Okay, I will bounce in here with a topic that NOBODY has actually put forth: POWER SUPPLY. As I said in my first post, were only half the way there
https://forum.audiogon.com/posts/1491862 Of course power supply and good circuit topology design is also needed, but that should be discussed in posts by themselves, otherwise this thread will end up all over the place. Let’s just assume in this thread the power supply and circuit topology are unsurpassed in design and quality, and can give infinite current. Cheers George |
P.S. I like it better when he’s pushing Schiit products as the best thing after sliced bread... Schiit is probably the best bang for buck on the market, better performance per dollar than that McIntosh blue xmas tree junk you have with autotransformers. I'd stack the Schiit Vidar at $699 up against it on speakers they could both drive easily. And yes Ralph as inna pointed out, are you nutz even suggesting any of your amps would compete with the Gryphon I mentioned on a speaker such as the Wilson Alexia, or others even with similar hard varying loads. Cheers George |
I don’t push the ZEROs because of the Maggies You started this Ralph with your second post. Didn’t say you pushed Zero’s because of the Magie’s, just any speaker that are hard to drive. Read a bit more carefully. What I did ask. " https://www.stereophile.com/images/217MagS52fig1.jpgBut what I will ask you Ralph, is one of your production OTL amps going to stay flat in frequency at a reasonable loudness level and envelope of +& - 1,2 or even 3db, into this load without the band-aid use of any external Auto-transformers (Zero’s)?? BTW, this is a yes or no question..." BTW: here’s Stereophiles test take on the Merlin VSM " The speaker itself was quite sensitive, at an estimated 88.5dB(B)/2.83V/m, which, in conjunction with its moderate impedance (fig.5), will make it an easy load for the partnering amplifier." As I said " In other words easy to drive speakers that are as close as possible to a pure resistive load," Cheers George |
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It was a trick question in a way. The trick was knowing Ohm’s law.
Really!!
Regarding our amps, they were designed with intention to work with speakers that do not require feedback of the amp;
In other words easy to drive speakers that are as close as possible to a pure resistive load, which Ralph there are not many good ones, Magies come to mind, not much else of worth, that why you push the Zero Autoformer. Cheers George |
is the current going to be higher with a high current amp as opposed to one that has less current? Given the Magico’s impedance v phase graph, the amp with "ample current" will stay flatter in frequency response than the one that is "current challenged" especially at 50hz where impedance and -phase is at it’s worst. https://www.stereophile.com/images/217MagS52fig1.jpgBut what I will ask you Ralph, is one of your production OTL amps going to stay flat in frequency at a reasonable loudness level and envelope of +& - 1,2 or even 3db, into this load without the band-aid use of any external Auto-transformers?? BTW, this is a yes or no question... Cheers George |
This is why the CJ tube amp worked on the speakers- it does not have a lot of so-called 'current' yet could do the job just fine.
Just picking one I had on file from his list Al, the Magico S5, a tube amp "may" work and sound ok with this sort of load. But you will not get the best from them until you hear it driven properly with a solid state amp that can drive this sort of load with current. There are likely others in that list that are even harder to drive. https://www.stereophile.com/images/217MagS52fig1.jpg "
The impedance does drop to minium of 3.15 ohms at 78Hz and 3.55 ohms at 900Hz, and there is a current-hungry combination of 4.3 ohms and –49° at 51Hz." Cheers George |
In no real order the speaker short list is:
KEF blades, I & II, either or.
VA Listz or Music either or.
Wilson Sabrinas, Sashas, either or
TAD Evolution one
Longshots if found used:
Magico S5 latest ver?
Lanch 7?
Wilson XLS ?
YG ?
Eggelston Ivy, andrea II & III. Most of these speakers (maybe not the Tad’s) without spending time to research their impedance v -phase angle graphs (EPDR), would want an amp that could deliver good (doubling wattage) current into low impedance’s, no amount of watts will make up for this if the amp doesn’t have that current ability. Don’t just talk watts, talk about the watts be able to double for each halving of impedance as well. BTW:
blindjim
There are two threads going at once on this one subject in different headings, ask the mods to get rid of one them. Cheers George |
Peachtree Decco, a 50/channel amp, had a lot of trouble driving my Dynaudio speakers (86db). The Dyns were much less efficient than my current Legacy speakers, but still, the Decco was struggling to drive them, so obviously it wasn't really able to output clean 50 watts peaks, or even constant 30 to 40 watts as that should have been enough to drive the Dyns in my smallish room to loud levels.
Classic example is your Peach Tree at 50w, if it had "good current" (almost doubling wattage for each halving of impedance) it would have been able to drive the Dynaudios easy, as the Mark Levinson ML2 monoblocks would have easily done it also with great sound (maybe not party levels). Cheers George |
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We really need to know which speakers you want to power before we can give opinions on which amps would be well suited for them. There are too many variables to give opinions on amps and speakers in general.
Exactly what I was trying to get across, the loading of the speakers impedance is just as if not more important than the wattage, but he and others seem obsessed by a wattage fetish. Cheers George |
Thus… at 3M a 91db sens speaker needs 4 watts. At one set freq. more if most of the bandwidth is being engaged.
Yes? No?
In my own case, the LP should never be more than 10 – 12 feet away from the front baffles.
My guess is 200wpc is plenty for generating aforementioned SPLs. Even a 120wpc amp would work for that matter. I think.
Every speaker I’ve looked into with interest have sens of 88db or higher. Most are 89 – 91db. If your after party levels, and quality doesn’t come into it then your thinking correct. Think about this, an old pair of Mark Levinson ML2 mono blocks can almost do these figures, flat out it can only do 25w into 8ohms 50w, but into 4ohms 100w, into 2ohms 200w, and 400w intoi 1ohm, this is an amp that can do very good current. These ML2 amps on hard to drive impedance loads, that are still high efficiency >90db or whatever, will sound better at normal loud listening (not party levels) than a 1000w into 8ohm amp that can’t double on it’s way down 4ohm 2ohm 1ohm ect. Cheers George |
This might help: http://chuckhawks.com/speaker_spl_amp_power.htm
Sorry it's not the full picture, nowhere does he talk about current into low impedance's, he's only interested in watts and spl. He's only half the way there by talking about efficiency, not impedance loading and difficulty to drive into low impedance loads. Cheers George |
More than a few people over the years on these pages have said only those SS amps which double down in output power as impedance drops are truly special or worthy amps. Eg., 200 @ 8ohms; 400 @ 4 ohms; 800 @ 2 ohms; etc. To put it more simply: No amp will exactly double all the way, anyone who advertises this is stretching the truth. Ones that can come close to doubling (usually good bi-polar output amps) all the way to 2ohms, can push good current into hard to drive speaker EG: most Wilsons especially Alexia ( .9ohm epdr in the bass) and many other brands. This is however not an indication of good sound quality, but your half the way there with a "very" important part of the equation to get it, but your half the way there with a very important part of the equation to get it. It's up to you then to sort these out with best one sound wise, as you taken care of the drive (current) factor. Cheers George |
