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Post by zleepy on Apr 27, 2023 6:52:56 GMT
Hi, I'm seriously pondering a Neurochrome amp, more specifically a modulus 286 or 686. Those of you who has experienced both of these, is there any difference in sq between them? With my TG Faital 3WC-10 I don't really need the power of the 686, but for peace of mind and covering eventual future needs, I'm still considering the 686. But is there anything else than the output power between them? Steve and Bruce, thanks for your inputs in my other amp thread!  |
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Post by firebottle on Apr 27, 2023 7:17:34 GMT
I have a 268, fully pimped.
Oli has a 686, fully pimped.
Technically the 286 has a smidge less distortion in the specification, but of a level that is irrelevant.
The 286 is standard Plus output and Ground to the speakers.
The 686 is Bridge Tied Load, meaning both Plus and Neg are driven, neither are ground and must remain floating.
Fully pimped is proper linear power supply with low ESR capacitors and well proportioned transformer(s). Plus Triple C internal wiring and solid copper input and output connectors.
Oli is a power fiend and would always opt for the 686, I think it is possibly 300W into 4 ohms (depends on the exact power supply voltage).
The 286 is more than adequate for my needs at 120W into 4 ohms. SQ difference is minimal.
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Post by zleepy on Apr 27, 2023 7:25:26 GMT
Thank you Alan, this is exactly the answer I'm after.
Have you used Toms' power 86 for your linear PSU? Was it so that you had a SMPS in it before? Did you notice a difference after installing the LPSU?
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Post by firebottle on Apr 27, 2023 8:37:54 GMT
I haven't used Toms PSU, just parts to hand. My transformer is a 400VA job.
There was a big difference replacing the SMPS with the linear setup.
I recommend not to buy the kit with the SMPS (if one is still available), just the amplifier PCBs and source the rest, plenty of help on here if you need it.
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Post by zleepy on Apr 27, 2023 8:55:36 GMT
Thanks, I might very well do just that. What a great forum this is |
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Bigman80
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Post by Bigman80 on Apr 27, 2023 11:16:31 GMT
Thanks, I might very well do just that. What a great forum this is Just to say that I don't agree with Alans assessment of performance between the 686 and 286. The refinement of the HF increases with each step up in the range, as does the LF control and dynamic swing capabilities. It's not night and day, and in comparison with other amps, well, I don't entertain them at all these days, but there is definitely a difference in performance in the range that I would personally consider to be worth the extra spend. Do it right, do it once. |
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Post by firebottle on Apr 27, 2023 12:12:35 GMT
Refinement of HF between 286 and 686? The circuitry is identical apart from the 686 being bridge output.
I suspect it is because you have better cables, Triple C.
Dynamic swing increase most certainly, but the actual dB increase isn't a great amount.
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Bigman80
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Post by Bigman80 on Apr 27, 2023 12:27:58 GMT
Refinement of HF between 286 and 686? The circuitry is identical apart from the 686 being bridge output. I suspect it is because you have better cables, Triple C. Dynamic swing increase most certainly, but the actual dB increase isn't a great amount. I felt the HF from the 86, 286 and 686 all got progressively more refined, as the amplifier went up the range. The 86 sounded quite lean Vs the 286 and 686. I was told that the circuitry is not identical between 296 and 686, but who knows? |
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Post by hifinutt on Apr 27, 2023 15:36:54 GMT
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Post by stevew on Apr 27, 2023 17:28:54 GMT
Being of simple mind it just feels to me that if you are going to do these things… don’t compromise. Ok, do it once and do it right.
Never heard the 286, so can’t answer that specific. However have heard Oliver’s, and the marriage of those with TG Ekta ii is one that stays in the mind.
For my build we (by which I mean Oliver) is ritually sacrificing a pair of Acoustic Revive cables. They will be happy enough in their new home though.
Thats my other reflection.. component choice should not be compromised. I think other builds may suffer to a degree as a result.
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Bigman80
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Post by Bigman80 on Apr 27, 2023 17:51:45 GMT
Being of simple mind it just feels to me that if you are going to do these things… don’t compromise. Ok, do it once and do it right. Never heard the 286, so can’t answer that specific. However have heard Oliver’s, and the marriage of those with TG Ekta ii is one that stays in the mind. For my build we (by which I mean Oliver) is ritually sacrificing a pair of Acoustic Revive cables. They will be happy enough in their new home though. Thats my other reflection.. component choice should not be compromised. I think other builds may suffer to a degree as a result. My thoughts regarding the circuits being different have been confirmed this evening. Expect a post in the coming days. |
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Post by sq225917 on Apr 27, 2023 19:57:50 GMT
The difference is in ability to deal with phase swing and low impedance. Where the 686 is better with tougher loads and more grippy in the bass as a result.
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Post by phonomac on Apr 29, 2023 7:52:49 GMT
Two differences between a 286 and a 686 affect performance. Firstly in circuit operational terms one half of a 686 module is the equivalent of a 286 - the difference is that the 686 uses three LM3886 devices while the 286 only has two. This means that, for the same working conditions (eg 100W into 4 ohms), the devices in the 686 are working at a lower more linear level assuming equal load-sharing amongst the LM3886 chips.
Secondly the 686 is a bridge-tied load (BTL) amplifier which affects performance much more than simply delivering more power. With a BTL amplifier both speaker terminals are isolated from amplifier ground which keeps most of the noise and interference out of the sound output, leading to a cleaner sound especially in mid and upper frequencies. Look at the graphs on the Neurochrome website of THD+N vs frequency for 100W into 4 ohms. The 286 shows a rising characteristic with frequency (quite normal) which reaches 0.001% at 300 Hz. The 686 crosses that threshold at 3.6 kHz. Across the frequency spectrum the 686 is approximately a factor of 3 lower THD+N than a 286, for the same operating conditions.
Surprisingly the Neurochrome website describes both the 286 and 686 measurements being limited by the test equipment which seems a bit odd since the two graphs looked at for this post would be the same, and they clearly aren't.
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Bigman80
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Post by Bigman80 on Apr 29, 2023 9:02:00 GMT
Two differences between a 286 and a 686 affect performance. Firstly in circuit operational terms one half of a 686 module is the equivalent of a 286 - the difference is that the 686 uses three LM3886 devices while the 286 only has two. This means that, for the same working conditions (eg 100W into 4 ohms), the devices in the 686 are working at a lower more linear level assuming equal load-sharing amongst the LM3886 chips. Secondly the 686 is a bridge-tied load (BTL) amplifier which affects performance much more than simply delivering more power. With a BTL amplifier both speaker terminals are isolated from amplifier ground which keeps most of the noise and interference out of the sound output, leading to a cleaner sound especially in mid and upper frequencies. Look at the graphs on the Neurochrome website of THD+N vs frequency for 100W into 4 ohms. The 286 shows a rising characteristic with frequency (quite normal) which reaches 0.001% at 300 Hz. The 686 crosses that threshold at 3.6 kHz. Across the frequency spectrum the 686 is approximately a factor of 3 lower THD+N than a 286, for the same operating conditions. Surprisingly the Neurochrome website describes both the 286 and 686 measurements being limited by the test equipment which seems a bit odd since the two graphs looked at for this post would be the same, and they clearly aren't. It's nice to see measurements actually reflecting my experience of the amps. Great post Angus. |
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Post by firebottle on Apr 29, 2023 12:52:37 GMT
Thanks for that post Angus, that's really interesting information.
I never doubted our venerable bat ears but good to see what the difference is. I suppose less of an issue if you have sensitive speakers and usually operate at a low output level.
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Post by jandl100 on Apr 29, 2023 17:41:47 GMT
The perceived differences between the amps would probably be less for older geezers like me and Alan, where we would be lucky for our hearing to reach up to 10khz.
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Post by hifinutt on Nov 9, 2023 14:50:19 GMT
nice 686 built by AD audio just come up on aos
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Post by hornucopia on Nov 10, 2023 15:08:19 GMT
Argh! MORE temptation!!
My CODA should be adequate, but.......
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Post by alit on Nov 10, 2023 16:37:38 GMT
Having now had a bit of a listen to the monos, I’d agree with Oli, these are a fair step up from the 86- good as that is.
There’s just more of everything. Yes, obviously more dynamics, but there is also a lot more air and space in the treble, and more detail too.
Not even run in yet and they sound this good..
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Bigman80
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The HiFi Bear/Audioaddicts/Bigbottle Owner
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Post by Bigman80 on Nov 10, 2023 17:26:43 GMT
Having now had a bit of a listen to the monos, I’d agree with Oli, these are a fair step up from the 86- good as that is. There’s just more of everything. Yes, obviously more dynamics, but there is also a lot more air and space in the treble, and more detail too. Not even run in yet and they sound this good.. The 686 is the best of the range IMO and it's insane that the 86 and 286 are as good as they are. Any of them would serve their owner extremely well. Enjoy! |
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Post by alit on Nov 10, 2023 18:31:30 GMT
Cheers mate, I am. These are really very good indeed!
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