Tubes in a Pleasant Mood

Early on in this hobby, I came across a glowing review of DNM solid core interconnects and became curious. I tracked down a mail-order for two lengths of 1 meter, sent a check, and waited a few weeks. When the cables arrived, I was surprised by their appearance - plastic ribbon attached to rather unpretentious RCA's. I ended up using these cables with a variety of tube gear over the next several years. I never tried other cables concurrently, so I have nothing valuable to add here, sorry. A newer version of these cables is still available directly from DNM , and they seem to have a strong following. Anyway, I somehow lost the DNM's during a move, and though it's shameful to admit, I replaced them with some cheap cables made by General Electric. So I've never been fussy about my cabling. Certainly I DO hear a difference, but unless the cable sounds veiled, I tend to just set and forget. Earlier this year, I tried replacing the GE's with the Spirit interconnect  fro...

Designing the layout on a chassis can be difficult, but this is only a step-up device so should be easy. Here are the raw parts: Enclosure (mine is a Hammond 7" x 5" x 3") 2 Partridge mic transformers 4 RCA connectors 1 phono ground post Hook up wire  To put holes into my chassis, I used a stepped drill bit and a Greenlee chassis punch. Morgan Jones recommends a chassis punch for any hole greater than 9 mm. I only wanted the top half of the Partridge cans to poke out, so I chose a 1-3/16" punch. These are easy to find cheap on eBay and usually come in sets like drill bits. To use the punch, first drill a 1/2" preliminary hole with the stepped drill bit. Then attach the punch and tighten until you "snap" open a hole. The hole is actually kind of smooth even without a file (I didn't have one available). Both transformers attached now. I subsequently took a break here and tried to remove ...

Today, I found a pair of Partridge mu-metal core mic transformers labeled "973A". Seller knew nothing about them unfortunately. Well, they're actually quite popular, and a quick search reveals that these have a 1:16 step up ratio. So far I only have experience with Partridge 977 step ups, which I paired a long time ago with Ortofon SPU mono. They're typically pretty grimy appearing - today's were no different: If you are new to these step ups, the two pins already wired together are ground, while the other two have red and white insulation: To figure out which is the input and which the output, measure resistance with your multimeter. The pin with the lower value is input. My pair measure roughly: White pin: 2 ohms dc (input) Red pin: 240 ohms dc (output) The retention brackets were in horrible condition and took nearly an hour to re-place. Yes, I plan to put them in a box. Soon...

My wife recently bought me a Shelter 201 MM cartridge from Japan. Unfortunately, my tonearm probably isn't a great match, so I've put it on the backburner for now. However, reading through the manual reveals the following specs: Shelter 201 Moving Magnet Cartridge Specifications: Recommended Load Impedance: 50kohm This presents a slight problem given that the "fixed stock" input resistance on my phono preamp is set at 270K ohms. I decided to create some loading plugs (easy enough) to change the resistance to the more standard 47K, so when the time comes to mount the Shelter cart - well, you get the idea... Quickly browsing the internet, I came across the following formula for parallel resistors: R = (R1 x R2) / (R1 + R2) If the desired R is 47K and R1 is 270K, we then solve for R2, which should give us the value of the resistor needed for the loading plugs. In my case, R2 is 57K. All that's left is to find two 57K resistors and solder them across RCA...

My wife and I recently spent our honeymoon in Hong Kong. I thought it might be interesting to check out local audio shops. My initial research took me to the Hong Kong Tube Audio Club webpage . In fact, I had subscribed to this yahoo discussion group maybe 10 years ago and forgotten about it. They have a handy guide for the audio enthusiast visiting Hong Kong. Here is a reproduction of their guide map to Central (a district in Hong Kong): I checked out locations 2-6. I was especially interested in #4, Vintage Sound. Unfortunately, this is what I found at 28 Pottinger Street (next door was a tofu shop with a long line): The other locations on the map were now either high-end malls or Omega watch stores. Later that night we took the train to Mong Kok (my favorite part of Hong Kong) to find the famous Tak Fat building mentioned here . That's the Tak Fat building across the street (ignore the "food panda" please) and again there were no vintage audio shop...

I recently changed the output transformers on one of my amps, a Darling with 12sl7 driver. I never felt like I was missing anything with the original Edcor XSE15-8-5K's, but I've been curious about the  Robin Hood series  from Magnequest for a while now. They're probably intended for biamping projects, but I figured the frequency roll-off wouldn't be that noticeable with my full range drivers. After exchanging a few emails with Mike LaFevre, I ordered a pair of RH-60's. The wait was about 2 months. The RH-60's are at least twice as large as the Edcor's, so I had some difficulty clearing out space inside the Darling. Here's the amp with the original Edcor's: Now with the Edcor's removed, new mounting holes drilled, and one Robin Hood installed: Final product: Well, "final product". If you notice, I also changed some of the capacitors to more boutique ones. Ultimately though I was unhappy with the sound - perhaps...