ti33er--I think it's likely you've hit the point where neither amplifier is the rate limiter. Congrats.Now, go worry about something else, haha.
...well I hope in one way you are correct, I can start growing my money in stocks and shares instead of squandering it on Veblen goods!!!!!
A board with two op amps, less than a dozen resistors, a handful of HF filtering and power decoupling caps and a few connectors would be hard to get very wrong. Besides the op amps, what components is Boggit using? High quality caps and thin film resistors? I think Boggit said that Hypex reviewed (and assisted with) their board layout. So maybe it's a stuffing problem on that particular board?
Ti33 - you can bring your NC500 amp over to my place and give it a whirl with my Egglestonworks Andra IIIs. We can start with a test run on my Egglestonworks Rosas which I have as surrounds. Or maybe we start with the Andra III centre channel just in case it all blows up! Sorry, but it will be rather difficult to bring the speakers over to your place...
I am following this thread with interest (thanks to all posters BTW) but have no clue about these modules.
I have some very ancient experience re OP AMP rolling (hate that word as you can't do that really) and noticed the sound issue mentioned here with the different input buffers. Doesn't completely baffle me what happens here. Not saying I have the solution, but 3 paths to explore, maybe?
1- There is a connecting problem - I take it these are all quick & dirty op amp rolling,"done as usual", that is "just" with supports you plug into supports etc. Perhaps 2 of the modules aren't connecting properly 100% to each legs, while still making contact. I don't really believe in that one, but can't rule it out... Especialy as you mentioned the device is noisy with the op amp it was designed for.
2- Op-amp is not equal op-amp and all these little devices are built differently, have different input impedances and are each best suited for a dedicated task. One can't really just swap them, not even mentioning comparing their best sonic results, without taking a few bits into consderation. Perhaps the rest of the input board has been designed for a given OP amp with given specs (input impedance, etc. etc.) and changing the op amp with another doesn't work as well. Not the op-amps fault really. That would be my personal second bet. Basicaly you can do some "quick and dirty" op amp rolling but taking PS requirements and also op amp specs into consideration (these have to be similar spec'd regarding the relevant parameters for your schematic)
3- Op-amps have different sensivities re current supply and decoupling. Despite their rejection graph showing marvelous values, some cope well with a low cost regulator miles away, while others want to have top feed and also their legs directly connected to various decoupling caps. However, I would expect the ones designing discrete op amp to take that into account already. Well, perhaps they didn't... But perhaps they did indeed and the board on which the amp goes does decouple aswell and there is a conflict?
Just thinking loud without any data, well noting I know none of these boards
I hope this helps
Claude (happy to still do sometimes op amp rolling on various devices but not without some prior considerations and quick study)
I have some very ancient experience re OP AMP rolling (hate that word as you can't do that really) and noticed the sound issue mentioned here with the different input buffers. Doesn't completely baffle me what happens here. Not saying I have the solution, but 3 paths to explore, maybe?
1- There is a connecting problem - I take it these are all quick & dirty op amp rolling,"done as usual", that is "just" with supports you plug into supports etc. Perhaps 2 of the modules aren't connecting properly 100% to each legs, while still making contact. I don't really believe in that one, but can't rule it out... Especialy as you mentioned the device is noisy with the op amp it was designed for.
2- Op-amp is not equal op-amp and all these little devices are built differently, have different input impedances and are each best suited for a dedicated task. One can't really just swap them, not even mentioning comparing their best sonic results, without taking a few bits into consderation. Perhaps the rest of the input board has been designed for a given OP amp with given specs (input impedance, etc. etc.) and changing the op amp with another doesn't work as well. Not the op-amps fault really. That would be my personal second bet. Basicaly you can do some "quick and dirty" op amp rolling but taking PS requirements and also op amp specs into consideration (these have to be similar spec'd regarding the relevant parameters for your schematic)
3- Op-amps have different sensivities re current supply and decoupling. Despite their rejection graph showing marvelous values, some cope well with a low cost regulator miles away, while others want to have top feed and also their legs directly connected to various decoupling caps. However, I would expect the ones designing discrete op amp to take that into account already. Well, perhaps they didn't... But perhaps they did indeed and the board on which the amp goes does decouple aswell and there is a conflict?
Just thinking loud without any data, well noting I know none of these boards
I hope this helps
Claude (happy to still do sometimes op amp rolling on various devices but not without some prior considerations and quick study)
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Anyway, my point really was about an oldish technology (fairly well regarded, 'boutique' possibly) amplifier vs the nCore best there is with 0.00000000000000000000000000000000000000000000000001% distortion right now... I'm not hearing very much difference ...as suggested possibly my hearing is impaired being in my early 40s; and fair enough maybe I do need to take another hearing test because my Wife often tells me I'm not listening to her
Not oldish. Nearly all my system is older than that and I also have a 1966 Radford I am restoring.
NEWSFLASH: below a certain level, which is argued about but around 0.1% THD you cannot detect any less. Below that it's all in your mind. Which is fine if you accept that. So an amplifier that was transparent in 1999 will be transparent today.
What Hypex gives you is the power and quality of 1990s big old ugly inefficient class A/B amps in a package no bigger than an integrated with no big sharp hot heatsinks. And the ability to drive low impedance loads with aplomb.
if you are buying new from a company that will stay in business rather than one that stopped making things 10 years ago its a compelling package.
If you expect 7 veils to be dropped and windows onto the music to be cleaned you should stop reading the audio press. Bruno's designs are really great, but they won't replant rainforests.
But at least they waste much less power than the 90's designs.
Without my Krell FPB and plasma tv I'd need to add another heater in my room!
But at least they waste much less power than the 90's designs.
Which was my point. SQ that 10 years ago would have required something dissipating 100W+ at idle that is stone cold. If that's not progress I don't know what is!
I do agree with you - I've left these nc500 on for almost a month, I think? Still cool to the touch and I'm not worried my electricity bill will cost me more than it did before ...so long as someone and I refer to Boggit, will still be selling nc500 and has bits in case something goes wrong after the warranty period, all is well
Ps. AUDIOLAB IAG and the (infamous but honestly, professional and courteous Kevin of AUDIOCELLAR) repair TAG and original UK for little money, so it wasn't bad hedge of a bet for me
I wasn't insinuating you couldn't get them repaired Just that some like buying new. Apparantly some idiots get a new car every 3 years. Like my hifi, my car is older that your amps. I'll probably replace it after 300,000 miles.
But at least they waste much less power than the 90's designs.
Much less?
With an SMPS dissipating 15W at idle the class d amp might not be more efficient as a total.
A good class A/B amp, powered by a linear supply, with +/- 50 volt rails and 50 mA idle current would dissipate 5 W at idle.
Most of our music played at average level on average loudspeakers takes no more than 1 watt of power from the amplifier.
Efficiency of the class d amp is higher than the A/B amp, but in the end the SMPS / class d combo might take more power average than the A/B / linear supply amp.
+/-50V does not a 200W amplifier make...*
Also other than the self designs who commercially would run a big power amplifier at that low bias. People want lots of class A and so the manufacturers give it to them!
* NC400 is 200W/8ohms. NC500 is 350 or 400/8 depending on who is selling them.
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