mike1127

What were you getting interference from? -Mike

Thanks. It looks like a simple project produced good results! The essence of that project is a set of "across the line" noise-suppression capacitors. I imagine it could be improved by adding "line to ground" capacitors, although for safety reasons those are only available in small sizes (4700 pF is the largest). I wonder if ferrites could help, too.

Has anyone here built a line-filter/power-conditioner kind of thing using RFI suppression capacitors? K Works makes something like that, the K Works Silencers, but I discovered that they don't use X2/Y2 rated safety capacitors, which you need if you don't want to kill someone via electric shock or fire. I want to build my own using safety capacitors. For "across the line" capacitors you need X2 class. This will not catch fire and generally will just trip a fuse if they fail. For "hot to ground" and "neutral to ground" you need Y2 class. These are guaranteed not to short. They are self-healing and will open if they completely fail. One might like to use a lot of capacitance, but Y2 capacitors are available at most 4700 pF. On the other hand, X2 capacitors can be obtained up to 10 uF. This stuff can be ordered in qty 1 from Mouser. Any comments welcome. Mike Arcotronics / Kemet Film Suppression Capacitors

Okay, here's my plan so far. Any comments welcome. My big question right now is: what case to use? Can anyone suggest a type of case (aluminum, steel, plastic?) and a source? What size is good? Is it always good to have it large, so it's easy to work inside? Or is smaller better? I've decided to make it a 3-input 3-output box with option to expand. So I'm going to get two 6-position 4-pole rotary switches from Percy Audio. Part 04-2261. Costs about $60 each. I'm also getting six sets of RCAs from Percy Audio. Relatively inexpensive Vampire brand. ($10.50 per set). Initially I'll only install 3 inputs, but leave room for more. For hookup wire and solder, Don is just going to give me some excess he has. Thanks, Mike

Thanks for the help everyone. I agree it is classier (at least) to go with rotaries. Also it would be nice to have three inputs rather than two for future flexibility. In fact I could get a 4 or 5 position rotary and just not put more than two input RCAs in the box for now. Remember these have to be at least three poles rotaries because I am switching ground. Are those the prices you are quoting? How many positions? Also, can someone explain what "decks" are? What is the difference between a 3-pole 1-deck rotary and a 1-pole 3-deck rotary? Thanks, Mike

Thanks, Pars. I was hoping to get a comment on the wisdom of using single-throw switches instead of a rotary switch to select the three output destinations. Instead of selecting on via a rotary switch, instead you would have three single-throw switches which "engage" the outputs. The primary reason is to save money (I'm assuming good rotary switches are $$$). Also, this way you could have multiple outputs engaged at one time, but that would cause my source to see a drop in impedance, so I would probably never do that. Does this seem like an okay idea? Thanks, Mike

Hello DIY guys, I hope you can clue me into good part sources. I want to build a switcher box. I have two sources and three destinations. (My two sources are my CD player and my computer; three destinations are two headphones amps and a speaker amp.) So I want to build a 2-in 3-out switcher. I want to switch ground as well as the signal so that the grounds of my sources do not have to be connected together at all times. A friend of mine is Don North, who is an experienced designer and builder of equipment, and could probably give me all the help I need, but he's a busy guy! I'm going to get info from this forum if I can. Don did give me just a bit of info. He said I could use a 4PDT (4-pole double throw) switch for the two inputs. It has to be 4-pole because I'm switching grounds. For the output he recommended a high quality rotary switch. Okay, my issue with that is it's expensive! Why not use three DPST (double-pole single throw) switches which each connect one destination to the common signal and ground? I could engage one at a time. Engaging two or three would mean my sources see a lower impedance but it wouldn't destroy them. This seems completely safe to me. So what places sell quality parts? I need the switches and I want good ones. I need RCAs (5 pairs). I need a case and I need hookup wire. Don favors silver-coated copper. Where can I get stuff like that? I also need a case for the project and quality solder. I have a temperature-controlled soldering iron already. Thanks, Mike

Hi, I tend to post more on head-fi.org but wanted to chime in on this thread. I'm one of the people who got to hear Don's prototype. Here are my impressions: I have heard several SET amps before, including the Decware MLB and the Wheatfield HA-2 (1?) I never liked them---they seemed too aggressive and forward. That doesn't mean I like a "laid-back" presentation, but I definitely don't like a forward presentation. Why? With a neutral presentation, I feel that my attention is free to move as I wish it to move... certainly musical events grab and hold my attention, but not so much that I feel a kind of "locked-in" feeling where I can hear only what the amp wants me to hear. Because I didn't have a lot of money and time to explore, at the time I settled on the ASL MG-HEAD. It's okay, but not terrific. Don brought his amp over. I got out my K601's and the source was a NAIM CD5x. My first impressions of Don's amp, listening to classical music, were - Sweetness on massed strings. That's a good thing! - Lovely beauty in the ebb and flow of phrasing. Secondly, listening to Mozart's Requiem, I realized that the amp was fantastically high-resolution compared to the ASL. I always prefer the term "high-resolution" to "detailed" because it suggests that the "detail" is honest and in service of the music. At this point, I was wondering if the amp was a bit too "tender" and "sweet", perhaps imposing its character on the music, so I put on a recording of a trombone quartet that I knew had some rockin' attacks. It was amazing how well differentiated the legato and stacco parts of the music were. I have decided to buy this amp. Honestly, I can't claim to be familiar with a broad range of amps and designs, but I feel this is a big step up from my ASL, and the first headphone SET I've heard that does it for me. The K601's sounded way better on the 120 ohm tap. The bass was not underdamped at all. I also listened to my DT880s and preferred the 28 ohm tap with those, at least in initial listening. However, this amp really made me appreciate the good qualities of the K601, such as the wide "headstage" and abundant "air".