From an interview with him about using empty 6550 tubes to house the GaN amplifier boards in.
"Company founder Alberto Guerra admitted that he did it largely for the sake of visual aesthetics. Otherwise a class-D amp just looks like a box”
You don’t have to be too smart to see the tube pins are going to be a problem with a bit of age on them, especially if being used with a speaker that demands a bit of juice sucked through those tube pins. (like I said you may as well have spring clip speaker terminals)
Otherwise, all that I can say is that, given Alberto Guerra's career in the industry and that of his principal decrier, I know whose opinion I would heed more.
Ralph, don’t skew things around "to seem" to suit your next product. I did not say "won’t handle", I said will not get "the best" out of the Alexia’s bass because of it loading. We
have the Alexia’s here in front of us and know what they like to get
the best out of them in the bass, and it’s not Class-D yet. (Maybe in
the future when they can come close to doubling from 8ohm to 4ohm to
2ohm wattages like big better linear amps can)
Again, according to Wilson themselves, the speaker does not suffer any performance loss strictly on account of class D. Some class D amps are not as good as others just as some class AB amps aren't as good as others.
And for the record I'm not skewing things. To be clear, if you want to get ' ' 'the best' out of the Alexia's bass', a class D amp can do that as well or better than a regular class AB amp. Here are the provisos:IF- 1) as long as it is designed with the same current in the power supply as the AB amp2) as long as it has adequate heatsinks3) as long as the output section as the same current ratings in its output devices-then it will make bass no worries, with 'the best'.
This is nothing about our upcoming product so much as its about Ohm's Law.
I was a bit astonished that in the face of advice from the speaker manufacturer in question that you were continuing to hang on to your position, which they regard as nonsense.
Now it may be that you are actually comparing some class AB amp against a particular class D amp on that speaker- and I'll totally give you that anecdote. But anecdote is not proof of your position (its a data point at best); if that is what you are experiencing then I advise you look for a different (probably newer) class D of more competent design. If you need tips on what to look for here are a few:1) avoid amps with SMPSs as most SMPSs will current limit if they are off the shelf units. Get one with a more traditional power supply.2) look for units that, if using feedback, are of the self-oscillating variety. The Hypex is a good example.2) The input circuit, if installed by the ultimate builder of the product, should use high quality opamps operating at low gain. Even though I like tubes, they are very difficult to use properly as the input circuit because the comparitor input impedance is so low. This will make it hard for the resulting amp to have good low frequency response.
What’s the issue with tube pins? I own 70+ year old Western Electric Amps and 300B tubes and have never had issues with tube pins, sure sockets can get loose but that’s a one minute fix and tube pins are easy to clean.
What AGD has done is brilliant on more than one level.
No not brilliant, more inept, but guarantees return service work in the future (maybe not so stupid.$$) There’s a HUGE!! difference in output wattage and current going through the tube pins, compared to a 10w SE 300B even a push/pull one . (do your homework) Especially if the AGD is "trying" to drive Wilson speakers with low bass impedances. You may as well have those nasty spring clip speaker terminals on the back of the AGD, because that’s just as good as the tube pins and the speakers are hooked through those to the GaN output stage in the 6550 tube envelop.
And the above post means what? That he was thinking literally outside the box?
What's the issue with tube pins? I own 70+ year old Western Electric Amps and 300B tubes and have never had issues with tube pins, sure sockets can get loose but that's a one minute fix and tube pins are easy to clean.
What AGD has done is brilliant on more than one level.
First sign of a shiller. Here some more for you to agonize over.
Interviewer: I ask
Alberto Guerra
, why put solid state components inside an old 6550 vacuum tube envelope, bet it’s not vacuum’ed back out and sealed again either. "Company founder Alberto Guerra admitted that he did it largely for the sake of visual aesthetics. “Otherwise a class-D amp just looks like a box”
PS: OK he’s shown all his cards, with that statement.
AGD is just GaN based Class-D slid into a "bogus" empty 6550 tube envelope, which uses (horror) the base pins for all it’s contacts, everything has to go through them, input output power supply rails everything🤢 Just the whole gutted tube thing, stuffed with solid state, and still using all the tube pins as power/current transmitting contacts, guess in time it ensures return service work when those pins start to corrode and arc over????
I’m refuting the idea that a class D can’t handle this speaker
Ralph, don’t skew things around "to seem" to suit your next product. I did not say "won’t handle", I said will not get "the best" out of the Alexia’s bass because of it loading. We have the Alexia’s here in front of us and know what they like to get the best out of them in the bass, and it’s not Class-D yet. (Maybe in the future when they can come close to doubling from 8ohm to 4ohm to 2ohm wattages like big better linear amps can)
Keep going like this and it will look like your shilling again, because of your yet to be released GaN Class-D
Measurements Sensitivity 89 dB @ 1 watt @ 1 meter @ 1 kHz Nominal Impedance 4 ohms / minimum 2.54 ohms @ 85 Hz Minimum Amplifier Power 20 watts per channel Frequency Response 19 Hz – 32 kHz +/- 3 dB Room Average Response [RAR]
We can see that Wilson does not think this speaker hard to drive with a 20 watt minimum. Because the AGD has such a low output impedance I think it should be able to drive this speaker quite well, depending on the power of the amplifier and the size of the room. If you have a larger room all you would need is more power.
So I guess I’m refuting the idea that a class D can’t handle this speaker (any more or less than any other class AB amp of the same power might). I really don’t see what the problem is.
I spoke to Jerron that works at Wilson (for the last 20 years) and he is in complete agreement. He says the older Alexia was a bit harder to drive but the class D amps handled it no worries at all. So I'm going with a 'furphy' on this one.
Trust fusers to back each other sunshine.(because your soooo bright)
(not you Ralph, the other fuser here with the AGD)
Ironically its the GaNFETs that George has been so enamored of in the last couple of years
Yes I have, and still do, but never that GaN could drive .9ohm bass loads like the Alexia’s to their best. Refute that Ralph As I said the AGD has no chance of driving the Wilson Alexia to sound their best in the bass because of their .9ohm impedance load. And refute that also Ralph.
Go and read any thread and you’ll have georgie calling anyone a shiller
Especially owners that claim these amps can drive those types of loads. Which gives out the wrong info on what they can drive, they do it because they are shilling.
George goes on about this EPDR thing. But he's not clear on what the impact will be on a class D amplifier other than saying that they won't drive it.
Almost any class D amp made today has an output impedance that is often a good order of magnitude lower than traditional class AB designs. This is because the On resistance of the output devices is (especially if GaNFETs are used) literally only a few milliohms (our amp has an output impedance of 10 milliohms as an example). When you have an output impedance that low, if a speaker has an effective EPDR that causes it to be effectively slight less than 1 ohm the class D amp will still behave as a voltage source while driving it. This is for the simple fact that at 1 ohm the class D amp may well have a damping factor of over 100.
That's not the same thing as the amp falling flat on its face! However there is a chance that the class D amp will go into current limiting mode to protect the output devices. GaNFETs are tricky to heatsink and as a result the heatsinks you have to use are unlikely to move heat away from the output devices fast enough to prevent failure when driving such a load. So the prudent designer will have some sort of protection circuit even though the output devices can easily handle the current.
As I've pointed out a good number of times in the past, the limits of class D amps to drive a low impedance are the same as they are for a conventional class AB amp: current rating in the output devices, current available from the power supply and heatsinks enough to move heat away from the output devices.
Ironically its the GaNFETs that George has been so enamored of in the last couple of years where this heat problem is most likely to occur; conventional MOSFETs are often packaged in a TO220, TO240 or other package that can be easily heatsinked.
Now we should be clear about one other issue regarding EPDR. In most speakers the region where this might be a problem is often just a very narrow range of frequencies, IOW not the entire impedance curve of the speaker! If this is the case with a speaker that has such a low EPDR rating, it won't be much of an issue for a class D amp because there just isn't enough energy needed over this narrow range to heat up the output devices. The Wilson Sasha and Sophias are good examples of speakers of this, and in practice mean almost nothing to any class D amp. At most clipping onset might occur slightly quicker, but frequency response is unaffected.
George accuses me of shilling nearly every time I explain anything about class D, so I reiterate that what I've said in this post has to do with most class D amps that are available today.
It’s nice all the Class D detractors have a thread to dump in.
There are different types of Class-D detractors, some only "dump" on those ** claims made by shillers of certain brand Class-D’s, who have no idea what they claim, especially in regards to what types of loads they are capable of driving. If they didn’t make these false ** claims, there would be no confrontation from those detractors.
I for one have heard certain Class-D amps sound great, "with the correct speaker", and have acknowledged it here on Audiogon.
progress is inevitable, some times for the better sometimes for the worse
in audio, there are always great engineers and impassioned music lovers striving for positive progress using new techniques and technologies
on the other hand, many people don’t have the time, energy, money or attention span to keep up and be truly aware of the progress being made by those who are making it
those people don't like to admit the above, and prefer to express negativity on discussion boards such as this
It was you that inferred it could drive the them to their best. You are the one that’s comical and preaching BS not me. If your going to shill something get your facts right
george You do these drive by posts and really have nothing to add from first hand experience you form opinion from others opinions. Your stuck in the 80's and have not moved past. You really need to spend time listening to music instead of forums.
I also do not own Wilson Alexia's so who cares.
Your posts are quite comical and show little value, just more BS to get past.
Class D sucks. I’ve said it many times. Dry and lifeless, sure. I’ve been weary of anyone stating that it can be really good. Short of being utilized for subwoofer amplification I had ruled it out pretty much completely. I mean, what could better class A/AB/Tubes? My ears don’t lie. I’ve been around. Case closed, not interested…Or so I had convinced myself. Then comes along GaN (Gallium Nitride) class D. Never heard of it. “Oh God, class D, here we go again”, I thought initially. I didn’t care to be honest.
Enter AGD. Unknown company. They seemed to have some really good reviews/feedback coming from those whose ears I’ve come to trust by and large. So okay I was curious…Apprehensive? Hell yes, and doubtful it could better really good SET amps. But regardless I was willing to take a risk and demo a pair of monoblocks (AGD Audions), yes doubtful and ready and willing to discount them. And then I LISTENED… At first I sat there a bit confused at what I was actually listening to…I continued to simply LISTEN. This was altogether DIFFERENT. “This can’t be class D”, I thought…WTF
My paradigm for what I had thought audio to exist within was being shifted with every track…this is (was) pretty amazing!
This changed everything for me with regards to my pursuit for sonic excellence. I could no longer deny that class D done right can exist right up there with best of the best. Sounds like hyperbole, I’m well aware. It’s simply what I’ve discovered and felt this thread deserved some truth. Enjoy!
When are your Class D amps coming out? I just sold an amp and looking for a new one.
We're doing limited shipping of Beta production right now. As with many things associated with the pandemic, we've run into supply side shortages that have caused us to design and fabricate some parts that should be 'off the shelf'.
And that’s where demagnetizing the aluminum CD disc furphy started back in 1996, and should stay. Along with all the other "snake oil" like directional mains fuses, Shun Mook mpingo disc etc etc etc
Both de-staticing and demagnetizing a CD will improve the sound.
Like I said it’s a furphy and to those promoting it. Maybe to de-static, but we weren’t discussing that. But you’ve got nothing but "snake oil" voodoo for the de-magnetizing.
What is true in audio is what we can hear. You can argue about science but it is just thoughts in your head. What is real, is what we hear. Both de-staticing and demagnetizing a CD will improve the sound. This can easily be heard. The effects of the procedure, however, are brief.....do to the spinning of the plastic CD......building up more static. Your ears are on your head........the ego is in the mind. Use your ears.....they work.
That's a nice bunch of tweaks you got there. A few are new even to me. And bonus points for noticing demagnetizing CDs only lasts about 7 minutes. Well done!
"If you want to know anything about my mods then please call me. Any mod done to an IceEdge module will void all warranties with the manufacturer (Legacy, in your case) and with IcePower. This is one reason most would not be interested in mods to expensive gear, like the Legacy. The modded Rouge Design would cost you very little.....the IceEdge modules (modded or stock) are super reliable. All 12 of my modded amps from 2019 are still going strong. "
@ricevs Thanks for the post. I have no idea how to contact you.....at least let me know how to look you up and find your phone#
If you want to know anything about my mods then please call me. Any mod done to an IceEdge module will void all warranties with the manufacturer (Legacy, in your case) and with IcePower. This is one reason most would not be interested in mods to expensive gear, like the Legacy. The modded Rouge Design would cost you very little.....the IceEdge modules (modded or stock) are super reliable. All 12 of my modded amps from 2019 are still going strong.
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