|
TUBE HUNTER VACUUM TUBE GEMS
THESE ARE THE SPECIFICS OF THE TUBE/TUBES FOR SALE
|
THESE ARE THE TUBE/TUBES FOR SALE:
|
MANUFACTURER:
|
TELEFUNKEN
|
|
PRODUCTION CITY:
|
BERLIN GERMANY
|
|
TUBE TYPE:
|
12AU7 ECC82 PREAMP
|
|
DESIGNATION:
|
CHECKED TEKTRONIX 12AU7 PAIR
|
|
YEAR:
|
1957
|
|
MONTH:
|
DECEMBER
|
|
Date code match
|
YES
|
|
SILK SCREEN CONDITION %:
|
100%
|
|
MICA:
|
2
|
|
PLATES:
|
LONG GREY
|
|
GM%:
|
124%,123% and 124%, 124%
|
|
SINGLE/PAIR/QUAD/MULTI:
|
PAIR
|
|
GETTER:
|
O GETTER
|
|
DATE CODE
|
mh = DEC 1957
|
These tubes are perfect in every way matched and balanced. They will not fail to please!!!
Telefunken 12AU7's are reported to be at the top of the audiophile food chain when it comes to sonic reproduction. They are very honest in all frequencies. They are the finest in delivering the highs with transparent open air at the top. Perfect mids with near perfect vocal presentation. The bass is punchy and not muddled in any way. These tubes are consistently the LEAST microphonic of all tubes.
What does "Checked Tube"
mean? Tektronix was the leader in high MEGAHZ machines. They were doing some
really fast switching. Tektronix was building equipment
that was on the leading edge of tube technology. They did things that required
careful matching of tube characteristics, such as 18 tube distributed vertical
amplifiers. Some of their circuits, by virtue of their being flat from DC to
100MHz, or so required tubes that had unusually stable characteristics. They needed the tubes to meet very
high standards in some critical circuits. At times only a single manufacturer
made tubes that met those standards. Because of these special
needs, Tektronix had a department dedicated to testing and matching vacuum
tubes. They assigned, special part numbers to these highly tested and selected
tubes. These
tubes were selected by Tektronix for use in critical sections of precision
testing equipment. They were hand selected for GM values and balance (within 2%
per section). They also were checked for NOISE. They are the lowest noise tubes you
can find for the brand selected. That is what the
CHECKED STICKER are all about. Tektronix was very picky about the
components that went into their equipment.
They made the VERY best test equipment of all
time in my opinion. These tubes are an embodiment of that fact.
They sound great in my headphone amp, and they will in yours!
Here is what Brent Jesse says about these tubes: "These tubes are usually characterized by an impressive open "air" at the
top end. The soundstage is large, even in mono applications these
tubes have a great 3-D image. The midrange is ruler flat, and the bass
is tight and accurate. For phono grade and critical high gain
applications, the Siemens Nickel Plate and the Telefunken or
ECC802S are awesome. These tubes have a fine sense of dynamics, and
most are impressively quiet. These are not "warm" tubes, and to some
ears their lack of midrange warmth may be heard as bright. I tend to
think of them as accurate, and their clean, focused sonic image is
astonishing. My personal favorites."
These tubes test NOS, and will blow your socks off!
On my tester a B&K 747 tester: Below 55 = BAD 55-66 = ?
65 -100
= Good 100-120+ = NOS
I want to see you happy with your purchase. I will never sell a tube that is below standard……
I have sold many tubes here on Ebay, and all my customers have been completely satisfied. I will work with you in good faith if there are any problems, or if you are unsatisfied in any way.
I want your business now and in the future, so I assume you are the boss, and I am the employee.
All tubes are tested for shorts, continuity, and emissions.
I prefer PayPal.
ALL CUSTOMERS PLEASE
READ ALL NOTES BEFORE BUYING FROM ME !!
1. RETURNS: It is my highest desire that you are
completely satisfied with your purchase from me. I will bend over backwards to
make sure that you are a happy customer.
If anything you buy from me is less than satisfactory,
message me BEFORE you either open a case or hit the “item not as described”
button.
Sound quality is tremendously SUBJECTIVE. For tubes returned for "noise" or "sound quality of any kind" you pay for the shipping we refund the purchase. We refund the price of the item NOT THE SHIPPING COST. If we sent the wrong tube we will of course pay for return shipping. For any tubes that are DOA we require that you send a us a picture of the shipping box to show us the damage. We test EVERY tube sent out and none should be DOA unless broken in shipping.
2.
PLEASE NOTE: Tube silkscreen
(lettering on the tubes) is VERY fragile. It can be wiped off and destroyed
VERY easily. If you wipe off the silkscreen while handling the tube you
diminish their value by up to 70%. DO NOT handle the tubes or hold them from
the cylinder. ALWAYS hold them from the ENDS. If you are returning tubes and
they are not in the same condition cosmetically I cannot give you a full
refund. THIS IS VERY IMPORTANT.
3. UNLESS YOU MAKE ARRANGEMENTS WITH US BEFORE YOU
PURCHASE, YOU MUST PAY FOR ITEMS PURCHASED WITHIN 2 DAYS OR A CASE WILL BE
OPENED FOR AN UNPAID ITEM!!!
4. TESTING: I test all tubes that I sell in one way or another, or I will state "untested". I have a B&K 747 tube tester. This is a mutual conductance tester. It give a percentage value of gm for the tube under test and checks for shorts and grid emissions. I also use a Tektronix curve tracer for testing triodes. I give a number of evaluations for tubes. One evaluation is a screen shot of the tube with a high voltage applied to the plate. This helps the buyer see the linearity of the tube in question at the highest voltage the tube will see in a real circuit. The Curve tracer steps the triode through 10 gate/grid voltages starting with -10 volts and going to 0 volts. The lines show how the tube conducts throughout that range. At 0 volt the tube is at max conduction and is the top line on the display. It is easy at that point to take where that top line intersects the plate voltage, find the milliamp level and compare it to the datasheet. I give those numbers for you in the "Item condition box". To further help the buyer I also include the "Design values", for gm and ma readings in the table. This can then be compared to other tube sellers using inferior test methods such as Hickok, Amplitrex, and other testers. The Tektronix curve tracer gives values within 3% of the actual value. The very best portable testers only can approach 10% accuracy. 5. Please
note: The numbers given for gm are what I see on my tester. I DO NOT guarantee
that you will see those numbers on your tester. I only guarantee that these
tubes will test good, with no shorts, or gas, on a decent calibrated tester. I
don't guarantee or imply anything else.
6.
VERY IMPORTANT!!! Vintage tube testers almost always,
due to age, have VERY LOW HEATER VOLTAGES!!!
Every tester I have ever bought is below 6 volts when selecting 6.3 volts.
They average 5.8 volts. The voltage NEEDS to be 6.3 and 12.6. You can calibrate
a vintage tube tester all you want. If the heater voltage is not right, you
will NEVER get the right gm value. I have customers complain that their tubes
are not the same as what I see on my tester. They say they have a calibrated
tube tester. I have 40 tube testers. On all of them I have an outside regulated
DC power supply that feeds the tube tester the correct heater voltage.
7. I don't check each and every tube for noise or tone. This is SUBJECTIVE and it is too time consuming. If you don't like the noise level or the tone we offer a hassle free refund policy.
International
customers note:
1. Please wait for
us to invoice you for the correct amount. If you have purchased more than one
item, we must calculate how much the shipping will be. Shipping will be HIGHER due to insurance and shipping methods needed for expensive item totals. If you are buying only one item this will not be an issue.
2. Under no
circumstances will we state on a US customs a declared value of less than the
sale price. This is an honesty issue. We are honest with everyone to the best
of our ability to do so. We want you to trust that what we say is true. There
cannot be that trust, if we make false statements knowingly to anyone. If your
country has tariffs/taxes so high that they cause large numbers of normally
honest folks to make false statements, we urge you to work for change of those
laws.
3 International buyers if you bought more than one item and
want combined shipping it will ship in 2 days.
4. And all the Angels sang because the heavenly music was
playing and it was turned all the way up.
|
|
