Seeing more of these amp modules lately appearing in many models of amplifier. Sometimes I have found success repairing and others no luck and had to replace them. The modules are expensive but are essentially reliable provided that ventilation.
If you are interested in getting one of these fixed but are not located near Bristol, then contact me about a remote repair.
List of Amps using ICEPower Amplifier Modules
Fender Rumble
Fender Bassman
Aguilar Tone Hammer
Aguilar TH500
Recently had success getting a fix with a TH500 Amp repair where both the amp stage and the PSU had faults although no circuit info was available it was possible to get a repair.
Came across this little box of wonder this week. Basic power supply problem. Small enough to be sent in the post so happy to take remote repairs on this one.
These Mackies beloved by users all over the world can suffer from a strange and rather annoying problem of volume reduction after a few years use. I don’t mean volume fluctuation; I am talking about a permanent reduction in output level – up to 80-90% in some cases. That is a hassle that we well can do without from our beloved monitors that we rely upon as a reference every day.
This gradual reduction of volume level can be hard to detect. After all, you might not notice it as it creeps up gradually over a few years and you get accustomed to it. The real clue to it is when the problem gets so bad that you think the monitors are unusable or when you notice that you have to excessively compensate for imbalance between a pair by increasing the input signal from your mixer or bumping up the volume control on the rear. The tone of the speakers does not seem to be noticably effected but I suspect that it is but we just get used to it over time.
The cause of the problem is that a couple of capacitors in the signal chain dry out over time and then instead of allowing signal to pass tranparently strangle it off instead. The only solution is replacement of course.
If you would like to get your speakers fixed please get in touch via the contact form. I can even take care of this via a courier.
If you are feeling brave and would like to try this repair your self then I can supply a PDF fact sheet illustrating what you need to do for this there is a small charge.
Not something I have much experience with but I was recently asked to help out servicing a neglected DJ classic.
The first thing that strikes you when dismantling the deck is the solidity of the unit. The plastic is heavy, the metal is shiny everything just feels built to last.
I just needed to sort out some ancient phono leads that had become unreliable. Although this is what I did for my client, upon reflection I think I would do it differently next time. Instead of just replacing the cable I feel like adding some short inline female connectors might be preferable especially if you want to keep the mixer setup tidy and maintain flexibility.
The other task i took on was restoring the pitch control. These old sliders are about 10cm long and easy to dismantle. Inside there is a small pcb with a wiper that glides across. A ball bearing, spring loaded for dismntling excitement, helps the titch control sit in its centre position. Inside this slider it was full of food crumbs, hairs and other bits of DJ detritus. This was mixed into a soup or more of a paste due to excessive cleaning activity.
Many people casually spray chemicals into their equipment hoping to wipe away years of wear but actually this is just doing damage. Most potentiometers or sliders are lubricated with a jelly like paste called silicone grease on the moving parts. This paste is not on the carbon track but the issue is that when cleaning if you use too much switch cleaner then it just dilutes the grease and causes a messy pot that doesn’t move smoothly.
How much is too much? Well I would say a tiny squirt which lasts the same amount of time as when you click your tongue. A real blip. Once applied you can move the pot end to end ten or twenty times. Exercising the pot distribute the cleaner and hopefully remove oxidisation but leaves the lubricant where it should be, that is on the moving metal parts. I suspect that many people think more cleaning chemicals is better but this is definitely not the case.
So think carefully before you spray.
Calibrating the speed control is performed in two stages. First measure the slider resistance and ensure that it is 2700 ohms between red and brown with slider disconnected from the main PCB. Next ensure that the frequency is as per the tech spec by measuring on the test point on the main board using a good frequency counting meter.
These humble practice amps have sold by the 000s I reckon based on the number of enquiries I get any way. Two channels, fizzy distortion, chorus, reverb effects and conections for headphones and line in audio. Great practice bundle especially practical for students and people on the move.
The few issues I have encountered are
channel switching issues where the the amp will get stuck in either clean or distortion and refuse to budge. This is caused by a problem with the switching controller chip and is very repairable.
Power amp failures caused by blown chip amp part, again a cheap repair. May also cause damage to the amp’s power supply.
Of course front panel damage to pots and the horribly cheap 3.5mm connectors on the front panel. The headphones signal interrupts the output to the speaker so any damage or dirt on that connector (like age realted oxidisation) means that the signal will drop down a bit just when you would prefer it not to.
All of these faults are highly repairable but the only thing is that the PCB tracks are very weak and easily broken. If you do attempt a repair keep your soldering iron temperature low and be patient.
I have not come acrosss one of these before so thought I would share some pictures of this nicely made bass amp.
Judging by the selection of Hitachi output MosFETs these amps come from the 1980s/1990s I would estimate. Build quality is very high and no reason these amps won’t go on for ever. The only issues I faced on this one was of volume dips and the cause was just some of the jacks sockets suffering a little corrosion.
If you have one of these amps and want to get it restored don’t hesitate to get in touch to book it in.
I would love to see some schematic info on the Peterson amps. If anyone has any please let me know.
The cloth has disintegrated with either age, UV damage or both. The replacement Marshall “salt n pepper” cloth actually looks superior and should last a lot longer.
The below Marshall cloth was damp damaged. Replacement is very time consuming as getting the cloth pulled really tight takes some strength and technique but the end result is fantastic and makes the amp look like new. Marshall keep a wide range of cloths available you can see them on their website under fret cloth.
I was recently asked to help improve the uncontrolable volume on the a Fender Princeton 122+ amp. The good folks over at music-electronics-forum, in particular, Steve Ahola have come up with some ideas so I thought let’s give them a try.
In stock form this unassuming amp is a great clean fender amp and most people might be surprised to learn that it is a light weight solid state amp. In fact second hand these amps are pretty cheap second hand at about £70-120 in the UK.
The mods below just help to improve usability and versatility.
Clean Volume Pot Taper Improvement Mod
First mod is to replace the clean volume pot with something more gradual. The stock pot is an anti-log pot 50KC and the suggested solution is to use a 50K Log (audio) taper pot. I was a bit sceptical about this since an anti log pot is usually a bit more expensive compared to a log pot so it seems like Fender consciously thought that this was for the best. The results are quite dramatic with volume contol about half as sensitive. On the stock amp full power is achieved at about volume of 4 or 5 but with the mod this is moved way over towards 9-10. Definitely a keeper.
With anti-log pot stock
With 50KA pot mod
Volume Control Level
Speaker Signal (volts RMS)
Power (watts)
Speaker Signal (volts RMS)
Power (watts)
0
0.022
0
1
3.6
1.2
1.8
0.33w
2
9
8.1
4.5
2.0w
3
15
22.5
8
6.4
4
19
36
5
27
73
Input conditions: 100mV sine and EQ flat
Drive Channel Gain Reduction Mod
This next mod is just to tame the drive channel a little bit. Steve suggests adding a 68K resistor across C14 which turns the metal more into rock. I went with a 56K which added a little more control but I think this is worth experimenting further in the future.
Master Volume Mod
This simple mod just adds a master volume control like we see on many amps and allows us a little more control such that we can operate at night-time practice levels without waking the baby.
The MV control is simply an extra potentiometer effectively controlling the gain beteen the power amp and the pre amp. At full volume the amp behaves as stock and as the pot sweeps down the level is adjusted progressively. For home use I have been keeping at about half level. The pot is most easily added to the rear panel due the limited space on the front and also keeps the front panel un-modified. It is actually quite usable on the rear and also discourages the player from constant tweeking. If you really want to have it one the front panel then the only option practically speaking is to fit the pot right over on the right near the power switch which would mean cutting a hole in the chassis wherer the “princeton 112 plus” legend is displayed.
Every now and again I am fortunate to work on some really beutifully made amplifiers. Although these amps are usually inspired by some vintage classic Fender or Marshall, it is the attention to detail that seems to make all the difference in terms of tone and playability.
Tone King Metropolitan
Take this Tone King metropolitan. The chassis is engineered from what appears to be airplane grade alloy held together with screw that don’t round off on the second use. The pots have a velvetty feel making you feel perfectly in control.
LazyJ J20
Simple enough 5E3 based amp with three.. err no four controls what could be simpler… Oh wait a minute round the back is a reverb with Tone, Reverb level and a Tremolo and wait there are more surprises. The Footswitch also has level controls… This amp is a great concept adding extra modules in the cabinet keeps the amp compact but allows for lots of flexibility. The addition of the attenuator is the attraction for me and allows you to operate the amp a all volume levels.
Build quality is excellent as is the parts with Switchcraft jacks through out, cloth wiring, solid fixings and tweed covering done to the highest standards.
Divided By 13 – JRT 9/15
An exceptionally well built amp from California where build quality oozes from every angle. Heater wiring, components lined up like soldiers, paper wound transformers, vibration absorbing pre-amp tube mounts. It is to die for. See Website for details and also the extensive list of top players that are using these great amps.
Orange amps are characterised by their distinctive colour, original sound, great build quality and over engineering that sets them apart and above their rivals.
Orange Bass Terror
The original bass terror in its small tin box with carry bag was an immediate success. Great sound and highly portable. It comes in 500w and 1000w variations and is pretty reliable.
Some issues that I have come across are:
Power supply dying, blowing fuses repeatedly usually suddenly. Fortunately repair is achievable and if not replacement modules from Orange are available.
Power amplifier burn out caused by overheating, overload or just bad luck.
Other faults are typical service things like valves, control pots and jacks.
Like all class D amps reliance on good fan airflow is essential so make sure to clean it out every couple of years or so.
Repair success is pretty good on these amps thanks to the excellent support from Orange.
To prevent damage to your OBT make sure you dismantle and vaccuum out all of the dust from the fan once in a while. Class-D amps rely on cool running to keep working any reduction in the cooling ability will cause the amp’s early demise.
Turn your amp of
Use a paint brush to dislodge any engrained bits from the fan blades whilst using the vacuum to suck away the debris.
Repeat every year or two.
Video showing power supplu startup proecdure following repair
Orange Rocker 30
These 30w, 1×12, dual gainy channel amps have very little to go wrong in them. The only issues I have seen are from typical wear items like damaged pots, jacks and valves.
I was recently asked to help improve the uncontrolable volume on the a Fender Princeton 122+ amp. The good folks over at music-electronics-forum, in particular, Steve Ahola have come up with some ideas so I thought let’s give them a try.
