January swap meet and listening session

The January meeting was a lot of fun. Here are some photos from the event.

AUDIO SOCIETY SWAP MEET – JANUARY 19, 2010

Here is a list of Equipment for the sale, if you have something to include send it to me at
cbottemiller@gmail.com

Paul Blizel

Atma-sphere MP-3 pre-amp
Green Mountain Audio Continuum 1.5i’s
Grado Sonata cartridge
Transfiguration Aria cartridge
Speltz autoboxes
GIK bass traps (2)
Records
DiscSox CD sleeves

Glen Cover

amplifiers, receivers, speakers, turntables and misc equipment

Glenn Halvorson

“I will bring some of the tonearms I have been working on.”

Gene Lyle

Apt-Holman Solid State Preamp
Luxman T-110 Tuner
2 Dynaco MK-III Amps w/mods
Dynaco ST-70 Amp (will include ARC mod board at extra cost)
Dynaco PAS2 Preamp
Fisher 800B Receiver, restored.
Fisher 400C Receiver
Scott LT-112 Tuner
Magnavox 460 CD Player w/mods.
Assemblage (Sonic Frontiers) DAC 2
Assemblage Jitterbug
Sony 2251 Direct Drive Turntable w/SME arm
Linkwitz Active Crossover
iRiver H340 MP3 Player
A pair of very rare Genalex KT-88 power tubes
Matched Quad (4) set of Electro-Harmonix KT-88 Power Tubes
Matched Quad set of Siemens EL-34 Power Tubes
Matched Quad Set of National EL-34 Power Tubes
2 Sovtek 6550 Power Tubes
6 National 6DJ8 Tubes
6 Sovtek 6DJ8 Tubes
4 Otki (Russian) 6DJ8 Tubes
2 Kenwood L-07M 150wpc mono amps.

I also have two items that need repair that I will sell cheap:

Sanyo Plus Series P55 liquid cooled Mosfet Amp
Marantz DV6500 DVD/SACD player”

Don Meger

Magnepan MMG’s with outboard crossovers
Magnepan SMGa’s in hardwood frames and custom crossovers
Tube linestage preamp with ultra mods
Music Hall MM/MC phono preamp
Dual turntable
High Output MC cartridge
Audio Tech Nude elliptical cartridge
Sonic Gen II class T amplifier
Madisound DIY speaker kits
Behringer equalizers
DIY remote volume control kit
Sony master remote


Tom Mittelstaedt

MB Quart Quart 2 two-way loudspeakers with stands
DCM Time Window loudspeakers (cheap - needs repair)
Marantz solid-state tuner (cheap - needs repair)
Kenwood solid-state tuner with mechnical scanning (cheap – needs repair)
2 Optonica cassette decks (first “computer-controlled” cassette deck – between the two of them, they’re perfect)
Harman Kardon T60 turntable with arm (works but motor is slightly weak)
Not quite audiophile-quality receiver and speakers (great for out in your garage)
Pioneer solid-state receiver with walnut cabinet and reverb (reverb…reverb…reverb)

Brad Syzmanski

“I have a full subwoofer cabinet, a subwoofer amplifer, a bunch of raw speaker drivers and a large selection of Solen caps, coils and PC boards for two way crossovers I'd like to thin out.”

Chuck Bottemiller

Counterpoint SA-7 Preamp
Harmon Kardon Citation 16 power amp
Speakers (From ASM contest)

Doug Stauffer

Rega RB300: incognito rewire, michell technoweight
various cartridges
Stax Electret earspeakers.
Thorens TD160 (bad bearing = cheap)
MarkAudio Alpair6 drivers

Paul Speltz

Sansui TU-919 tuner
Sansui TU-9900 tuner
Revox B-261 tuner
Mitsubishi DA-F20 tuner
Yamaha T-2x tuner
Sumo Charlie tuner

Robert B Burke

one pair of Coincident Speaker Technology Super Eclipse loudspeakers in their original boxes.
Cherry veneer. Each loudspeaker consists of (2) 8-inch woofers, (2) 5-inch mids, (1) 1-inch twtr.
I recently took some pictures of the speakers, and posted them at http://www.flickr.com/photos/franklin_stove/sets/72157623122889274/

ARC Meeting Highlights

What can be said of our November meeting other than “Wow”! Not only were we treated to a “one-of-a-kind” tour of the Audio Research facilities in Plymouth, we were also the recipients of a very generous donation from Audio Research.


We are very fortunate to have a company like Audio Research in the Minneapolis area. Not only do they make world-class audio products, but also they are willing to open their doors and share their knowledge. They have been a long time supporter of the ASM and have proven it time and again. For those of you who were unable to attend the tour, Audio Research has generously donated a model SP-17 preamplifier to the Pavek Museum for use by the Audio Society

A simple “thank you” is not enough for the members of the ASM to give to Audio Research. The level of generosity and involvement that ARC has shown in our audio society is simply outstanding. The new preamplifier will certainly be a “crown jewel” in our system and be enjoyed for years to come!


Our tour and meeting was led by five key members of the Audio Research team: David Gordon, ARC’s North American Sales Manager, Terry Dorn, President, Warren Gehl, Materials Engineer and Quality Control Technician, Chris Ossanna, Field Service Technician, and Dennis Petrich, Product Design Engineer.

We began with a plant tour of the Audio Research facilities including the Production, Quality Control, Product Update, Engineering, Production Sound Room, Paneling and Stock Area

Production is planned by a three-month forecast. This allows ARC to determine materials and manpower needed for future production. It begins with “board stuffing” which involves preparing and cleaning circuit boards with very specialized and expensive solutions as well as hand wiring and soldering components to those boards. Specialized production workers each focus on unique tasks for each board culminating in a final Quality Control check before being passed on to the assembly area. Once all boards are assembled, they are tested, burned-in and retested before being passed on to the “chief listener” for final review. Once cleared, product nameplates are attached and the item is packed for shipment.

An interesting side note to ARC production is that Warren Gehl acts as the “chief listener” and he personally listens to each product before it is shipped out. This listening includes not only new products, but also products in for updating and service.

Following Production, we were able to tour the Service and Updates department. To show their long-term commitment to product support, we were able to watch a legendary SP-3 pre-amplifier being updated to SP-3C status. Company founder Bill Johnson strongly believed in customer service and support and set up ARC to offer upgrades to virtually any model of equipment ever produced at ARC.

To demonstrate the level of commitment for upgrades and service to its products, we toured the Paneling and Parts departments where we were amazed at the size of the parts inventory on hand. Part of that commitment is the availability of parts for older models and that created a sizable inventory. The Parts department also tests and grades all tubes and FETs. Because ARC maintains documents on each serial number shipped, it is possible for customers to get an exact tube or FET replacement if needed.

Finally, in Engineering, the room was filled with both modern and vintage test equipment. One ASM member even recognized a testing console that Bill Johnson personally used 35 years ago. Given the length of time ARC has been in existence, it is easy to understand why the engineering group has gathered such a wide variety of test gear.

With the completion of the factory tour, we moved to the listening rooms. Audio Research has two listening rooms: a smaller room for service and update evaluations and a large room for new products. The smaller room features Wilson Audio Watt/Puppy Series 8 speakers along and the large room features Wilson Max 2 speakers.

Being the “Chief Listener”, Warren Gehl was our host in the large listening room and demonstrated the versatility of the ARC products with various music selections. Utilizing the CD-8 CD player and driving the Wilsons with the new DSi-200 integrated amplifier, we were treated to a magical experience. The music was very natural sounding and well controlled. If given the opportunity, everyone would have stayed late into the night enjoying the set-up.

After our tour, we met for a Q&A session that included many questions about the new DSi-200 class “D” amplifier. Dennis Petrich, who was heavily involved with the products development offered great insight and offered us a very in-depth technical discussion about the merits of the product and the proprietary ARC technology utilized.

Terry Dorn ended our meeting with a totally unexpected surprise. Audio Research announced that it was donating a SP-17 preamplifier to the Pavek Museum for use by the Audio Society. The announcement brought a huge round of applause from the entire group. The model SP-17 is a current full-featured preamplifier that will provide our society with a state-of-the-art system and most importantly, one that has a remote control!

The Audio Society of Minnesota once again would like to thank Terry Dorn, David Gordon, Warren Gehl, Chris Ossanna, and Dennis Petrich for their time and hospitality. It was a memorable experience for all the members of the society and we genuinely look forward to using the donated equipment far into the future.

ASM Loudspeaker 101 meeting

On December 8 at 7pm at the Pavek Museum of Broadcasting, coincident with the WAM Turntable setup meeting, we will be holding our second meeting for the members-only Loudspeaker 101 Tutorial Series. The topic is Thiele-Small measurements and box design. Please come join us, and bring questions!

In case the interested reader is not familiar with Thiele/Small parameters and wants to brush up, there are a number of resources on the web:
http://en.wikipedia.org/wiki/Thiele/Small
This wikipedia article has a useful description of terms section at the bottom along with some more technical/academic content at the top.
Many more articles on the topic can be found by searching for "thiele small" in your browser.
Notably, someone has posted Thiele and Small's articles from the 1960's and '70s at:
http://www.readresearch.co.uk/html/articles.htm

We may be able to demonstrate several different (see * below) free or inexpensive measurement systems that are targeted at the hobbyist (use a decent quality soundcard). Some examples...

Free:
* Speaker Workshop - http://www.speakerworkshop.com/
HolmImpulse - http://www.holmacoustics.com/holmimpulse.php

Inexpensive:
* Sound Easy - $200-300 - http://www.interdomain.net.au/~bodzio/
ARTA (free demo mode) - 80-150 Euros - http://www.fesb.hr/~mateljan/arta/

More expensive:
Praxis - (Free demo mode) - ~$1k - http://www.libinst.com/PRAXIS.htm

Once T/S parameters are known, box design can commence. At one time people were getting high dollars for box design programs. Many of these programs are superseded in quality and accuracy by free programs. It is quite possible now to design boxes without a financial outlay.

Some free box design/modeling programs that can be used:
WinISD - venerable program, the pro alpha version is more highly touted by users than the older WinISD beta, but the beta version is easier to use.
Unibox - free Excel spreadsheet that uses one universal model for sealed, vented, PR and bandpass enclosures. It is quite powerful, but can be difficult for beginners.
For the technically oriented, many of the design formulas may be found at www.diysubwoofers.org
Apart from downloadable software, there are many javascript calculators out there.

Remember that these models are simplifications and there is a law of diminishing returns on how complex you can make these things. Sometimes simpler is better.

The next few meetings will be held with a shorter hiatus, if possible, and we will characterize the drivers on a test baffle and start thinking on crossover design. We will also need to come up with a final aesthetic concept.

Upcoming ARC Tour Info

ARC Meeting information,

7 PM, Nov. 17th ASM tour of ARC will be at the ARC factory located at 3900 Annapolis Lane North, Plymouth, MN 55447-5447.

Exit 494 to Rockford Road (Cty. 9). Go west on Rockford to first intersection, Annapolis Lane. Turn left (south) on Annapolis. Follow road around behind strip mall to second building in office park. Turn left into 3900 entrance, then immediately right and park in lot in front of building. Entrance is half way down building on north side.

--------------------------------------------------------------------------------

This tour will be open only to DUES PAID ASM MEMBERS!!! If a visitor comes along, they must join the club and pay the $20.00 annual dues to the ASM treasurer to take the tour. NO EXCEPTIONS.

We will meet in the lunch room to introduce our staff to the ASM group. They probably will talk briefly about ARC history and current products. Depending upon group size, we will most likely split into 3 smaller groups of about 15-20 people.

Group 1 will go on a factory tour. The group will see the Production, QA, Update, Service, Engineering, Production Sound room, Paneling and Stock room areas. The idea will be to follow the flow of a product through the production process from board stuffing to shipping.

Group 2 will go into our larger development sound room for a listening demonstration. We have CD and possibly LP as music sources. We will play certain preselected music that highlights some aspect of the ARC equipments' performance. If time permits, we may also allow some requests from the group to be played.

Group 3 will discuss club stuff in the lunch room until the one of the first two groups returns.

We will rotate all groups, so everyone gets a tour and sound room experience. At the end of the tour, we will all gather in the lunch room again, where light snacks will be served, and any additional questions will be answered. Each person will be given an ARC literature package.

We would like to wrap up the tour at 9:30 PM.

Chris Ossanna

October 2009 Meeting-Turntable Setup and Optimization

The Audio Society of Minnesota would like to thank Wally Malewicz of WAM Engineering for such a great presentation on turntable set-up and optimization. Wally is always entertaining, and all would agree that he went out of his way on Tuesday night to make a complex issue very entertaining. Thanks, Wally!

-----------------------------------------------------------------------------------------------------------

Turntable set-up can be a daunting task. Let’s face it, our heads spin when faced with such a volume of acronyms. VTA, SRA, VTF, AS, zenith, azimuth etc. Setting up a turntable can be scary. By using humor as a foundation, Wally was able to explain and demonstrate each acronym and why it mattered. To compound the complexity of the discussion, the meeting was filled to capacity with users who needed answers. Beginners wanted to learn about fundamentals. Advanced users needed details. It didn’t matter; Wally handled each question without losing stride. Other than his Russian jokes, Wally kept the crowd fully entranced far into the night. In the end, all left happy and eager to go home to adjust their turntables with their new-found knowledge.

We have posted photos from the meeting as well as providing links to the articles Wally referenced during his presentation. Please take time to browse the page and take a look. The close-up photos of our Grado Reference cartridge are of special interest. One look at those photos and you will be online buying a USB microscope within minutes.
It was the use of an inexpensive USB microscope to assist in SRA/VTA set-up that drew the most attention at the meeting. With the microscope focused on the stylus, Wally was able to demonstrate the proper way to dial-in the Stylus Rake Angle (SRA) and Vertical Tracking Angle (VTA). Up until now, that has been done by ear alone. With the aid of the microscope, this angle can be definitively set and only tweaked by ear. Our system was a great example. By measuring our stylus angle and adjusting it by only one degree, the sound opened up and became more well-defined. In short, there is a very small “sweet-spot” for the SRA setting and the chance of doing it by ear alone is a formidable task. With the USB microscope, it was spot-on within a few minutes.

We always welcome Wally’s presentations and he certainly hit a homerun with his latest discussion. His insights are always informative and we look forward to seeing him again in the near future. From the members of the Audio Society of Minnesota, a sincere thank you.