Servicing & Restoration

Like a well performing vehicle, every now and then it's good to get a checkup to ensure everything is running as it should be. 

Biasing is the term given to the adjustment of the output devices.  Many people believe that only valve amps are biased, this is a bit of a myth.  To understand biasing we need to understand that to make a full wave we need drivers for the plus part of the wave and the negative.  This can be the pair of valves you see in the back of your amp, that is why valve amps generally have pairs or quads as their output valves, there are other configurations however this is the most common layout and is known as a Class AB.  The purpose of the driver be a transistor or valve, is to convert the low current of the signal into a high current designed to drive speakers. 

Due to the losses and construction of a silicon transistor/ MOSFET means that it does not start to operate until it has a minimum of about 0.6V to turn it on.  As you can imagine that levels below this do not get amplified correctly and gives the wave a 'knee' curve and non-linear operation as can be seen on the below graph.

 

Heat can cause a big problem in amplifiers, power supplies and in fact all electronic devices.

Heat can be caused by and cause drift on tolerances, component behaviour and complete failure as well as sound difference on solid state amplifiers.

We now use thermal imaging to show us component temperatures speeding up amplifier repair and ensuring that we get right to the root cause of the issue! 

mosfet thermal imaging

Regularly checking of valve biasing can avoid an amp being continually overloaded and stressing the amp out.  This resistor had burned and blew as a result of the valves going short and damaging.  The remaining valve was very worn, with regular maintenance and servicing the valve should have been changed quite a while ago!

Capacitors can dry out over time, however can progressively age quicker due to heat.  In Electrolytic capacitors the electrolyte is a liquid and can boil and expand under stress, either heat, drying or excessive voltage.  The picture shows a raised top of this capacitor, due to the deforming of it the foil had shorted causing a short across the power supply.  If this had not been discovered sooner it may have exploded, though not terminal would have created lots of white smoke.  Regular servicing could identify this before it becomes close to irreparable damage.  Book in your equipment now to avoid a potential failure!

 

we'll take on board most valve amplifiers and old solid state amplifiers for restoration.  We also offer standard servicing packages for valve amps

 Portable appliance safety and finding the illusive PAT 

 

Information on upgrades and modification categorised into Makes of amplifier.  We'll always consider a reasonable request for a modification, from FX loops to master volumes to adjusting tones.  Please be aware though that often what you read about on forums is hard to recreate in sound and therefore you may be disappointed by the actual final outcome.  We'll also take judgement, for example we get people asking to make their amp as clean as a Fender, with the overdrive like a Marshall, and the power of an Ampeg, you do have to be realistic.  We often refer our services to that of a car garage, you wouldn't take a small 1.6L fiesta to a garage and tell them you want to race it around a F1 track.

Tubesync is a beautiful blend of microprocessor technology controlling vintage valve equipment, it provides fully automatic and intelligent biasing control and power valve protection.

Sickamps is an authorised service point who can install, manage and tweak the system for you. 

Some modifications we've come up with over the years for Fender amplifiers

Some pedal mods we've done,  Simple items such as true bypasses can be added to most pedals. We've also come up with our designs and redesigned some existing pedals

Raise a support ticket

Raising a support ticket with the workshop is the fastest means to get your equipment repaired. Its quick free and easy to do. You can view past repairs and raise new ones once you have an account.
Repairs Failed
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Fixed under 5 Days
93%
Feedback Satisfaction
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