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Audiolics Anonymous Chapter 51
Updates, Tweaks, Mods and Maintenance Part 2 

Walker Audio Velocitor AC Enhancer
Vivid CD-DVD Enhancer
Homegrown Audio LOK Silver RCA Connectors
And Zero-Autoformers
Article By Bill Gaw


  Welcome to another edition of Audiolics Anonymous for the audio addicted. Last month I went over Mods and maintenance to improve our systems, and today I'll talk about the other two methods with a couple of products I have found that fit the bill.



Unlike modifications, which are changes to equipment usually done by others, Updates are product developments done by the original manufacturer to try to improve a piece without changing it so much that it becomes another product. Some updates are done for valid reasons relating to new experimentation that the developer has done which significantly improves upon previous functioning. Others are done for purely profit motives, I am sorry to say.

This is a very gray area for several reasons. First, if a product is originally built to the manufacturers best standards then why would they have to improve upon it unless they have come upon some wondrous new part which significantly improves on the original. Maybe the product should not have been let out of the factory in the first place. Second, is their an ulterior motive? Maybe they are selling fewer products than they wish and need to add to cash flow. Third is it the so-called "four month phenomenon". How often are they updating their products and how significant are the costs? Honest companies will charge you cost of parts and labor plus postage and give some guarantee that you will be happy with the result. Many will even do it for nada if they feel the update was a necessary quality improvement, or some defect was found in a product run that needs to be changed. Less than honest companies will change some part every few months, and charge exorbitant amounts. Then when you get it back and find no improvement, they will fall back on the excuse that maybe your other equipment or ears are not good enough to pick up the subtle but supposedly significant difference. Caveat emptor.

You can probably tell I have been burned in the past by updaters. Nowadays I always try to get some guarantee that if the product does not live up to my expectations money will be refunded or the equipment will be returned to original condition. An honest company will agree to that. One such honest high ender is Lloyd Walker of Walker Audio. I have written up many of his products in the past, all of which have given excellent sound for the money. All, unhappily, are fairly expensive but all are built to the highest quality. Every time I have tried something new or updated from his recommendation I have been very satisfied… and he does give a money back guarantee. His latest update recommendation is to his Velociter.

Walker Audio VelociterI originally got two of these from Lloyd Walker and wrote them up very favorably in AA Chapter 44. Matter of fact, with the Sound Application CF-12X units, I found I could not listen to my system with satisfaction without them in place. The combination completely eliminated the horrible AC line noise problems experienced here. The results were so positive a third unit was added to my system for video. Lloyd called a few weeks ago to let me know he had found an upgrade for the units, changing some parts and wire that would only cost $ 150 each unit, a reasonable price considering their $2,695 original cost. As I was bringing my turntable down to him for updating while on vacation, I just brought along the three units.

On arriving home after a week on the road, I had to rewire my system using only the Sound Application units, as the Velocitor's had not arrived. I do not know if this happens with you, but usually on returning home after a break from my system it seems to sound the best it ever has. I do not know whether it is the separation from my first love, or the listening to inferior systems (or possibly something reforms in the system which worsens as the system is left on), but I am always amazed at how great the music sounds. Not this time though. The music had lost some of the beauty I had remembered. What a disappointment.

So I called Lloyd to plead for the units quick return and happily he had sent them out that day. They arrived two days later and into the system they went. There was joy in Mudville again! Back was the musicality of my system with SACD/DVD-A and more so than I remembered with the original units. I do not know what Lloyd did, but there is more quietness between the notes, more tightness to the bass, and cleaner highs. I have not been able to listen to analog as he still has my turntable, but the improvement in digital was enough to make a recommendation for the update.

In addition, video has shown a definite improvement in the vividness of the colors and the acuity of the image. For example, there is a show on HBO called Carnivale, which opens with the camera scanning through pictures. It has taken on an unbelievable 3-D dimensionality on my 10-foot screen with an Electrohome 9500LC projector, which I do not remember from before the new Velociters were placed in the system. Considering he has not changed the price of the Velocitor from its original $2,695, the new units are even more of a buy and I feel the update's price is certainly worth it. I even bought a fourth. Now I am ready for any additional equipment that may come here. Was hoping to add the Walker turntable updates here, but Lloyd is still working on it.



I define tweaks as anything you do to your system other than maintenance to try to improve sound reproduction. They can be products bought from the original manufacturer or some other company made specifically for your piece of equipment, or something generic made for a type of product. They can also be some homegrown change either you or someone corresponding with you has thought up to try. The nice thing about them is, for the most part, they are either relatively inexpensive or free. They can be undone if they do not satisfy and give you something to do during those long winter nights. Each may or may not work, but hopefully they will not cause harm to the equipment or void your warranty.

Tweaks can be anything from changing position of equipment to changing parts of the equipment's cabinets or feet, to changing internal parts, to changes in the room. There's a multiplicity of them, with an infinite number of combinations. The majority will cause a temporary improvement, but that improvement will usually fade as one realizes that the sound was just different or the change was nonexistent and we had imagined it. A few will cause a significant change far exceeding their cost, and those are the ones to keep. Others will immediately degrade the sound.

Unhappily, tweaking can become a disease, the worst form of audioholism (a new word for Webster's). I have been partially cured, but still go off the wagon every once in a while. This month I have had several come my way for trial, and happily they've all been of positive value.


Homegrown Audio LOK Silver Point RCA's

Homegrown Audio LOK Silver Point RCA Homegrown Audio is the sole distributor for the LOK Silver Point connectors. They state that these are the first locking barrel RCA's to have a 4-9's pure silver center conductor. The barrel is also silver-rhodium plated and the dielectric is Teflon. These are the same connectors they use on their top of the line Silver Lace interconnects. I was interested in trying them out with my Alan Wright designed home brew silver foil interconnects, which I have been using for several years now, (AA Chapter 5 & 6). Alan has always suggested using the lightest RCA possible as he felt that the heavy, expensive RCA's only muddled the sound. So I have used the Radio Shack RCA's usually priced at six for $3.99. For experimentation purposes, I tried several of the expensive ones and have always found them wanting. These inexpensive homemade wires have held up very favorably against some very expensive competitors, and have only been outclassed recently by some I will be reporting on next month.

Having had problems with the Radio Shack RCA's, as the outer ground connector is easily stretched and sometimes the ground contact is weak, this lead to some hum in the system. Also, they do take away from the professional look of the foil and thus I thought I would try the LOK units. The connectors are very well made, especially for their ridiculously low selling price of $17.99 each, or less than $72 for a set of four, and have that professional look and feel. The locking barrel also works nicely to make a firm ground connection. They also sell a 4% silver solder for $7.95 an ounce which melts beautifully, making the building of your own interconnects relatively easy to do.

The solder and RCA mate superbly with the Alan Wright's silver foil. Soundwise, I could find no fault using them on my longest interconnect run. The interconnects sounded as clean and clear as ever and certainly looked more professional. They gave an excellent ground connection, and the center pin was just slightly thicker than the Radio Shack's, so I am sure there was an excellent signal connection as well. Homegrown Audio also sells their own interconnects for very reasonable cost, using solid silver wire, and offers them as a kit at $50 less. With their easy to use solder, the kits should be very easy to do. I have not heard any of their wire yet, but I have seen a very good review and they do have a 30 day return policy, so what could you lose by trying them.


Walker Audio Vivid Disc Enhancer

Walker Audio Vivid Disc Enhancer I have discussed this tweak before in AA Chapter 32 and would not have brought it up again, but Lloyd Walker called me the other night and asked me to try a new way one of his customers had used to apply it to discs - by rubbing in a linear fashion from the center to the outside and back rather than in a circular motion. At that moment I was watching a rental DVD called Endeavour, about the Earnest Shackelton expedition to Antarctica. While the movie was enthralling, the picture and sound appeared second rate. The majority of the movie is of black and white stills and film originally taken by Shackelton's photographer. Odds are the negatives were damaged over the years as the picture appeared somewhat blurry and washed out. The audio was a so-so AC-3 transfer with a well-written score but the sound had no dynamics.

Had not thought of using the Vivid on a rental disc. I was amazed at the improvement. What I thought was a poor transfer turned out to be of excellent quality with marked improvement in both the video and audio. The picture became cleaner and more three dimensional, less washed out, very close to some of the best anamorphic transfers. The film sound score, which can be listened to separately, even in AC-3, sounded super, and I thought one of the best musical movie scores I have heard in a long time. For a couple of pennies, I had transformed the disc. Still do not know whether the new application technique was any better than the old, as it would take me doubles of several discs to try, using one with the old and one with the new technique, but it taught me to always use the Vivid. By the way, it also works superbly with SACD and DVD-A discs, adding more three dimensionality to the soundstage and hall.


Zero Autoformers

Originally, when men were men and high wattage amplifiers were 4-watt flea types, most loudspeakers were built for 16-ohm impedance with very flat impedance/frequency curves. With the advent of solid-state amps, loudspeaker designers went toward trying to improve their output by using 4 to 8 ohm input impedance and became sloppy with the impedance curves. There are actually some out there that go down to 1 ohm, which need a super powerful solid-state amplifier to control. Unhappily, this sometimes leads to less than the best quality sound that can be achieved with high quality low wattage or OTL tube amplifiers that require high loudspeaker impedance to function properly.


Paul Speltz owner of Zero Impedance came up with the idea of matching speaker to amplifier impedance through the use of an autoformer, a single winding toroidal transformer which changes impedance that the amplifier sees from the speaker by tapping off of the winding at different lengths from the end of the winding. If the speaker's input impedance is lower than the amp's output impedance, it will decrease the ability of the amp to control the voice coil movement. The larger the driver, the more control is needed, especially with drivers that have large impedance drops. Thus, flabby bass, and less power. Unhappily, one cannot raise the input impedance of the speaker much higher than the output impedance of the amplifier; otherwise you will lose power transmission to the loudspeaker. He originally developed the units as a tweak for his own self-built speakers with which he was using an OTL amp, which require a high speaker impedance to function properly. He was so happy with the sound that he thought the units good enough to sell on the open market.


He makes two types, an open unit that looks like a toroidal transformer with long leads for $450 the pair and a wooden boxed set for $950 (as seen above). The open unit looked like the better deal, not only for the cost (I am of Scotch heritage you know) but because he includes long leads on both the in and output, thus obviating the need for loudspeaker wires between the amplifier and loudspeakers. I had found that this concept worked superbly with my DRD amplifiers that I had built with long leads from the output transformers. Each unit has six leads, and by varying which two leads are used for the in and output the relative impedance change can be adjusted from x2 to x4.

I became interested in these units for two reasons. First, there had been two reviews on the Enjoy the Music.com™ website by Wayne Donnelly and Dick Olsher and they came to somewhat different conclusions. Wayne had used it with a low impedance speaker and an OTL amplifier, and found the higher impedance that the autoformer presented to the amplifier significantly improved the combination's sound. Dick, using a home-built 300 B SET amplifier, found that while the unit tightened the bass it added a cloud to the midrange with a decrease in transparency. Thus I thought this would be an easy way of determining whether there is an impedance mismatch affecting the sound on my system and how valid the previous reviewer's conclusions were.

Second, the impedance of my mid-tweeter horn combination is actually 4 ohms, while the DRD amps I use to drive them were set for 8, and would take some work to change. Also, I could run my double woofer horns with Plinius SA-50 two channel amps either at 4, 8 or 16 ohms into the amp bridged at 50 watts, or at 8 or 16 ohms two channel, 25 watts each. Thus I could test out all of the combinations easily and with the effect on both the bass and mid-highs separated out, as I had be bi-amplifying.

Theoretically, the optimal speaker impedance should be equivalent to the output impedance of the amplifier's transformer. The lower the input impedance of the loudspeaker relative to the amplifier, the less control the amplifier will have over the drivers -- especially the woofer -- leading to underdamping and bloated "slow" bass. Unhappily the impedance given for a loudspeaker is an average, with the true impedance varying by frequency, with each driver having peaks and valleys. It can drop off sometimes to less than 2 ohms, where most tube and even many solid-state amplifiers can lose control. So, theoretically, increasing the impedance is a good thing.

Unhappily, there is a point where overcompensation can occur. The higher the impedance the more work the amplifier has to do to get the signal through, which decreases the amplifier's efficiency, thus possibly leading to overload and distortion. Second, one is adding a fairly long length of wire and a metal core, which could affect the sound.

On to the experimentation. First I used them on the bass speakers, which are dual Electrovoice 12L drivers into a 50 Hz. six foot horn powered by a Plinius SA 50 two channel amp per side. Normally I run each driver off of a side of the Plinius at 25 watts per channel at 8 ohms, pure Class A.


Setup and results were as follows:

1. Dual 25 watt amps to dual x2 autoformers to dual drivers - 16 ohms.- Did this one using one speaker as I had only 2 of the units.

2. Single bridged 50-watt amp to dual drivers in series - 16 ohms.

3. Single bridged 50 watt amp to dual drivers in parallel - 4 ohms to x2 autoformer to 8 ohms

4. Single bridged 50 watt amp to dual drivers in parallel - 4 ohms to x4 autoformer to 16 ohms.


The Results:

1. Tightenened up the bass compared to running the units without the autoformers at 8 ohms but on very loud passages I did hear what I thought was some clipping that I did not hear normally. My horns are 106 dB efficient, and the music was loud but not jet engine loud, and 25 watts per driver should have been sufficient so I am not sure what was happening.

2. Actually sounded a little worse than normal, with flabbier bass than normal. Maybe running two woofer drivers in series even through the autoformer bringing the impedance up was not the way to go. Perhaps one voice coil was interacting with the other one.

3. This worked very well. Bass, especially the area around 50Hz to 60 Hz., which is at the crossover point for the woofers to the subs, was much tighter, with improved slam. On the Telarc Berlioz Symphony Fantastique SACD run two channel, near the end of the last movement the bass drum and tympani go crazy, and so did my pants, which actually felt like they were flapping in the breeze. This was the best bass I have heard in my system.

4. DITTO. I do not know why bridging the amps to 50 watts is any different from running two amps at 25 watts into two drivers, but the bass was just as firm and tight with slam as #3. On the other hand, I did not hear any improvement over #3, so adding the excess impedance did not improve over bringing the impedance up to 8 ohms.


Next, I tried them on the mid-tweeter horns. Normally these run in parallel with a 4 ohm input impedance off my DRD SET amp with an 8 ohms output impedance. I put the autoformers on the left and right mid-tweeters at both x2 and x4 using its leads as the speaker wire. This produced both good and bad qualities.

The highs seemed to extend higher, almost like adding another half octave to the top. It wasn't just an increase of tweeter volume, but an extension of frequency range. On the other hand, there was a slight veiling of the mid range information, almost like a faint haze between the music and myself. This is possibly what Dick Olsher had heard on his loudspeakers. While I was enthralled with the added frequency range, I could not give up the mid horn's clarity that I had worked on for so long.

In summary, while these units were originally built to mate OTL amps with low impedance loudspeakers, with my horn loudspeakers there was a significant improvement in the woofer's solid-state amplifier configuration, but a mixing of good and poor qualities on the mid-tweeters. For those individuals that bi-amplify using active crossovers, the autoformers may be just the thing to improve your bass. For those very esoteric individuals who tri-amplify, they may also be the just the thing to add snap to your tweeters. They obviously work very well with OTL amps, as derived from Donnelly's article, and may also do wonders for the appropriate low wattage system. If they work for you, they'll be well worth the price.


Comments from Mr. Spelz:


Thanks for spending some time with my ZERO-Autoformers. One has 
to admit, if you like tweaking your audio system, the ZEROs can keep you busy for a while. I think you have broken the record for the most different ways the ZEROs were configured in a single system. Congratulations! I get a lot of guys that like the idea of the ZEROs, with their long leads, being able to totally replace their existing speaker cables as you did.

Just two weeks ago one customer told me the ZEROs "completely trounce" his $6,000 (retail) cables "in every auditory way". Many guys will sell their existing cables for more then the ZEROs cost, so they end up coming out ahead. I offer a 30-day no risk trial period, so nobody gets stuck with them, if they are not needed. You see, the ZERO-Autoformers solve a mismatch problem, but the mismatch needs to be there first, before the ZEROs can come in and save the day. If the ZEROs are placed into a system that is already optimally impedance matched, then all they can do is off-balance the match, and demonstrate what a mismatch sounds like. At one extreme there is flabby bass and higher distortion (under-damped). At the other extreme, the music sounds dry (over-damped).

Because today's speakers are typically so low in impedance, they are typically under-damped by the amplifier. Using the ZEROs to increase the speaker's impedance will increase the amplifier/loudspeaker damping factor. The sweet spot is usually when the speakers are "critically-damped". More info on damping can be found at
at this web page. This also works out well since a higher impedance speaker requires less current, but more voltage, to produce a watt of power. Tubes like producing voltage, but are not so good at producing current.

Since the ZEROs return rate is in the single digits, I have to say the guys that buy them have a good idea that they have a mismatched system. In other words their system sounds a bit flabby or stressed, maybe even compressed or a bit lifeless. They get a big kick when the the ZERO-Autoformers are added in place of their existing speaker cables, and the music firms up and comes to life.

One quick note: If your amplifiers are far away from the speaker, you can keep using your existing speaker cables and bind their spades to the ZERO's spade connectors with an inexpensive set of binding posts. Thanks again for you efforts. I'm glad the ZEROs were a part of the best bass you have ever heard in your system.

Paul Speltz


Company Information

Homegrown Audio Co.
28 Kirk Avenue
Roanoke, VA, 24011

Voice: (540) 767-2600
Fax: 540-767-2601 
E-mail: sales@homegrownaudio.com
Website: www.homegrownaudio.com


Paul Speltz
Voice: (651) 735-0534
E-mail: PaulSpeltz@hotmail.com
Website: www.zeroimpedance.com


Walker Audio
Voice: (610) 666-6087
Fax: (610) 666-5057
Website: www.walkeraudio.com












































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