#ECC99 - Notes by users
http://www.jj-electronic.sk/tube_ecc99.htm
http://www.ampdesign.de/ECC99%20Artikel.htm
Driver of power triodes such as 300B, 2A3 ..., output stage
headphoneamplifiers, CDs, power stage little P-P triode amplifiers in class A
(10W-4xECC99) and parallel voltage power supplies. Can be used instead of
6N30P, 5687, E182CC, 6840, 6BL7.
ECC99 (mu 22, rp about 2.5k at Va 150V/Ia 18mA).
Heater 0.8 amps Like the 6N30P, it consumes a fair bit more heater current than
a 6SN7
General Comments
The ECC99 sweetened up this amp. Very nice. I'm operating it at 11mA and 120V
with a CCS load. Why buy the 6H30 when this ECC99 has arrived? Kurt
I was running the ECC99 at 150v, 4v I think. 6H30 will be at 100v, 4v. Same
25mA for each.
I really like this tube. I don't know why it has gotten so little attention
Pete Millett
Use an ECC99, either single or parallelled sections, without a cathode
follower. This is alot better sounding than a 6SN7 or 5687 (or even a 6N30Pi)
to my ear. However, it does consume alot of plate current at the op point I
like for preamps (120V on the plate, 20mA or so plate current per section), so
plan on a substantial power transformer upgrade.

I have been there, playing with the 6H30 in a preamp through various
incarnations, and have also tried the ECC99, and the latter is a better
sounding tube, IMO. The 6H30 is just a shade too lean in the mids, although it
is a nicely detailed sound. The ECC99 has more body, and a bit more ease to
the sound. A quick rewiring of heater pins makes it a snap to try. You may
also add the 12B4 (though two tubes) to your list. That is what I am currently
using to keep the overall system gain down within reason. Pretty nice sounding
once you get quiet ones, though I think I like the ECC99s more.
As a driver, I compared it to many other tubes and found it one of the best. I
have also used the 6SN7 and 6SL7 in the prestage and found them there as the
best, although I am using nowadays more the ECC83, but just because it comes in
a Noval socket. If you what to visit my homepage (sorry it is in German) it is
www.ampdesign.de By the way, where have you read my article? best regards Hans

JJ
Current manufacture. See www.eurotubes.com
I use this tube as a phase splitter for my Triode Electronics Driver Board in
my Dynaco Stereo 70 The manual for the Upgrade Board says to use a 12AU7 or
12BH7 but Uncle Ned from Triode Electronics really likes this tube. I spoke
with him and he wholeheartedly recommends it!
ECC99 pops right in, no mods necessary.Yes, we've tested these for a good long
time as phase splitters in both the ST70 & Mk3 boards. Uncle Ned
You can use the ECC 99 as pincompatible replacement for a ECC82. I have tried
them in a preamp and in a 300B PSE amp in the input section.The ECC99 work
fine. Lyn Olsen uses it, among other alteratives, in his Raven preamp as well
as his power and integrated amps.
I find them a little bright compared to my 5687.
I just changed my Dynaco ST70 to use two 6CG7s in the front end, and the 6cg7s
are a large improvement over the 12AU7s or 1 12au7 and 1 ECC99 i was using
before; the soundstage has a "vintage" feel to it now-- wide open, with
enormous midrange and upfront detail, and with warm, extended bass. With the
12AU7s, they had a much more laid-back staging, and sounded almost solid state.
I started out with RCA clear-top 6cg7s but decided to try out Ei/yugo 6cg7s.
The clear tops are now back in their boxes. I'm not sure yet about EIs
life-span, but WOW! Great sound at any price, let alone $10 per.
I am in the twin cities and have both a pre-amp and a recently built (still on
breadboard) ECC99 / 6B4G amp. email me at Sounds very good for
a 3W amp. More than enough power for me. A lot of detail, warm rich sound.
Everytime I turn it on it sounds better! Less grain more liquid and warm. Very
SET like
I like ECC99, 6H30 I am using one as an output tube in a transformer coupled
headphone amplifier I am building for a friend. First impression is that it is
somewhat warmer sounding than the 6H30Pi I had in the circuit before, but
doesn't seem to pass quite as much detail. This is operating with 210V on the
plate and 17mA DC current, BTW. It is an interesting tube, something I would
like to experiment with further.
Well, the 12AU7 is not as linear of a tube as a 76 or 5687. Tubes that I enjoy
and love a
27/76/56
WE396A/2C51
5687 or equivalent
ECC99
6N1P
6H30
6SN7/12SN7 etc...
These are really my personal favs for linestage use. The 12AXX series and 69XX
series (even the Amperex 7316PQ or Simens Gold Pin 7308...both of which I own)
don't come close to an *equally* well designed preamp using the above
aforementioned tubes.

Operating points
- has tested them, onfo on website
I am starting with the ECC99 at 200V, 6V bias. From what I gather there is no
advantage to using battery bias in a IT amplifier but I could be wrong.
I looked at that tube a few times and from the published curves, anything over
about 10 mA is not necessary to get into the low plate resistance region. I
think beyond that you are just using up the tube...
Keep your ECC99 in maximum opening working condition. 18mA is minimum plate
curent for that.
I have used these with 180 to 190 volts on the plate, biased around -5V, which
gives a voltage swing of over 200V PTP, current around 20mA. If you need more
swing, you raise the voltage higher on the plate. I like this tube more as a
preamp tube, as a driver it does the job, really low coloration and refined,
but lacking in excitement. As a preamp tube, it is full bodied, detailed, clean
sounding (low coloration), and dynamic. Perhaps I haven't found the right sweet
spot as a driver.
Hey-hey!!!,
If the ten watts is not a hard limit, you could run them at something like 180V
and run the plate dissipation to near its limits. I suspect you'll have a hard
time telling the diff betwen 7 and ten watts anyway. OHOH, since the 6Y6 has a
far lower plate resistance than 6L6, you could probably go to something like
4300 Ohm p-p( like the Dyanco A-470)which would net you a bit more power. I
suspect that the standard sort of exceeding of screen ratings for UL connection
can be observed to something like 170 or 180 V, and go for a 100 Ohm resistor
anyway....Douglas

In my power amps I changed the input tube from E80CC to ECC99. The E80CC was
already very good compared to the 12AU7 in that position. I wasn't expecting a
drastic improvement when I put in the ECC99, but after some minutes I knew this
tube is a winner. Compared to the E80CC I got an increase in body, bass and
dynamics, also more low level details could be heared and followed through the
music, in other words: better separation. The ECC99 is not a direct plug-in
replacement for the E80CC or the 12AU7.
The ECC99's filaments are rated for 6.3V @ 800mA, the E80CC requires 6.3V @
600mA and the 12AU7 requires 6.3V @ 300mA. Also the ECC99 uses more current,
I've biased them for 9ma, 4v on the cathodes and 130v on the plates.
I'm using the ECC99 in my own DIY KT88 PP amp:
Source --Sowter 9395 TVC -- ECC99 -- teflon cap -- 2c51/5670 -- IT LL1660
splitter -- KT88 -- LL1623 OPT
Since it's DIY I know the circuit very good. Before installing the ECC99, I
simulated it with B2 spice to know the correct values for the resistors. For
9ma I only had to lower the cathode resistor, biggest change is the DC heater
supply: it uses 400ma for one triode. If you know your circuit and you can
change it, I suggest to give it a try. You'll be amazed of the difference: much
larger 3D, microdetails and background instruments remain audible when
everything plays together, instead of drowing in each other. Just be sure that
you can put at least 7ma through it and that there's no problem with supplying
the 400ma for the heaters.

I am running this tube in a typical SRPP circuit(in the AN1.2 dac tube output).
With the setup I have it has a plate current of 7.2 mA. It sounded really good
(better than the 6N1P, 12BH7 and 6DJ8 I tried) but lacking excitment...its a
bit "polite" in the mid-bass. By reducing the cathode resistor I should be able
to run the ecc99 harder. What's your optimal plate current to bring back that
kick in the butt and keeping the sweetness of the music? The plate voltage was
supposed to be regulated by a pair of stacked 0B2 at 220V. The ECC99 has
brought it down to about 215V.

Pete Millett says: I run them at about 300V (across both tubes together) and
20mA in an SRPP headphone amp, seems to work well there. In general the
medium-high Gm triodes (E182CC, 7119, 7044, 5687, ECC99) all seem to sound
better run near their plate dissipation limits. Pete
ECC99 SRPP headphone amp

You get the best out of the ECC99 by running them with higher current.
Somewhere around 15 to 20 mA. I am used to running these at a higher voltage
than you are using in the SRPP, but that is in driver applications where one
needs voltage swing. In any case, you will need to look at the power supply
carefully, since you will probably need to reduce value of the dropping
resistor in the shunt regulator so that the VR tubes will still sink current,
and that the power supply can handle an increase in overall current.

Sounds like your 0B2s are under voltaged and not working in this circuit. If
you have a droping resistor before the stage try decreasing it's value to get
some more voltage. With 215v B+ and half across each tube in the SRPP the ECC99
could easily source 20ma for about 2 watts plate dissipation. Try 80-100 ohm
resistors. See triodeelectronics.com for tube data.

As a 200vpp driver, I'm using 12AT7WC for my VV32bSE power amp. The driver is
supplied by +b 500Vregulated, Rload 33kOhm, running at 7,7mA. 12AT7WC is direct
conected to the cathode follower ECC99, Rcathode 16.8K running 15mA, sounds
fast and tight, and has a nice band width. Heater is floating at 50V on 12AT7WC
and floatin with on ref on the ECC99
I am running mine at around 175V on the plate, 19mA current, using a 3.6V
(charged to 4.2V) NiMH battery pack from RatShack on the cathode. I really
recommend the battery bias option, much better than the BG FK series E-cap I
had for bypass, and you get the full gain of the tube. I didn't mention in the
previous post some of the design philosophy of the High Speed (Lightning?)
Aurora. The really wonderful thing about Gary Pimm's PP47 amplifier is the
stunning depth, immediacy, and really deep silences. Gary and I are convinced
this is the result of extremely low capacitances in the forward path - by low I
mean 1pF or so between the input and output section. Very low. This is an
advantage of the all-pentode signal path. I want to keep the triodes, but have
a way to reduce the capacitive load as much as possible. The buffering offered
by the GPimm current source mu-follower output drops the capacitance seen by
the input ECC99 to less than 1pF, and drives the 2A3 grid with a source Z of
less than 60 ohms. This, as you might imagine, implies a very high slew rate,
and freedom with the peculiar distortion that Miller capacitance and stray C's
imposes on the input input. The drawback of direct coupling without benefit of
a balancing choke is that the forward gain of 22 * 4.2 = 92.4, which amplifies
any small DC imbalance in the two halves of the ECC99. This is the classic
scope-drift problem, and constant twiddling on a balance pot is not the answer.
Fortunately, GPimm has designed a DC servo balancer for his PP47 amplifier
(time constant longer than 20 seconds), and a future version will appear on his
Website. Don't pester Gary about this gizmo, it's not done yet!!! He'll let you
guys know when it's done. Anyway, this is the part I'll be using in the new
Aurora. High Speed Aurora
http://home.pacifier.com/~gpimm/47.htm Gary Pimm's PP47


=== Andy Evans ===
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