, I turned the integrated volume pots to approximately 40% and listened for any noise, hum, etc. I heard absolutely nothing, even with my ear right up against the tweeters. That may change at higher volumes, but I didn't want to overload anything before I even got started, so I didn't turn it up any higher.

I connected my CD player, an unremarkable 301-disc changer from Pioneer, and selected a recording of Dvorak's "New World" Symphony. I was immediately blown away by the clarity of this amp. I don't have any prior experience with tube-based hi-fi, so I can't say how the amp compares to other valve amps, but I can honestly say it is far better than any solid state amp I have encountered. Compared with my old receiver, listening to this amp felt like I had cleaned my ears out! I could suddenly hear the most amazing minutae, including musicians shuffling in their seats and flipping pages in their sheet music.

Furthermore, the amp puts out just 18 watts per channel, which is a far cry from the 100 watts x 5 channels that my older solid state receiver put out. Before my purchase, I was apprehensive that the amp simply would not get loud enough for comfortable listening anywhere except for right in front of the speakers, but it does just fine. My speakers have a sensitivity of 90 db, which is better than most low-quality bookshelf speakers but worse than many higher-end speakers (and much worse than the often-gigantic "high sensitivity" speakers), and I found that turning the volume to approximately 50% on my preamp (a solid state Gemini PA-7000 Professional) and approximately 50% on each amp block is loud enough to hear throughout my house and too loud to comfortably listen to directly in front of the speakers.

Next, I put on the first track from Pink Floyd's Atom Heart Mother, an epic 20-minute song that includes the usual guitar, bass, keyboards and drums, as well as a brass section, a full chorus and horses(!). What struck me most while listening to this track was that I lost the sense of sounds reproduced by a pair speakers. Instead, with my eyes closed, I felt like I could point to the individual band members in the room with me. Rick Wright's haunting keyboards drifted in from the left behind the bookshelf, while Dave Gilmour played from somewhere in the vicinity of my kitchen sink. I believe in audiophile parlance, this is known as the 'soundstage,' but don't hold me to that. When the brass kicked in, I thought I heard some distortion, but it was actually just the way brass instruments sound. I had become so used to hearing that part of the song through my muddy solid state system that it took me a minute to remember how the instruments actually sound in person!

For frequency response, the highs are extremely crisp and the lows are rich without the booming I had become accustomed to with my older 5.1, subwoofer-driven system. Since my initial listening test, I have attached my powered subwoofer to the second output of my preamp to add a little more bass to it, but this is just a personal preference and many "experts" would probably say it's too much.

After the Pink Floyd, I listened to some Yes and was impressed by how distinct the layering of their instrumentation was. It's now possible for me to mentally separate each layer of the vocals instead of just hearing the harmonized mishmash.

After that, I put on Chris Isaak's Baja Sessions, which was a great match for this amp. I never expected to hear the sound of fingers on guitar strings and drumsticks bouncing off drum heads, but it's all there, lending a sense of realism that defies description. Now, to be honest, how much of that is unique to this amp and how much is just an effect of moving from solid state to tubes, I can't say. What I can say, though, is that I am now rediscovering my music in a way I never thought possible. I feel like when I got my first pair of prescription glasses; like I am finally privy to an entire world of beauty and crisp resolution that was heretofore hidden just out of reach.

Other Thoughts

A lot of folks online have mentioned that the Chinese tubes that come in these amps are terrible, but they sounded fine to me. Luckily, all of the tubes are available for relatively low prices online and I plan to try out quite a few. I'll post my results here whenever I do.

If anyone has any questions about anything in this post, including specific questions about the amp and/or choosing a first tube amplifier, feel free to leave a comment.

Now, on to the tube pr0n:

الجمعة، 26 فبراير 2010

How to Run New Steam UI Beta in WINE

If you've opted-in for Steam's Beta user interface in Linux via WINE, you've probably noticed some serious issues, such as the main window not drawing properly on your desktop. Luckily, this is actually really easy to fix. All you have to do is go into your WINE configuration and change the Windows version from the default Windows XP to Windows Vista (or Windows 7, either one works):
Restart Steam and it will notify you that it needs to install a Steam component that requires administrator privileges. Click 'ok,' wait a few minutes, then start Steam again. Everything should begin rendering just dandy:
Everything I tried in the Library and Friends sections seems to work, including downloading and installing games, launching games, chatting with friends, etc. Unfortunately, the store, news and community features still don't show up properly :(

Also, in-game chat using the overlay appears broken in that the game hangs when you try to switch and you can't see what you're typing if you try to chat. However, alt+tab still works, so that's something.

As an added bonus, the 'minimize to system tray' feature works swimmingly:


Original post (for posterity):
I just opted-in for Steam's beta version of their fancy new user interface, which includes a number of improvements such as a greater focus on social interaction and switching from the Internet Explorer rendering engine to a WebKit-based renderer. I had assumed that this would grease the gears a bit on using the UI in Linux via WINE, but it has unfortunately done the opposite.

Now, if you try to launch the updated UI, the Desktop Switcher down in the bottom-right corner of the screen shows a big window with a Steam logo on it, but the window isn't drawn on the desktop as far as I can see.

This post is primarily a placeholder for anything I might find/come up with to correct the problem. So far, I haven't tried disabling compositing or anything like that, so that's next on the list. Feel free to leave me a comment if you have any clues to what's going on.

الخميس، 18 فبراير 2010

Quick batch tool for comparing encoding quality

I was pleased to come across a really handy Linux-native tool for analyzing video quality in a number of clips quickly and efficiently. It is known as 'qpsnr' and it was written by a nice fellow named Emanuel Orlani who posted it at the HandBrake forums.

The program is designed to take a reference file (presumably your original video source) and then compare it to any number of derivatives (e.g., a series of reencoded clips that were produced using different settings) to produce objective quality comparisons, outputted in either peak signal-to-noise ratio (PSNR) or structural similarity (SSIM).

This tool is perfect for individuals who like to tinker with encoder settings to find exactly what works for them. Now, instead of hunting through activity logs searching for quality measures, you can batch-encode a series of clips with your settings, then run them all through qpsnr and see what effect each setting had on quality.

It is only available as a source download at the moment, but the author suggested deb binaries will be posted after more testing is done. If not, I'll package some up in my PPA repository.

الثلاثاء، 12 يناير 2010

Beginner's Guide to SF4 Normal Map Editing

Street Fighter 4 uses relatively simple, low-poly models but adds detail using a special kind of image file known as a bump map or normal map. This normal map is rendered as small variations in depth of the model, either raised or recessed into/out of the overall model. Editing the normal map attached to a model will make any mods look much more complete.

To get started, download the normal map filter plugin for GIMP from this link. To install it, place the normalmap.exe file into your Program Files > GIMP-2.0 > lib > gimp > 2.0 > plug-ins directory. You will also need to install GIMP's DDS plugin (available here) if you haven't already done so.

Next, download Piecemontee's Asset Explorer from this link. You may have to install DirectX 9.0c (available from Microsoft) to get it to display properly.

Now, open the Asset Explorer and open both the *.cos.emz file you want to edit (notice the black and white lines representing raised/lowered areas; this is the normal map):
and the *.col.emz file for the color/mod you'll be using:
Next, navigate within the cos file until you find one or more DDS files. When you select one, it should look weird and purple. This is your normal map, which will correspond to the DDS files within the col file. Export it and name it something descriptive, such as 'chest normal map.dds' that you can use to identify it later:
Do the same thing with your col file so that you have a pair of DDS files, which will open in GIMP. First off, we should notice that the normal map DDS is higher resolution than the color DDS:
We need to change that, so we'll scale up the color DDS to match the resolution of the normal map DDS:
>
Next, if your color file is a little grainy, that will show up as texture, which we may or may not want (depends on the mod, really). To get rid of this grain, we'll use a Gaussian Blur filter:
>
Now, we're ready to create the normal map, so go into your filters menu and select Map > Normal Map:
At default, the normal map filter's scale is way too low, so we want to crank it up. I usually put it around 15, but this might be too much for some mods:
You'll just have to play around with it, checking your results in the 3D preview window, until you find a setting you like:
Once you're satisfied with the results, click OK to apply the filter:
Now, save your file using the same DDS characteristics as the unmodified normal map:
Go back into the Asset Explorer, navigate to the old normal map DDS file, and replace it with your newly created one:
Now, your model file should refresh and reflect your new normal map (notice the sunburst pattern on her stomach that wasn't there with the standard normal map):
Just follow these steps with each of the DDS files and normal maps and you should be all set.

الثلاثاء، 22 ديسمبر 2009

Testing Ubuntu 10.04 Lucid Lynx Alpha 1

The latest version of the popular Ubuntu Linux distro, known as Lucid Lynx, was just released the other day and, though it is an early alpha release, I wanted to give it a shot in a virtual machine. Installation in VirtualBox was smooth and polished, but I ran into some problems with installing VBox's Guest Additions, which allow for higher resolutions and, more importantly, mouse pointer integration (the magic that lets you move your cursor from host to guest OSs without mucking around with capturing the mouse pointer).

Here is a simple fix for the mouse pointer integration:

Fire up a terminal and type:
sudo gedit /etc/X11/xorg.conf
This file used to be how Ubuntu managed devices attached to your computer, but they're trying to move away from it. Now, the system will accept such a file, but it tries to figure things out on-the-fly as much as it can, hence the currently-empty file.

So, into this empty file, copy/paste:
Section "InputDevice"
Identifier "VBoxMouse"
Driver "vboxmouse"
Option "CorePointer"
EndSection
All this is doing is telling your virtual machine to look for the vboxmouse driver and use it. Now, when you reboot, you should have proper mouse integration.

However, if this somehow causes problems and you want to undo it, just type into a terminal:
sudo rm /etc/X11/xorg.conf
and then reboot your system.

To fix the small resolution, you just need to add another section to your xorg.conf, so type into a terminal:
sudo gedit /etc/X11/xorg.conf
and below the mouse section, paste in:
Section "Screen"
DefaultDepth 24
SubSection "Display"
Depth 15
Modes "1920x1440" "1920x1200" "1900x1200" "1920x1080" "1600x1200" "1680x1050" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "1440x900" "1280x960" "1366x768" "1280x800" "1152x864" "1280x768" "1280x720" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1920x1440" "1920x1200" "1900x1200" "1920x1080" "1600x1200" "1680x1050" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "1440x900" "1280x960" "1366x768" "1280x800" "1152x864" "1280x768" "1280x720" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1920x1440" "1920x1200" "1900x1200" "1920x1080" "1600x1200" "1680x1050" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "1440x900" "1280x960" "1366x768" "1280x800" "1152x864" "1280x768" "1280x720" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1920x1440" "1920x1200" "1900x1200" "1920x1080" "1600x1200" "1680x1050" "1600x1024" "1600x1000" "1400x1050" "1280x1024" "1440x900" "1280x960" "1366x768" "1280x800" "1152x864" "1280x768" "1280x720" "1024x768" "1280x600" "1024x600" "800x600" "768x576" "640x480"
EndSubSection
Device "Device[0]"
Identifier "Screen[0]"
Monitor "Monitor[0]"
EndSection
Important: Each of the lines that start with "Modes" should have all of the resolutions following it on the same line, and they should only include resolutions that your monitor can actually produce, so you might have to delete some of them (e.g., my monitor is a 20" that only goes up to 1680x1050, so I deleted all of the resolutions that were greater than this).

Again, if this causes any problems, you can either delete the section of the xorg.conf file or delete the xorg.conf file entirely and then reboot to get things back to the way they were.

Shared folders between the guest and host also appear to be broken at the moment, but I don't know what to do about it. Other than that, things have gone well for me. Compiz works fine and I have a fancy composite desktop with wobbly windows and true transparency.

الأحد، 29 نوفمبر 2009

Using Gizmo5 with Google Voice to call landline and mobile phones

I, like many others, pay a lot for home phone service, which is becoming increasingly obsolete with the ubiquity of cellular phones. In an effort to cut out this mostly needless expense, I decided to try and combine two free services, Google Voice and Gizmo5, to make and receive free calls with actual landlines and cell phones via my existing internet connection.

The concept works like this: when you sign up for a Gizmo5 account, they assign to you a free SIP number, which you can basically think of as an IP-based phone number. This is already pretty cool, but the catch is that only other IP-based phones can call this number, and that's where Google Voice comes in. Through this free service, Google will connect any number--physical or SIP--with any other number--again, physical or SIP. Once the initial connection is made (the hard part for Gizmo), Google steps out and you're left with a working SIP-to-landline call without a phone line and without paying a dime.

To get this sweet deal going, you have to have an account with both services, which could be the biggest stumbling block: Google Voice is currently in an invite-only, privite beta stage and Gizmo5 has stopped accepting new registrations after it was recently acquired by Google (existing accounts still work, though).

If you've managed to snag some accounts, though, and they are all set up (you've chosen a local phone number for Google Voice, Gizmo has assigned a SIP number, etc.) you're ready to get started.

First, open your Gizmo5 account in your favorite web browser and find your SIP number (it will have an area code of 747):

Next, open your Google Voice account and click on 'Settings.' Under the 'Phones' tab, click 'add another phone' to forward your calls to:

Name it something recognizable (I called it 'Gizmo'), type in your Gizmo SIP number into the second blank, and then select 'Gizmo' from the pull-down menu:

Next, we'll want to install the Gizmo5 client on our computer (you can also use the gizmocall web-based interface, but it is made in flash and feels a little kludgy). Go to Gizmo's download page and download the client program for your operating system. If you're using Linux (like me), you'll notice that this is a bit of a problem, as the links are all missing. Luckily, you can still download the deb installer file for Debian-based distros, such as Ubuntu, from a direct link. UPDATE: the Linux download page is back!

Once the client is installed and running, you can enter your Gizmo account information and login. You can also choose to configure the client to manage your IM accounts, but I chose not to.

From now on, calls made to your Google Voice number--which is accessible to normal phones, either landline or cellular--will cause your Gizmo5 client to 'ring.' That means we can now receive calls from normal phones on our computer! We can also make calls to normal phones, but the trick is to use Google Voice instead of Gizmo's built-in (for-pay) calling feature:

When you click 'connect,' Google will call your Gizmo client (you answer it when it rings) and then call the number you have entered, merge the two calls, and then step out, just like your own personal secretary:


Conclusions

This method is not a perfect replacement for a home telephone. It only works when you have internet access (the silver lining of which is that you can use it at Starbucks, your hotel room, etc.; anywhere with a broadband connection). More importantly, it doesn't provide emergency 911 access, so if your house catches on fire, you'll just have to watch it burn because the fire department won't be able to look up your information via your phone number.

Furthermore, this method may not work forever. Google has just purchased Gizmo, so things are sort of up in the air until they figure out what they want to do about the way the services interact. Hopefully, if anything changes, it will be for our--the users'--benefit.

There has also been speculation that Google is planning to fully integrate these services together and then make them run on a wifi-enabled mobile device (Android-based, of course). This will essentially create a mobile phone that only works within wifi, but that can make and receive calls to/from any other phone without the need for a carrier (no carrier means no contract, no fees, etc.). That is, a fully ad-supported phone powered entirely by Google services and software.

Google, if you're reading this with your all-seeing robot eyes, please make it happen as soon as possible.

الثلاثاء، 6 أكتوبر 2009

HandBrake Nightlies for Windows

Update (4/26/10): I will no longer provide these packages because the HandBrake devs are now providing real-deal official nightlies: http://build.handbrake.fr/

**These are UNSUPPORTED, BLEEDING EDGE builds of HandBrake. DO NOT ask for help in the HandBrake forums if you run into any issues with them. If you have a problem, ask it here and I will try to help. Otherwise, YOU ARE ON YOUR OWN.**

Additionally, these are not true nightlies because I won't be building them quite that often, but I plan to compile a new version each time a substantial update (such as an x264 bump) is checked into the SVN repository.

The CLI binaries are cross-compiled on my Linux box and the GUI is built natively in Windows.