agedhorse

There's noting inherently wrong with SMPS, they just require a lot more knowledge, skill and test equipment to repair. It's a trade-off for smaller size and weight and greater performance. Because SMPS (not unlike transformers) area custom product, there's only so much support available when the parts are no longer available. This is one reason why we went with the more expensive ICEPower platform, they build these by the tens of thousands because they are used by other bass amp manufacturers and in other industries as well. This means that the parts are stocked by many more sources. Without being able to identify what exactly is not working properly, it's hard to suggest a solution.

One of the biggest issues with the coiled cords is that they are usually manufactured with twisted "foil wrapped around a fiber core" tinsel wire which has a smaller than expected cross sectional area. What appears to be say 18 AWG may in fact be 22 AWG in reality. (AWG = American Wire Gauge). Because of the cylindrical wrapping and twisting in the tinsel wire fabrication, the inductance can also be higher and depending on how it's fabricated (twisted or braided), even the capacitance can be higher too.

Unfortunately, I see thing often enough to suggest that your next step is a new set of pots. They will probably continue to deteriorate due to the element being damaged. D5 contains all the lubricant necessary for regular rotary pots, just the tiniest amount possible is plenty. The F5 is for faders, it's way more oily and frankly doesn't work well on fader or rotary pots. Faders, being so exposed, are particularly vulnerable to debris and all that lube does is attract more debris.

The problem has nothing to do with tubes or anything like that. Generally the power supplies are not repairable because the safety certification (especially in the EU) depends on many critical factors within the power supply itself. It's no different than trying to repair a conventional power transformer that fails... it can't be rewound without break-down voltage testing and re-certifying as the EU safety regulations view these parts as critical to safety. This is true of all SMPS (including those integrated into class D power amps, mostly designed in the EU by the way, we are not allowed to repair except for a limited number of specific faults). That said, I see a failed NeoPak SMPS maybe once a year at the most, and I'm the factory service guy (the brand is still supported, but sometimes it's not economical to do so outside of N. America. Generally I can repair most defects, but some components are no longer manufactured and as of the beginning of this year I don't have any of those components left. I did have a few replacement supplies, but none are left. The amp was discontinued 18 years ago, and though I still support just about everything with the amp except the parts (specifically the power supply) that I do not have. I can support any Fender authorized service center in the EU that is willing to work on it though. They are not easy to work on however (even with the factory test fixtures), they are tricky and depend on critical timing throughout the circuit. They can also be very dangerous without a transformer isolated test bench and equipment. Most techs don't work on SMPS for these reasons. Regarding the more recent amps that use the ICEPower modules, these are all still in stock (still a current part) and available to any Fender authorized service center through the Fender EU parts network. For those in N. America, there's an $85 flat rate factory service program for all of these amps. I know that doesn't help you, but those members in N. America may find this useful. If you message me, I can look to see who in your area might be an option. The challenge is that the cost of repair is likely more than the amp is worth because of the amount of labor involved. If you were in the US, I certainly look at it, but even if I couldn't fix it, I would make you an offer because it still has value as a boneyard piece.

That's exactly what you don't want to use (actually one of the two worst kinds, especially for pots). Contact cleaner is like brake cleaner, it dissolves "stuff" and washes it away. It's fine for electrical switch contacts, connectors and contactors/power relays and such, but it's not intended for electronics. That's why they call it "electrical" rather than "electronic". It's intended for automotive use (they distribute brake cleaner, car polish and such), where pots are not used (or fully sealed for things like servo feedback or sensor applications). 1. The solvent is formulated for dissolving grease... the grease needs to stay exactly where it's been placed inside the pot, because it's an essential component to how the pot is supposed to operate. 2. There's no lubricant... that leaves the carbon track and wiper assembly vulnerable to rapid wear. The lubricants used for the pot's conductive element surface is specially formulated for the application, and when properly applied is microscopically thin (in the angstrom range). 3. Only use the tiniest amount possible, this application is an instance of "less is more". A can of DeOxit D-5 lasts a couple of years in a busy commercial service shop.

They use a switch mode power supply combined with a class D amplifier, designed by ICEPower in Denmark.

What’s ironic about your post is that the class D (has nothing to do with digital) power amp modules are far more available than the earlier class AB parts. They are still a current part stocked by Fender (the last owner of SWR), and it’s a part that I also stock as we used the same part in some Genz Benz amps.

There should be no difference between connecting from amp to cab to cab versus amp to cab x 2. If there is a difference, either the cable is absurdly undersized or there is a defective termination. One problem with driving any 4 ohm 210 with a Subway amp is that the amp is capable of overdriving (and likely damaging long term) every cabinet that I have ever tested. The woolly sound from the 210 might be due to this. Another possible and even likely cause is if the cabinet is really 12 ohms with the drivers switched into series mode, it will be ~3 ohms when the drivers are switched into “4 ohm mode”. If the amp is set to 8/4 ohm mode, it will try to deliver over 1000 watts the the cabinet and internal protection circuitry will limit this power which will not be a good sounding result. The amp should be set to the 2 ohm position, which will limit the power to ~600 watts into a real 4 ohm load, and ~800 into a 3 ohm load. Running all cabinets in parallel from the amp will result in a load of ~1.5 ohms which is NOT an appropriate or safe load.

This is the best and most accurate answer posted. Note that the tiniest spray possible is best, less is more. I see a fair number of repairs that come through the shop that need a new set of pots and thorough PCB cleaning because somebody used “miracle cure-all spray”, turning a simple inexpensive repair into a much more expensive repair.

When players go out to buy a cable, they are generally buying from the general/pro audio market, and the pro audio cable market is MUCH larger, bridging cables are more common in that market. There were quite a few bridgable bass amps, mostly older lead sled designs by companies like Carvin, Ampeg, Matrix, Eiche, Peavey, etc. I run into this from time to time while helping players troubleshoot their rigs. Almost always the assumption is that the amp or speaker is defective when the real problem is that they mistakenly used a bridging cable wired 1+/2+ at the amp end and 1+/1- at the speaker end.

For accuracy's sake, there are some conventions with SpeakOn that are being mis-understood: 1. NL2 or NL4 plugs will fit NL4 jacks 2. Only NL2 plugs will fit NL2 jacks 3. Bridge mode wiring for conventional stereo amps are generally wired 1+/1- at the speaker end but 1+/2+ at the amp end. This is specific to bridging where both audio channels are available on the SpeakOn jack (QSC & Crown for example). Other amps with a DEDICATED SpeakOn bridged output jack will typically be wired 1+/1- at both ends. This is why it's important to read and understand how the amp is intended to be connected to, and the mode of operation for those with dual channel power amps.

The most likely cause is simply an intermittent speaker cable or connection.

I assure you that it CAN be a very real thing. Getting away with it is quite different from good practices. There are 2 possible problems, the first being that the conductors themselves may be too small to carry the necessary current, and the other being that with some instrument cables the capacitance presented to the amp can create an illegal load (a load that the amp was not designed to handle safely) and damage the amp. There are other benefits that can be attributed directly to SpeakOns, but that's a different topic.

No, do not over-tighten the screws, the maximum torque is clearly specified in the assembly instructions. Over-tightening of the screws distort the machined saddle assembly and can actually crack the material (or strip the threads if you don't twist the had off the screw first). The screw can also cut the conductors in half if you d get it that tight. https://www.neutrik.com/media/11062/download/bda-114---speakon-nl4fx--nl4frx.pdf?v=1

One of the biggest causes for intermittent failures of SpeakOn plugs is using non-Neutrik branded parts, or knock-offs or counterfeit plugs that are sold mail order as the real thing. The second biggest cause, is the wires loosening up because the plugs were assembled incorrectly by tinning the wires. Never tin the wire of a pressure type connection, the solder will cold flow under pressure and loosen. This is actually addressed in Neutrik's OEM notes to manufacturers of cables. Of course, knock-off and off brand plugs probably won't have this information, in addition to being poor plugs.

Standard SpeakOn (non-bridging) are in fact all wired the same... 1+ to 1+ and 1- to 1- You need to be using a standard SpeakOn cable. They are not a pain to test if you have the proper equipment. Bypassing all the extraneous "stuff" is one of the most fundamental parts of structured troubleshooting. Panic is not part of the process. Before screwing with anything else, just plug straight into the amp and verify that the basic system is working properly.

If the preamp is what’s clipping, and lowering the input gain on the preamp doesn’t help, the next thing to try is to lower the volume on the bass a little and see if that resolves the symptoms.

Virtually everything in transducer and speaker cabinet design is all about balancing multiple tradeoffs simultaneously without leaving real world performance on the table.

Be sure that whatever cable you buy, it uses genuine Neutrik SpeakOn plugs. The cheap Chinese knock-off plugs are notoriously problematic, and the source of many frustrating problems out in the field.

Maybe, maybe not. It depends on what you are after with your tone, and if the (constructive/destructive) interference between point sources is a problem, or perhaps something that you actually prefer. A single vertical column still has constructive and destructive interference, it's just in the other plane and it may or may not be an issue as well. I remember when large flown line arrays first came into fashion, and the claims of no interference between cabinets was often touted as the biggest benefit. What many of these folks making these claims didn't understand is that the interference in the vertical plane is there and it's necessary for the line array to work as a line source. In fact this is the the basis for one of the two ways of coupling the mid and high frequency elements into the array... either each element has a narrow vertical pattern and they are all placed so that they overlap as needed for the coverage, or they are a wider vertical pattern and while they are guaranteed to overlap, they do so in a more gradual manner but with a little less control. The earlier cabinets with narrow vertical elements would lobe as you walked from the stage out to FOH, whereas in a horizontally arrayed point source system they would lobe as you walked horizontally across the auditorium. It's just 2 ways of dealing with the real world interference that occurs between any 2 point sources (no matter how they are arrayed). It also occurs with reflections off of boundary surfaces, at some point you can't do anything practical about it, it is what it is and you move onto more important things like catering and getting paid.

Respectfully, to counter the common argument that the polar pattern (response versus frequency versus axial angle) of a speaker depends only on the diameter of the driver and the spacing to adjacent drivers, this is only partially true. It is possible (and commonly done in the real world) to alter the polar patter of a driver at higher frequencies by changing the cone depth, shape and the size/material and location of the dust cap. All of these elements contribute to the non-theoretical aspects of a driver's radiation pattern, and is why 10 different 15" drivers will have 10 different polar patterns. As an extreme example, the JBL D-130 utilizes a shallow, light weight curvilinear cone, and an aluminum dust cap that is directly bonded to the top edge of the bobbin. This dust cap acts to radiate the higher frequencies differently that the cone itself. As another extreme example of what could also be called a secondary radiator, the "wizzer cone" concept is a dust cap with a radiation element that is bonded directly to the top of the bobbin and can extend both the frequency response and polar pattern by an octave or more. Polar patterns are something that designers consider when developing transducers for practical applications.

Oooh, and it has both slots AND triangles too!

Slot and triangular ports do not have to be an issue, again when designed with this in mind. The pro audio industry has used both for decades without any problems being described. The common theme is that designers using such ports design them so that they typically don't have an aspect ratio much over 1.5:1 depth to short leg dimension. These are products that have tens of thousands of pro touring shows under their belts, so there's no doubt that they have proven themselves many times over. I have used both types of porting as well, and haven't experienced such difficulties either. DAS: Community: RCF: JBL STX series: JBL ASB series:

Agreed, and in the case of the part failures we saw, we would have had to test hundreds for over 3 years because we didn’t really begin to see them for that period of time, and even after 10 years there was only a ~10% failure rate. Here’s a little data sheet that documents the qualification process and analysis that’s behind the basic process of reliability metrics. This covers known failure modes, at the time this failure mode (production issue) was not understood. https://dammedia.osram.info/media/bin/osram-dam-2496614/AN006_Reliability and lifetime of LEDs.pdf

Good perspective. Nothing is 100% risk free, and without taking at least a tiny bit of risk, everyone would still be playing uprights, acoustic guitar, etc. I don’t know if you remember when the high brightness, high temperature LEDs came out for traffic light applications, but they also had higher than acceptable failure rates that took several years to show up. This was in spite of extensive testing and qualification. This too was addressed in the upgraded parts and semi fab process. The average person would probably be surprised at the amount of effort that goes into maintaining reliability metrics in modern products. Unfortunately, no process is 100% perfect nor 100% thorough. To do so would put the cost of new products out of reach. It’s why commercial aircraft are so expensive, yet in spite of a level of qualification, traceability and testing that’s an order of magnitude higher than what’s used for bass amps, mistakes still happen and every aircraft manufacturer in the world has experienced it too.