A great deal of thanks go out to Mike Galusha and his wife Mary for hosting this small get together. More thanks go to Mike Smith for sending out the Altmann for audition. Thanks to a third Mike, Mike Garner of TweekGeek for bringing over the Mark & Daniels speakers. These are VERY special!!. I highly suggest that anyone who can audition these speakers.
mgalusha covered all the broad topics of the listening sessions in his first post. I will get into some details. First, I do want to state that I am a dealer and the manufacturer of some of some of the products under discussion. My thoughts and viewpoints are therefore biased.
I will try to keep my comments factual and report on what we heard, however my personal bias about certain things will certainly come into play and may irritate some parties.
I was the first to arrive. mgalusha moved out onto the eastern plains some time ago. His new house has lots of room, open space between him and his neighbors and he can see the stars at night without having them washed out by the city lights. He is also close to fifty miles east of where I live. I think it took Mike Garner close to an hour and a half to get there.
mgalusha has changed his system a bit since the last time I was over. He is now actively bi-amping his $14,000.00 a pair Meadowlark Blue Heron 2s. He has a Rotel power amp running direct to his woofers voice coils. No passive crossover parts in the way. He is using a much modified Marchand XM-44 active electronic crossover before it. The amps driving the mids and tweeters are REI Designs LNPA.
The room is very well treated with products from GIK Acoustics. When I first arrived, mgalusha was running the output of the Altmann DAC into a tube buffer/preamp he recently built. He was contemplating using that, as it had an analog volume control built into it, to match levels to even the playing field between the different products. Unfortunately, it also made it's presence felt in terms of the sonic signature. It simply wasn't as clean as the Altmann or SB direct into the crossover. The Marchand does have level controls on the front panel, so it was fairly easy to adjust the controls for the 6db difference in gain between the DAC and the modded SB for comparisons. The tube buffers was removed from the system and all the rest of the afternoon the outputs of the components were run into the crossover or direct to the amps.
mgalusha pulled the 12VDC battery from his lawn tractor to first listen to the Altmann DAC. When he invited me over, I mentioned I had a couple of 12 VDC 5Ah SLA batteries. I offered to bring them over for ease of comparisons. I charged both batteries overnight, tested then with a Monica 2 DAC I had and then topped them up before heading out east.
I also put together some cables that I thought would help in making comparisons of power supplies to the DAC. I assembled a cable with push on connectors that would fit on the SLA battery's terminals, this went to a male XLR connector. This is the same connector I used for DC output when I built my prototype 12 VDC power supply. I put together another cable with a female XLR that could be used to connect to the SLA battery or the AC powered supply. The end of that cable was made with alligator clips. This was what mgalusha suggested as the cable to the Altmann was terminated with ring terminals. After think about this, and some rooting about in my parts bins, I came up with a pair of Vampire binding posts. These do not keep the nut captive on the posts, so the ring terminals can be tightly fastened down to the posts. I installed a pair of banana plugs on the ends of the DC wires to the Monica 2 board. I also found some slip on connectors and ring terminal that would fit on the binding posts to allow me to add a capacitor bank to the DC input to the DACs.
(Digression #1: Some time ago I was working with battery powered Tripath amps. To my ears, the sound improved quite a bit when some capacitance was added after the battery, before the line reached the board. As magusha points out in the first post this reduces the impedance of the power supply and improved the power delivery speed. The cap bank was made of various values and types of caps. The overall value came to something around 13,000 mfd with some film caps added as final bypass.)
I also brought over a prototype 12 volt supply I made some time ago. (Digression 1.5 :This was an experiment to see if a very good AC based supply would sound better than battery supply when used with the Harmonic Technology CyberLight interconnect cables
http://www.harmonictech.com/products/cyberlight_p2a.html . TweekGeek brought a pair of the analog interconnects over to a previous listening session and I was quite amazed at how good they sounded. After looking the cables and power supply over, I though I might be able to make them sound even better if I used the same design of a power supply as I used in the Ultimate PS for the SB. I finally built one and tried it out. It was quite a startling improvement. Anyway, the prototype was what I brought over to compare with battery power for the Altmann and Monica 2.) I also brought over my personal CyberLight 1.5 meter digital DataLink and an XLR "Y" cable so I could power both the CyberLink and the DAC from a single supply, either battery or AC.
mgalusha and I listened to the Altmann for an hour or so off of the tractor battery and compared it to his highly modded SB2 powered off of his version of the Ultimate PS MKII. We played around with firmware and polarity of speaker cables for a bit until we could easily switch between the sources without having to swap speaker cables about. We had a bit to eat for a light lunch and then TweekGeek finally arrived.
The three of us sat down to try to compare all the variations of power supplies, cables, sources etc. First up was the Altmann. It was listened to running off the SLA battery with the digital cable that came with it. The cable appeared to be an Alphacore RG-59/U 75 ohm coax with an RCA connector on one end and a BNC on the other with a BNC to RCA adapter in place. The sound was very smooth with a slightly recessed high end. We compared this to mgalusha's modded SB2 and preferred the SB. It was more extended on both highs and lows. More dynamic and provided a deeper and wider soundstage. It was easier to hear the "air and space" around the performer.
We then switched the power supply to the Altmann to the AC. We also changed out the digital cable to one offered by BOLDER Cable. It had the Silver WBT RCA connectors on it. For comparison sake, it retails for around $200.00. There was quite a change in the sound of the Altmann running off the AC supply. The highs came clear and the soundstage and depth improved. To determine what had the bigger effect, we changed back to the stock digital cable. With the JISCO circuit off, it was very easy to tell the difference between the two digital cables. The BOLDER sounded clearer with more detail and dynaimcs. With the JISCO on, the difference was VERY subtle. I could tel the cable was different but it was not really THAT different. The JISCO circuit does reduce the difference between digital cables at this level.
(End of Part One)
