agedhorse

Happy to do so ‘ol man!

The UK often uses a different type of branch circuit than we do in the states. A ring type branch circuit is fed from both ends and even if fused at 10A at each end will result in 20A @240V under a fault condition. The fuse in the plug body is the additional protection for a fault occurring beyond the receptacle.

Switches are different than pots. The less you screw with pots, the longer they typically last. I don’t have much experience with Servisol, but it must contain a small amount of sliding contact lube. On solid state amps built within the last 40 years, the life expectancy of caps is at least 40 years. My experience is if the amp is working properly and the fan is working as designed, you are probably better off leaving things alone. I see a fair number of amps “made broken” by well intentioned service attempts.

This is true under 2 conditions: 1. if one of the two cable is wired reverse polarity. 2. if each of the two speaker jacks is connected to a different power amp channel. This is common in some amps, using stereo or 2 channel power amps internally.

Interesting question. I am both a real engineer (electrical engineering degree) designing products for the bass, guitar and pro audio markets) as well as a FOH mixer (40 years in the international touring act market). I never have to worry about misuse of the word engineer. There are colloquial uses of words like engineer, but being an engineer (having graduated from an accredited engineering university program) carries with it certain assumptions if you operate as an engineer… that you know and follow the regulations in your industry, that you are licensed (for some work) that you carry certain insurance coverage (called professional liability coverage here in the states), you may be required to carry a bond, etc. In different parts of the audio industry, a FOH mixer may be called the BE (band engineer), FOH engineer, FOH guy, A-1, board op, etc. There are other terms for the monitor mixer like ME, A-2, monitor guy, monitor engineer. In other segments, you have playback techs, playback ops, dubber ops (from cinema days where mag film was unmarried from the picture in rush or daily screenings), sound op, etc. Of course different areas of the world have their own vernacular, and often it’s based on very loose translations. In the end, it generally doesn’t much matter what they are called so long as they are not representing themselves as a “real engineer” and doing things like signing documents as an “engineer” might.

If you swap the tweeter, be sure you include a suitable crossover (HPF) too.

Here's an article I received that puts the shipping challenges in perspective: https://asia.nikkei.com/Spotlight/The-Big-Story/Port-in-a-storm-No-end-in-sight-to-global-shipping-chaos

The amp is rated at 900 watts RMS into 4 ohms.

I have a friend in the automotive industry and they are in the middle of a massive struggle for everything. Finished parts of all kinds, sub-assemblies, wiring harnesses, and many things electronics (micro-processor, micro-controller, memory, certain types of capacitors, semiconductors, PCBs). Some of these semiconductors are also used in the audio market (including some amps, home audio, flat screen TV's, phones, cameras and throughout the auto infotainment worlds), and one plant that was responsible for a variety of ASIC parts suffered a devastating fire a few months back as well. Really, this is SO much bigger than the guitar/bass amp industry... in fact most larger companies in the above industries consume more semiconductors in one week than our entire industry consumes in 1 year. https://www.autoweek.com/news/industry-news/a36211012/chip-shortage-continues/ https://www.mau.com/workforce-insights/the-2021-semiconductor-chip-shortage-what-why-and-whats-next https://www.pro-tools-expert.com/production-expert-1/2020/10/29/akm-factory-fire-could-affect-supply-of-a-to-d-and-d-to-a-convertors-for-12-months

To follow up, shipping amps and cabinets by plane can be done but the cost (including handling and processing fees) can be outrageous. My experience shipping a TT by air these days (I just had shipped a box almost the same size, weight and distance) is around $400 USD and VAT would apply to that amount, making it $500. Also, there are some restrictions on shipping speakers due to the magnetic fields generated by the motor assembly. Shipping a Subway 115 would run about $500 plus VAT. The same costs are affecting parts that sometimes must be shipped by air because the cost of delay is even higher than the cost of shipping (which was the case for the shipment I experienced).

Yes, this is absolutely part of it. I did explain this to Dave over on TalkBass but I think it might be good to include the same information here. 1. It has nothing to do with Gibson period. The decision was made everybody involved because we are having great difficulty getting parts in sufficient quantities to fill the large number of orders we already have. Not just orders outside North America but also within North America. It makes no sense to try to ship a couple of amps at a time overseas, that's how products get lost and damaged. Especially tube amps. 2. Why are we having challenges with parts? It's not just us, it's the entire manufacturing world that is experiencing these shortages. Raw materials are delayed getting to our suppliers, our suppliers are delayed in their own manufacturing and some of our component manufacturers are experiencing delays from their suppliers. It's not our fault, it's not our supplier's fault, it's a global problem and no matter how much we wish it wasn't so, throwing money at it makes no difference when the parts simply do not exist. 3. In our case, we don't use a lot of generic parts. Many of our parts (like transformers, PCBs, pots, switches, sheet metal, speaker components, enclosures) are custom parts and have longer lead times than generic parts. These have been delayed by our suppliers, and not just suppliers from any one region but suppliers from France, Italy, Spain, Taiwan, Hong Kong, the UK, Germany, China, the US and Canada (I'm sure I'm missing some, but you get the point). This is mostly related to COVID, but because there are many steps in the manufacturing process, each step's delay adds to the total delay. 4. Then there's shipping delays... never have I seen the delays throughout the shipping world. Of course there's the shortage of containers, this was expected, BUT what was not expected was the ship getting stuck in the Suez Canal. It's not the week or two of direct delays, but the resulting suspension of operations at the ports because the ships they were waiting to unload and reload were all sitting out at sea waiting for passage. All those ships loaded with hundreds of thousands of containers that should have been unloaded and ready for their new loads. Combine this with the number of cancelled sailings (where a ship scheduled to depart is cancelled and waits for the next scheduled cycle. If you had containers scheduled for that ship, you were struggling to find alternative passage but often the logistics and global paperwork make it impractical. Containers with perishable goods, as well as livestock have priority, that's how the maritime laws are (and it makes sense). Then, the port delays, the inland shipping, the transfer companies, the rail companies, EVERYBODY is delayed. Oh, and the costs are out of sight too. This has not improved in the last 3 months, and may actually be worse. 5. We had our own factory delays, almost all of last year we had to operate in specialized "safe work cells" with all the necessary isolation and PPE gear. Because of the county we are located in, there were many weeks where we couldn't run ANY production due to stay at home orders. This applied to many of our suppliers too, and not just here, but much of Italy has been locked down pretty hard. Italy and the US are where many of our speakers come from, and THEIR suppliers were also locked down. Some of our suppliers simply didn't survive, we had to use back-up vendors and test sample parts in order to re-qualify the parts (especially where they are part of a safety agency approved assembly)... oh, and the safety certification agencies were also impacted, so there were delays in certifying the new parts so that the entire assembly could be re-certified. This impacts the EU specifically because of the change in EU market standards for legacy products (that do not apply to North America). It's a lot more complicated than "we just didn't want to ship outside of the US". The decision was more of what is practical, and promising something that we have almost no control over doesn't help the situation either. Nobody is happy about this, everybody shares your frustration and disappointment (including me) and we are all very, very sorry. When I know more, I will communicate it with you. Fortunately, there are a lot of good choices in bass gear these days, and if a manufacturer more local to you has stock, it may make better sense to move on for now and maybe revisit this at a later time. Hope this helps.

Inconvenient and messy as well. I see players complaining that few if any manufacturers are building their old, lead sled products anymore. Why would they when you can buy them used all day long for pennies on the dollar (or for scrap price). This was a very eye opening exercise that resulted in hauling off a truck load of amps as scrap because it wasn't worth the cost of packaging and shipping. Watching entire amps run through the scrap shredder (similar to what's used to shred cars and industrial scrap) is sad, but at least the resources are being recycled. Of course there are still collectible models, and amps that are still quite desirable, but the used market has adequate inventory to support the demand for years.

They already had more than they could use.

It would be interesting to learn about how the peak power was measured and how long the peak was defined as... or if it was purely a theoretical number based on unloaded power rail voltages into a theoretical 2 ohm load. Interestingly, this amp does not have ANY protective limiting present in the power amp, so a short circuit would prove devastating to the output stage and possibly the class H commutator switches.

I can't even give away older heavy iron amps anymore, the cost of shipping exceeds the value of many (especially older pro audio amps). I reluctantly sent several hundred pounds of old iron amps to the shredder/scrapper because nobody wanted to pay for the cost of shipping.

Yes Davs, they are not your "grandpa's" cabinets. Now you know exactly why the Subway line was developed, and why light weight and small was not an obstacle to performance.

If they use the Honda inverter style generators and take them out of Eco mode, they have even more effective voltage regulation built into the generator's control system. They are also VERY quiet.

Again, just a design choice/preference.

Ashdown DIDN’T get the volume so wrong. It was simply a design choice. By any chance was that tweeter ADDED to the cabinet in the existing port???

Ok, I just ran the numbers and I think you may have gone down a rabbit hole. If the internal dimensions of the box are really 41 liters, a 3" diameter port 2" deep is going to be fine at 100 watts RMS. If you go to a 4" diameter port, the depth will increase to 4" and you will increase the power handling to a little over 150 watts RMS (a better choice).

Bill's right here. What's necessary is to make the best choices so that the compromise can be lived with. Looking back at your first post, are you SURE that your port velocity is being calculated correctly. for a 75mm diameter port, I would not expect that much velocity from a single 10" driver. I'm starting to think that there is an error somewhere... since you are using WinISD, that's the first place I would look. Buggy software is a charitable way of saying it.

The port area is too small, increase the diameter by ~2cm and see if the length remains reasonable. With that driver in that size box, you may not be able to achieve an acceptable tuning.

It's ok for power cords IF a heavier gauge is necessary and the strain reliefs are appropriate. Speaker cords are generally a heavier gauge because the voltage is lower and the current is higher for the same amount of power transmitted.

Correct, it’s unrelated to the power amp (power tubes/valves, transformers, etc.) Proper troubleshooting will narrow down the area responsible for the noise, then it can be appropriately repaired.

Neutrik specifically warns OEM manufacturers of cables against using tinned wires with their SpeakOn plugs for the reasons I mentioned earlier. Assembly with tinned wires also invalidates the safety approvals of the plug since the plug’s safety certification is for untinned wire termination only.