Monday, April 20, 2015

Solder Bars

I was getting a bit low on bar solder for my leaded solder pot so off to the 'bay I went.  The first purchase was 12 pounds of Alpha-Solder.

Unfortunately upon getting it I quickly realized it was lead free with a small 3.5% bonus.

Back to the 'bay for some good old fashioned lead solder and without thinking I bough these.

Now I have a bar of 60-40 and a bar of 55-45 that I don't have the heart to melt down.

Oh well.... To the 'bay batman....

Friday, March 27, 2015

New Toy

I always found it frustrating to be working with an automated limit of ~90Kz from my 192 sound card since the good stuff, particularly with SUT's always seems to happens above 100kHz. 


I have seen the Velleman pcsgu250 with its claims of Bode plots to 1mHz for some time and asked about experiences on a number of forums with no response.  I finally sent $150 to newegg last year and procured one.  Flash forward several months and i took some time to rewrite my excel macro's to import the data and I must say I am quite happy with the results.  Sure it is no Audio Precision but it is a million times better than manually entering 100 sets of coordinates per trace on the test bench.

Thursday, March 19, 2015

Name that SRA.

I'd call it close enough to 92 degrees but the sound wasn't the greatest.  It was sounding really good until things abruptly went bad and a quick visual inspection explained the problem.


Note to self... hot glue and field coils do not play well together.

Sunday, March 8, 2015

Hudson Valley hiking in March...

means hiking *on* the river...

as you know I moved to the Hudson Valley from Memphis before last winter... quite a weather shift... I heard from locals that last year was the coldest they could remember in decades.. "what winters used to be".. or "what winters are supposed to be"... it was cold... well, that was before this year came... we set a record in February - average temperature = 9 degrees Fahrenheit... not average low... average *temperature*.... whew... but you know what?  it is good for working.... and this past Friday when the sun came out, having long eclipsed forty hours in the shop, a few of us took off for a hike in the sun... it was wonderful...

we started off from the house.. hiked down Burget Creek... then onto the Hudson.. all the way down to Catskill Creek... and finally back to the Mill to finish up the day's work...

notice the crazy ice breaks.. the Hudson is tidal... and that makes for some really cool ice breaks...


obligatory HiFi Heroin photo:


Friday, February 27, 2015

finally got his 16-A....

... and Elmore James has never sounded better... 

initial placement

it is a Subaru thing

road trip!

yep... pile o' parts

random barn photo

final setup

repro 16a (better bends than any original I have seen)
original WE555's, single Coral tweeter
rebuilt amp (globe 50's), 416's bi-amped

shocking how good this sounds... you just sit there with your mouth agape... 

so much detail.. transients... and then you end up dancing!

*so* much fun....


Wednesday, February 18, 2015

Round Plates

This is a circa 1990 Alessa Vaic copy of a Marconi R-type and it has that beautiful round plate structure we have grown to love. 

Unfortunately the tube has no emission and the real purpose for this post is behind the tube which is a set of iron for another round plate tube that does the R-type X 4... the 304TL.

The bigger ones are the SE outputs that can take 200ma of plate current while putting out 40 watts at 50hz.  They have bandwidth (-1dB) from 7hz to 49Khz and can do all of this due to the offset winding that runs the 12.5A filament current through the outputs in the opposite direction as the B+.  This brings the other two chokes into play which are the 20mhy 12.5A filament chokes that keeps the offset winding from loading down the tube.

The set of 4 weighs in at 46 pounds of copper and amorphous and boy am I glad the topic of silver never came up.

Sunday, January 11, 2015

DIY Western Electric 417A Kit.

 A four+ year ebay hunt finally payed off when I bagged this little gem.  I first saw one down in DC at mikes place and from that moment I needed one.    According to mike, they made these at the factory and used the vacuum pump to get all of the air out.  The pics below are from some different angles so you can see all the parts.