LM4780 Balanced Dual Mono-Block Amps

Bought the dual mono LM4780 kit from Peter Daniels’ @AudioSector.com and received it in the mail the other day. I’m excited, because the National Semiconductors’ LM4780 chip package allows for easy implementation of a bridged/balanced configuration of differential (e.g. balanced XLR/TRS) inputs from professional level sources. Most “pro” grade equipment uses XLR as it allows for longer cable runs and provides a greater degree of noise and signal interference rejection.

On my EMU 0404 USB DAC I’m forced to “balun” from the TRS output into the Denon PMA-850’s RCA line input (note: in this configuration I’m using the EMU 0404 as a pre-amp as well). Sadly the PMA-850 has been blowing fuses and has started to sound muddy and as much as I’d like to pull it apart it’s full of 1970s Japanese solid state circuit technology that I wouldn’t feel comfortable playing with. The LM1875/LM3886 & LM4780 [etc] packages (aka Gainclones or Chip Amps) have a really simple circuit topology and as a result have become really quite popular over the past decade in the DIY audio community.

So I’m excited to finally do some soldering and enclosure design for this kit. Also, I was able to breadboard a slightly better power supply circuit for the EMU 0404 using a LM317 chip; I have a decent 7.5V DC 2A wall wart that I could use to feed the LM317 and then down-regulate to 5V DC 1A for cleaner audio. In my tests, using a bank of D alkaline batteries, there was a definite increase in clarity. My one concern with the EMU 0404 is whether the USB is galvanically/transformer isolated from the line outputs, as I’m sure the USB out of the Mac Mini server is not great for noise. Again, in my limited tests, the external linear regulated LM317 power supply using both USB and Toslink SPDIF inputs improved bass and high-end clarity.

Also, I’ll probably be adding some speaker toe spikes to the old Advent Heritage tower speakers. I found some cheap ones @Parts-Express, $0.48 each. Not bad.

Sam Catch's Gainclone build, Back - on Flickr

“Gainclone build BACK” by Sam_catch, on Flickr (CC License)

lm1875set4 by Nonexistence, on Flickr

“lm1875set4” by Nonexistence, on Flickr

Large Cryptographic Hashes with Whirlpool and a myriad of coffee brewing methods

Who doesn’t like a nice long 512-bit message digest to confirm that the file they’re opening is secure? Cryptographic hash functions are one method of verification to insure file integrity between two parties (or as a signature or authentication code). The most commonly used hash verification is MD5 check sum (proven insecure). Apple uses SHA-1 for it’s package update manager (also likely insecure). But if you want to get deep, go with Whirlpool, and I’m not talking about appliances here, I’m talking about 512 bits of hash (the authors, Barreto & Rijmen have a page here). Ironclad and md5deep are two easy to use packages if you’re looking to implement Whirlpool under most *nix and Win 32/64 systems.

In coffee news, here is a nice webpage devoted to a myriad of coffee brewing methods: http://www.brewmethods.com/


Image via USGS National Center for EROS and NASA

Latte Swirl by Flickr member Mr. Pauly D

Latte Swirl image by Flickr member Mr. Pauly D

Big Wheels Keep on Turnin’

Put a deposit down on a “semi custom designed” / “semi crowd-sourced” metalic white Snekka model (700c rough-stuff randonneur style). The frames are from Rawland Cycles based out of Northfield, Minnesota and are being TIG welded in Taiwan. Having visited both Taiwan and the State of Minnesota, I’m excited to support each in their own respective rights. I was looking for a new “rough stuff” type frame and was seriously considering the Surly Cross Check, however, I really wanted a taller stem height and I think the Snekka will be a good compromise between off-road ability and touring, plus it’ll have a nice back story.

Snekka Geometry Chart

Awesome Nerdage

The NYTimes had a good article about a Brooklyn based father and son team who launched a weather balloon with a small HD Video camera up to 100,000 feet (their site: brooklynspaceprogram.org).

Homemade Spacecraft from Luke Geissbuhler on Vimeo.

And in a similar vein, Wired has an article about the creation of “hand made” computers within large virtual video games. The idea being, using virtual building blocks from these worlds (and components with special properties), entire computing machines can be built (virtually).

Win some lose some

Some people are upset, horrified even, by change. Others simply want to be able to carry handguns into drinking establishments. Two logos walk into a bar, stop me if you’ve heard this one… (here’s the interview). Gawker explains it pretty well, and you can even create your own at craplogo.me. Other times it’s a good idea to check underneath your car’s exhaust and in the engine compartment for tracking devices, especially if you’re Arab American. Also, before you go out and look underneath your car, why not clear out those 3rd party tracking cookies Macromedia Flash has on you? Godspeed.

New Logo for The Gap
FBI Tracking, older model

NPR All Songs Considered –
Best New Electronic Music

A few tracks stuck out from NPR’s All Songs Considered – Best New Electronic show. My three picks are below, but you can go to the show’s full playlist here, while the embedded tracks below from NPR also require Flash.

EDIT: I’ve added SoundCloud.com links where possible above NPR’s Flash player, they’ll take you to a Safari HTML5 version on SoundCloud.com’s site of these tracks.

Danish Jatoma’s “Little Houseboat” out November on Kompakt:

UK based Mount Kimbie’s “Carbonated” from the album Crook’s and Lovers:
Mount Kimbie - Crooks & Lovers

And finally, LA based TOKiMONSTA and her badass track “Sa Mo Jung 思母亭” from her new release Midnight Menu:
TOKiMONSTA - Midnight Menu

Turning and turning in the widening gyre

The ’70s are ripe. Nature, nurture and nudity. I’ve had these music videos in the back log.   First up (via Molly) Spain’s El Guincho and his track Bombay.  NSFW (Not safe for work in Protestant countries guided by God) though in Spain or Sweden you’re probably safe as it’s mostly like a disco trip with Luis Buñuel and some nude ladies.

EL GUINCHO | Bombay from MGdM | Marc Gómez del Moral on Vimeo.

This music video has no nudity and features a song by UK band Summer Camp that is cut from the classic “A Swedish Love Story” aka “En kärlekshistoria” released in 1970:

SUMMER CAMP – Round the Moon from Paddy Power on Vimeo.

Or if you prefer the band Thieves Like Us this is their music video Shyness cut to the film:


The original trailer for En kärlekshistoria will of course make you cry sad teenage Swedish tears, with Staffan Stenström singing:

And a few related links about this film: