Dekox Technology Solutions

A vintage pair of pioneer speakers brought in for a check up. While the capacitance values of the electrolytic capacitors in the crossovers seemed to be within tolerance, their ESR readings were less than desirable. At the request of the customer they were changed out for new polypropylene capacitors with extremely low ESR values. When returned and tested out by the customer, his words were, "Wow, what an improvement!😎".

Another dead on arrival unit. A dbx 231s equaliser. Power supply filter capacitor had reached the end of its life, which then shorted out the rectifier diodes, which in turn took out the fuse protection. An additional capacitor in the PSU was also changed for good measure as it wouldn't be long before it would also be on its way out. All up and working again.

Dead JBL LSR308 studio monitor came in for repairs. All up and working again after identifying the problem on the input side of the power supply.

A customer's DIY Guitar tremolo pedal came in for a checkup. Connections and solder joints given a look over, with a few connector leads trimmed down to prevent them shorting out against the metal enclosure.

Marshall VS30r came in for repairs. Power surge to the input caused tracks on the circuit board to blow and burn out. All active components on the preamp side also blew. Tracks repaired and a few components replaced, however two of the needed components are no longer in production, or easily available, with no equivalents to substitute them with. The best solution was to manufacture mini circuits that provide the same function and piggy back them into the space the original components occupied. All good and working again.

Vox AC15 in for a service. Was in a storage facility for a year gathering dust. Was given a full clean up, sockets and controls included. Preamp tubes still tested good, but power tubes needed replacing. Owner was very happy, and reported back a few days later that it has never sounded better. Some hum and buzzes that it had ever since purchasing it were now also gone.

Elk FD-61 amp came in for a service. This is a transistor based amplifier model vs the other tube based Elk amp models that are normally seen going for sale on groups. While in for a service it was found that it did not have an earthed power lead, and additionally had the famous death cap installed. Due to having experience in being zapped by a similar amp long ago, the owner gave the go ahead to remove the death cap and install a proper three core, earthed power cable.

Vintage Melody 306 tube amp came in for some TLC. Based off of a Lectrolab R609B, which is based off a Harmony H-306A, but with changes in some tube and component values with each iteration. Origional tubes still tested good, so no need to replace any of them. Death cap and two prong power cable removed and replaced with a three lead earthed power cable. Speaker tear repaired and passed the Rub and Buzz test afterwards on the analyser. All electrolytic caps replaced as they were mostly all dead, so no more super loud hum. Some leaky coupling capacitors also replaced, and other parts in the tremolo circuit. In the end, a very clean and "quiet" sounding amp back to its owner.

Cheap switch on a CNC controller that is only a few months old decided to fail. Replaced it with a more solid and durable one. The replacement also has a built in LED, so it was wired into the board to give a bright indication of when it was powered up and not left on to drain the batteries by mistake.

Fender Single Showman Amp came in for the full treatment. A few capacitors on the power supply section were leaking, and a few other also tested way out of tolerance. All electrolytics were therefore replaced. Resistors were all checked, quiet a few had drifted to double their original value, so they were also replaced, which included the screen and grid ones that sit directly above the heated tubes. Somewhere in its lifetime the amp was worked on by someone before, and the bias control was removed and hard wired. A new bias pot was installed and bias correctly set. The vibrato intensity was very weak to none functional. This was traced to the dead opto "roach". A new one was made up and fitted to bring the vibrato back to life again. It was discovered through conversation with the customer that they were running the amp with a dual Showman cab wired at 16ohms versus the cabs normal 4ohm configuration. The single Showman however requires a 8ohm cab load for optimal performance. The best short term cost effective solution was to pull two of the four power tubes which would now match the amps output to the 16ohm cab. As the customer only uses the amp for low volume home playing, the loss in power from not running all four output tubes was not a big issue for them.

Greer Amps Lightspeed Pedal came in for a repair. It's a bit of a problem when you pay top $ for something, but the maker "goops" the whole circuit board in a tacky resin to prevent people copying their design, but also makes future repairs extremely difficult to near impossible. Even when possible, it pushes up the repair costs for extra time and labour involved in trying to work through the hidden maze of buried components. After cutting and stripping a whole lot of the "goop" away, the pedal was finally repaired and sent on its way.

Locally made Craig Amp came in for a service and cleanup. Besides all the dust, some moth eggs were found hiding on the speaker cone. These were carefully removed so as not to cause any further damage should they have hatched. The reverb tank had come loose, and attributed to the very short screws used to attach it to the base of the cab. New longer screws were inserted to give a more reliable hold down. All the usual tube, electronics and control checks and cleanups were done.

H&K Triamp came in for repairs because of channel switching issues. It had already passed through two other local techs before reaching me. On opening it up, I found a mysteriously soldered in yellow wire that didn't belong in there. One side was soldered to a tube pin, and the other side free floating. A high potential for the current and further future damage. After removing it, and troubleshooting the amp, a whole lot of damaged transistors and other components were detected on the switching circuit side. One of the drive pots on Channel 2 was also found to be open circuit. After replacing all the faulty components, the amp was back to working condition again.

Fender amp footswitch controller came in for switch replacements. Old ones had seen their day.

Nebula by JP Le Roux Amp Works came in for a service. 12AX7s all checked out good. New set of EL84s installed. All the other normal checks and cleaning of internals, inputs/outputs and controls done.

9PM on a Sunday evening and the work never seems to end at the home of Dekox Technology Solutions. The electricity supply to the neighbourhood has been out the whole day due to "planned maintenance" at the local substation. On power finally being restored close to 7PM the switch on surge caused the home alarm panel to go dead. After some emergency tracing and fault finding (nobody wants to go through the night with the security down), a shorted 1N5401 (100V / 3A) diode was discovered on the control panel. Fortunately I was able to find a RM4Z (250V / 3A) diode in my workshop as a replacement. Once fitted everything was back up and running again. Outside beams armed, family safe, home and workshop contents secured, time to sleep.

MESA Dual Rectifier came in for a service. Two of the controls were found to be non responsive and internally damaged (plastic inner pieces had decayed). This could be the result of not using the right stuff for the job when doing it yourself or sending it to someone inexperienced. As the specific control pots are non standard values, the local MESA agents were contacted for replacement parts. They were however not very helpful, so the parts were ordered directly from MESA USA and received in order to fit and get the amp up and running to full spec again.

Boss DD-3 Digital Delay came in for repairs. The output was the constant dry input signal whether the effect was disengaged or engaged. After signal tracing and only under high magnification was a micro fracture discovered in a solder joint on the effects level control. Once resoldered it was back to normal operation again.

GENZ BENZ Bass Amp came in for a service and small repair. A world of difference to the sound after all was done. Don't underestimate the power of having your amp serviced and maintained. Pay small now, rather than big later.

A few guitar pedal repairs that came in. A dead Danelectro Fish & Chips. A faulty Pitchblack tuner. Two Boss pedals that the customer requested new footswitches installed which fortunately I had my own stock of as they are not locally available.

Hand made by Dekox. Order yours today for R850.

Be the master of your big valve amp. The preamp attenuator lets you tap into your saturated preamp tube tone at a fraction of the volume you'd usually need.

This attenuator is a useful tool which are placed between the preamp and power amp section of a guitar amplifier. In essence, you can reduce your volume without losing quality on preamplification tone.

Simply put the box in your amp's series effects loop and turn the single volume dial to your liking. This adjusts the amount of signal sent to your amp's power section. Your neighbours and family will really appreciate what it can do!

Also useful for amps like the Fender Hot Rod Deluxe, and Blues Deville where you can't get the volume past 2 in a room without blowing the doors down.

Passive circuit (No battery required).

Only works on amps that have a send/return; line in/line out, effect loop or something with a similar name.

Note: This is not to be confused with a power amp attenuator that sits between the power amp section and your speaker.

This amp came in with the previously posted speaker repairs. Cause of the failure was the earth wire in the plug coming loose and making contact with the live terminal. The amp still switched on, but the chassis was now charged up to a dangerous mains voltage level. As soon as the owner plugged the aux connector into his laptops audio out, a path to ground was established via the laptop, thus tripping the mains breaker, but destroying the amp and laptop in the short time. Two ground tracks on the PCB blew right off the board and had to be repaired. The associated +and- 12v voltage regulators had to be replaced as they were providing 0V and -7V. After the first stage of repairs it was found that there was an unwanted DC voltage present at both the left and right speaker output connectors at turn on before the protection circuit kicked in. It was initially thought that there were faults in the power amp section, but after testing this was ruled out, and the problem was traced to the preamp section where three op-amp ICs had gone bad and were providing a DC voltage to the directly coupled power amp section. After replacing these the amplifier was back to full working order again.

This set of speakers came in with an amp repair. When the amp blew, the speakers burnt out to. Not hard to see why some of these flemarket specials are so cheap. Firstly the original drivers are only rated at 30W, so I fitted a pair rated at 100W each for home social use. The new drivers were also secured in with screws, as the old pair were just placed loose inside and clamped down with the plastic speaker grill securing clamps. When opening up it was found that none of the wires had been soldered onto the connection tags, but only wrapped and twisted on, obviously to save time and cost for quick and cheap assembly. The copper wiring was also black and burnt out when stripped away. New better quality wiring was fitted and soldered into place. Another cost saving measure was the ommision of any kind of crossover circuit for the sub and tweeter, so one was hand wired into place in order to maximise efficiency and handling of the power to the individual drivers.

Fender Frontman 15R practice amp in for a repair to its input jack. Opening it up found that there was a previously unsuccessful attempt to repair it with hot melt glue. Old Jack was removed and a new one installed.

Orange Crush 10 in for a clean up and repair. Owner complained that although it was playable, there was a constant high source of noise always present on the output. Problem traced to a faulty op-amp IC in one of gain stages.

Orange Micro Terror in for a Service / Cleanup, and a new 12AX7 preamp tube.