IT-11 Audio British Blues Amp

Based on a very classic and well known 18W, with a tube booster …







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‘70s Fender Twin Reverb

A nice Fender Twin Reverb from 1976. Master volume, export version.



40 years old caps, I prefer to replace them …

Export version …

The voltage selector is dead :

I replace it with a new one from TAD …

Wiring :

Fender voltage selector

TAD Voltage selector

Hope this helps …

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Boss Chorus Ensemble CE1

A nice Boss CE1 to fix (in fact, the switch ON/OFF is malfunctioning … need to be clean up)

Anyway, here are some pictures of this nice effect pedal, hope this will help if you want to fix or build one.

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Neal Black Facebook page

Neal uses IT-11 Audio HonkMachine OD and Active ABY Box on stage !

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How to bias a Blackstar HT Studio 20

A nice Blackstar HT Studio 20. My customer asked for new tubes.

I do not have the schematic, but what I see is that this amp has a mix cathode / fixed bias system … so bias must be adjusted.

Edit feb 2017 : another Studio HT 20 to deal with. This time, I got the Blackstar HT-Studio 20 schematic !

First of all, connect a speaker cab, then plug in a jack in the input : input jack is used as a standby : no jack = standby on (no high voltage), jack inserted => standby off (high voltage applied to the tubes).

Bias and bal pots …

[1] Look at R221 and connect a multimeter, then adjust the bias pot. You must read 11.5V

[2] You can check the « bal » adjustment to have the same voltage for grid1 (pin5) for both EL34. On my customer amp, I can read :

  • Pin3 (anode) : 333V
  • Pin5 (grid 1) : -14V
  • Pin8 (cathode) : 11,5V

Hope this helps !

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PHP set cookie localhost not working MAMP

In case you can’t set a cookie from PHP when testing locally (localhost) with MAMP, you have to check « output_buffering » in your php.ini file.

Go to the right MAMP folder  that contains the php.ini file. Be careful, there is probably several directories related to php.

On my Mac (MAMP 2.0.5), the path is :


Default php.ini file :

Change to :

Then stop and restart MAMP !

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Deluxe 5E3 saturation

Here is a nice Tweed Deluxe 5E3 made by IT-11 Audio (see

This amp is great for blues and rock well known for its early breakup.  What is the first stage involved in this saturate tone ?

Here is the schematic : deluxe_5e3_schem

Here are the voltage (DC and signal AC 1kHz) for the IT-11 Audio Deluxe  :

No doubt that the cathodyne PI is the first to be overdriven :

Yellow trace : « input » : 12AX7 pin 7
Blue trace : « non inverting output » : 12AX7 pin8
« Clean » mode

Higher signal injected :

PI Spiced !

On this SPice model, PI enters saturation with a 40Vpeak signal (28VRMS). On my 5E3, it breaks up when input signal is 22VRMS … Real tube Vs simulation !

Here is the schematic simulated :

… and the non inverting output signal :

By the way : when you use your voltmeter to read the voltage at pin 7 of the 12AX7 PI, you read 17V or something like that : here is what happens (voltmeter impedance) :

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Tweed active AB Box

An active AB Box covered with tweed (Input A : harp, input B : lap steel, active output to amp), made for Cotton Belly’s singer (see Greatness video)

Very simple buffer :

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Ceriatone JTM45 !

A nice JTM45 / KT66 from Ceriatone, with IT-11 Audio 2×12 speaker cab and Gibson SG circa 66

Perfect combo ?

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IT-11 Audio Supercharger on stage

Neal Black plays this live concert on Supercharger amps, Honk Machine and Active ABYBox !

Manu Lanvin and Neal Black on stage

(see amp page :

See Honk Machine web page

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