LSA Voyager GAN Amplifier
Tweak1 not for him Go over to diyAudio check out what abraxalito is all about, he’d design and build his own if the GaN’s weren’t smd and guide/show others (including the bothers in arms here) how to do it right. |
@abraxalito Yeah, my hi-tech friend was very excited with this and is getting one of these GaN by GaN with SMP Eval bundles it just left the US for AU. It’s got pre/dac/volume control/input switching/variable feedback, they set the feedback low, they say for better sound so the distortion figures aren’t out of this world, still good though. The SMP is only +32 0 -32. But you can take it much higher, then you may have to heatsink the GaN fets, but the data sheets seem to say it’s not needed. https://forum.audiogon.com/discussions/gan-by-gan-class-d-with-smp-complete-for-940-ready-to-go-just... Cheers George |
viber6 Can't wait for this one. |
IME there’s no point going over 150kOhms input impedance on an amp; it will cause it to be more sensitive to the interconnect cable capacitance and for that matter, induced noise in the cable. Go back to what I said 4 days ago georgehifi 09-11-2021 1:58pm |
viber6Viber as I thought, Ricevs answer to is was his own jibber jabber, with no facts as you asked. And Ralph’s chime in that wasn’t asked for, (almost seems like an auto technical protection response for ricev) is a coy smoke screen to try to turn things around again with using the word "may introduced" and "tube" (high output impedance) as the active source. This was the correct thing to say "Changing the input impedance from 38k to 150k will do absolutely nothing if the "active" source has a "normal low’ish" (say <150ohm) output impedance that will drive both" Both of these are guys bothers in arms protecting their own interests only, it obvious from a mile away. |
Woah!!!!!!!! https://youtu.be/YTY26k0CA0I?t=2 If anything that sort of frothing at the mouth will make you less customers |
You are both wrong.....he he....resistor types/brands can make as much difference as anything.....That was always going to be a given, doubt very much you could tell any difference between all the "known good branded" same value/wattage metal film resistors as an input loading resistor to ground. Just like you say you can see many mods you can do to this amp to take it to another level just by looking at this photo, https://ibb.co/Dr86JY6 |
Viber No, what I’m saying these are two very different scenarios, one (the phono cartridge) has quite variable output impedance due to it being a electro/mechanical device, it "could" go very high impedance in the highs. Where a solid state output stage is quite fixed, especially if it direct coupled, if capacitor coupled and not large enough it can go very high in the lows. You try the same but with the preamp output stage(<100ohms) vs the poweramp input stage 37kohm or 100kohm, you won’t find a difference. Also you haven’t mentioned what’/if the parallel pf capacitance has been used across each channel of the cartridge, or in the phono stage. I’ve done many presentation at our audio society, with a solid state direct coupled low impedance output source (eg: <100ohms) you will not find any difference in sound with a load impedance of 38kohm v 100kohm, and nobody at the meetings could pick the difference, the 100kohm "could" get slightly more noisier, as seen on a scope, and create filtering effects if the interconnects are extremely high capacitance. Cheers George |
Different story with a mechanical/electrical source as MM or MC Cartridges, they need sometime none or lots of electrical damping, which in some cases can give the impression of more detail extension and clarity, maybe because of reduced bass output. As they do not have a mostly fixed output impedance like a solid state output stage has. We used to load down the Supex SD900 with 10ohms to get them to sound right. Cheers George |
Yeah like this one https://www.youtube.com/watch?v=ctrx8PhOhqQ&ab_channel=RickSchultz And you really need to change the bong water every now and again. |
Always the peace/love/dope/Woodstock card comes out when backed into a corner. Changing the input impedance from 38k to 150k will do absolutely nothing if the source has a "normal low'ish" (say <150ohm) output impedance that will drive both, making the input 150kohm, could very well "only serve" to have higher measured noise in the end. And willy/nilly changing the input of an amp to something 4x higher "can" create offset and other problems, there was a reason it was 38k to start with. Cheers George |
I don’t like charlatans bilking people out of their money by claiming they can do a few superficial "tweaks" and suddenly take a solidly engineered product with state of the art performance and, wave hands, dramatically "improve" the product. It’s a con. People want to believe and there’s always a prophet willing to accommodate them, for a fee. History is full of these scammers and the world full of those all too willing to believe their tale.Here here🤙 especially when they don’t say what mods they will do for how much, when they just see a pic of it with no measurements and or oscilloscope bench testing and say they can take it to another level. Cheers George |
I am not dismissing mods but if the item is so great, why does it need to be modded, especially during the warranty period? +1 Very bazar behaviour, and if done, hopefully not by some who takes one look at just a picture of it, (no bench measurement/scope tests) and says he can see quite a few modds to take it to another level, without any explanation of what mods can be done take it to that next level. Cheers George |
If you’re avoiding feedback you’ll need that sort of bandwidth to prevent significant phase shift.Like Class-D have with switching frequencies at 600-800khz, like this Icepower has https://ibb.co/5Kj0rcP that has significant feedback, and still has rubbish phase shift measurements(red trace).
If that is correct, this is what Technics did (with SE-R1) fixed 1.5mhz switching frequency/output-filter to move the phase shift up and out of the audio band in the above graph. And why you can get to 100khz bandwidth without too much roll off (phase shift). BTW your positive feedback link doesn’t work here it is fixedCheers George |
But the more attention you give to reacting and being in resistance....the more miserable you are.Well, you know what to do.🙏 As I said to others before, this is just a strange thing to say, that you can see many mods to do to this to "take it to another level", just by looking at this picture. (it's just "snake oil" talk) https://www.underwoodhifi.com/sites/default/files/GaN%20350%20inside%20shot.jpg Cheers George |
Please if you don’t know what it means by now, don’t keep asking. This explain it all, https://ibb.co/Bs1tJ7d at 600khz Even at Technics at 1.5mhz there is still some small amount of phase shift in the audio band, so at 800k it's still there "almost" as bad as Icepowers 600k |
Very easy to drive, no bad -phase angle at those 4ohm dips, so yes Class-D friendly, 4 ohms is where they do their best work, but start to panic at 2ohms, especially if it’s accompanied with >-40 phase angle https://www.stereophile.com/images/714R208fig1.jpg Cheers George |
This is correct, but even more important for Class-D to be able to do to over take the best linear amps, is that they cannot come close to doubling their wattage for each halving of impedance from 8ohm to 4ohm to 2ohm for those speakers that are very hard to drive eg: Wilson Alexia And the even bigger problem to get rid of, is the phase shift in the audio band that the output filter creates to rid the output of most of the switching frequency noise https://ibb.co/Bs1tJ7d . And the only way to do this is to take it all up higher x 3 (switching frequency and filter) to 1.5mhz or more instead of 600khz. ONLY then, could it be called to be better, than or equal to, the very best liner amplification. Cheers George |
riaa_award_collectors_on_facebook +1 For those in denial look at this (red bad squashed to death) compressed They only got together once and made the one album master, but it was re-released many times but got gradually squashed to death with compression the newer the release got. Just for listening in car/streaming/download/ipod and background music https://dr.loudness-war.info/album/list/year?artist=Traveling+Wilburys Cheers George |
In denial is the only phrase that comes to mind. I find it very sad that the bothers in arms, have never heard the saying "Krell Like Bass" in audio, quite is bazaar, and that they think it wrong!!! https://www.google.com/search?q=%22Krell+like+Bass%22&sxsrf=AOaemvIs0dkJ7onfJdG7SzPF9XZNB4LZXw%3... https://www.google.com/search?q=saying+%22Krell+Bass%22&oq=saying+%22Krell+Bass%22&aqs=chrom... |
Like I said either under a rock or too much OTL listening, with most hard to drive hi-end lower impedance speakers. Shouldn’t bass be like the music in which it exists rather than a certain brand of amplifier??Yes, it’s obvious from that answer/question, you have not sat in a jazz venue when the unamplified drum kit is being severely belted. It’s closest in audio as I said (Krell like bass) and similar amps to it, like Gryphon etc etc etc and defiantly not OTL and most tubes with the majority of hard to drive hi-end lower impedance speakers. |
You never heard anyone use the saying "Krell like bass" It's sad then, you’ve either been hiding under a rock, or don’t get out much. https://www.google.com/search?q=%22Krell+like+bass%22&oq=%22Krell+like+bass%22&aqs=chrome..6... |
Is there any word of GaN-based amplifiers hitting the pro-audio market "Right now, the company is seeing a growing demand for smart and battery powered speakers, multi-channel automotive and high-end home audio systems, and is also targeting traditional home theatre and professional audio markets, including stadiums. And according to Reigel, feedback from reviewers in the audio industry, so far, is good." https://compoundsemiconductor.net/article/111521/GaN_Systems_All_Eyes_On_Audio_Amplifiers Looks like it's coming, they're always a bit slower to pickup on the newer technologies, took them an age before they adopted Mosfets. Cheers George |
That’s a real beauty, (it’s a good laugh so long as your not serious) atmasphere: I’ve not seen anyone detracting from Krell on this thread.Pays to look a little harder, or you only see what you want to see " Larger quantity of bass is always associated with lower quality and accuracy, as shown by the Krell." |
Larger quantity of bass is always associated with lower quality andOnly one thing to say about that, and it’s double phooey!! I would say that the KRELL would be preferred by the majority of people.True, nothing wrong with Krell bass, it’s most controlled, tight and dynamic bass of nearly any other amp I’ve heard. (BJT (bipolar) done right, can’t beat it) And it’s does hard loads better than the AHB2 because it does far more current into them than it can, and bridging the AHB2 into mono won’t get it up there with a Krell, if anything it’ll be worse just louder (more watts but less stable) than the stereo into low impedances. Cheers George |
There is, made by GaN them selves, so you know it "should" be good. (Could very well be the best of all GaN amps) (single purchase only, not available for multi purchase for commercial Class-D manufactures) But you’ll have to put it in a box, comes with all you need, power supply and integrated GaN Class-D stereo amp and DAC!! (if you can build simple kits you can build this it quite simple to make up) . You have volume control, analog input, 2 x digital spdif inputs optical and coax (yes it has a dac in it too) and variable feed back for those that don’t like too much for the sake of "better" measurements" all for just $1.3K https://gansystems.com/evaluation-boards/gs-evb-aud-xxx1-gs/ https://au.mouser.com/ProductDetail/GaN-Systems/GS-EVB-AUD-BUNDLE1-GS?qs=vHuUswq2%252BszP6hR0ubJmfw%... https://gansystems.com/wp-content/uploads/2020/05/GS-EVB-AUD-xxx1-GS_Technical-Manual_Rev-200526.pdf Cheers George |
With these sort of gain selections (below), perfect for using a dac direct into it that has a digital domain volume control, set the LSA gain so the dac’s volume is just 30-10% down from max for normal loud listening level and still have some left in reserve, that way you won’t be "bit striping" Mid or low would be the one in most systems
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