Sunday, January 24, 2016

Big Change Coming to this Blog


IMPORTANT

Soon, this blog
http://Audiophile-Musings.blogspot.com

will be renamed to

because of an issue with a registered trademark  in the UK of which I have only recently become aware.

The owner of this trademark and I have come to a win-win agreement without the need for involving other actions. I personally feel that this is an excellent resolution. As a respected author, I have no desire to infringe upon this trademark and I completely understand this trademark owner's position. If the shoe were on the other foot, I would be doing the same.

All of my previous posts will be moved to a new blog site that is currently under development called "Audiophile-Muzings," a variant of this original name intended to be inspirational as my blog was originally conceived to be. The trademark owner has also agreed that this is an acceptable name change. However, this will take some time to implement since there are about 200 posts involving numerous links and external sites that must also be informed and coordinated about this move.

I will post updates to my progress as they become available. No new postings will appear on this site other than these updates. Please be patient with me since this is indeed a monumental effort.

To minimize confusion at this point, let me clarify something.

If you are looking for the blog AudiophileMusings, you have reached the wrong blog.

Click this link to take you there.

I publicly apologize for any inconvenience and confusion this may have caused.




Yours for higher fidelity,

Philip Rastocny

I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate by purchasing one of my eBooks or through a PayPal donation, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style (like that of the Discovery Channel), it targets one star that has never been considered before and builds a solid case for its candidacy.

My other titles include:




Copyright © 2016 by Philip Rastocny. All rights reserved.

Sunday, January 10, 2016

Bespoke Aria/Monacor RBT-95 Mod

I have used this driver as a super tweeter in my system since March of 2015 and I have fought a sibilance issue with this driver ever since the very first day. I have tried literally over a hundred different things to tame this nasty issue - new crossover components, new crossover alignments, shifting crossover points dozens of times, over 30 different series notch filters, etc. - all with zero success. Some changes made things better but caused other problem like sporadic oscillations, mid-bass dips, and combing issues. Things were so frustrating I considered tossing the driver and chalking it up as a costly and time-consuming experience.

However, this morning I disassembled the box trying to recall if the driver was bipolar (it is not) suspecting it may be a cabinet-induced resonance. While inside, I removed the driver from the front baffle board (two center screws are all that hold it in place; the two top and two bottom screws sandwich the driver together and should not be loosened), removed the driver from the baffle board, and removed the protective screen by lifting the edge with an X-Acto knife. WARNING: The risk of removing this screen is huge: anything of ferrous composition coming close to the face of the driver will instantly be sucked through the thin planar diaphragm destroying it in an instant. But how often are steel or iron things flying through the air in my listening room? Never! So what did I have to lose? Nothing...I was going to put the driver in the spare heap anyway so I decided to give it a try.

Stock RBT-95

Long story short, this is a very positive modification and one that is incredibly easy to do and undo. After removing the screen you must tighten the two screws a little more so that the face of the driver is flush with the phase plug/baffle. This was about an extra 1/4-1/2 gentle turn (and I stress the word GENTLE since stripping out these screws ruins the baffle board).

Modified RBT-95

So what did I hear? First, the nasty resonance is almost completely gone (YAY!!!!) and the overall sound of the driver is vastly improved. What I once thought was a metallic sounding super tweeter, similar to that of a well-designed titanium bullet tweeter, has now approached similar low-sonic colorations that a good AMT or other planar driver does. It truly is magic and well worth the risk and effort.

My first impression of Nils Lofgren's Acoustic Live - Kieth Don;'t Go was jaw dropping. The overall timbre of the guitar previously sounded great but un-homogenous sort of  like several instruments combined in one with weird overtones to fundamentals. Now, all of this weirdness is gone and the strings resonate properly pulling out the fundamental sounds of the guitar body along with it. In Iver Klieve's performance of "Bridge Over Troubled Water" on his deUSYNLIGE album clearly reveals the position of the organ ranks in the church. In Patricia Barber's Regular Pleasures you can hear the strings of the double bass buzz against the finger board and the drummer tap the high-hat cymbal that is recorded in amazing clarity and detail. In the Bill Evan's Trio album "Walts for Debby" the My Foolish Heart cut exemplifies the superb talent of Paul Motian pushing brushes on cymbals and snare drums. Listen here for the incredible inner detailing captured in this recording of the metal wires slowly chaffing against the instruments - it is hard to believe that this high-quality recording was made in 1962, a mere 54 years ago.

Since my driver is outboard of the satellite box, I can move it forward/backward to time-align the sound. Now instead of chasing down the cause of this annoying sibilance, I can focus on the best possible sound stage. I can personally attest to the positive benefits of minor forward/backward movements where at some point the depth of the sound stage just comes alive. Ambient clues from rear-wall reflections in the original recorded room contribute a spaciousness to live performances you may never have experienced before.

Outboard Super Tweeter

Another thing you may note in the above picture is that I added felt to the face and sides of this speaker. This modification was already done as was the removal of the stock network (see this blog entry for other details about this speaker). I also tried swapping speaker polarity to assure myself that the absolute phase of this driver matched that of the others (it is correctly labeled).

All I can say is WOW!  Persistence and perseverance prevailed and I now have a harmonious and seamless top octave that I can easily live with. As it is when climbing the audiophile ladder, once one issue is resolved it reveals other shortcomings. But hey, that's the fun of this hobby, right? What flaws did it reveal? Stay tuned and find out!

Yours for higher fidelity,

Philip Rastocny

I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate by purchasing one of my eBooks or through a PayPal donation, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style (like that of the Discovery Channel), it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:




Copyright © 2016 by Philip Rastocny. All rights reserved.


Thursday, January 7, 2016

The Golden Ratio

OK, I get it. It's been several months since I've posted and many of you suspect I've fallen off the face of the earth -- NOT! Many excuses surface in my mind but know this: I have not died nor have I become a zombie. I have been busy with my new solar panels building a 2.7kW system above our carport (believe me, this was a serious undertaking, not for the faint of heart). And now guess what: as our friend Arnold is fond of saying,  I'M BACK!


I have been fussing with that silly crossover point with my super tweeter and made good progress although I am still unhappy with the way it sounds. It is far better than it ever has been but you know how golden-ear types are: mercilessly critical. So the journey continues.

To refresh your memories, I use a Mundorf AMT for my tweter and a Bespoke Aria for my super tweeter. After countless attempts at a revised crossover point I have narrowed down the cause of the sibilance issue on the ST to a cavity resonance in  its enclosure. This combined with a mechanical resonance of the planar suspension of th ST at this same frequency proves to be a real nightmare.

At this point, I have been experimenting with series resonance filters (near 8KHz) to tame the wild beast and I have been marginally successful in doing so. But when I get the sibilance under control, the bass response goes out the window and vice versa. Now that the design has matured, I hear an occasional sporadic electrical resonance that is driving me literally bonkers. I tried not to redesign the enclosure (I like the way it looks) but alas, at this point I must yield to common sense.

So two things must be addressed: 1) the enclosure dimensions, and 2) the mechanical resonance of the diaphragm. Since this mechanical resonance is impacted by the enclosure resonance, it makes sense to redesign the enclosure first before tackling the mechanical issue.

Since their introduction in 1993, I have admired the design of the Bowers and Wilkins Nautilus speakers with their ground-braking logarithmic spiral woofer enclosure (also the Golden Ratio M,T,ST enclosures). For the Golden Ratio, the enclosure dimensions continuously converge in a1.618:1 ratio as shown below. BTW, the Nautilus speaker borrows its name from the sea creature whose shell also conforms to this same logarithmic spiral.


What interests me are the M-T-ST enclosures, what appears to be a unique tapered transmission line (TTL). Their super tweeter crosses at 3,500Hz. But the wavelength at 3500Hz is less than 4" so they must be using a multiple of that frequency (i.e., an inter-modular) for that enclosure. Interestingly, the model 804 uses a TTL enclosure for its ST of the 4" length.

So the next tale in the ongoing saga will be this new super-tweeter enclosure. I am uncertain as how I will go about this but old trumpets, horn flares, and waveguides come immediately to mind. We will see...


Yours for higher fidelity,

Philip Rastocny

I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate by purchasing one of my eBooks or through a PayPal donation, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style (like that of the Discovery Channel), it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:




Copyright © 2016 by Philip Rastocny. All rights reserved.

Monday, October 19, 2015

I'm in Love - again

It is amazing to me that capacitors sound so different. I have been swapping out non-polar electrolytic crossover caps for higher and higher quality kinds for several decades now each time believing that I have found the perfect combination. Moving from NPE to a mylar made the sound smoother but soft. Moving to a metal-film mad the sound crisper but thin. Moving to a wax made the sound clean but back to soft again.

Well folks, we have stumbled again into the realm of the unexplainable: the paper-in-oil capacitor. Musicians who actually listened to their music found that PIO caps made their gear sound much better. Tubes found their way back into guitar amps and keyboards and ever since musicians could access PIO capacitors, substitutions and modifications were made. To them the results were a more pleasing, more melodic, less irritating sound.

High-end gear sometimes uses PIO caps and other times a variety of other esoteric combinations. Rel Caps are favorites of Audio Research and Teflon caps commonly found as shunts for a variety of other metal-film brands. But the lowly PIO has found its way into more and more of my gear after a brief revelation as a shunt in the crossover network of my speakers.

While PIO caps are not the end, IMHO they are pretty close to perfection. But from which manufacturer would YOU choose? Mundorf? Angela? Amp-Ohm? Obbligato? Jensen? Deuland? I suspect that your funds would dictate your choice since the prices of these types of capacitors are extraordinarily high.

Consider the surplus market. For decades, the Russians produced spectacular capacitor products and the PIOs are no different. The series I lean toward is the K40Y-9. When used as tiny shunts (1/100th the value or less) across your existing signal-path capacitors, these little gems completely change the way they sound. And replacing them for a 1:1 value produces striking results.

So, if you want to make a huge change in your gear, try adding the 200V version of the K40Y-9 as a shunt to your crossover network's midrange LPF or your tweeter's HPF. If you are brave, hack into your preamp or amp and do the same for the input/output coupling caps. You just will not believe how spending a few dollars for 0.015uF caps (and waiting 30 days to get them) can transform your listening pleasure.

Yours for higher fidelity,

Philip Rastocny

I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate by purchasing one of my eBooks or through a PayPal donation, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style (like that of the Discovery Channel), it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:




Copyright © 2015 by Philip Rastocny. All rights reserved.

The Path to a High-End System

You probably started out in your quest for the ultimate high-end system as an infant in your car-seat by listening to the stereo in your family car. One day, you got an MP3 player, probably in your cell phone. Swapping earbuds helped you to appreciate the quality or lack thereof in your player and one day you strolled into Best Buy (or a friend''s house or another big box store or a THX movie) and seriously listened to a good system. The lights came on: you heard something and found there is more art in music than a beat and words to a song!

Details never heard before began to appear and (possibly with the help of some medicinal ingredients) your appreciation for quality music took off. Soon, that MP3 player of old just didn't hack it anymore and it was time to get serious about tunes. With your driver's license came freedom and the opportunity to deck out your ride. Before long, thumps and tinkles captivated your commute to/from school or that job you got to help pay for that amp.

Down the road, probably after your second or third REAL job (flipping burgers doesn't count), you decided to take the plunge and get a decent system for your digs. A simple receiver, possibly multi-channel surround, showed up next to the Samsung TV and entertainment bliss was on its way.

This lasted for a while and then things started to sound not quite right or just a little off. Your ears matured and you began to listen to the decays and silence between the notes. "Mr. Scott...we need more power...NOW!" or something like that ran through your mind. Off to the new audio salon in town; time to spend some serious bucks.

Ever since that day, things have moved in and out of your listening room. Speaker sizes grew, you discovered that cables and wires do make a difference, and CDs just sounded a bit off. That old receiver found its way into your office (or garage) and separate components lined the shelves. Esoteric DACs and high-res software showed up as if by magic on your desktop and you were off to the digital races.

But then, on a chance meeting, you heard an old analog system. Something else came from the speakers you never heard before. What you thought was audio nirvana was now reformed. Tubes, vinyl, and turntables may have crept their way into your rig as did your constant comparison between the two sources. One was more convenient but one was more real. Quite the dilemma.

And then came along DSDs and higher quality recording techniques. The difference between old school and new narrowed and you may have questioned whether old school was worth keeping. But you were too busy moving your speakers around and adding acoustic treatment to the room to seriously consider selling your turntable

But regardless of your choice, new gear rolled in and out of your system and the evolution continued. Some diverged into the DIY realm and others found happiness in off-the-shelf gear or hiring folks to do upgrades. Power conditioners, equipment footings, speaker spikes, and other accessories each contributed to that tiny improvement that pushed forward the state-of-the-art.

Today, you are happy, at least until you hear your friend's system or something blows up. And then the search for that next step in upward spiraling audio nirvana continues including your never-ending expansion to your software library.

Such is our hobby and so is our happiness. Eventually a balance is struck between funds allocated to your rig and your other monthly bills, but that piece of the pie dedicated to your hobby never really gets completely cut from your budget. Your dreams of a better system and your enjoyment of just listening to a good performance never changes, NEVER. Even when life demands your attention in other directions, you find yourself still enjoying the magic and mystery of you ears.

The path to a high-end system is a long one, one that never ends. Sometimes it takes a while for technology to become affordable and other times you just settle for "good enough." But deep down inside, you hear that old refrain from your first venture into the audio void, "Mr. Scott...we need more power...NOW!"

Yours for higher fidelity,

Philip Rastocny

I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate by purchasing one of my eBooks or through a PayPal donation, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style (like that of the Discovery Channel), it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:




Copyright © 2015 by Philip Rastocny. All rights reserved.

Tuesday, September 8, 2015

Another OPPO Mod

My OPPO BDP-105 has undergone several major transformations since its original purchase. What started out as a fine sounding streaming player right out of the box has been upgraded to a true high-end streaming media device through careful attention to proper modifications. Many articles appear on the web regarding tweaks, upgrades, and hints on "how to DIY" fixes for such a stellar product and this blog is no different.

After reading about what others have tried, I used what they suggested in combination with what I already knew "worked " and came up with a series of modifications that made my ears rejoice. It takes a while as you push your system to musical nirvana but with each change you climb one more rung up the long, long ladder.

The latest discovery is a paper-in-oil capacitor, nothing new to the universe but new to me. Finding the right combination of equipment, cables, line filtering, and capacitors to resemble reality is what this hobby is all about but when it all comes together, you get that magic that transforms your listening pleasure from something that sounds great into something that sounds real. You hear the details the reviewers write about coming from your own speakers and you understand that they are anything but crazy. Even lowly MP3s sound decent but when compared to a SOTA DSD, you understand why some accomplished musicians are seeking higher and higher resolution for their recordings. It's that obvious.

I recently considered removing the DC-blocking capacitors from the final analog output stage of my BDP-105 but after further consideration I decided against it. If I ever took my OPPO to someone's home, it would have to accommodate a possible DC offset from the OPPO (read DC blocking capacitor input of their preamp). So I went off to work figuring out how to safely shunt the stock capacitors. To start, one must be certain which capacitors one needs to shunt. Below is the audio schematic for the BDP-105 (note CE93 and CE94 are the 100uF/16V DC-blocking capacitors).



Others have used shunt capacitors from the underside of the PC board but the PIO capacitors I chose are quite large (about 3/4" in diameter) and will not fit. The task was to figure out where to add wires to the ends of the readily-accessible resistor leads to accomplish the same results as soldering them to the underside. Note from the above schematic that R128/R140 connect to one end of this capacitor. Resistors R23/R28 (or R25/R20) connect to the other end. Below is a highly magnified view of the output stage showing where these resistors are located from the top of the PC board. The red arrows show which resistor ends are used and the rear of the chassis is on the left.



The Mod

The first thing I did was to insulate the metal body of the PIO capacitor by putting heat-shrink tubing around it (for obvious reasons). Fortunately I had some large tubing left over from a tonearm modification I performed a while back and after a few minutes these capacitor grew in diameter to just over 3/4".

The next step is to remove and replace the stock ferrous-alloy leads of the capacitor. These leads are soldered to the end terminal of the capacitor; heating the wire and removing it is not recommended since it may damage the capacitor. But cutting the wire short off at the terminal eliminates the two inches of ferrous alloy and provides a point where the new wires can be attached. I chose to use new wires made from two twisted strands of #26AWG Teflon-insulated silver-plated OFHC wire-wrap wire.

Now comes the tricky part: connecting these new wires to the resistor leads. In concept, this should be a "no-brainer" to the average DIY tweaker but the component density on the OPPO is quite high making it necessary to use a fine-point tip and very low heat on the soldering iron. In reality, soldering the wire-wrap wires to these resistors takes a lot of patience to get a good solder joint without destroying surrounding components, lifting the trace off of the PC board, or disrupting the integrity of other existing connections. In other words, this mod is not for the inexperienced or faint of heart. Feeding the wires under the resistor lead provides the best electrical+mechanical connection but I found this to be impossible without lifting the resistor out of place. So the next best solution is to make a non-mechanical connection (just tack the wire to the side of the resistor lead). This "works" but it is not a truly professional solution. If I had used just one #26AWG wire, I could have fed that wire under the resistor lead (hind sight is always 20/20).

Finally, I attached the free-floating capacitor to some surrounding electrolytics with a few dabs of hot glue and the mod is done.

The Sound

Frankly, this is initially a subtle mod that requires some patience to appreciate. What to listen for is the fullness of the strings in a guitar body and the inner detailing of its harmonics. A good piece to use as a before/after test is  Nils Lofgren's "Kieth Don't Go" on his 2006 Acoustic Live album. Although only a 16/44 recording, it clearly provides evidence to the fruits of your efforts. Listen to the timbre and color of the lower strings as Nils artistically plucks them. Listen to the inner detail of the guitar body in response to how hard the string is plucked and where/when he rests his palm on the body to contour/alter its sound. This is the region I noticed most of the changes to occur.


My wife, a movie fan, even commented on how dramatic and forceful the sound now emanates from the system. Historically, asking her if she notices a change in the sound after a modification yields a simple response "It sounds great!" which loosely translated means she likes it but cannot articulate why. This time she was able to fit words into her perception and the results is another successful modification.

The capacitors took a mere 10 hours to break in and the sound is now so sweet and mellow that one may easily compare it to that of a good tube. You will notice a definite change, one that is very easy to get used to. Instruments that may once have been "strained" are now more accurately reproduced fully. Saxophones have that unique round "bell" sound that one hears in a live performance but rarely finds in a home stereo system. Sounds once blurred appear cleaner and vocals, well just listen and you will not be disappointed.

See also http://audiophile-musings.blogspot.com/2014/09/an-easy-oppo-bdp-105-modification.html
for another great idea on upgrading your OPPO.

Yours for higher fidelity,

Philip Rastocny

I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate by purchasing one of my eBooks or through a PayPal donation, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style (like that of the Discovery Channel), it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:




Copyright © 2015 by Philip Rastocny. All rights reserved.

Sunday, August 23, 2015

Mu-metal Part 3

In Parts 1 and 2 of this 3-part series, I found a new friend: mu-metal. It worked wonders in my line conditioner so I thought I might give it a go in my low-level equipment. In Part 2 I applied the same chassis shielding technique to my OPPO BDP-105 with the same positive results. In this part, we'll look at how (if?) further shielding in the OPPO would benefit and then apply that treatment to my Onkyo P-3000R preamp.

Tearing down the OPPO is getting to be a routine; I've done it now 10 or 11 times for various reasons but I was excited about adding mu-metal to the switching power supply (SPS) section. Reading how nasty this supply is made me believe that there were more issues with SPS than just the high-frequency band smearing associated with their inherent design. And I had a surprise when pulling off the cover of the SPS: mu-metal on the inside. At least two sides of the supply were already shielded so now the side between the supply and the remaining electronics needed to be shielded.

So the first thing I did was to remove the rail and coat it with mu-metal. Instead of carpet tape, I used a spray contact cement on both the cut-to-fit mu-metal pieces and the bracket.



Next, I wrapped a band of mu-metal around both transformers and used a cable tie to hole it in place (yes, I wrapped the already shielded toroid too). WARNING: Make sure that the mu-metal is properly insulated so that it does not short out the wires on the transformer! Remember the edges of this metal is sharp and it will easily cut through any insulation these wires may have.





The next step is to make "hats" for the tops of the transformers and then use another cable tie to hold the hat in place.

While the cover was off, I also added a 0.01uF/200v shunt capacitor to the fuse. Doing this takes care of any thermal non-linearities in the resistance of the fusing element.



Put it back together and all should be well.



First, I want to say that the P-3000R is an under-rated preamp and with a few minor tweaks brings it up to truly high-end quality (change those Full-Wave Bridges to four discrete FRED diodes [2 FWB = 8 FRED diodes] and see for yourself!). So I was happy with the way the preamp sounded with these mods, but hey, what do I have to lose but a little time and maybe a band-aid for the nasty paper cuts on the edges of the mu-metal?

So I first performed the same chassis wrapping as with the OPPO.



And then I did the same transformer wrapping.


Button it up, plug it in, and turn it on. Be prepared to be amazed.

What I noticed was even more low-level grunge removed (I had no idea that it was there). The inner detailing is now a quantum level better than before and I am not exaggerating one bit. The instruments show more nuances than I suspected were captured by the recording process. It is in a word breathtaking.

Now you must realize that your system is a chain and the weakest link limits how much you will observe on yours as compared to mine. Know that all of my gear is seriously tweaked and the attention to detail is unsurpassed. But as you make these changes in your own system, each thing you do you will eventually hear even if the changes are not as obvious. You just have to identify what in the chain is the limiting issue and once it is resolved everything can come alive.

So grab your scissors and glue, buy some mu-metal off eBay, and shield!

Yours for higher fidelity,

Philip Rastocny

I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate by purchasing one of my eBooks or through a PayPal donation, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style (like that of the Discovery Channel), it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:




Copyright © 2015 by Philip Rastocny. All rights reserved.