April Birthdays 
Hi all,
Charlie Hall (Hank Marvin's echo engineer) is coming up with a preamp analog pedal(EF86 Project)that will emulate the 2 different EF86 circuits from the AC15 models of 1959 and 1960 which will reproduce the very sought after early Hank sound.
The unit should be available before Christmas at a price around $200 US.
It should be about 6"x4".
I grabbed for those interested and conversant with the electronics (unlike me), some of the precision Charlie added in answering people's questions after the specs presentation below:
Here is a list of the main features taken from the draft user manual:
-
Quality steel casing with attractive burgundy powder coated finish for superior ruggedness and long life.
-
All analogue solid state design emulating closely the sound and harmonics generation of the British 15 and 30 watt amplifiers known as circuit 2 and circuit 3 from 1959 and 1960 respectively.
-
Power amplifier emulation circuits are included. These feature distortion and overload characteristics as well as crossover distortion and compression and sag normally heard only with push pull power amp design (as opposed to single ended power amp design) guitar amplifiers and the amounts of these effects can be simply controlled with the TONE and VOLUME settings.
-
A speaker emulation is included. This can be switched on or off.
-
A MASTER OUT level control is included to ensure that optimum signal levels are transferred to the next item in the signal chain.
-
A footswitch for true bypass signal flow with red LED indicator (the input sensitivity and impedance will vary with the selected settings and will be the same as the amplifiers being emulated when the unit is unbypassed with the footswitch. Otherwise, when bypassed with the footswitch, the sensitivity and impedance will be that of the equipment connected to the output of the EF86 Amp Emulator, and the length of the cables connected to the input and the output of the EF86 Amp Emulator can affect the sound because of the total signal cable capacitance. This is true of any equipment that features a true bypass.
-
Powered by a separate 12V AC power adaptor to help eliminate frustrating earth (ground) loop hum problems. Does not require any kind of battery power.
The unit should work perfectly with the normal channel of your amp. You would most likely want to turn off the speaker emulation of the EF86 Amp Emulator.
This unit does not contain an EF86 valve, it has solid state circuitry that emulates 2 different EF86 circuits from the AC15 models of 1959 and 1960
The unit can be used with or without a guitar amp. It has a speaker emulator that can be switched out when used with a guitar amp.
the pedal also incorporates an output stage emulation with levels compatible with the input stage of an owner’s amp.
The pedal would usually go last in the signal chain, just before the guitar amp, or mixing board line in, or computer line in.
The EF86 is a valve that was used in early Vox amp designs from 1959 and 1960. The EF86 is a pentode high gain valve that has a somewhat different harmonic structure than the usual triode valves like 12AX7/ECC83 etc. This in conjunction with the amp designs at the time gave a sound that is difficult to replicate on newer amps, even Vox ones.
My EF86 project is an amp emulator that includes the sound of the 1959 AC15 EF86 channel and the 1960 AC15/AC30 EF86 channel. It also includes a power amp emulator that can give the overdriven sound and compression sound of a Vox power amp being driven hard, at any desired output volume level. It also includes a speaker emulation circuit that can be switched in or out. It sounds very good when connected between the echo unit and the normal channel of a Vox amp.
The unit would be very useful if your Vox amp does not have an EF86 channel. The only modern Vox amps that had the EF86 as far as I know were the first versions of the AC15/AC30 HW. They are no longer produced.
There won't be presets. It works as though it is a 2 channel amp, selecting one channel or the other, with each channel having a volume and a tone control, so yes, you set by ear.
This unit will not contain actual EF86 valves or any other valves.
It will use solid state components to emulate the sound of the Vox EF86 channel versions known as circuit 2 (Apache, Quatermasster's Stores) and circuit 3 (many other early Shadows hits)
Blessings,
Abdel
Last edited: Oct 20, 2019 22:54:06
