agedhorse

Yes, it matters to those who worked hard, or paid for the considerable costs of developing such. It affects us for sure. It should also matter to players, because advancements in design and technology come from reinvestment of earnings from preceding products. Not paying for the cost of R&D reduces costs and enables cheaper products but can impact future advances by other more innovative, creative products. Are you suggesting that it’s ok to take the work of others as long as it’s cheaper, even if the work is not yours?

Different industries source their products differently. Also, there were some earlier suppliers for both the computer and TV/monitor industry that sourced caps from vendors using counterfeit (and defective) materials. This is a much different situation, and not something that i have seen in the audio world that I live in. As long as the design respects the appropriate limitations of the caps being used, i almost never see an issue with caps.

No, the ONLY cap failures I have seen in (quality) class D amps are in the SMPS when the user connected the amp to 230V while configured for 115V. This is not a cap issue, and generally there’s a lot more damage from this kind of accident.

Here in N. America, the Streamliners are still covered under the factory flat rate service program. I so rarely see a bad power module that it's almost the last thing on the list of potential issues and the replacement modules are in stock and still a current part. All the other things are generally simple and straight forward for a QUALIFIED tech, but what's becoming far more of a challenge is finding a truly qualified tech... that's FAR more concerning than a class D amp (or any other amp for that matter). As far as cost of repair of tube/valve amps being cheaper, has anybody priced out a set of tubes or a replacement transformer lately? Replacing a power module (as rare as it might be) is less costly (by quite a bit) than replacing a set of tubes/valves. Tube/valve amps (in my experience) are much less reliable than a quality solid state amp of any type.

Streamliner on the outside, nothing like it on the inside.

Yes, all over eBay, Ali Express and Ali Baba. If they aren’t purchased through ICEPower directly, or one of their AUTHORIZED distributors, there are usually fake. They look just like the real thing, just a little bit cheaper and no warranty.

I have also had designs stolen, it’s becoming a bigger and bigger deal as design cycles shorten with increased competition. I feel you pain here. Even if I was to design an SMPS/class D module, due to the complexity and difficulty to troubleshoot versus the cost of building the module, it would still be less expensive in most cases to simply replace the module. The problem with the higher technology is that it’s very expensive and time consuming to develop, and even more so to do it reliably. (There are plenty of examples of unreliable “roll your own” designs by big and small manufacturers alike). In order to amortize these costs (and that includes global safety and EMC certification) to keep the cost per module down, the production volumes need to be much higher than most in the bass industry could ever use in several lifetimes. This is why top tier companies like ICEPower exist, they sell to other industries also, in addition to dominating the bass market. This allows them to spread the NRE costs across hundreds of thousands to millions of modules. Economies of scale are responsible for class D being a viable solution AND a good value to the players.

I can address this specifically. ICEPower did have some IP that was stolen by (ultimately) a Chinese fabricator and they counterfeited one of their modules which cost them a LOT of money (ultimately in the millions of dollars US). The investment in developing this technology at the level that ICEPower (and other major players) have done is staggering and it's simply not right (morally or ethically) to take away such protections from any company developing their own IP. For those of you that might suggest that ICEPower goes after the Chinese company that stole the IP, you must be unfamiliar with the "their country, their rules" concept of business. It's almost impossible to be successful, the loss is both real and unrecoverable.

Most claims made in the HI-Fi cable world are preposterous at best and many border on fraudulent IME)

Correct, they are not, and that’s what I thought I posted.

This would get you a lot closer to determining the closeness of the two amps, but you would want to repeat the tests swapping the speakers so that if the preference changed it would indicate that the speaker was the most significant variable. Speaker variables can vary by as much as 20% in a production run. This CAN be significant.

No, it's the truth and it was a statement that I posted publicly several times.

Yes, it is true. Actually, there are several stories and one (not involving class D specifically but involving confirmation bias and over-confidence in listening abilities) where I rigged a double-blind listening test to select between the same power amp and added only 1/2dB to one amp's level caused a high percentage of people to be "positive" they were listening to two different amps (presented to the group as 2 quite different circuits). Of course there was the cork sniffing swagger, the golden ears proclaiming all kinds of absurdities, the hyperbole, etc. When the curtain was parted and they saw that they had been listening to the SAME amp, the excuses started coming out and it became clear that I had just finished my last day with that company (and the high end Hi-Fi industry as a whole). This was in 1981 or 82 and I was planning on quitting the next day anyway, so it wasn't an unexpected or even unwanted outcome (This industry was just full of snake-oil marketing that had no bearing on reality or truth of any kind). The point being that even a small difference in level, or in preamp voicing can make a much bigger impression than most folks realize.

It might be a coincidence, but it's also just as likely (maybe more likely) that you prefer the voicings that were more common in the older designs. Preamp (and speaker) voicings have evolved a lot in the 40 years that I have been designing products and this has been driven primarily by changing player preferences along with changes in music styles. One of the best examples of this that I can think of (off the top of my head) is the Darkglass models, they are what the industry refers to as "Euro-modern hard rock/metal" and is quite different from products we used to offer in our lines (Carbines and Strategy/Prodigy) which were American hard rock/metal oriented. The Euro tone evolved from the American tone as the music itself evolved. Because class D wasn't available (in practice) when these older products were developed, they were by default class AB. When Darkglass revisited this theme with their approach, class D was available and a practical option so that's the direction that they went. The appear to be very successful for those players seeking that voicing. I did test a Carbine preamp with a class D power amp, it was close enough that nobody was really sure which power amp they were listening to when testing... but that voicing was becoming less and less popular so the decision was made to evolve the Subway line into something that followed the evolving tastes. In no way does it make you wrong for preferring the amps that you like, but there's a lot more involved than just the amp class.

I’m not going to get into those specifics here.

There are all kinds of dynamics and voicing modifiers that go into a preamp design. The Streamliner that was mentioned earlier was very much about voicing and dynamics and sounded/felt totally different from the Shuttles even though they both used the same power modules. There’s a lot more to how an amp sounds/feels than just the power amp design (which can also be designed in ways to exploit or reject a particular aspect of tonality and feel.

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How are the pre’s “very similar”? Change one or two component and the voicing can change wildly. Unless the preamps are IDENTICAL, you aren’t comparing power amps, you just think you are (which is where confirmation bias comes into play) Now if you were to say that you preferred one amp over another without insisting that it’s due to the class of power amp, I can totally appreciate that.

I have done double-blind tests regarding which preamp players prefer (not just my designs) and it’s ironic that what many players are convinced they like ends up not being what they chose when they couldn’t see it. This is why double-blind testing is come, to remove the effects of confirmation bias. I have designed some very high powered class AB amps back in the day, well received in the pro touring world, but today’s better class D designs are every bit as good when mated to the identical preamp.

Failure and overheating is not a class D issue, it's a "poor design" issue. I haven't had any of these issues with any of the class D amps I have designed, going back over 15 years.

Of course the powered speaker is class D with a SMPS

In some cases they are identical. I have designed both bass amps and touring pro audio powered cabinets using the same modules.

Class C is not a viable topology for audio signals, not in any way. ALL amps must have a power supply transformer in order to pass safety standards everywhere in the EU and just about everywhere else in the world as well.

Kris needs to put him in touch with Rich. Rich will be able to help him. There is another problem that’s causing these symptoms. It could be a failed bias supply, a short from grid to cathode in one of the tubes, a screen to grid short in one of the tubes, etc. Correctly identifying the cause is essential to a proper repair.

He can always e-mail our service manager Rich, he will know who to contact in the UK/EU. The speaker muting relay stuck in the mute position is unlikely (very unlikely) to cause a set of power tubes to fail.