agedhorse

Indeed, he got factory support directly from me, I had already advised him to contact Westside Distribution to have the work done because there were quite a few additional parts that needed to be changed and that the voltage change is fairly complicated. I had also advised him that the transformer should be the same so he wouldn't need a new transformer as long as the part number matched 561852. If the part number is different, then he would need the correct transformer. Most export models (and some USA models) were built with #561852, so the change shouldn't be very expensive. If by some reason the amp has a domestic only transformer (I do not have the build data on all versions throughout the 5 year build cycle), then it will be an expensive change because it's a very costly transformer with 3 primary windings and 3 center-tapped secondary windings). As always, the devil is in the details, Westside Distribution will know or be able to get the details.

With a power attenuator, this is true in most cases, but I was also addressing the use of a DI (with a speaker load) from a speaker output.

Yes, generally. Just be aware that many of the newer amps are in fact bridged, especially class D amps because there are some specific benefits to class d amps that do not apply to linear amps like class AB/G/H amps.

Yes, this is correct. Most class D power amps and all class AB/G/H amps that use bridged output stages are not ground referenced. When used with a load box or a DI (like the captor) at the speaker output, the minus terminal is connected to pin 1 audio ground which is connected to the power system's protective ground at the mixer. This effectively short circuits the minus half of the power amplifier and can cause major damage. It can also damage the mixer as the input ground network is not designed for such currents.

The WD-800 is quite different as it was modeled after the Walkabout. The Subway channel on the TT-800 has more or less the tone of the D-800/D-800+ but with some added texture (like the WD-800) due to the tube driven nature. That's the best I can do with a description, I'm sure there will be more posted about this when players start receiving them and posting their experiences.

This is certainly a significant part of it IMO. Yes, there is distribution which also includes warranty support and customer service. I know from talking with UK players and the service folks at Westside Distribution (UK), that they also take customer service seriously and provide a quality experience to the customer. I'm not defending the pricing, simply explaining that there are additional costs that are responsible for some of the difference. I don't really know why the differences are larger. Good question. The TT-800's Boogie channel is a re-imagination of one of our most classic, iconic bass amps (Randall Smith's design) from over 20 years earlier (the Bass 400 and 400+) with the benefit of such hindsight. The Subway channel is my re-interpretation of the D-800/800+ concept using tube gain stages, something that I was able to take artistic license from my own original design. I don't believe that GK was re-interpreting any of their earlier iconic designs as I can't recall them using tubes in their earlier designs. If I'm wrong about this, please let me know.

Yes, in part, including shipping to and within the UK, UK import fees/taxes, UK Customs clearing/brokerage fees, and let's not forget an additional 20% UK VAT. It should be noted that these additional costs are borne virtually entirely within the UK, some of which go towards social programs that we do not have to the same degree in the states. If you knew how much we have to pay for heath care insurance, you might better appreciate what you currently have (supported by those fees/taxes). Different countries of origin pay different fees/taxes so there is some difference here too.

Creasing of the cone will soften the suspension and change the moving mass because that crease will become the new hinge point. I have never tested a driver with mechanical damage like that and found the TS parameters to be anywhere near what they were originally. In fact, the change in TS parameters is one of the gold standards in assessing mechanical damage to a driver. It's used all the time when developing maximum power handling speaker ratings.

I think this is a great gesture of good will towards the industry as a whole.

The back view (showing the numbers on the cone) also shows fatal damage due to mechanical overpowering. This driver will be so far from spec that it won't perform well in the cabinet it was designed for. If you look closely st the front, you will see damage at the transition between the inside surround edge and the cone. Reconing or replacement are the only two options.

It's pretty expensive to support them myself in Europe, but there are a few qualified and authorized shops in the UK that I work with that have a nice track record.

Ask me about sewage treatment plants some day Paul

Thousands of tons (tonnes) of old school dimmers (resistance, auto-transformer/variac, and Triac/SCr based) have been scrapped in the last 10 years, as have tens of thousands of fixtures (instruments) due to the acceptance of LED dimming. The improvements in LED fixtures is really mind blowing, I designed one of the first high brightness room lighting systems about 15 years ago (called house lights in the theatre world) using at the time "exotic" 1 watt devices. There were almost 600 of them on custom made, plug together strips that were powered by redundant switchmode power supplies and zoned DC PWM dimmers. This room (a large custom home theatre for somebody in the movie theatre business) went from needing 4000 watts of halogen lights to only 600 watts of LED lighting. This was before there were any practical codes for LED architectural lighting, it was a proof of concept system that we built to commercial/industrial standards in order to pass design code review and inspection. LEDs are now twice as bright per watt, but this system is still in full operation without a service call in probably 10 years now. [/off-thread]

The triac and inverse parallel dimmers are based on reverse phase control of the 60Hz (or 50Hz for many of you) AC waveform. There is a PWM version that modulates the AC waveform by slicing up the waveform into tiny slices and eliminating slices throughout the waveform. There's also a type that converts the AC to DC and then PWM modulates this DC, either into an AC waveform or into a DC equivalent signal. Different companies have different ways of doing it (and different patents). LED lamps are usually dimmed by converting the AC to DC, then PWM'ing the DC voltage based on the RMS current rather than on the voltage since LED brightness is proportional to current through the device and independent of voltage across the device.

For conventional incandescent lamp dimmers, a few do, but most do not. For LED dimming, almost all use a form of PWM dimming,

Guys, I think you are (at least in part) misunderstanding some differences between how commerce is done the UK and commerce is done in the US, including HOW pricing is presented. 1. In the UK, your prices INCLUDE 20% VAT, in the US, our prices do NOT INCLUDE state sales tax (our version of your VAT), which runs between 9-10% average. 2. Importing into the UK costs roughly an additional 10-12% on top of this VAT for things like transportation, licensing, bonding, insurance, registration, and safety/EMC inspections and certificates. 3. There are some additional costs for warehousing, distribution and servicing/support which are generally covered by the importer of record, but of course this is a real cost as well. So, as an example let's take an amp that is advertised for sells for and sells for $1000 in the US and calculate what the real differences are... To the US consumer, this amp will cost approx. 1000 x 1.1 (sales tax) = 1100 USD which is the out the door cost to a US consumer To the UK consumer, that same 1267 GBP amp which has the VAT included Now, to look at why the amp is more expensive, we need to have the import costs of ~10% subtracted out because that's an ADDED COST of bringing a product into the UK, so now that's about 1140 GBP which would otherwise be the out the door cost to the UK consumer after the added taxes and fees levied by your government of our product. We do not have a choice in paying these added costs, which get passed onto the consumer in the end just like for all taxes. That said, all of the taxes paid by importers and yourselves go to cover things that do greatly benefit you, things like your extensive public transportation system, health care and retirement programs. You might be shocked to learn that many of us Yanks pay on average ~$1500-$2000 USD/MONTH for the same healthcare that you receive as part of your government services. While comparing prices might seem like you are getting the short end of the stick, it's nowhere near that simple... the grass is not always greener on the other side of the fence/pond. In fact, it's debatable that the stick is equally short on both ends Hope this helps.

Properly designed, any class of amp can be plenty reliable, but not well designed can affect the reliability of any class of amp. I have designed all types of amps, tube, solid state class AB and class D and haven't experienced any reliability issues (or unrepairable issues) on any of them. While many power sections of class D amps are not easily or economically repairable, often replacing the power module is less expensive than the labor and parts on a conventional tube or class AB solid state amp. Generally, the preamp and supporting assemblies are easily repaired BY A QUALIFIED service tech. Now the problem I am seeing lately is that many who call themselves techs do not have the knowledge, qualifications or aptitude to properly repair this gear. That's not a technology problem, it's a service tech problem. We are losing the really good ones as they retire out of the industry, not too many coming in to take their place.

Note that for musical instrument use, JBL recommends between 1/2x and 1x the thermal rating depending on how it's being used. See section 4 which covers the applications that would apply to bass guitar. https://www.jblpro.com/pub/technote/spkpwfaq.pdf

I believe that's the cost for the entire driver and horn, not the replacement diaphragm that I suggested (which is MUCH less expensive).

Your dealer or the service agent of record for your region can order a replacement diaphragm, there is no reason to replace the entire driver unless you prefer to spend additional, unnecessary money.

As Bill mentioned, low frequency extension is generally one tradeoff, another is power handling. As power handling increases, sensitivity generally decreases. The idea is that the SPL gain from increased power handling exceeds the SPL loss due to higher power handling (which it usually does up until a point). For instance, you may lose a dB in sensitivity to double the power handling. Regarding sensitivity specs, I typically use the average sensitivity from 50Hz to 5kHz for bass guitar because this seems to reasonably represent the bandwidth that most players perceive as "volume". Unfortunately, there are plenty of examples of sensitivity that are simply impossible to achieve using such metrics. Also, it's important to distinguish sensitivity at 1W/1M from 2.83V/1M because 2.83V/1M with a 4 ohm cabinet will result in numbers 3dB higher due to it now being the equivalent of 2W/1M rather than 1W/1M.

Your dealer would need to contact the distributor for your country. I do not know what the policy is for this kind of accessory

Correct, I should have been clearer in my explanation. The footswitch operation on the M6 is different, individual contact closures for each voice (1, 2, 4, 5) with 3 being default. Sorry for the confusion. The original concept of the switching on the M6 came from the guitar amp side of things where MIDI switchers and contact closures were commonplace. When a program change is sent via MIDI, it triggers the appropriate contact closure to enable that voice. With the M9, this was simplified and it kind of works in reverse, you set the voice you want to switch to on the voice knob, then the footswitch toggles between no voice and the selected voice. This is the tip contact, the ring contact is for mute. Hope this helps.

Just be sure you get the latching type.