Elmaformers

It is such a task for people (including myself) to solder the $400 autoformers to a switch so I am doing a circuit board that wires them directly to an elma switch.

While not being the smallest of finished items, it fits together nicely and can stack for as many decks as needed which makes true balanced operation a breeze.

This is a simple two deck "proof of concept" on proto boards with a 24 position switch that can have any desired taper you choose.  They will wire up lust like a traditional pot with In, Out and Ground connections for each deck.  I am so happy with the results I am planning another version on the 47 position switch that can have 1dB steps.

From Russia With Love

So I receive a belated holiday present from a friend and it comes in a box with cyrillic letters on it so I get a bit excited.  When I open it, my first thought is why the hell did Fred get me an ugly red sweater?

Upon closer examination I quickly realize that there is something hiding inside that sweater.

Ahhhh,  now I feel much better but I am still really confused why this sweater used as packing has no armholes.  This naturally brings me to the conclusion that this isn't a sweater but a Soviet Era method of packing valuable tubes.  (take that eimac!) While the boys were having fun playing with the "armless sweater" their mom comes in and asks why there were playing with a skirt? We all need to go out and mow the lawn now.... or work on the car.... or something.....

Random says 10

Random picked 10 as the winner.





drop me an email with your address and they will find their way to you.

dave

Freebruary

Just got these back from a vendor and they need a new home.  They are the current modules and have a cheap pair of interconnects soldered into them for a quick audition.  I'm leaving them as is and it is up to the lucky winner to decide what to do with them.

Leave a comment below with an identifiable name and Random.Org will pick a winner in a few days.

Micro-Bomb

I finally sourced some MuMetal cans that are big enough to house the SUT's.  Two of them will fit together to house a pair and a band of adhesive backed mumetal holds them together nicely.

While not exactly small it goes a long way to getting the required shielding to package these things up.  Simply add a steel box,  some RCA's, solder and enjoy.

dave

Music Maker - Stevie K with a 16a

.

so my friend steve... no, not that steve with a 16a from North Carolina... this Steve... lives in a quiet little town... nice sunsets... small farms... and he is that guy who hears the records calling his name from every Goodwill he drives past.. which was a great very many as he drove quite a bit for work... now he just feeds his cows and spins those records... so he bought a new music system for all of those records... yep, another Western Electric 16a in North Carolina... and GIP 555w drivers..... which are beyond amazing... 

and Steve is a super hardcore DIY'er.... DHT line stage... DHT amp with DHT driver... built it himself!  and it sounds great... just fabulous... and he built the "Bass Base" for the 16a... check it out!

proper way to clamp

expansion shown with bracing every eight inches - super important!

walnut ply looks good

*live* Muddy, Chester, Buddy, Sonny Boy!!

NERDS!

 how is that for documentation?

and packaging...

these things sound absolutely stunning.. and remember, I have originals... contact me if you want to hear some.. 

Hey Furby!  You look like a sheep!!

peace,

me

Drug thru the Kongeå

It is ETF time again and this year the promoters took into consideration 'Birthday Month' so Jackson and Slagle are going with mercury and nickel.  This year the competition is for a preamp power supply and 16 different designs will have at it.  Of course a little pandering to the judges always helps!

Tiny Coils

I thought things were getting a bit out of control when I was seriously considering mounting a microscope on my lathe.  Never mind that I am attempting to keep 0.01mm precision and doing other silly things like spending $16 on a 0.2mm diameter cutoff wheel for a dremel.

Seems like 1997...

Dave is testing Sovtek 6B4G's and building push pull amps.... Dear god say it ain't so.

In his defense the DHT's are replacing triode wired EL-34's and the outputs are 49% nickel (soon to be 80%)

Big (ger) Amorphous.

The old "Big Amorphous" cores have been downsized.  They were perfect for a 10W from a 300B or a 75TL but the requests for 20W at gobs of current keep coming in.  Sure I can gang up multiple cores or add an offset winding but the winding window gets small quick. 

 

 

The new option takes up a 6" cube and stay tuned to see what gets built from them.

A nice small system.

Not everybody has all kinds of room to dedicate to audio and one of our friends put this together.

I really like the way things are laid out and the use of steel and wood for the rack.

CAF

Back and recovered from the Capital Audiofest.  This year we continued to bring things that were different and had no possible chance of selling.  This time the main difference was presentability.

I'll admit it looks a bit like a late 90's projection TV but there is a reason for this look.  Once you step around back you see the 'direct drive' power amplifier neatly tucked into the base.

 For this round it was Push Pull triode wired EL34's and while this isn't technically a "direct drive" amp,  I have not come up with a better term.  The two interesting Key points are the panels are biamped through discrete step up transformers loading the EL-34's and the crossover is in the amplifier circuit allowing the transformer direct connection to the panels.

The cabinets are Walnut with some bloodwood inlay and there are a few other tricks going on inside.

The two biggest comments at the show were along the lines of 'I thought quads didn't have any bass' and 'who says quads cannot go loud'.  It was mentioned on some of the forums that we only seemed to play things that showed off these two points and neglected to play the girl on a stool with a guitar that quads are known for.  Oh well... we can change that for RMAF.  Check out what Herb has to say at the link below.

Herb on the ESL

Binaural

This is another one I haven't seen before.

  

This nicely pigmented album only appears to have two tracks but in reality it only has one since it is a binaural recording which requires two cartridges to play it.  This means you need a tonearm with two headshells,

The arm appears to work like a linear tracker and may have been the inspiration for the Garrard zero 100.  Here is a crude video showing it in action and some liner notes.

B is for Boron

Best taken in 4.4mm doses.

High Current

Lets pretend I have a friend who is in need of some 2.5V @ 25A filament transformers.

It seems you can scour the world and not find an appropriate beast when in theory it is really a pretty simple job.

Simple... Just take an $18 100VA antek toroid and pull off the secondary.  Then all you need is 12 turns of #9 wire and you are done.  Since the final use needs to do 2.5V @ 25A * 2,   I was a bit concerned that the extra 25VA over would be problematic.  My first go was using some #10 wire I had which gave me 10 turns for an experiment.  The next problem was how does one draw 25A of current?  since I didn't have any 0.1 ohm 100W resistors I had to make due.  Luckily in my junk bin I had a 10 pound spool of #20 nichrome wire so a few inches should do it.  Well, that got really really hot really quickly but three strands in parallel about 8" each did the trick.  The #10 showed promise but I was a few turns short so off to the "home despot" I went to get some #10 stranded house wire for round 2.

The stranded wire was a failure.  First, the nichrome wire gets really hot and copper being a good conductor of heat gladly wicked the heat back into the transformer.  For kicks I was able to flow solder into the junction of the two and the first few inches of copper got so hot that they could cut styrofoam through the insulation.  In reality, I suspect the #10 would have been fine but since I was already pushing the VA rating I decided to go for #9.  Luckily I have a few spools of #12 and a twisted pair of 12's = a single 9.

The black flecs in on the core are nichrome flakes from the making of the video but I have run the unit for an entire day with both windings drawning 25A  and it didn't get hot enough to concern me.  As an added plus the voltage didn't change as the units reached full temperature under load.

It is a bit of a shame that the #10 didn't work since apart from the "home despot" green, I also have three different types of #10 Litz wire.  Just think of all of the Audiophool Hype you could come up with as you painstakingly strip 420 strands of #36 per connection.

Audio Intersections.

I had the fortune to visit a house a few hundred feet from this intersection and thought the names quite fitting for audio.  On this visit I saw a few interesting things the first being this amp.

 That Marantz meter is really telling of the specialness of this particular amp.  This was the prototype for the Marantz model 5.  Another really cool thing was this 7C.

 The collector would probably scoff at the labeling on the back but this was Sid Smith's 7C so I suspect an exception could be made.
  

It also represents a relatively low serial number which adds to its coolness.