Bourdet-Luxe Amplifiers

The inspiration to build a custom tube amp came after a rainy visit to Altadena CA to see the great Ry Cooder perform.  I kinda elbowed in to get a closer look at the amazing gear onstage and ended up enlisted to help carry his various 1950s tweed amps in rain soaked dash to his car at the end of the show.  I walked away that day with the smell of wet tweed in my nose and a big desire to have the sound, look, and feel of those magic amps for my own music making.  Credit must also go to my amp mentor, legendary tech, Mike Franceschini who I got to watch work on a number of these classics, and hear the results.   

 

I chose to base this amp on the most famous “tweed” of them all, the Deluxe, albeit with a much larger cabinet size to shift the resonant frequency down lower, give a bigger feel and tighter sounding low end.  The front end of the amp is altered to allow for a 12ax7 to be used in the first gain stage instead of the traditional 12ay7. This is done in such a way so that the added gain from the 12ax7 doesn’t oversaturate the amp, rather it adds high frequency detail and great dynamics.  Several different value components were chosen at strategic parts of the circuit, generally to promote great harmonic distortion and to let it propagate up the frequency range before attenuating some low end further down the audio path.  Different potentiometers were chosen to give a more usable range of volume sweep than a traditional Deluxe circuit.   The wire routing and grounding scheme of this amp was copied quite closely from a great sounding 1956 Tweed Deluxe owned by my friend and bandmate Connor Gallaher, the thought process behind that choice being, “don’t mess with success.” 

 

New old stock SoZo 1st generation film capacitors were chosen based on my knowledge of and affection for them when I worked for the boutique company 65amps.  Sprague and MOD electrolytic capacitors have proven to be highly reliable in various repairs I’ve done.  Hammond Transformers from Canada are wonderful and robust.  12” ceramic magnet Celestion speakers are simply my favorite speaker for electric guitar.  Several new old stock and old stock parts are used in the making of these amps, the continuation of their use is based on availability and, inevitably, may be subject to change. However, instead of accepting any quality decline due to part availability, I vow to simply discontinue this amp if I ever determine that a part substitution compromises the performance or quality of the product. 

 

These choices I made in components and design are based off my experiences working with boutique amp companies Matchless and 65amps, a general desire to use lots of made in America parts, from playing guitar in various club and recording situations where the value of elegant simplicity became so very obvious, and, to a certain extent by pure intuition.  I sincerely hope you enjoy creating music with it. 

-Joe Bourdet  

 

Channels:

The “Normal” channel is optimized for brighter and lower output Fender style single coil pickups.

The “Bright” channel is optimized for more powerful Gibson style pickups and other humbuckers.

The input marked “2” on each channel has a significant attenuation on the signal and is intended for ultra hot signal sources that might unpleasantly overload the preamp.  

I recommend that your starting point be the “1” input on the “Bright” channel for all instruments, and you can audition other channels as desired. 

 

Specifications:

-Famously reliable 15 Watts Class A vacuum tube circuit design.

-8 and 16 Ohm speaker output jacks for use of external speaker cabinets.  Caution: use only ONE output jack at a time, never both. 

-Transformers by Hammond Manufacturing Canada. 220v - 240v transformer for international use is available upon special order

-Uses highly reliable and commonly available tube types: 6v6GT 2pcs., 12ax7 2pcs., and a 5y3 1pc.  Matched pair replacement tubes may be installed by the user without any adjustments to the circuit. 

-Solid Pine cabinet with Birch plywood speaker baffle and back panels.  

-“Tweed” cotton twill wrapped cabinet with nitrocellulose lacquer that is mildly relic’d.

-12” Celestion speaker. Either: 8ohm G12-H30, or 16ohm G12-65.    

-High quality Belton tube sockets are so snug and reliable, they eliminate the need for tube retainers.  Tube shields are also omitted as they impact the tonal quality.  

-Fast, low turning resistance Bournes potentiometers.

-2 amp fuse.

-Pilot light bulb is a type 47.

-A standby switch is present for muting the output for brief periods when switching guitars etc.  I do not recommend it be used for startup and shutoff of the amp or for long periods of time.

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Warranty:

5 year parts and labor. 90 days for the tubes. Modding the amp, mis-matching output impedance or running power soak devices will void the warranty.

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A word on microphonics, and physical rattle:  

This amplifier is loud, has high gain, is in a very resonant solid pine cabinet, and closely follows a perfectly imperfect design from the 1950s, inevitably, some microphonic tube behavior and physical rattles will be present and may at times be audible.  Effort has been made to minimize these artifacts, but eliminating them is unrealistic given the components I want to use.  Therefore please consider these sounds to be part of the charming character of a lively analog tube amplifier and remember that no digital emulation yet can recreate this stuff.