REPAIR SERVICES

AMPLIFIER REPAIR SERVICES

Nottingham, Derby, Leicester, Lincoln, Chesterfield

40+ Years of Experience

I have over 40 years of experience in refurbishing and repairing valve amplifiers to the highest standard.  Read more about my background.

My pricing page will give you an idea of likely costs.  

I will need your amp make & model and approx. year of manufacture and a description of the problem or service you are looking for. 
Vintage valve amp repair policy:

If I am requested to undertake any work where components are replaced, I will ensure all old components are returned to the client with the amplifier.
On vintage amps, components will only be changed if absolutely necessary and with suitable quality replacements.
I will undertake modifications if requested - example Fender SF to BF conversions, but only after discussing the implications of such changes with clients, I am a firm believer in keeping amps as original as possible (I have 4 unmodified SF Fenders of my own, which to my ears sound fine just as they are!) 

Typical valve amp issues:
Over the years of repairing valve amps, I have found that faults generally fall into one or more categories and these can be identified (and often rectified - parts permitting) within the first hour.
  • Valves problems - low emissions, grid shorts, physical damage, loss of vacuum,  O/C heaters etc.
  • Transformers - shorted turns, internal arcing, underrated from new causing overheating and eventual burn out.
  • PCB faults - dry joints, cracked tracks, faulty valve bases, often caused by excessive heat over time..
  • Component failures - high wattage resistors O/C, electrolytic capacitors, carbon comp resistors out of tolerance, reverb tank spring or transducer failures etc.
  • Physical damage - the amp has been dropped or fell over in the back of the van, causing one of more of the above.
  • Broken switches, pots, sockets due to misuse over time.
  • Solid state component failure - op-amps, transistors e.g. reverb drivers, relay switches etc.   

Miscellaneous services:
  • Fault finding general repair of non-working or faulty amplifiers.
  • Bias check & adjust, using TAD Biasmaster BM2.
  • Electrolytic capacitor replacements (cap jobs).
  • US to UK voltage conversion (mains transformer change).
  • Modifications or upgrades as per customer request.
  • Reverb tank upgrades.

Valve check & safety Inspection:

General amp health check, recommended prior to putting an amplifier up for sale, or before the start of a new gigging season..  
  • Physical inspection of amp in current state - report findings.
  • Remove all valves, carry out full test using Orange VT1000 valve tester & Mercury 1100 valve tester for rectifier valves.
  • Check / adjust bias.
  • Carry out physical safety inspection, PAT test & label.
  • Soak Test (see major service for details).
  • Produce report for client.

Valve Amplifier Major Service:

Physical Inspection of cabinet and hardware:
  • Check main cabinet for damage / rigidity
  • Check security of baffle board to main cabinet.
  • Check security of speaker to baffle board.
  • Check security of reverb tank.
  • Clean inside of cab
  • Remove speaker and carry out physical inspection of cone & suspension – extra if requested.

Physical inspection of Chassis and electronics:
  • Remove chassis from cabinet, undertake physical inspection.
  • Check for dry joints particularly around areas of heat e.g. valve bases, high wattage resistors etc.
  • Check integrity of resistors (particularly any carbon comp types).
  • Inspect electrolytic capacitors for leakage.
  • General inspection of cabling.
  • Check security of transformers / choke.
  • Apply switch cleaner to potentiometers, switches and sockets.

Valve test:
  • Remove, test and grade valves using Orange VT1000 valve tester & Mercury 1100 valve tester for rectifiers, log results.

Soak test:
  • Check / set bias adjustment - adjust within data sheet parameters to clients' preferences.
  • Connect signal generator to amp inputs, inject 1kHz signal.
  • Connect dummy load to amplifier output (4, 8 or 16ohm).
  • Monitor signal waveform on digital oscilloscope, measure and log RMS voltage readings at point of clipping and max output.

Safety Check:
  • Carry out physical safety inspection and PAT test and label.

Reassemble:
  • Guitar sound test, checking all inputs, controls, foot switch etc.
  • Issue completed job sheet to customer.




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