Andrews Amp Lab A50 Plexi - Express Shipping - (AAL-A001)


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A-50 Head

The A-series are the original Andrews amps. The design and tone is inspired by classic “plexi” style amps of the late 60s.  We start with the classic 50 watt plexi design. Then we add bias test points and voicing refinements to eliminate the need to bridge two channels. Then we install a post-phase inverter master volume control and added slightly more gain to achieve the cranked tone at reasonable volume levels. Additionally, original plexi amps have a capacitor on the volume control that boosts treble.  This was originally good idea because vintage guitar cables, effect pedals caused a big loss of treble as did well-used “greenback” speakers. With the advent of modern cables, effects and a variety of speakers available, the treble boost can sometime be too extreme. Some players get their amp modified to remove this capacitor.  We have reduced the effect of the boosting capacitor and added to pull switch to switch it complete off when desired.  A great deal of time and effort were spent selecting the perfect components to create a finely tuned tone machine that will take you back to the best of those classic vintage British style sounds and improve reliability.  The A-50 amps feature hand-wired construction, American-made transformers, custom designed chassis, heavy duty turret boards, compact size and reasonable weight.  The “small box” heads also more portable than the giant vintage designs.  Tube layout consists of three 12AX7s and two EL34s.


Hand-Wired Construction – Sometimes call “point to point” wiring ensures solid durable long-lasting reliability. There are no copper traces to burn or peel away. All components are hand soldered to heavy duty turrets, tube sockets, pots, switches, etc.  The amps are road ready and roadie tough.  Sockets are mounted to the chassis rather than the boards so that heat and vibration don’t break down the solder connections, the board or other components.

American-Made Custom-Wound Transformers – The A-50 amps feature very high quality USA transformers that meet our stringent specifications to meet the exact requirements of the amp designs.  The power transformer is custom wound to deliver lower plate voltage than the off-the-shelf units that many other builders are using.  The lower voltage delivers a “browner” sound without the harshness heard on similar amps.

Straightforward Dependable Single Channel Design – Simple to operate, solid classic design.

Custom Designed Chassis and Turret Boards – We utilize very heavy-duty G10 turret boards and custom designed chassis. We custom design the critical parts to insure that every part in mounted it the correct location for optimal tone, stability and durability. Using the custom components adds to the manufacturing costs but we feel it is necessary to achieve the highest quality product.

Compact size and reasonable weight 

This amplifier is pre-owned and in excellent condition!

We are closed Sunday and Monday but will respond by Tuesday. If a guitar is purchased on Saturday, Sunday, or Monday it will be shipped on Tuesday.

It is our belief that the right instrument can be truly inspirational.  If you have ever experienced the bond that can occur with the right guitar, you understand what we are all about.  We pride ourselves in having the finest instruments around and treat each one with the realization that it is someone's dream guitar.  

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