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    Fender Jack Socket Upgrade – £12

    May 31st, 2021

    Most of Fenders popular mid range amps like Twin 65, Hot Rod, Blues Deluxe and Junior are fitted with cheap plastic Jack sockets.

    A simple upgrade is to upgrade them with the vintage style metal chassis jack made by switchcraft as used on most guitars and all the old fender amps.

    The nice thing about this upgrade is you feel the benefit every time you plug in and play.

    No Comments "

    Trace Elliot AH250 bass head – £110

    May 31st, 2021

    Very old but working bass head. Heavy, tatty and simple to use.

    GP11 pre amp, Transformer fed DI.

     

     

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    Orange Rocker 30w combo. Fully serviced £450

    May 29th, 2021

    Exceptionally nice condition Orange amp from the early 2000s.   As I understand it that is quite an early Orange.

    It has been a regular gigging amp for one of my clients that wanted to try something more suited to clean tone like a Traynor or Fender.

    It is in very original condition with just and some light wear  to the corners and nick or two on the tolex and some evidence of stickers on one side. All of this could be hidden with a little paint if it was a bother.

    Features:

      • Original English made Celestion Vintage 30 speaker
      • New JJ Power Valves less than 10 hours use.
      • Original pre-amp Ornange branded- no microphonics.
      • All new from panel items all pots, jack socket and lamp holder.
      • Inside the amp is in as new condition with no circuit board wear and tear whatsoever.

    Come and try out this lovely amp.

    Comes with one-year guarantee on everything except the valves and a free service (excluding parts) in the first two years of ownership.

     

     

     

     

     

     

     

     

     

     

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    HiFi

    November 30th, 2020

    I don’t really work on HiFi, why you ask?  It’s a fair question and the reason is that there are just so many different makes, manufacturers that it is difficult to gather any experience on them all.  So there are a few makes that I like or have success with and I will accept them for repair projects.

    Some of these makes  are:

      • Marantz
      • Exposure
      • Cyrus
      • Most valve amps

     

    No Comments "

    Marantz Hifi

    November 30th, 2020

    I really love the sound of the old Marantz HiFi amps from the 1970s.   Walnut veneer chip board surrounds, glowing lights what a joy.  I don’t usually work on HiFi but here I make an exception.

    These amps are made to the highest standards and feature great transformers and parts top to bottom.

    A couple of issues I have come across and are worth sharing to help others.

    Crackling no matter volume level

    Seen on Marantz 4240 but applies across the range.  In this scenario the amp works as normal but produces a fairly constant rustling / sizzling bacon style crackle. The fault may increase gradually folowing switch on or be permanent.  Even with no input connected the fault is present and not effected by the volume control.

    The cause is leaky tone recovery transistors on the PCB driving the amplifier blocks.

    Worn Capacitors

    Everywhere on the internet people talk about replacing capacitors.  It’s a bit over stated.  Often their are visual signs like rupturing. leaks and yes these should be replaced in pairs but shotgunning the whole amp is wasteful of time and money and unlikely to be worth it.

    So concentrate on where it is needed.

      • visibly worn decoupling caps
      • interstage electrolytic coupling caps
      • Tantalum caps

    If you have one of these amps that you would like to sell either for restoration or parts donor I would be interested to hear from you.

    No Comments "

    Fender Princeton Reissue

    October 27th, 2020

    Cabinet resonance problems with the great little amps is a major nuisance. The cause is the chipboard baffle. This would have been ply in the old days but in Fenders reissue they have gone for a more affordable design choice.

    You may be able to fix yours just by tightening the securing screws up a little. It’s a hard life being a combo and they will loosen off in time.

    See below for an attempt to solve the problem with a little DIY cabinet rework.

    Steps

    Remove baffle add bracing at top. Some folks like bills used angle aluminium but this model already has had a ply brace added but it is just pinned in. Here I have added several decent screws carefully drilled in, glue and some additional brace.

    Refit baffle applying wood glue and adding additional securing screws.

    At the back of the amp I added a brace to reduce the rear panel resonating.

    Rear brace
    Great little amps
    Beefed up brace screws

    No Comments "

    Slim Devices or Logitech Squeezebox repairs

    June 25th, 2020

    These gadgets are fantastic streamers with a loyal community following. 

    One common fault is a drop in output from one or both of the channels. The fix is quite simple in most cases and I am doing these by post for £34 each plus shipping costs.

    If interested contact me for details.

     

    2 Comments "

    Matchless

    March 3rd, 2020

    They really are…


    Shock absorbing valve sockets
    Matchless Clubman 35

    Great build quality start to finish.

    • Carpeted capacitor bed. Though red tape is a bit of surprise.
    • Sealed pots
    • Paper wound transformers
    • All screws locked with sealant
    • Anti vibration valve sockets
    • Valve clamps
    • Ventilated pre amp tube shields
    • Neat wiring and point to point layout
    • Very low noise.
    • Anti vibration pad lined chassis

    No Comments "

    Mesa Boogie MK IV

    November 29th, 2019

    Too many controls on a Boogie’s front panel for me to be a fan but people seem to love them.

    This one below was cursed with a strange fault of bias instability which would lead to humming as the bias drifted off and ultimately to red plating after 30 mins or so.

    The cause of the fault was some sort of PCB contamination. I initially thought that this was some sort of chemical residue on the PCB but after much cleaning it didn’t really improve.

    In some conditions the amp would actually spark as voltage jumps between worn out circuit pcb paths as in the case of the bias supply or worse when adjacent parts of the pcb are a little too close. Then unrelated HT would jump to say a channel switching circuit. Take a look at the videos for examples of this.

    The solution in this case was to remove affected parts from the PCB and mount them off the board following point to point construction methods. The challenge here is the space. Boogies are famous for cramming a lot in so it is a very cramped working environment.

    No Comments "

    Fender Supersonic Twin 100

    October 14th, 2019

    Seen a few of these recently and worth sharing some problems and interesting solutions that I have found.

    Fender no sound or fading sound

    If your amp produces no output and the lights on the back are flashing about then you might have a faulty autobias unit.

    The auto bias unit fitted to these amps,  as well as some Fender Bassmans I believe dynamically control each valve’s grid bias thus ensuring that your amp’s valves stay perfectly adjusted no matter what the wear level or matching level is with the tubes. The board does this by measuring the bias current and comparing it with a reference signal and adjusting the grid bias accordingly in fact it does this thousands of time a second thanks to an innovative little chip. You can adjust the control a little as well between cold, medium and hot levels which is nice.

    Unfortunately this innovation seems to be a little unreliable. The two issues I have observed are either: 1), unreliable cables connecting the auto bias unit on the amp’s rear panel to the main PCB,  or 2)  a faulty autobias unit which seems to either permanently fail or work for a moment at start on and then fail with flashing lights and no sound. Fortunately the board fails safe and pushes the power valves bias way into cut-off silencing the amp but protecting those precious tubes. So, what is the solution to this annoying issue?

    Well you could just replace the auto-bias unit and hope that it works out ok. However the amps that I have seen with this fault are just a few years old and so I wonder if replacing the autobias unit could be a just a temporary short term solution.

    What about another approach such as down grading the amp to a simple bias pot and accepting that you need to always use well matched valves. Well that is an option and just what one of clients recently asked for as he was fed up having an unreliable amp.

    In theory this should be quite a simple mod but the complication lies in the fact that this amp has two operating levels: club and arena and this means two different bias levels rather like the Famous Fender The Twin (or evil twin) from the late 80s.

    With my mod you preserve the club and arena feature by automatically switching between two bias levels as you move between the two modes.

    The mod consists of removing the auto-bias PCB completely and replacing it with a tag strip of parts, a bias pot away from the hot power valves.  The bias pot is located on the underside of the amp near the effects loop well out of the way of the power valves and does not add significant noise levels.  The result is an old school amp and one that is much more reliable.

    This seems like a downgrade but really it is copying the design of the Fender twin which has been successfully powering amps that belong to some of the world’s most successful musicians. So why not?

    Fender Supersonic Crackling Noise

    Another problem with these amps is excessive cracking noise. This sounds a bit like crackling of old plate resistors or more descriptively the same as sizzling bacon in a frying pan; just a little louder and really annoying. It certainly does not have any vintage amp charm. None at all. In the case of the most recent amp it was impacted by the reverb control which can be helpful to know when trying to fault find such an issue.

    What I have observed is issues with internal layers in the PCB multi layer board. The layers have broken down and make am unreliable connection and that gives you a crackle through your speaker.

    If you have been affected by these issues leave a note on this page or get in touch to book yourself in for repair.

     

    No Comments "

    Vox AC15

    May 19th, 2019

    Restoration project of a 1962 Vox AC15.  Clearly seen some earlier work clue being the orange drop capacitors fitted around twenty years ago.  Most of the carbon composition resistors were high asnd showing signs of surface cracks so all replaced.  The Mullard valves appear to be original and in fine working order.  What a  great find.

    No Comments "

    Wurlitzer 750-E

    June 2nd, 2018

    All the way back from 1941 this is got to  be one of the oldest amps that I have worked on.  Pair of 6L6 output power valves red chassis, lots of rust – sounds good as gold.

    Bit of history with this amp as it was stationed in Pearl Harbour back in the day and presumably saw some action.  Later on it found its way over to the UK at some point where it has been waiting for restoration for some time.  Virtually all of the old resistors were drifted so much in value that the amp would barely output anything.  That restored and a few worn out valves replaced and the amp is back to full power.  Not surprisingly it sounds great and distincively to a different era.

    Wurlitzer 750-E

    2 Comments "

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