7025; this is actually a 12AX7 with an American INDUSTRIAL
part number. The 7025 designation indicates additional testing
for low microphonics and low hum. Similarly, you would choose
one of my Applications Graded TM GAIN tubes, which additionally would be tested
for the greatest gain, burned in and listen tested in an actual
amp with a specially optimized brutal high gain circuit! It sounds
like an Applications Graded TM GAIN tube is better, and it is! Application
Graded TM; There
are three different types of circuits in your amp that use 12AX7
tubes. There is the GAIN stage which is the most demanding in
terms of sonic qualities, followed by the FUNCTION stage(s) which
may or may not increase the gain of the signal but not by much,
and then lastly the DRIVER stage which must have each triode
within it operating at the same potential in order for you to
benefit from those matched output tubes. By sorting the tubes
for their best application the amplifier performs far better.
Its tone is stronger, the sustain is longer and more natural,
and each tube in the amp lasts longer! Hi-Fi tube amps are laid
out much like a guitar amp, featuring gain stages and a driver
stage. They also stand to gain from properly selected tubes.
For other tube based equipment like expensive studio gear and
tube foot pedals, a GAIN tube should always be selected.
Burn in; most electronic equipment including tubes will
fail within the first 24 hours if it premature failure occurs
at all. So to bring out failures, power is applied along with
the typical load for a period of time (burn in time).
Clean; the ability of a tube to amplify a signal as designed
without adding harmonic overtones.
Compression; In a word, punchy. The quieter parts of your playing
are made to sound louder. For example your picking, plucking,
swishing and single notes made to sound the same volume as a
chord. Or the breath of a singer made to seem as loud as her
voice. Technically when the tube runs out of headroom (ability
to accept larger input signals while still resulting in proportionally
larger output signals) instead of distorting the tube puts out
a clean signal but the louder parts don't get represented by
as loud of a signal as it otherwise would. If this sounds to
you like it gets quieter, then you thinking right, however, the
brain interprets the new softer loud part as being a louder soft
part. In other words, compression makes the quieter parts of
the sound seem louder. For example, a single note could be made
to be as loud as a power chord. Distortion; tubes either compress or generate harmonic overtones
when asked to do more than the tubes' construction allows. Distortion
refers to the latter, rich harmonic texture that is desirable
and specific to the way that tubes distort.
Driver; the last tube before the output tubes. In push-pull
amps (almost every amp over 15 Watts) the output tubes should
have matched performance, although there would be little point
if the driver tube was not also matched. More on this and more
on the about tubes page.
ECC83; this is the European part number for the American
12AX7. They are in every way the same tube.
Gain; when the signal voltage comes out at a larger
magnitude than it went in then it has gain. For example, the
voltage from your guitar swings one tenth of a volt, and the
voltage of the same guitar signal after being amplified by the
first tube circuit will increase to maybe five volts! Now that
is some gain! If the input is the same as the output then it
has unity gain. You do have circuits in your amp near unity gain.
A tube would really have to be messed up, or you would have to
really be rocking the amp for a microphonic tube to be a problem
when in a near-unity circuit! 12AT7's are very prone to high
frequency microphonics, but due to their pingy tone they only
find use in very low gain stages like the reverb driver or output
driver. Different tubes within a batch exhibit differing amounts
of gain. The more "healthy" a tube is the more rigid
it must be in its construction in order to be usable, ie; a tube
may have so much gain that it exhibits an unusable amount of
microphonics in a gain stage circuit, and still be perfectly
suitable for use anywhere else in the amp.
GAIN/DRIVER; these are a bit hard to come by, and an ideal
choice for experimenters. You can use them as top performing
gain stage tubes, or as balanced section Driver tubes equally
well. One of these of each tube type make the ideal experimenters
kit, as they can be used anywhere in the amp. Offered at a slight
premium.
Microphonics; when the vibrations caused by amplified sounds
cause an internal part of the tube to vibrate in sympathy resulting
in a runaway effect similar to sticking a microphone in front
of speaker. All tubes are microphonic to some degree. In preamp
tubes the problematic notes always tend towards the higher frequencies.
In output tubes the tendency is towards low notes. Since preamp
tubes and circuits have more gain, they are more likely to be
a practical problem for the player. Most amps are laid out so
that the input jack is closest to the tube whose circuit has
the most gain. This first tube also imparts the greatest effect
on the sound of the amp.
Overtones; notes in addition to the fundamental one that
is a product of the electronics and not necessarily part of the
musical source.
PRIVATE STOCK; For a long time I would not sell these to anyone.
They are truly the best tubes available of their type. Very few
tubes make the grade. When you read about guitar legends who
utilize a technician to hand pick the best tubes after listening
to hundreds, THIS IS IT. That's what I'm doing, these are the
tubes. Offered at an appropriate premium.
Punchiness; a sound quality similar to bassy response but
relating to the ability to move a lot of air quickly. Like a
punch in the chest.
CREATE YOUR OWN SOUND! The very best part of this whole thing is
that you don't need to settle on just one single tube sound! The
tube closest to the input jack, V1, is the tube that effects your
sound by the pound. The next tube down the line alters the sound
by the ounce, and so you now have the opportunity to bake a sonic
cake. The next tube down the line is the last tube before the
output tubes, the driver tube. This one does in fact amplify the
signal voltage too - so its a gram of spice to finish it off.
Now its time to cook.
Mix different tubes - I can tell
you that when I voice an amp that my clients seldom choose three
tubes of the same type! Pick what two or three different tubes
sound like what you want from the descriptions and then
try them out in different positions to hear what the effect is!
Remember that V1, usually the tube closest to the input jack is
the one tube that has the most dramatic effect on the sound. Most
of the time people nail it with their choices the first time.
The experimentation validates the choices that you made. If you
choose to do this experimentation you will need to select "gain/driver"
application grade TM for each tube.
Advice on choosing
new tubes - First
try to figure out what your starting with. Do you want less razory
trebles? Do you want a more realistic, connected feel? A punchier
sound? A brighter sound? Richer texture? More, or maybe less distortion?
From there you really have your own answers, its simply a matter
of priority. As you read the product description ask yourself
if that is something important to you.
What are the characteristics
of a bad preamp tube? There a few common failure modes. Excessive microphonics
will render a tube useless because of the high pitched squeal.
A shorted heater will make a loud hum but you may still be able
to play. A vacuum leak usually discolors the glass bluish gray,
but it wont work. A quick way to determine if a bad tube is in
the preamp or output stage is to see if the offending noise can
be turned up and down with your amps volume or gain control. If
so, then the bad tube is between the input jack and the volume/gain
control (V1 and or V2). All preamp tubes are used in 'self biasing'
circuits so you can replace them without a tech. To refine
your bad tube search pull one tube out and see if the noise stops.
You wont hurt anything aside from burning your fingers, and yes
tubes normally do get scalding hot. Generally, preamp tubes seldom
go bad. The worst failure is bad tone, and since that is a matter
of taste you may never experience what an incredible amp you already
own.
What is different
about the tubes? Thankfully every time someone makes a 12AX7 they
have different materials, different physical dimensions, different
vacuum levels, and invariably a different sounding tube. It's
my business is to know what tubes sound like so that I can test
them and offer you reliable choices. Choices that vary as much
as possible.
Who makes the best
tubes? There is so much talk
about this, and its all opinion. All tubes sound good, that is
why we have tube gear. Some tubes sound more like what we want
than what we currently have, others bring us farther away from
our goals. The ONLY way to buy a tube is to select one for the
way it sounds, NOT where it's made or how reliable the
particular type is! Tubes that are subjected to a burn in period,
high gain listening tests, and Application Graded TM
are going to last a very long time regardless of who the manufacturer
is. This process allows tubes of any initial level of reliability
to screened for a very long life. In the case of the 12AX7 the
expected life of the tube will be decades. I want choices! Because
of my unique process, we can have tubes that both sound the way
we want and are highly reliable! We live in the golden age of
tubes!
There are no brand
names displayed on this website.
I do not reveal the brands for a reason - I
want you buy your tubes from me!
I offer a service that is truly unique. It evolved from decades
of experience. If you want the benefit of all that expertise,
then you will need to buy the tubes from me. Here you get to buy
the tubes that sound the way you want, plus you get to model your
own amp sound. A little trust here. I do not remove the names
from the tubes, only from the website. If later you want to try
to save some money and buy more of the same brand tube from someone
else, you're welcome to. But you won't be getting the same quality
or performance! I know this because I reject as much as 80%
of the tubes I buy! If by chance you were to choose the exact
tubes that are in your amp now, it will sound stronger have better
tone and increased reliability using my tubes!
Guarantee All tubes are guaranteed 90 days. Preamp tubes like the
12AX7 are guaranteed for 180 days.
If you are unsatisfied with the tubes you may exchange them for
a 15% restocking fee.
Confidentiality: WE HONOR OUR
CUSTOMERS RIGHT TO COMPLETE PRIVACY. Still no name dropping. I
won't sell my customer list, etc.