but I do have some Friday curves for you to ogle...
First, just a picture of the remote Passive Aggressive I need to box up and ship out. It was done in a more traditional form factor to fit a rack. This design also leaves plenty of room for future expansion into line level crossover parts.. so it is sneaky evil...
Next is the real excitement. I flipped when I saw these pictures of the 75tl close up. It makes me want to learn a little more about proper photography to document some of these beauties. Sneak peak here:
Got the original field coils back from Johnny who decided to take them from high voltage to low voltage for safety reasons. This means I needed to crack them open and remove the 22,500 turns of #30 wire from each. While unwinding them a new beast came to life and in case any of you have ever wondered what 6.5 miles of wire looks like I introduce you to Wire-Man.
The two things on my hands are the pole pieces of the motor structure and only yesterday, all of this wire was neatly held in place. I originally wanted to introduce you to Iron-dog but I quickly found that was a really really bad idea.
For reference jeffrey was kind enough to offer a similar treatment with the size of wire they will be rewound with for LV. I'll let him tell the rest of that story at another time.
My entire front end is on the west coast. They are doing well, but I miss 'em. Both phono and line are traveling about. I was ok with this as I needed to work on my whole music server digital rig, BUT.. BUT.. I hit a snag. My ten year old (sweet sounding) dac doesn't like driving the autoformer volume control directly. Its output impedance is way too high. I tried the op amp analog outputs on my Rega Planet that has been my trusty transport - I kinda gagged a little bit - Awful. So I cobbled together something that turned out to be a real beauty.
It is just a line stage. However, it has a very high input impedance and will happily drive the autoformers. The sound is just as I remembered. I love those tennis balls. They have some nice gapped nickel on their plates, of course. Oh, and mercury... Tomorrow I will try it as a strain gauge supply... WE tennis ball strain gauge supply... pure evil... three tubes needle to speakers.. and all directly heated triodes..
I had a freakish goodwill experience the other day. I have been looking for a number of titles on ebay and constantly getting out-sniped. When I went into my local thrift to look, from 30 feet away I saw this.
Stupidly thinking I was in a movie, I sprinted to avoid all of the other fanatics and dove on it first. It was clean enough and I was dreaming about what must be below. Could I find all of the music of my young adulthood? Sadly that wasn't the case and it cost me $8 for my prize and 6 other things that need to go into the "needed to be cleaned" pile which as the lyrics say "push it along".
I think it is time to introduce a new repeating post to the Blog - MMM - Music Maker of the Month. The goal is not to show who had the best, we have already moved well past that. The goal is to present systems that meet that magic threshold of getting out of the way. With these systems, you hear music, not the system. Do they have issues? Sure. Do they make music? Absolutely.
So enter Mats. Mats is one of my heroes. The man has two walls of vinyl. And a seriously thick section of those orange and black 1960's Impulse artists that I like. Those Impulse pressings are the perfect example of not being the ultimate recordings, but very full of music. Mats has two turntables up and running... a five way system... four of the five are horns... he is quad amplifying with line level crossovers.... Mats even has true 20Hz horn bass with an old tapped horn of mine from years back... keep in mind that all of this is in a city apartment!
Mats is also my healer. How he knows what he knows, I hope to one day understand. He has somehow moved past what most of us think (worry?) about on a daily basis and moved to sensing the pulse of the universe. From more than 500 miles away, the man can correct my ailments from inflections in my voice. Fix my diet even though he has no idea what I am actually eating. and then there is this:
He cannot know that for years now my favorite reply when Lisa gets onto me about not sleeping enough is "I'll get plenty of sleep when I am dead."... And yet this is what shows up in my inbox from Mats. I often tell people I subsist on solder and coffee... and speaking of, on this Monday morning that the heat in Bessie (my old volvo wagon) decided not to work, I am ending this post and headed to the kitchen for second coffee... then to solder...
Been working on various ways to shield SUT's over the past few years and I must say mumetal is a pain to work with. It cuts nicely with a paper cutter but getting holes in for RCA's and such is no small task. I went to the local hobby store and bought some 1/32" birch with the idea that adding some support to either side would allow it to be drilled easily. As an added plus the 1/32" spacing gives a nested effect.
The mumetal I had already has adhesice on one side and some simple spray glue kept everything together. It still has some wiggle but i'm sure all that is needed is some permanent glue. The most interesting thing about it is the result of the "rap" test. Unlike normal plywood which is quite lively, this stuff is surprisingly dead.
My old dual lambda PS has seen better days. I was testing some 103 concepts and the burn from the finger test on the coil made me mad... no it made me angry! While watching channel 103 heat up, I figured channel 2 would be fun for some play so onto the story.
It is really odd how some things happen. I was debating if I should give the update of what is new and I even went as far as trying to take a picture. Since Marvin tried to put his better half into the picture I just felt the natural progression is to go with it. (pay no attention to the duct tape just out of frame)
Aside from that gray furry tail hot glued in place, this is another Field coil project that JJ and I are working on.
JJ's mention of the switch to the aa strain gauge has me inspired to let another cat out of the bag. I will be ordering up parts for a simple pentode riaa that we have been dreaming about and it is time I revisit the traditional riaa camp to keep myself grounded.
I am floored. My blacksmith came through town yesterday. The passion was evident in every aspect of his work. We have just been talking via email about the stands for the big horns (Exhilaration III - in the works for years now, but finally close). I had no idea of his depth of work. I knew he held the same ideals about quality and craftsmanship that I did, but I am just stunned at his attention to detail.
Check out the lacquer on that half inch thick, twenty pound chunk of bronze... multiple coats... wiped back... worked the edges to show the bronze.. and the engraving is simply over the top.... Then he said they were working on the CNC, so he just experimented by making a few badges. Acid etching.. engraving... heavy... These are definitely where I am headed. We both spent hours and hours studying the 1920's radios I have around here. The attention and thought are in every joint, every fastener, every finish. Look for some new chassis from me soon, half rack width, inspired, as always, by the past. Likely the DHT strain gauge supply will be first.
and now to the horn stands.... I will upload some profiles and 3-d drawings soon, but for now examine some of the detail work on this horn support. I totally agree with his assessment that we don't want to hold up those mahogany midrange horns directly with metal. Something more organic is required. I have used rope in the past, but this leather strap is totally the way to go. It is extremely thick, cut to the horn angle, and sewn together in a nice, heavy, double layer construction. It reminds me of well-made saddles - strong, tough, and designed to task. It is then attached with brass rivets to a pivoting steel connector, patina''d, of course. The stand itself will be this triple steel construction. Each steel outer edge is brass riveted to the inner truss-work. Heavy, solid, simple. I can't wait!
I am the cover model for the triode mafia. All triodes, all the time!... Use a pentode, go to jail!... and then it happened... on one of the many long conversations dave and I have while working late night, the conversation turned to why anyone would ever use a pentode. We inadvertently made a list not only of what triodes do better, but also a list of what pentodes do better than triodes. The two that are very obvious and very big are that pentodes are several orders of magnitude easier to drive, and that they have lower distortion driving low impedance. Guess what? This is exactly what we need to drive an LCR RIAA circuit.
I have now compared in two different circuits - IT coupled (yes, IT coupled pentodes!) to an S&B 10k LCR and also nickel plate choke loaded and direct coupled to a teflon and nickel Intact Audio LCR. In both cases, it was not even a contest. I am a believer! Much more music! When you find yourself enthralled with the ballads of Art Pepper as much as the hard cuts, you know you have found it. Critical comparisons stopped being critical thirty seconds into each band.
So add phono to the list of things that I do not think will be revisited anytime soon. DHT linestages with nickel 1:1's and nickel autoformers - check! stacked supply direct coupled amplifiers - check! pentode phono front end - gasp - check!
oh.. and no wondering where the chassis style for this one originated.... It is funny though, as I originally built this phono years ago, long before I owned a WE7A. I guess I have been pulled this direction for years. Now to work out the Western Electric pentode input and tennis ball triode output version.
One of the more controversial things I do is wind Nickel Chokes for PS usage. These 80% nickel units are going to a customer in Canada and are to be used in the L2 and L3 position of some mono amps he is building. I know many of have heard the light and embraced nickel for PS usage and while we don't exactly know all of the "Why's" Our ears tell us we are not making this up.
These things are small, the size of a Dyanco ST-70 choke and I first caught wind of the nickel PS choke thing paging through Sound Practices and seeing the ads for April Audio selling the Nature Sound permalloy PS chokes. For those of you not familiar with Sound Practices, Spend the best $29 you ever will and learn about Papa Joe. Back to the topic at hand.... I was firmly in the PS choke is a PS choke camp and laughed at the concept of $500 a pair for PS chokes. I had the great fortune to meet Uchida-san of April audio before he passed away and the most memorable moment from the visit was him cradling a Permalloy PS choke in his hands and passionately stating "Very beautiful sound".
A number of years later, Steve Berger who took over Aprilsound paid me a visit with a pair of the Nature Sound chokes and I skeptically clipped them in place of some potted milspec Low DCR chokes. My life has never been the same. Like my first experience with mercury, I was hooked and needed more nickel in my system.
That was over a decade ago and the stash has been growing ever since. The good news is my habit doesn't take up anywhere near the space that Jeffrey's does.
then I don't want any lip about making small horns!
This one is for the experimenters on a Friday afternoon.
I often listen to things in the shop just to get a feel for them... to see if they are worth spending the time to fine tune. I guess it is really just listening for "potential." On one afternoon JP was out of school, and I was needing to setup a smaller horn for some some JBL Beryllium diaphragm compression drivers to mate them to these 15" woofers I had been listening to. I wanted to see if the woofers would cross higher if the horn was small enough and close enough. I made a template of the basic petal. JP then traced and cut out petals from poster board thick paper. We scotch taped the pieces together starting at the throat and working down to the mouth. Sitting the horn face down on a table helps. one we shot with black spray paint just because spray paint is fun.
I made a mounting face from some foam from the shipping and receiving department (compartment?) I just hot glued it in place. One trick here to get the throat a bit rounded is to put a dowel or even a forstner bit that is the same size as the throat down into the throat to force the paper to go round. It is paper, totally malleable. Make sure you either get the throat flat or seal it up with thin gasketing to keep a tight seal.
If you want to stiffen it up, 3M makes this really cool preset fiberglass gauze. They use it to make casts (14 year old has broken four bones). Just open the package, dip in water for a second or two, and wrap your horn. Wear gloves! On an earlier one I used strips of an old towel dipped in shellac. It really had a nice tone when struck - a quick ring down.
Since I still have these the answer is obvious. Yellow Dog is far too impatient and would just swallow the things whole. Now you guys know the real reason I have shamed the name "Clippy" and GASP am soldering connections these days. When it comes down to it, a clip lead only has a lifespan of 3 days at my place and if anyone needs about 100 "half clip" leads sans the vinyl insulators, I have a good source for you.
Two weary travelers on a mission swung by my place for a few hours today. Their Journey started from a knight named Walter in Boston and the only requirement was to be at the land of Pennsylvania for a 6AM flight. Under normal circumstances, this would be a simple task, but the Fury of February was scheduled to dump 82 feet of snow from DC to Maine so their task was set.
No amount of snow could keep them away, they arrived beaten but not broken and quaffed some ale and listened to some music. They brought booty from the land of Walter in the form of GE pyranol caps. In speaking with the caps, they are proud to be near their homeland next to the Hudson River, but will accept the task of their 1000V rating (dude 4uf @ 3KV) and may relocate to the land of elvis near another great river and reside in the home of another mythical builder.
The man named chris gifted me some exotic #36 wire for my RS labs tonearm to be re-wired with and any excess wire after the deed is done may travel to the land of Schroeder. I completed the deal with the other traveler who shall remain nameless for now for security reasons and returned his Panasonic cartridges and granted him some electronic gear to power said cartridges.
Given the nature of air travel these days, I enclosed inside the box a signed paper justifying the movement of such a device in order to expedite things.
(OK my calliper says the N and T are 48mm apart.... sorry)
Back to Reality.
The snow was piling up with another 100 feet expected by dawn so the travelers had to go. I strapped the trusty snow dogs to the sled and lead the hearty souls to the promise land of the interstate. I can only pray they make it.
I just read that ridiculous Audio Asylum thread... about big horn systems and wives. I am afraid there was just way too much testosterone and ego in there for me, but I guess I am lucky. Lisa puts up with a whole bunch of stuff from me. Only a few times has she even had a hint of that worrisome look in her eye... when I moved the horns back home from the shop, she had the look... but less than half way through the first band of Ella and Louis, she was literally crying... so that bought me some leverage.. :^)
so.. thanks to the wife... on a good day it looks like this:
You gotta give props where they are due... and from my perspective, the props are due when you do anything that breaks out of that old and lame 1980's HiFi mentality. We are still struggling with too many faux rack mount chassis and rectangles with cones wrapped in veneer. So I want to throw out a few props...
Silbatone gets first props - for the Aporia speakers... definitely rule breakers: Manger drivers, back loaded horns, and those wild lenses....
I had the pleasure of hanging out late night in their (really nice, BTW) penthouse suite at the Venetian during CES. Mostly just Dave, their PR man, and myself... just sitting at the bar and playing whatever I felt like from my travel cd case... and I wasn't showing at CES, so this was just music.. and that is what the speakers do so well. They just play music. I think the back-loaded horn is what I like so much.... well, I know that is what I like... a ten foot long horn loaded by an eight inch driver and enough mouth size to avoid that one-note bass... clean, solid bass.. some very early James Brown was strutting... enough to make that suit of a PR man bounce when he walked... :^)
and then there is the construction.... man, you really have to see it and touch it... I cannot imagine the molds and time it took to make these. A true work of art. The mouth is lined with this beautiful hand stitched leather that has been dyed to match the cabinets... and the cabinets themselves have paint that leaves you flat out jealous...
oh... and I forgot.. they also have the sickest collection of vintage gear in the world... so there's that, too...
I uploaded a few pictures and some light text to the Field Coil Supply page on the Experience Music website. I think it is cool to see the slightly different blues of the Western Electric 354A's and 355A's. The 355A's have Argon as well as Mercury, while the 354A's are pure Mercury. The lighter blue is the Argon 355A..
I want you all to know that there is a new player in town and her name is Stephie. In a previous life she has mentored us all and I want you all to know she is back and happier and healthier than ever. Some of you may already know her and JJ and I want to welcome her back.
Back in the day on the joenet, Bob D would make "What I did last weekend" posts and I realized it was sort of like an early blog. I hope he doesn't mind me borrowing most of his letters for this post. The majority of last week was spent on two words. Baby Nickel While I was dreaming of big nickel I found out that I have been placing a lot of the small stuff assorted boxes and shipping it off.
Earlier in the month another batch of autoformers went off to John at Bent Audio for the remote units. The cool thing was half of them were wound with some really nice Ohno continuous cast copper wire for some OEM stuff he is doing for Audience. Another Batch of units for Thomas Mayer also shipped. He is using a diode matrix to handle the switching. J_Rob is getting 3 more sets of LCR inductors for his guys in Korea. Also of interest were some small output transformers for a Wolfson Dac and pair of small OT's for a PASS design that Mr. Lowther is working on.
to follow along the song title theme of dave's Another One Bites the Dust, this post will be Zeppelin.. Good Times, Bad Times... unfortunately, the bad times portion is just like dave's.. and another one down:
that one hurt... it was the STC (Western Electric of England) equivalent of one of my favorite transmitting tubes... so sad to see something this wonderful die due to poor packaging...
BUT... there is a good times portion to this as well... more blue bling arrived.. and they are beautiful.. the proper blue.. not the deathly purple blue...
and it gets even better... remember that Aa that I love so much? the Valvo is a perfect globe.. sounds wonderful.. no complaints... but look at these Seimens beauties that just landed:
I can't wait to try these in the amp... and then they are going in my strain gauge stage.. they will drop in place of the 841/VT51 with only a filament voltage change.... I can't think of a better way to spend a cold, rainy weekend.. spinning records... through an all DHT system...
Been listening to a few different OT's the past few days and I just love nickel! I swapped out the 8W 5K 49% nickel units for some 10K amorphous units and spent a couple of days with them. They have that clear direct sound that I have come to expect of amorphous. Next in went a pair of smaller 49% nickel 5K's that are good for 2-3W and 60ma of DC current. Playing them with the 2A3's is like listening to an old friend. Just for kicks I tried to run them hard and i'm reasonably sure that 3W of the 2A3 was the limiting factor and not the OT being abused.
This brought me back to the 80% nickel OT's I did for a certain feline in Boston. These were for 1200hz and up so 5hy's was the primary inductance. They were on the same core size as the 49% units pictured above and when I gave them a run in the kepco I heard some of the most incredible sound ever. The bass was limited but the rest was glorious. From that day on I have been dreaming of big 80% nickel cores and in the future I see some lovely 3W 80% nickel full range OT's in our stable.
Will someone please take me up on this one??? I have paraded the idea around for years. To me, it seems obvious. We love these giant Le Cleac'h front horns with Lowthers, but always have the issue of where to put the tweeter.
Luckily, we have been unanimous in the preference of the large wooden "lightbulb" phase plug. I think that comparison was both first done, and put to rest at VSAC 2003. This phase plug is *huge*... and there is room to sneak a tweeter inside..
granted, the tweeter needs to be at least 105dB.. and 108 is better, so maybe that was the catch... but I now have an answer... there is a new B&C... a ring radiator.. and that just beautiful sounding mylar diaphragm... clean, clear.. and with the inside slug of neodymium, it is both small enough and efficient enough for the application...
So I have this new listening room... the bad news is that it is too small.. and has too many doors.. BUT.. but it sounds very good, so I am happy...
now, you guys know me... I am wondering what is the max horn I can get into the room... and it is not enough... so time to think outside the box... literally... what I want is this:
I love that picture. I am not even sure who sent it to me... but when I start my church, this will be my steeple... and Blair already calls me the Reverend, so I figure that will be coming along any day...
Man, I wandered off topic again. Back to task! so, leaving that box.... I finally noticed that I have a nice five foot by five foot picture window in between the speakers. The window leads to the back yard... so the evil scheming has begun...
the only drawback I can see is time alignment... it is always the issue... but maybe worth a try? My wife loves me, but I might ought to run it by her...