Winner - Prettiest and Worst Website of 2013

After very little time, thought or deliberation the winner of my personal award for "Prettiest and Worst" website of 2013 goes to danger!awesome. 

The website is the worst for wasting as much bandwidth as it does saying nothing.  It's essentially a worthless placeholder with a lot of forethought.  Unless you already know who and what danger!awesome is or does, this site is useless.  It's like a very expensive fashion watch that can't actually tell time and as such is to me a great example of the very worst kind of web marketing tripe.

At Long last, an affordable Audio Analyzer from QuantAsylum! Uncork the casks and let the feast begin!

An audio analyzer is a high precision tool used to measure the performance of a variety of components involved in sound recording and reproduction. Pretty much everything except for speakers.   Think of it as a combination precision signal generator and spectrum analyzer that let's you at the very least do noise and distortion tests to a high degree of certainty. 

Despite the proliferation of cheap components which could be used to build audio analyzers in recent years an "affordable" unit was still in the neighbourhood of $5,000 or more.  Easily more.  Keep in mind that the audio analyzer market is not the same as the audiophile gear market.   Audio analyzers are not meant to appeal to those with more money than sense audiophiles or use diamond transistors and tubes recently "appropriated" from the radar of a Mig-23.  I'm comparing prices and performance from real gear from Audio Precision or Hewlett Packard here.  Even the cheap imports were still far too expensive for the 21st century small manufacturer or repair shop, not to mention a hobbyist. 

Some alternatives that have come close have appeared from the PC oscilloscope vendors.  Companies who leverage a PC to use as a test bed, but from my point of view, they were not yet a serious challenge.   While they may have offered wider frequency ranges in the Gigahertz ranges, and a great combination of digital and analog measurements and signal generation their use of bit limited analog to digital converters made them of little use or interest to the likes of me or any audio repair shop either.  I've yet to see one in the range for instance provide distortion measurements directly. 

Within the last week however I became aware of the QuantAsylum QA400 Audio Analyzer.  Finally, a piece of kit in line if not less expensive than a PC oscilloscope with the technical chops to rival the serious offerings from Audio Precision and others.  It's exactly what it should be.  An external 24 bit/192Ksps DAC and ADC with software to use it.   At $199, most audio designers without deep pockets would be ecstatic.   Given that it also throws in serious automation capabilities this device is a steal.  This company from a city in Washington state with an unpronounceable and indecipherable name ( Snoqualmie ) has broken the barriers!

I hope to see them featured in places like PartsExpress and PartsConnexion soon, not to mention a Linux port as well. 

Optical S/PDIF is the only reliable way to get high quality sound from a PC.

If you are using a PC for music or movies, you should avoid taking the audio from an HDMI, USB or coaxial output.  The reason for this is that PC's tend to create ground loops when connected to other pieces of equipment.   This is readily audible with analog connections, but insipid in digital.

The issue with digital is that you'll get a ground loop introduced into the signal which can cause very high amounts of jitter and you'll be listening to just OK sound which you won't notice until you get something better.

There are some exceptions though.  Unfortunately magazines like Stereophile won't test these options.  They deliberately use test in a way that negates the benefits, so you can't tell from a review if your DAC has good isolation or not.

Using an optical connection between your PC and audio system guarantees that you won't be listening to a DAC under the worst possible conditions.

There have been some that argue that coaxial S/PDIF connections are better, but those arguments were made assuming dedicated CD transports and DAC's which have far less ground loop and noise issues than PC's.

So, until something better and reliable comes along, I'd suggest to always use optical. 

The best Linux for your Home Theater system is Xubuntu

For me Xubuntu kicked the pants off of Fedora 19, and Ubuntu.  First, it does everything I need it to do relatively easily.  Secondly it's a relatively lightweight installation compared to the default Ubuntu.  Thirdly, the UI itself is really CPU light, giving you extra horsepower for watching movies and playing games.   Lastly, SteamOS is built on Debian, with official out of the store support for Ubuntu/Xubuntu. 

In case you dont' know, Xubuntu is Ubuntu - (bunch of fat apps and an ugly default UI) + Xfde.  From a binary perspective, Xubuntu IS Ubuntu in a different, leaner packaging.  Anything you can do in Ubuntu you can do in Xubuntu using the native Ubuntu installs.

A lot of people may be wondering why I'm not recommending XBMCubuntu which is in fact a distro specifically designed to give the home theater experience.  The answer is simply that I found XBMC really not ready for the casual user.  If you want something to install, to just work, and not be Windows, Xubuntu is a much better idea in my mind.  Below you will find some examples and installation instructions.

Squeezebox Server

Due to missing and impossible to resolve conflicts in the Perl graphics libraries, Fedora can no longer install squeezebox server.  It has to do with a native image compression library and that there is no way to resolve it without going backwards and some serious hackery.

Xubuntu installed Squeezebox server with no issues at all.

AnimeCrave.com

Perhaps the best source of legal anime on the web, AnimeCrave uses some Windows specific codecs which are hard to reliably implement in Fedora.  On the other hand on Xubuntu they are installable reliably from the Software Center.   Search for "totem."  Click on "Videos."  Scroll down to the list of "Optional add-ons".  Select them all.   Click on the "Install" button near the top when it's done updating.

[Update January 6, 2014]  There is an issue with the default gstreamer settings which causes repeated audio stuttering.  It has an easy fix.  Type the following in a command line terminal:

     gsettings set org.gnome.totem network-buffer-threshold 4.0

Someday Linux will just work.  Until then we are faced with these silly quirks. 

Congratulations, you can now watch everything on AnimeCrave in high quality.

Steam

Installs directly from the Ubuntu Software Center though you will need an UbuntuOne and Steam account. 

Netflix and Amazon

http://www.compholio.com/netflix-desktop/

 

 Video and Network Drivers

This part is really easy but it takes a little patience, because the application takes a while to update itself.   In the system menu select "Settings Manager" then under "Hardware" select "Additional Drivers".  Click on Ubuntu Software tab.  Turn on all of the checkboxes.  Click "Other Software" tab.  Turn on "Canonical Partners" but you can leave off "Canonical Partners (source code)" unless you want to do some compiling on your own.

Now comes the patient part.  I'm not sure if this is related to other software updates, so you may want to go to your command line and try:

sudo apt-get update
sudo apt-get upgrade

After that, restart the "Software Updates" app, and click "Additional Drivers" where you will see cool things like proprietry nVidia and Broadcom (Wi-Fi) drivers show up if they are compatible with your hardware.  You may need to wait 1-2 minutes for this screen to correctly populate, or even try it a couple of times.

Audio Devices

This is the one place where Xubuntu sucks.  The audio device management should be integrated into it's otherwise great Settings Manager application but it's not.    If, like me, you are using S/PDIF outputs to feed your home theatre processor, it won't be on by default.  Now, you'd think you'd go into "Settings Manger" scroll down to "Hardware" and find a "Sound" app.  But noooooooo.  << sigh >>

Fortunately, it's relatively easy to find.   From the main system menu, or from the Application finder (the magnifying glass icon in the bottom of your screen) select "PulseAudio Volume Control. "  This is where you will need to enable your fancy digital audio outputs, whether it's via HDMI or an S/PDIF connector on the back of your motherboard.   You may have to dig around a little bit. 

Flatware Cleanliness Test

Have you ever gone to a "high end" restaurant only to be served with dirty flatware?  Isn't it a huge disappointment?  I have.  Last time it was a high-end Chinese-like chain restaurant.   The chopsticks I received had particles of food on them you could scratch off with a fingernail.    Ugh!!

I've also been to places where several sets of flatware looked clean but were still dirty.  Maybe I was pickier than most, but I could feel the greasiness on my fingers.  How could others not notice?

So, here's a test, and if you are a kitchen manager I highly encourage you to try it.  Take two identical pieces of flatware.  Take a paper towel to one of them and rub it as clean as you can.  With clean, dry hands feel both of them.  If the one you did not clean off feels slick, but the one you cleaned feels tacky you still have plenty of oil and grease left on the flatware.   Clean flatware should not feel slick.

I should add of course, this is not meant to be a substitute for adhering to industry  best practices and regulations, or biochemical analysis and regular inspections.   It is meant to help diners, washers and kitchen pro's see something they might have missed otherwise.

The Truth about Dish Washers

The Myth of Dishwashers

A lot of people think of dish washers as being a type of sterilizing system.  The heat, water and detergent will kill all bacteria and leave all surfaces surgically clean and are always better than hand washing.  Unfortunately heat sterilization - killing of bacteria by applying near boiling temperature or steam above boiling - is not part of the dish washing process.   The temperatures inside the dishwasher never achieve the high temperatures needed to achieve this.

Chemical sterilization also does not take place.  The soaps used in a dishwasher are no more caustic than your counter top dish soap.

Making Dishes Clean

There are two things that must be done to make a dish clean:

• Food substances to be completely removed.  This especially means any oils, greases or sugars.
• Surfaces must be dried and kept that way for storage.

If you leave food, or worse, food + moisture on an eating utensil it will be ripe for bacterial growth, no matter how good your dishwasher or detergent brand may be.

The Three Pillars of Dish Cleaning

Abrasion - Removal of food and other particles by physical means (a sponge, scouring pad or jets of water all count).  This process assists and is assisted by dilution.

Dilution - Removal of grease, oil and any remaining food particulates by dissolving them into the water/soap mix which is then flushed and rinsed away.  This is the main reason for using very hot water.  The detergent's main job is also here.  The soapy bubbles we associate with soaps also demonstrate emulsification, that is, trapping oils in bubbles so they stay dissolved into the water instead of being redeposited on the dishes.. 

Desiccation - Drying the dishes completely.  All life needs moisture.  Removing this moisture quickly after washing will prevent disease.   If a dish is not dry, it's not really clean.

At home, if you achieve all three of these steps routinely then you will have clean and safe dishes.

While institutions like hospitals and restaurants take things further they still have to build upon these three basic steps, as opposed to replace them with others.

Replacing the battery in a Boogie Board

The Problem

I really liked my Boogie Board, I may have even bought it at Brookstone.  I was looking at the Brookstone web site, thinking about a bigger one but then something dreadful happened.    After six months the battery died.  So, like any other person who has grown up with coin batteries in his watches, heart rate monitors, flameless candles, etc.  I went looking for the battery slot.  That's when it struck me,  there was no such thing.  So I went to their website to find this disappointing bit of misdirection:

"Never needs batteries"  

That really upset me.  This to me means that it's solar powered, powered by the action of the button itself, or something else.  It does not mean that I will throw the entire thing out when the battery decides to die out on me.  It seems they got the message that companies that misdirect customers to make a sale do not actually believe in the value of their own products.

This has since been changed to:

"3V Non-replaceable"

The manufacturer's idea of this large piece of acrylic is that once the original battery dies you throw the entire thing out.  What?  How does that give with the tag line, below? 

The answer is: it does not.  Not only is the battery soldered in, but they replaced the screws that hold the assembly together with special, stealth screws that look like rivets.  Come on!!!  Seriously??  That pissed me off.   They go through the extra expense of getting magic screws just to foil the user? Ugh! 

The Solution

Here is the complete, step-by-step battery replacement guide.

Tools and supplies

Wherever possible I have listed an example of the tools you would need. With luck you already have most of them. 

1. A fine flat head screwdriver, approximately 2 mm wide.  If you don't have one, something like this is perfect  or if you must have an exact fitting driver this one. 
2. A replacement battery, with the appropriate soldering tabs which can be bought from Amazon. The one's you buy at the pharmacy won't work for this. 
3. Soldering iron, preferably temperature controlled. The one I use
AOYUE 936 Soldering Station or this neat little kit from Aoyue which has everything but the screwdriver. The soldering iron is perfect for those who use it once or twice a year but are sick of the $20 soldering wands. I can't stress enough how much easier it is to use a temperature controlled soldering station than not. 
4. Desoldering wick or suction device.  I like the push button, spring loaded pump kind myself like this one. 
5. Lead-free, rosin core solder.  Acid core is for plumbing only! Also, in the 21st century the world is more environmentally conscious.  In the US 98% of car battery lead is recycled, but less than 10% of lead in electronics, so please use lead-free whenever you can.

Notes

• The case is made up of two pieces.
• The back is one solid piece of acrylic.  The LCD panel is embedded in it. 
• The top containing the reset button is a solid, narrow piece.
• Do not try to separate the PCB or the LCD screens.  The replacement can happen with them in situ.

Instructions

You should use a cloth to protect the face of the board before you begin.  You may also wish to use a pad of paper to lift the body up so it stays parallel to the work surface to free a hand while unscrewing. 

1. Place Boogie Board face down on top of the towel. Use a pad of paper or similar to lift the body up so it stays parallel to the work surface.
2. Notice the four silver round rivet looking things.  They are actually screws. They may be hidden by labels.
3. Fit the largest slotted screwdriver you can comfortably insert until it sits at the bottom of the screw hole.  Yes, it is a screw hole, despite its shape.  Test it by turning it in the hole.  It should just catch the indentations. 
4. Unscrew all four and save for later. 
5. Turn Boogie Board over.
6. Using the stylus that came with the Boogie Board, pry the top from the body from within the stylus holder chamber. 
7. Desolder the battery terminals at the PCB.  Don't bother attempting to pry the battery tabs from the battery.
8. Solder your replacement. 
9. Reverse the assembly steps. 

 

 Soldering Suggestions

The battery tabs should come loose in 10 seconds or less, closer to 5. If not, try in this order:

1. Make sure your iron's tip is shiny. Tin it by adding a little solder and then cleaning it on a wet sponge or metal wool pad. Repeat the cleaning often, and tinning only when needed.
2. It's not about pressure, so much as contact surface, so hold the iron so as much of the flat, shiny part of the end is making contact with the tab and press down evenly and gently. This usually means you have to hold the iron at a low angle to the work surface, instead of at 90 degrees.
3. Use the right tip. If you have multiple tips, find a tip a little wider. All of the Aoyude irons have replacable tips.  Probably the default is fine for very infrequent use on small items, but with thicker wires and parts you'll get frustrated fast.
4. Turn up the power a little at a time.

With practice, you'll get a sense for when solder isn't melting fast enough, and realize it's time to clean the tip, or try the other ideas, above.

Say Hello!

Since I posted this page, tens of thousands of viewers have read the instructions, but no one ever says thank you, or says "Hello!" So please leave me a note.

And from me to you: Thank you! 

 More Hacks

• Replace the included screws with normal, Phillips head screws. 
• An alternative to a battery may be a 3V solar cell from Amazon but it is untested.  You may need to add a small cap (1-4.7uF at 5V) .

Hope some one finds this useful. 

Theta Casanova is dead. Long Live Theta Casanova!

Not soon after the Theta Casanova III HD was released, the Casanova IV [sic] has been announced in a couple of sites I'd never heard of, one of them being here:  http://www.ecoustics.com/products/theta-digital-casablanca-iv-preamplifier/

It saddens me that this continues to be sold to installers instead of enthusiasts who provide most of the support, but good for Theta for showing steady progress.

I also wonder if sales wouldn't have been better for the Supernova instead.

The Mac OS X GUI Sucks

After using Windows Vista/Windows 7, and several KDE and Gnome UI interfaces on Fedora and Ubuntu, I have come to the inescapable conclusion that the Mac OS X GUI is the worst of them more than any of them.

The Mac UI is the vi of modern user interfaces.  It sucks unless of course you would love vi and all of it's keyboard quirks.  Then it is what you should use.  I rate it below Gnome 3 and Ubuntu Unity.

Windows 7 and Cinnamon, followed by KDE are at the very top.

That is all.

Yamaha P2100 Upgrade, stage 1

By the numbers:

Items Removed:

• Over 36" of signal wire from input to volume to DA board.  
• Stereo / Mono switch and associated parts, including jumper wires and an electrolytic capacitor
• 5W cement resistor that goes to thermal LED. 
• Wiring to extra pairs of jacks. 

Items replaced or upgraded:

• All 14 remaining electrolytic capacitors replaced.  Mostly with Panasonic FM's, but Elna Silmic IIs for the coupling and Nichicons for 220uF axials.  Straight replacements except for 470uF caps in auxiliary power supplies.  Those upsized to 1,000 uF.   Main PS caps Nippon Chemi-Con.
• Two 1/4" phono jack's replaced with gold plated, non-shorting RCA jacks

Items added: 

• 4 x 1uF bypass caps for B+ and B- to ground. These are yellow Cornell Dubliner low inductance metal poly.
• 4 x 0.1uF yellow Cornell bypass caps for Elna coupling caps and 220 uF Nichicons.
•  6 x 0.1uF red Panasonic metal poly film to bypass remaining electrolytics on DA board. 
• Shield lift board (see below). 
• 2 jumpers to short long traces going to stereo/mono switch.  

Interesting Readings

I'm going to use this blog post to share some interesting information.

First, I've been looking at the Leach class handout and the Yamaha P2100 design.  In particular I've already said that I'm really pretty shocked that the amp sounds so good doing so many things we wouldn't do today.

From the Stereophile Carver Challenge - Page 4

I would like to quote:

On the face of it, what Bob Carver pulled off should be impossible. You can't make a silk purse from a sow's ear. What about the audible differences between transistors, capacitors, internal wiring—all the things that we know contribute to the superiority of no-holds barred amplifiers? What about all the things that amplifier designers have learned during the past 20 years, which enable them to build better amplifiers (at whatever price) than have ever been built before? How could all of these things have been factored into the relatively quick and painless transformation of an average amplifier into a world-beater? But, of course, the "factoring-in" was the key to all this.

This is kind of where I started with the Yammies.  WHY do they sound so good despite doing a number of things "wrong" compared to today?   And why do they spend money on an extra pair of transformer windings to provide extra negative voltage to the cascode differential pair on the inputs?

A very interesting read on circuit memory and the use of the cascode differential pair inputs:

http://peufeu.free.fr/audio/memory/

It's all starting to make sense.... just barely.

Yamaha Protection Circuitry

I spoke a little too soon about the Yamaha not having any protection circuitry.  Looking through my class handouts/notes from Dr. Leach's lectures, TR12 and TR13 provide current limiting.  If either saturates they remove voltage from the base of the drivers, TR14 and TR15.

I stand by my original assessment that the temperature light is a waste of good power best used elsewhere though.

I'm still trying to figure out the extra windings which are used to add about 14V of negative supply, which seems related to the bias and input stages.   It's almost as if they are trying to keep the input off center, so it operates linearly, before driving the rest of the amplifier in a more balanced manner.

Ideas?

Assaulting the Yamaha P2100 Amplifier

It's been a while since I did anything related to audio.  I've been too busy and broke, but recently a few things have happened to accelerate my descent into madness. 

To make a long story short, I had a P2100 (85/140 watts into 8 and 4 ohms) running my front Focal 918s, and a P2075 running the Monitor Audio on the rears.   Last week I found a local e-bay vendor selling a P2100 for $49 "untested."  They were local so I decided to take a trip up there to visit them and test it before buying.  It turns out, the "untested" part was a lie, as there was a tech there named Bob who not only knew his stuff, but had a lot of history around the Boston audio manufacturer's scene, having worked with Henry Kloss, Snell, Boston Acoustics, etc.  so we had a great time chatting about how we used to listen to music while playing with baby dinosaurs.  Tested the amp, sounded great, threw it in my trunk and drove to Newburyport for a fun afternoon.

OK, that's not a very short story.  The short part is, I ended up with two P2100's for my 4.0 surround sound system.  Each amp now handles either the left or the right side of my music and movie system.  This way when I listen to music, which is much more often than movies, I essentially have a dual mono setup, and the power supplies act stiffer.  Not a bad thing since these Focals do have a dip into around 3.6 Ohms somewhere.  Not as bad as electrostatics, but the crossover designers didn't care too much about the amps either.  During movies the amp upgrade really improved the immersive experience as well.  So, win-win.

Before turning on the new amp I wanted to replace the main PS caps which were original.  I still have some recent vintage NOS caps that fit so I decided to go ahead and replace them.  While in there I took a long hard look at the signal paths. 

Surprising Discoveries

Many audiophiles around the world have discovered the Yamaha professional amplifiers from the 70's, 80's and 90's before Yamaha went digital hybrid with the EEEngine technology.  They are struck by the quality of the sound, low noise, and often how inexpensive they are to buy in good condition in the used market.  I agree with them.  So, from my perspective as an audiophile, these amps perform very very well as is.

What surprises me still is how well the amplifiers sound despite many design decisions we would now consider unacceptable in the hi-fi world. 

Flexibility.

When I first hooked up the amp which would be named Brianna, the right side sounded hard, and was significantly warmer than the left.  Checked the bias and sure enough, it was biased hot, 36 mV vs. 22 in the spec.  Adjusted, treble sweetened up, amp cooled down.

I did the same in the second, original amp, but this time I started looking at the input signal path.  As is often the case, this investigation led to even more discoveries and surprises.   First, it is important to note that being a professional amplifier, the P2100 had a lot of features included to enhance flexibility and ease of use for the installer or sound producer / engineer.  Unfortunately this leads to what we would now call compromises by comparison to the modern trends in Hi-Fi amplifier design and marketing.

We'll start with the most obvious.

Volume Controls

Mandatory in a professional setting, these are rarely available any more as consumers use the preamps or processors to manage signal balance.  In this amp this adds 2 feet of signal path before a single active component.  See the drawing.

In addition, examining the back panel and insides you will notice more features (or compromises):

• A total of 8 input / output jacks.  This adds loads of extra wiring and junction points.
• Phase inverting switch.  Again, more opportunity for poor contact resistance and capacitive signal coupling.
• On the inside you will find a Stereo/Mono switch in the middle of the voltage gain (DA) board.   This switch adds several additional solder points, the switch itself and a few more inches to the distance the A channel signal has to travel before being amplified.   Audiophiles would be aghast, AGHAST I say!  Yet, the amps both sound great.   In addition, the amp is only spec'd for bridged mode with a 16 Ohm load.  The audiophile who can and will use this feature is truly a rare one.

Parts And Design

 Again, compared to modern trends and practices there are some major differences to how we might expect a high end amplifier to be designed.  I'll bullet them here:

• Single-sided circuit boards.  Common back then, PCB's were more expensive and double sided even more so.  The PCB's appear to be hand traced using curves and fills wherever possible.   Today we would not hesitate to use double sided boards at least, which would save on space and trace lengths.
• Cement power resistors.  Again, common even in mid to high end amps, today we would use wire-wound non-inductive resistors which are much smaller. 
• 100uF electrolytic capacitor used as DC coupling cap, without bypass.  Seriously!  How can a 20+ year old electrolytic cap still sound this good??
• Metallized polyester film bridge rectifier caps.  Yamaha was ahead of their time here.  Those little guys must have been expensive.
• PS Bypass caps - Non existent. 
• Resistors - Metal Oxide used throughout, no skimping here! 
• Connectors - Cannon XLR plugs are solid copper with silver plating.  Wow! 
• Signal wires - Bunched tightly together, yet still the amp achieves over 80 db channel separation.  Impressive, in a day where mono amps are the cats woolly pajamas.
• Inputs - High impedance, unbalanced.  Yes, that's right, the XLR plugs are practically for show.  
• Power paths - Here it gets a little interesting.  Power goes from the transformers, through the current gain boards on the heat sinks to the DA boards. 
• Ground - Yamaha takes quite a bit of care here.  While the XLR and 1/4 inch jacks are grounded at the back panel, the ground is maintained separately through the volume controls until the DA board.  Here they join the PS ground (E) for the first time.  In addition, the E net is continued through the DA board and through the output boards back to the PS ground.  Any modifications I undertake will have to keep this in mind, I don't want to begin experimenting with an already effective system.
• Amplifier protection - Almost none.  Some fused resistors is about all you have.  "What about the thermistors on the output boards?" you may ask.  Well, turns out they only turn on 1 LED on the front panel to warn you about heat problems.   They don't actually do anything else.

Strategy

Since I have 2 stereo amplifiers, and 4 channels of changes to make, I've decided to sit back and truly study the design for a bit before making any changes.  Overall however, here are my strategies:

1. Shorten the input path as much as possible by removing all extraneous features which will not be used in my system.
2. Replace every single electrolytic capacitor.   Mostly with Panasonic FMs.
3. Replace almost all cement resistors.
4. Add differential inputs. 
5. Improve amplifier service lifetime.

Tactics

1. Replace coupling caps (2) with Electrolytic +  Wima or Vishay film.
2. Remove phase (2) and bridge (1) switch from signal paths.
3. Shorten paths on DA board by bridging paths to mono/stereo switch.
4. Replace bias pot (2) with higher power, plastic film if possible. 
5. Remove thermal warning light resistor (1).  Wastes 3/4 watt while amp is idle.
6. Add new circuit board for differential inputs and film bridge caps and mount to DA board in place of existing connector board.  Will add 2 watts of power dissipation, but since we'll remove thermal resistor, we only use additional 1.25 watts.  Also, by reducing bias voltage to specification we have probably gained a little there as well and will be power neutral when done.
7. Keep input XLR jacks, they're sweet as is. 
8. Replace one set of 1/4" jacks with RCA.