Answering the question of "What's the best AM receiver/tuner I can get" is contingent on your definition as to what "best" means. If you want the best quality audio from local stations with a good antenna and ground, the old crystal radio is still the best.
For the uninitiated, a "crystal radio" has nothing to do with a crystal in the modern sense, the resonant piece of quartz used to define frequency in RF circuits including most every computer in existence. Crystal tuning for receivers and transmitters goes back to the twenties or thirties, but in this context we mean a crystal detector,i.e., a semiconductor diode, called a "crystal" because in the old days it consisted of a fine wire poked onto a chunk of lead pyrite or some other rock so that the wire or needle and rock formed a semiconducting PN junction. The actual tuning is done with LC circuits, traditionally made from a coil wound on a Quaker Oats container or similar. With a good antenna and ground, you could pick up enough RF so when the modulated signal was detected it would directly drive a pair of the old high impedance watchcase headphones. No battery was needed: it worked for free. All the energy used to drive the diaphragms of the headset came from the transmitter, tens, hundreds, perhaps under ideal conditions thousands of miles away.
A surprising amount of energy can be had this way. Within a few miles of a 50 kW daytimer or clear channel station, enough actual power can be developed-with the right RF and output matching- to light a flashlight bulb and certainly a LED. In fact, Klipsch used to have a demonstrator radio that would drive the midrange horn of a Klipschhorn or similar and provide a surprisingly loud signal in the room. At night one could listen to several stations in most cities almost as loudly as a nine-volt-powered transistor portable could play, and with better fidelity.
Of course, with enough power, an inadvertent crystal set can be accidentally assembled with humorous consequences-such as the elderly couple who complained that when Howard Stern was on the local station, sounds surprisingly resembling penis, vagina, and Baba Booey would emanate from the tub of their washing machine-or tragic ones such as the occasional premature dynamite explosion on a road project when some trucker with a 'foot warmer' keys his trusty CB rig.
A crystal radio, then is a passive, tuned-radio-frequency RF tuner. If the output were plugged into a good high impedance amplifier, the result is audio amplified as loud as we want it, just like any other line level audio source. In the beginning days of high fidelity, the RF coil houses like Miller introduced passive AM tuners that were nothing more than the old crystal radio. Because of the gain in a good preamp and power amplifier, you got good results in many cases with only a small antenna. Sensitivity and selectivity were not of the highest order, but with a good local station without much interference, the fidelity was superb. And, it still is. These passive AM tuners can still be found fairly cheaply or you can build one yourself, like generations of boys did in the past.
If on the other hand, you want broadcast band overall DX capability, you can either buy a serious communications receiver, or the next best thing-an old car AM radio converted to work at home. By the end of WWII, car radios were generally better radios than their domestic counterparts. They had to be, because of the environment they worked in. This was true until AM functionality came to be regarded as just a legacy as compared to FM performance around the early 1980s, at which time they cheapened the AM sections of the radios.
You want an AM only set for best Am performance. Either tube or solid state sets will work fine, but avoid like monkey plague the GM hybrid radios with 12 volt plate supply tubes and transistor output. Avoid Wonderbar or other auto tune radios: in fact a non-push-button set is best if you can find one made by Delco, Philco Ford or other Big 3 supplier. Avoid most aftermarket or foreign radios: the only ones any good are Blaupunkts or Beckers worth a lot to VW or Mercedes buffs. Overall, I think Delcos are the best. YMMV.
Needless to say, avoid ones with tape players, CB radios or the like. The cheapening started before digital came out, so avoid digital units entirely. You want either a 1947-1955 tube set or a 1964-1975 or so solid state one.
In the case of the solid state set you just need a 12.6 volt DC supply. These can be bought or built. It does not need to be regulated but it should be pretty quiet.
Tube sets can be run the same way, but it's inefficient. Instead, remove or disconnect the stock vibrator, power transformer and rectifier and provide a B+ supply with a conventional HV transformer, diodes and filter caps. You will also need a 6.3 or 12.6 volt heater supply of course. Generally, the limiting sonic factor is the stock output transformer, which you will want to replace with a larger and heavier one for a single ended amp using whatever tube is in there, usually a 6V6.
Most of the pure tube sets are for 6 volt supply, meaning they'll have 6 volt heater tubes, but some were 12 volt for the few cars and trucks that were 12 volt before the hybrid and full transistor sets came in. Usually those just have a different power transformer and use 12 versus 6 volt heater tubes. In some cases they seriesed the heaters on the small signal tubes and just used a 12V6, or used other odd arrangements. Almost always the filaments were run directly off the DC supply though.
Thursday, February 2, 2012
Tuesday, January 3, 2012
Using "industrial control transformers" for tube power supplies
A few years ago, an unemployed vacuum cleaner salesman with a fetish for "low DC resistance" power supplies decided that you could use common, fairly inexpensive, industrial control transformers for plate supplies for tube audio amps. And, you can. Hams did that for years, as did laser experimenters and people building worm and nightcrawler collecting shockers.
There are upsides and downsides for this. The upside is price, they are not that expensive new, and they are often available for free or very cheap as pulls from building salvage and old air conditioning equipment. They are ruggedly potted and insulated.
The downsides?
They are very heavy and awkward. They usually have the connections on their topsides which in an amp build need to be covered over for safety and long leads have to come through the chassis. The size they come in usually starts at 250VA, meaning they are too big to fit most amp chassis and still have room for other things.
The voltages they put out are usually direct multiples of 120 volts, meaning that you get 120, 240, or 480 volts out. If you need a center tap for a bi-phase half wave rectifier (i.e. you want to run rectifier tube(s))this means you are usually stuck with 240-0-240.
There is only one secondary, in effect, you need another transformer for filament voltage, and a third for bias voltage unless you have one wound. You are already pushing the space and weight budget. This makes it worse.
What this means is that ICTs are better utilized for bench supplies or for providing "foreign" voltages to imported equipment than incorporated into actual amp builds in most cases. But yes, they are a tool in the armamentarium of the DIY builder.
In my opinion, the best source of cost effective power transformers for homebrew and small production tube gear is to use guitar amp replacement units-IF you can get wholesale pricing on these. The music industry works on a pricing scale where "A Mark" (a phrase never to be uttered in a music store unless you want to be kicked out) is fifty percent. Most replacement guitar amp transformers from the bigger distributors are A Mark, sometimes B Mark, items. (B Mark is variously 40, 35 or 30 percent, depending.)
There are upsides and downsides for this. The upside is price, they are not that expensive new, and they are often available for free or very cheap as pulls from building salvage and old air conditioning equipment. They are ruggedly potted and insulated.
The downsides?
They are very heavy and awkward. They usually have the connections on their topsides which in an amp build need to be covered over for safety and long leads have to come through the chassis. The size they come in usually starts at 250VA, meaning they are too big to fit most amp chassis and still have room for other things.
The voltages they put out are usually direct multiples of 120 volts, meaning that you get 120, 240, or 480 volts out. If you need a center tap for a bi-phase half wave rectifier (i.e. you want to run rectifier tube(s))this means you are usually stuck with 240-0-240.
There is only one secondary, in effect, you need another transformer for filament voltage, and a third for bias voltage unless you have one wound. You are already pushing the space and weight budget. This makes it worse.
What this means is that ICTs are better utilized for bench supplies or for providing "foreign" voltages to imported equipment than incorporated into actual amp builds in most cases. But yes, they are a tool in the armamentarium of the DIY builder.
In my opinion, the best source of cost effective power transformers for homebrew and small production tube gear is to use guitar amp replacement units-IF you can get wholesale pricing on these. The music industry works on a pricing scale where "A Mark" (a phrase never to be uttered in a music store unless you want to be kicked out) is fifty percent. Most replacement guitar amp transformers from the bigger distributors are A Mark, sometimes B Mark, items. (B Mark is variously 40, 35 or 30 percent, depending.)
Don't mess with the Stereo 70...pass it on, or pass on it.
The first really popular component stereo amplifier was the Dynaco Stereo 70. Something like a quarter of a million were made over a roughly fifteen year period, and many still exist. Every day, people find them in closets, garages, basements and other places and put them up for sale or decide to fix them up (or have it done for them) and use them.
Approximately twenty firms offer upgrades, replacement parts and services related to the venerable little amp. In my opinion, investing good time and money in them is a bad idea. If you find one, my advice is pass it on to someone else and start from scratch, unless you have a fixation on assembling an early-sixties-era college dorm setup as a nostalgia trip.
Why is something so popular something I think should be avoided? Because the Stereo 70 isn't a jewel in the rough, but rather a case of a product that was designed to shave costs so thoroughly that making a good unit out of it means replacing everything. It makes little sense to replace everything and still wind up with a undersized, crummy old chassis and a product that you can't resell very easily for nearly what you have in it anyway.
Let's look at any effort to upgrade the amplifier. Inevitably, the original circuit board has to be replaced, either with a recreation of the original circuit or one of a dozen others on new board material. We also must replace the filter capacitors, and usually all the wiring and connectors. This means we are reusing the chassis, the three transformers and the choke, and that's about it.
But let's look at those transformers. They're between 35 and 50 years old, and insulated with old materials that have a habit of breaking down. In addition, both the power and output transformers have flaws that mean we'd rather have new ones anyway. The power transformer is undersized, for one thing, and runs quite hot. It also has a primary meant for 115 volts when the line voltage in the US has increased by five to ten volts in most areas over the past half century. If we replace the tube rectifier with a solid state diode pair, as one might want to to reduce load on the transformer, both the HT primary and the heater voltage will increase. We will have to increase the voltage rating on the filter caps, which is a good idea anyway, and we might put the 5 volt heater winding in series with the primary to drop the voltages a little, but still, the HT voltage will be more than we really want.
Replacing the power transformer definitely helps: we want one with more lams, more copper, designed for current utility voltages, and perhaps with a primary set up for solid state rectifiers. But then we still have the old output transformers, which are both arguably the best thing about the old warhorse and the limiting factor on what can be done with it. They were wound according to a Hafler patent, which allows for perfect AC balance at the expense of DC symmetry in the primary. Why suppliers so proudly offer "perfect reproductions" of these compromised parts is beyond me.
Replacing the output transformers on the Dyna chassis is problematic due to the space available.
The bottom line is that if you find an old Dyna Stereo 70, the best move you can make is to pass it on to someone else and put the money into a new clean build. Buy or fabricate a decent chassis and a good pair of output transformers and go from there.
Approximately twenty firms offer upgrades, replacement parts and services related to the venerable little amp. In my opinion, investing good time and money in them is a bad idea. If you find one, my advice is pass it on to someone else and start from scratch, unless you have a fixation on assembling an early-sixties-era college dorm setup as a nostalgia trip.
Why is something so popular something I think should be avoided? Because the Stereo 70 isn't a jewel in the rough, but rather a case of a product that was designed to shave costs so thoroughly that making a good unit out of it means replacing everything. It makes little sense to replace everything and still wind up with a undersized, crummy old chassis and a product that you can't resell very easily for nearly what you have in it anyway.
Let's look at any effort to upgrade the amplifier. Inevitably, the original circuit board has to be replaced, either with a recreation of the original circuit or one of a dozen others on new board material. We also must replace the filter capacitors, and usually all the wiring and connectors. This means we are reusing the chassis, the three transformers and the choke, and that's about it.
But let's look at those transformers. They're between 35 and 50 years old, and insulated with old materials that have a habit of breaking down. In addition, both the power and output transformers have flaws that mean we'd rather have new ones anyway. The power transformer is undersized, for one thing, and runs quite hot. It also has a primary meant for 115 volts when the line voltage in the US has increased by five to ten volts in most areas over the past half century. If we replace the tube rectifier with a solid state diode pair, as one might want to to reduce load on the transformer, both the HT primary and the heater voltage will increase. We will have to increase the voltage rating on the filter caps, which is a good idea anyway, and we might put the 5 volt heater winding in series with the primary to drop the voltages a little, but still, the HT voltage will be more than we really want.
Replacing the power transformer definitely helps: we want one with more lams, more copper, designed for current utility voltages, and perhaps with a primary set up for solid state rectifiers. But then we still have the old output transformers, which are both arguably the best thing about the old warhorse and the limiting factor on what can be done with it. They were wound according to a Hafler patent, which allows for perfect AC balance at the expense of DC symmetry in the primary. Why suppliers so proudly offer "perfect reproductions" of these compromised parts is beyond me.
Replacing the output transformers on the Dyna chassis is problematic due to the space available.
The bottom line is that if you find an old Dyna Stereo 70, the best move you can make is to pass it on to someone else and put the money into a new clean build. Buy or fabricate a decent chassis and a good pair of output transformers and go from there.
Sunday, January 1, 2012
Can't Solder?
So often I run into people who "can't solder".
My sister can solder. In fact, she's a rework operator at a big electronics plant which shall go nameless and she teaches the new hire class for assemblers. Her pass rate is well over 99% and except for techs and engineers going through, all her pupils are women who have never soldered before. Guys, if a bunch of GIRLS can do it, why can't YOU?
Proper soldering is not that tough. I learned to do it out of books, and later went through a solder school or two while working in electronic plants while in college. The only thing that ever gave me trouble was the smaller surface mount stuff. Yet, so many people in audio and ham radio have a huge problem making acceptable solder joints and others refuse to try. I refuse to believe anyone who can play any musical instrument at all-except maybe a trombone- can not learn to solder correctly and in a short time.
The biggest mistake people make is not understanding what is required to make good solder joints. You need a soldering iron with a clean, tinned tip, a clean pair of metal items-wires, leads, tags, pads, whatever-and some solder and flux.
For chassis and panel soldering, a regular electric iron-NOT a gun, an iron-will work, but if you want to solder circuit boards, it HAS to be a temperature controlled iron. You HAVE to be able to CLEAN and TIN the tip, EACH USE. You need to have the surfaces clean, so you will want a small ACID BRUSH and some SOLVENT, usually mineral spirits or methanol.
Tinning the tip means you need a SPONGE with some WATER on it. You can use real natural sponge or the kind sold just for soldering, (but not the cheap kitchen type) and DI or distilled water is better but not mandatory. You also need some SOLDER.
The ONLY kind of solder to use until you are highly experienced is FRESH, ROSIN CORE solder of 63/37 lead-tin composition. It has a special name, EUTECTIC solder. That is because it goes from liquid to solid in one instant as it cools instead of going through a mushy stage. It has to be ROSIN CORE, you must NEVER use acid core solder on electronic items. It is for plumbing and sheet metal work.
You will also want some FLUX. The kind you want is called RMA Flux. That stands for Rosin Mildly Activated. You must carefully clean each joint you make after using it. You will also want a little solvent for the flux and a small needle bottle for dispensing it. You should use little flux. There is also a paste flux you can get that is non-acidic that is good mostly for tinning old or chewed up soldering iron tips. Rarely you might use a little on a particularly big solder joint. Flux goes bad which is why you want to start with a fresh roll of solder.
You will also want some tools such as a couple of picks, needlenose pliers and other miscellany.
If you have acid core or fluxless tin/lead solder, unless you do tinsmithing or plumbing, get rid of it. If you have a soldering gun, put it aside for other purposes or get rid of it. If you have old cheap unregulated irons, they can be used for chassis and panel (point to point) soldering if you can get the tips cleaned and tinned, otherwise get rid of them.
If you buy everything you need at one time from a good supplier like Stanley Supply and Services, (the former Jensen Tool people) you
are going to lay out a couple hundred bucks. If you do some hamfest trading you can get everything but the solder, sponge, holder, and flux for less.
Chassis and panel soldering is well described in the old military electronics books. The thing to do is get some wire and supplies and practice. Practice a lot.
I have been through a couple of company solder schools, but the best I have been through was as a guest with the old GTE Telephone craft class for inplant repairers in the early eighties. One of the exercises we did was to take a piece of wire-regular solid copper wire, perhaps 12 or 14 gauge, and cut it into twelve exactly equal pieces. We then had to build a square of four pieces and then a cube using all twelve. The only tools we were allowed were the soldering iron, solder, a pair of phone man needlenose pliers and a pair of surgical forceps like needle clamps or hemostats. We also had a steel plate about 3x5 inches which had a surface that looked as if it had been rusted and then oiled and buffed.
When we were done with our perfect cubes-which took half the day-they crushed them. The solder joints had to hold.
The first cube took hours. By the end of the day most of us were on our fourth or fifth. The instructors then showed us how they did it-they could do it in five minutes flat, starting with the untrimmed, unstripped wire.
Today, phone companies do very little soldering-it's all punchdown blocks. But in the old days, they got really good at it.
My sister can solder. In fact, she's a rework operator at a big electronics plant which shall go nameless and she teaches the new hire class for assemblers. Her pass rate is well over 99% and except for techs and engineers going through, all her pupils are women who have never soldered before. Guys, if a bunch of GIRLS can do it, why can't YOU?
Proper soldering is not that tough. I learned to do it out of books, and later went through a solder school or two while working in electronic plants while in college. The only thing that ever gave me trouble was the smaller surface mount stuff. Yet, so many people in audio and ham radio have a huge problem making acceptable solder joints and others refuse to try. I refuse to believe anyone who can play any musical instrument at all-except maybe a trombone- can not learn to solder correctly and in a short time.
The biggest mistake people make is not understanding what is required to make good solder joints. You need a soldering iron with a clean, tinned tip, a clean pair of metal items-wires, leads, tags, pads, whatever-and some solder and flux.
For chassis and panel soldering, a regular electric iron-NOT a gun, an iron-will work, but if you want to solder circuit boards, it HAS to be a temperature controlled iron. You HAVE to be able to CLEAN and TIN the tip, EACH USE. You need to have the surfaces clean, so you will want a small ACID BRUSH and some SOLVENT, usually mineral spirits or methanol.
Tinning the tip means you need a SPONGE with some WATER on it. You can use real natural sponge or the kind sold just for soldering, (but not the cheap kitchen type) and DI or distilled water is better but not mandatory. You also need some SOLDER.
The ONLY kind of solder to use until you are highly experienced is FRESH, ROSIN CORE solder of 63/37 lead-tin composition. It has a special name, EUTECTIC solder. That is because it goes from liquid to solid in one instant as it cools instead of going through a mushy stage. It has to be ROSIN CORE, you must NEVER use acid core solder on electronic items. It is for plumbing and sheet metal work.
You will also want some FLUX. The kind you want is called RMA Flux. That stands for Rosin Mildly Activated. You must carefully clean each joint you make after using it. You will also want a little solvent for the flux and a small needle bottle for dispensing it. You should use little flux. There is also a paste flux you can get that is non-acidic that is good mostly for tinning old or chewed up soldering iron tips. Rarely you might use a little on a particularly big solder joint. Flux goes bad which is why you want to start with a fresh roll of solder.
You will also want some tools such as a couple of picks, needlenose pliers and other miscellany.
If you have acid core or fluxless tin/lead solder, unless you do tinsmithing or plumbing, get rid of it. If you have a soldering gun, put it aside for other purposes or get rid of it. If you have old cheap unregulated irons, they can be used for chassis and panel (point to point) soldering if you can get the tips cleaned and tinned, otherwise get rid of them.
If you buy everything you need at one time from a good supplier like Stanley Supply and Services, (the former Jensen Tool people) you
are going to lay out a couple hundred bucks. If you do some hamfest trading you can get everything but the solder, sponge, holder, and flux for less.
Chassis and panel soldering is well described in the old military electronics books. The thing to do is get some wire and supplies and practice. Practice a lot.
I have been through a couple of company solder schools, but the best I have been through was as a guest with the old GTE Telephone craft class for inplant repairers in the early eighties. One of the exercises we did was to take a piece of wire-regular solid copper wire, perhaps 12 or 14 gauge, and cut it into twelve exactly equal pieces. We then had to build a square of four pieces and then a cube using all twelve. The only tools we were allowed were the soldering iron, solder, a pair of phone man needlenose pliers and a pair of surgical forceps like needle clamps or hemostats. We also had a steel plate about 3x5 inches which had a surface that looked as if it had been rusted and then oiled and buffed.
When we were done with our perfect cubes-which took half the day-they crushed them. The solder joints had to hold.
The first cube took hours. By the end of the day most of us were on our fourth or fifth. The instructors then showed us how they did it-they could do it in five minutes flat, starting with the untrimmed, unstripped wire.
Today, phone companies do very little soldering-it's all punchdown blocks. But in the old days, they got really good at it.
Thursday, December 29, 2011
Google makes it tough to find blogs
I guess I don't know how to make a blog show up. Sound and Flavor, soundandflavor.blogspot.com, Pendleburt Lengerton and lpendleburt get no respect-or notice-from Google's home page.
I'm an analog builder, not a programmer, damn it! (Well, DeForest Oelley is dead, but you get the idea.)
I'm an analog builder, not a programmer, damn it! (Well, DeForest Oelley is dead, but you get the idea.)
Tuesday, December 20, 2011
ROTFLMAO-without compromise?
"Hand built without compromise to perform without equal". Such is the official motto of one transformer vendor, Magnequest, of Philadelphia, PA. It's pretty safe to say no other transformer maker would make that assertion, because no engineer or component buyer would be ordering from that vendor.
They'd be laughing too hard!
Years ago I was into another hobby activity which is, like transformer design, mostly the province of degreed engineers. I was talking to such an engineer and I was going over the drawbacks and advantages of some of the various designs available, and I said, "Boy, I'd like to design one right, with no compromises." He sprayed the Coke he was drinking all over himself laughing at my stupidity, for stupidity it was. When he got done cleaning himself up and regaining his composture, he said something that has stuck in my brain ever since. "ALL ENGINEERING IS COMPROMISE. All designs are a matter of trading off one thing for another. What separates a good design from a bad one is knowing what to trade off for what else, when, and how.."
Boy, was he right. I've learned that lesson in studying and DOING THINGS in several fields and anything requiring what can be called design really is a compromise. You NEVER have an infinite supply of anything, ever. Any real world implementation of something is always a series of tradeoffs.
Look up the properties of a perfect transformer sometime. It can not exist in the real world, because transformers are made out of actual materials that do nothing perfectly.
So how does Magnequest carry off a motto like that? Simple. It does not do business with engineers or commercial component buyers, only with technically unsophisticated and gullible people. Magnequest is not a transformer wind shop in the usual sense of the word: it is one individual, with no engineering degree nor any hands-on experience in the workaday transformer manufacturing business, who bought up some old blueprints (or salvaged them from a dumpster) and got a few of the many retired transformer winders in eastern Pennsylvania to show him how to run a winding machine.
As it happens, I actually have worked in a transformer plant, and I know enough to know that one guy with an old Universal winding machine does not constitute a facility capable of putting out the kind of transformers he is claiming to be able to offer. In a real transformer plant, you have a lot of women who wind transformers all day, under the direct supervision of both their wind line supervisors and an engineering QC staff who continually test the product. It takes a fair amount of time for an one of them to learn to wind any given transformer, when dealing with complex interleaved designs as most good audio transformers are, and each of them is in effect certified to wind one or a limited number of parts. You would no more hand a winder an unfamiliar wind sheet and have her wind one on her own than you would take a 737 captain who has never seen an Airbus, hand him the pilot's manual and checklists and send him out to an Airbus full of passengers on a revenue flight.
It's telling that with a "design library" with dozens of in demand designs for matching and line transformers highly sought by the recording industry, he refuses their business and winds mostly his own designs aimed at the single-ended-triode, no-feedback cultists. There, a part can be pretty flawed and no one would know the difference, since the amplifiers perform so marginally anyway, and the builders usually have no test equipment nor would they care to use it if they did. The proprietor isn't a 737 captain trying to fly an Airbus: he doesn't even have a pilot's license.
They'd be laughing too hard!
Years ago I was into another hobby activity which is, like transformer design, mostly the province of degreed engineers. I was talking to such an engineer and I was going over the drawbacks and advantages of some of the various designs available, and I said, "Boy, I'd like to design one right, with no compromises." He sprayed the Coke he was drinking all over himself laughing at my stupidity, for stupidity it was. When he got done cleaning himself up and regaining his composture, he said something that has stuck in my brain ever since. "ALL ENGINEERING IS COMPROMISE. All designs are a matter of trading off one thing for another. What separates a good design from a bad one is knowing what to trade off for what else, when, and how.."
Boy, was he right. I've learned that lesson in studying and DOING THINGS in several fields and anything requiring what can be called design really is a compromise. You NEVER have an infinite supply of anything, ever. Any real world implementation of something is always a series of tradeoffs.
Look up the properties of a perfect transformer sometime. It can not exist in the real world, because transformers are made out of actual materials that do nothing perfectly.
So how does Magnequest carry off a motto like that? Simple. It does not do business with engineers or commercial component buyers, only with technically unsophisticated and gullible people. Magnequest is not a transformer wind shop in the usual sense of the word: it is one individual, with no engineering degree nor any hands-on experience in the workaday transformer manufacturing business, who bought up some old blueprints (or salvaged them from a dumpster) and got a few of the many retired transformer winders in eastern Pennsylvania to show him how to run a winding machine.
As it happens, I actually have worked in a transformer plant, and I know enough to know that one guy with an old Universal winding machine does not constitute a facility capable of putting out the kind of transformers he is claiming to be able to offer. In a real transformer plant, you have a lot of women who wind transformers all day, under the direct supervision of both their wind line supervisors and an engineering QC staff who continually test the product. It takes a fair amount of time for an one of them to learn to wind any given transformer, when dealing with complex interleaved designs as most good audio transformers are, and each of them is in effect certified to wind one or a limited number of parts. You would no more hand a winder an unfamiliar wind sheet and have her wind one on her own than you would take a 737 captain who has never seen an Airbus, hand him the pilot's manual and checklists and send him out to an Airbus full of passengers on a revenue flight.
It's telling that with a "design library" with dozens of in demand designs for matching and line transformers highly sought by the recording industry, he refuses their business and winds mostly his own designs aimed at the single-ended-triode, no-feedback cultists. There, a part can be pretty flawed and no one would know the difference, since the amplifiers perform so marginally anyway, and the builders usually have no test equipment nor would they care to use it if they did. The proprietor isn't a 737 captain trying to fly an Airbus: he doesn't even have a pilot's license.
Friday, December 16, 2011
A trainwreck that's no Trainwreck
Amongst guitar players, two makes of guitar amplifier inspire fanatical devotion and the expenditure of insane sums (many tens of thousands of dollars) to own one, the Howard Dumble and the Trainwreck. Both were built in very limited numbers by one solitary basement genius, one Alexander Howard Dumble and one Kenny Fischer. Dumble is out of California and Fischer, who committed suicide apparently after determining that he had terminal cancer, from New Jersey.
Both these legendary pieces of equipment-I don't like calling a guitar amplifier an amplifier, because in most cases they are selected not to amplify but to modify and add to the guitar's sound-have, as one might expect, been intently copied by hobbyists and by a few small "boutique" companies-most one man garage operations themselves.
One might ask, why the Chinese don't simply copy them also, sell them cheaply and make a fortune. After all, that is what they are often accused of doing to so many other things. But as it turns out, China isn't as good at copying as many think.
To be sure, I have seen some well built equipment out of China. Often it is good value, reasonably well built, and intelligently engineered-whether they did it themselves or relied heavily on the existing art. But when it's crap, boy is it ever crap.
"Poorly Made in China" is the title of a book-an excellent book, I might add-by one Paul Midler. He has a great blog and I urge all and sundry to avail themselves of it.
http://www.paulmidler.com/
Both these legendary pieces of equipment-I don't like calling a guitar amplifier an amplifier, because in most cases they are selected not to amplify but to modify and add to the guitar's sound-have, as one might expect, been intently copied by hobbyists and by a few small "boutique" companies-most one man garage operations themselves.
One might ask, why the Chinese don't simply copy them also, sell them cheaply and make a fortune. After all, that is what they are often accused of doing to so many other things. But as it turns out, China isn't as good at copying as many think.
To be sure, I have seen some well built equipment out of China. Often it is good value, reasonably well built, and intelligently engineered-whether they did it themselves or relied heavily on the existing art. But when it's crap, boy is it ever crap.
"Poorly Made in China" is the title of a book-an excellent book, I might add-by one Paul Midler. He has a great blog and I urge all and sundry to avail themselves of it.
http://www.paulmidler.com/
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