PSIL O GRAM™
547 C Via Estrada, Laguna Woods CA 92637
E-mail firstname.lastname@example.org (310) 454-4651
USER-ADJUSTABLE EF86 / 6267
TYPE VACUUM TUBE ADAPTERS!
HOT-LINK HL-86 adapters shown above with
► Plug-in adapter converts the EF86 / 6267 socket mini-bias PLATE voltage control at front
in your amp to easy-to-get alternate tube types. No center.
tools needed; zero amplifier modifications required. Adapters are fitted with 6AU6, left and smaller
► Special circuitry cuts hum, noise, microphonics, 6AK5, right. Retainer springs may be adjusted
to fit a variety of socket types or omitted if
and improves detail retrieval.
► Mini-bias control unleashes wide shifts in tonality Each background square is ¼ inch in size.
and dynamic range.
► Safe for use in all EF86 / 6267 MI applications.
► Choice of 25 (!) inexpensive and electrically compatible “top tube” types furnish you with
convenience, economy and expansive range of voicing options.
Now there is an amazing new way around all of the guesswork and gambling when
considering buying EF86 tubes. And it even saves you money in the long run. How?
Introducing the first in a series of special plug-in linking adapters from Psilogram: The
Hot-Links brand EF86 adapter, model HL-86.
The ingenious EF86 was originally developed sometime after the venerable 12AX7 and
presented a best-effort example of the kind of performance that a low-noise small-signal
audio pentode could provide. The best units from the good old days had gain and noise
performance so attractive that it inspired many musical instrument and hi-fi amp
designers to use that tube as the valve manufacturers intended, namely, to improve
performance and cut costs of the gear then being made.
Since then the best vintage examples of the EF86 / 6267 tube types have become very
scarce and very expensive. The Psilogram HL-86 adapter was created to address these
issues by solving several problems at once.
The HL-86 fix is a two-part solution, consisting of a
custom 9-pin to 7-pin adapter designed to easily and
directly plug into the 9-pin EF86 socket in your
amplifier, and specially designed circuitry inside the
anodized aluminum link housing.
The 7-pin socket on top of the HL-86 is intentionally
designed to accept a variety of commonly available small-signal pentodes, such as the
6BA6, 6AK5 or the venerable 6AU6, to do the job of voltage amplification. The small
adjustment knob on the side of the adapter body is the mini-bias control, which permits
the player to adjust key tube electrode voltages and the amount of current flowing
through the adapter/tube combo. The control may be easily adjusted with the fingers, or a
small + or – screwdriver may be used as well.
Rest assured that this product is NOT merely a simple
adapter fitted with nothing but wires connecting plug and
socket pins together inside the aluminum housing. There
is a small amount of additional circuitry inside which
adds amplification and kills off hum, noise and
microphonics. Without the internal circuitry, the 6AU6
(or any tube for that matter) would still be hampered with
the same old pathological tube noise sources in a high-
Here's some HL-86 facts and features highlights:
Lower the noise floor of your amplifier.
The adapter’s noise performance does not depend on the electrical condition of the
(normally functioning) tube on top! Experience the mausoleum-like silence from the
front end of your amp, possibly for the first time, and hear details previously hidden by
hiss, hum, crackle, microphonics and other crud that can originate at the front end stage
of your amp. You won’t miss those players once they’re banished…
Eliminates front-end heater hum.
Using AC on the heaters of high-gain valve audio amplifier stages almost guarantees
some amount of hum will be introduced into the audio path. A 6.3 volt AC heater circuit
means that nearly 18 volts peak-to-peak will be present inside the tube whose job it is to
amplify the guitar pickup signal by tens or hundreds of times! Thanks to the circuitry
inside the HL-86, the front-end hum interference from the AC heater power is killed off.
Acoustical coupling from the loudspeaker to the input tube is also left behind! No more
howling combo amps from microphonic EF86 tubes situated next to speaker cones,
regardless of gain settings! Fit the adapter to the amp’s ’86 socket, and gently tap the tube
in the adapter while it is on; no ringing can be heard! Instead a soft ticking sound may be
heard, and only when the amp’s gain is at or near maximum.
Zero modifications to your amplifier.
Plug-in module means no modifying or hacking up your prized new or vintage amp!
Switch between the HL-86 and the stock EF86 as quickly and easily as changing a tube.
Preserve your amp’s value by leaving it in stock form. Yet still get the tone you crave,
free from hum and noise marring the sound. The HL-86 puts the same or less of an
electrical load on the amp’s circuitry as a standard EF86, and it is safe for use in all
standard EF86 applications.
Relies on inexpensive and easily available pentodes for amplification.
Uses plentiful high quality USA-made tubes, with no sorting or other hassles, and costing
a few dollars surplus from many different suppliers. Designed to use standard 6AU6
sharp-cutoff tube or alternate 6AK5 or the exotic 6BA6 remote-cutoff type, which
together with the mini-bias control, leads to new and different tonal territory that the
regular EF86 cannot reach. Never pay 30, 60, 90 or whatever dollars for unknown or
unreliable EF86s again! Plus, the tube used on top of the adapter should last many
thousands of hours in typical use.
The HL-86 is designed around freedom of tube-type choice, and this we provide. Here’s the list
of the other 22 tube types that may be used with the adapter:
6AG5, 6AH6, 6AJ5, 6BC5, 6BD6, 6CE5, 6CG6, 6HR6, 5590, 5591, 5654, 5749, 6096, 6136,
6186, 6660, 6968, 7543, 8425, 8426, 9001 and the 9003. Tube numbers in italics are remote
cutoff types. Many of these can also be found for a few dollars or less at assorted vendors. Be
careful to first thoroughly research other types you may wish to try that aren’t on this list.
Adjustable mini-bias control.
On-board user-adjustable and finger-compatible bias
control furnishes the player with a wide range of tonal
shifts and a variety of dynamic responses. Sweep the
input stage bias from end to end, harmlessly raising and
lowering the plate voltage, and shift the tonality from a
full and round sound with big dynamics and an explosive
attack profile, to one that is crunchy and constrained,
with forward treble and limited dynamics…or anywhere
in between. Always a revelation to explore the variety of tonal character and personality
that was previously hidden, and that this control will reveal.
Preserves full voltage swing from the input stage.
No need to throw away half of the input stage’s voltage gain and headroom, as seen in
dual-triode tube cascode substitutes offered elsewhere. Full voltage swing and response
means that all of your amp’s downstream tone and gain/drive controls may be left at your
favorite familiar settings, instead of cranked up to compensate for losses produced by
certain other EF86 substitution methods.
Each HL-86 adapter is furnished with one set of malleable retainer springs as shown in
the photographs, and your choice of one of these three tube types: 6AK5, 6AU6 or the
6BA6. If none is specified, the 6AU6 type will be included with the adapter.
Here’s the general tonal character you may expect when using the top-tubes tubes in the
The 6AK5, a sharp cutoff pentode, has a medium dynamic character with good tonal
range sweep heard when adjusting the mini-bias control. It is the “roundest” of the three
types and has the most bell-like tonality of the three in some amplifiers.
The 6AU6 is a stronger sharp cutoff pentode, with somewhat more dynamics and a shade
more punch depending on the bias setting. It is a more linear tube in this application, and
is best at hitting the “known-good EF86” tonal bulls-eye. This depends a bit on the amp
The 6BA6 is a remote cutoff pentode, and this produces a slightly darker tone, with
unusual “large-curd” middle distortion response and overload sounds, depending on the
bias control setting. Interestingly, when the control is turned clockwise and the plate
voltage is raised enough, the 6BA6 will start clipping on positive peaks giving bright
highlights to the louder sounds. The player may adjust exactly where this effect kicks in,
at ƒ , ƒƒ, ƒƒƒ, and so forth, adding emphasis and even urgency to the sound magnified by
the amp stage.
Incidentally, the terms “sharp cutoff” and “remote cutoff” refer to two families of tube
construction, purposely designed with different internal physical structures for different
electrical behavior. The sonic differences are quite audible in this application.
Once installed, the adapter will give you the means to simply and safely alter the
character and personality of your amp for less than the cost of a good tube-based effects
The HL-86 is $94.95 including 6AU6. And if you prefer, you prefer to substitute the ‘AU
for the 6AK5 OR the 6BA6 / 5749 at no additional cost.
All three of the compatible tube types may be ordered with the HL-86 for an additional
$10.00, total price of $104.95. You’ll soon be wanting to explore them all…
For more information, please contact the sales desk at:
PSIL O GRAM™
Or Voice: (310) 454-4651