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Thread: Yamaha NS1000M - Tweaks

  1. #231
    Join Date: Aug 2009

    Location: Staffordshire, England

    Posts: 16,242
    I'm Martin.

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    You've blazed a bit of a trail there Ken. Certainly be less work for anyone following you in activating these speakers.
    Martin



    Current Lash Up:

    Technics SL1200 with Sumiko h/s & Nagaoka MP50 * Firebottle valve MM phono stage * Parasound CDPi1000 * NVA P90SA passive pre / Krell KSA50S Power amp * JM Lab Electra 926 loudspeakers *



    "I hate to advocate drugs, alcohol, violence, or insanity to anyone, but they've always worked for me." - Hunter S Thompson

  2. #232
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

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    Thanks Martin, folks may as well benefit from my experience and the numerous things I tried.

    Note: In this application, the stock set of OPA2134 supplied, just sound too smooth, rounded off and a bit shut in, lacks air, bite and attack.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  3. #233
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

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    I've been quite on this project for some time.
    It's taken the back seat as I do some experimenting purely on the active crossover circuit.

    I have a two way circuit I'm working on, everything I learn from this will eventually carry over to the Yamaha's three way circuit.

    There have been way too many things to cover in detail, some of the things I have tried/incorporated:

    Converted the single ended input to balanced by summing the two halves of the balanced input through the buffer op amp.
    This involved cutting PCB tracks and soldering point to point alternatives adding a couple of resistors and changing the value of two existing resistors.
    To do this I also had to modify the 2 terminal phono socket to a three terminal screw block.

    Changed the basic Lytics de-coupling the power rails to Elna Cerafines, also tried Panasonic FC and FM before settling on the Cerafines.

    Used Vishey MKP1837 (PP) caps instead of Polystyrenes for the filter elements.

    Removed the basic 0.1uF ceramic bypass caps on each op amp that were across the power pins and replaced with 4.7uF Tantalum/0.1uF ceramic in parallel from each power pin to the ground plane. Added a 0.1uF Wima FKP2 film/Foil across the power pins on each op amp.

    The board designer used dual op amps throughout so he could supply one type of op amp. This made it idiot proof for assembly, any chip would work in any socket, providing you fit them the right way round in the socket. Trouble is the buffer only uses one channel, op amps being fairly unstable devices, I have considered whether this could be a problem, the unused side is powered up but has no input or output tracks to the pins, it may be an issue, but I'm only guessing. To rule this possible source of distortion/noise out, I have changed the pin out on the buffers dip8 socket to accept a single channel op amp, which has different +V and Output pin allocation.

    I have just ordered some of the SPARKOS LABS single channel discrete op amps to try in the newly configured pin out. The other reason for changing to single channel is they are a lot cheaper than duals, especially when you get to discrete prices.

    I changed the basic power supply that KMTech offered to a Chinese regulated supply board, I swapped out the Chinese smoothing caps on the board for Panasonic FC's.

    In changing the power supply board this also required a new transformer as I increased the voltage at the rails from an unregulated +/-9.2vdc to a regulated +/-11vdc. The Burson v5 discrete handle an absolute maximum of +/-15v but they were running a bit hot at even +/-13.5v so I backed it off to +/-11v. They run a lot cooler at this voltage and would probably be OK up to +/- 12v.

    I had to increase the PCB pillar height to accommodate the mods I did to the underside of the PCB and give good clearance to the metal enclosure, also wired in some XLR sockets using Klotz MC5000 cable.

    So I've been quite busy.

    When I get to a final solution, I will post details and pictures of the mods I used for the Yamaha's and start a new thread for the 2-way project.
    Last edited by Qwin; 26-10-2016 at 08:34.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  4. #234
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

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    With all my dealings with the NS-1000M it is clear, to me any way, that the mid range driver is the star of the set up, world class. The tweeter blends well with it, but has only average performance and drops off a cliff at 15kHz. With the high crossover point and gentle slope the mid driver is extending well up the range, switch the tweeter off and you barely miss it. The bass does its job, is fast, packs a punch and again blends well, but rolls off fairly early.

    I sometimes wonder if this mid dome could be matched with a modern Tweeter and bass driver to give even greater ability across the whole range?
    When I get my Scanspeak 12" bass drivers, it is very tempting to try these and my Fountek ribbon tweeters with the Yamaha mid dome, just to see!

    I looked for spare mid domes on the bay, the only thing I found was a single driver and they wanted £284 for it.

    If any one is interested a guy in Greece is selling a pair of brand new (NOS) bass drivers and a pair of tweeters, all still in the original boxes (on the Bay), he wants over £900 for the pair of bass drivers though.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  5. #235
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 3,380
    I'm Alan.

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    Quote Originally Posted by Qwin View Post
    Trouble is the buffer only uses one channel, op amps being fairly unstable devices, I have considered whether this could be a problem, the unused side is powered up but has no input or output tracks to the pins......
    If you (or anyone else) is in this situation again then the best thing is to just earth both input pins of the unused op-amp.

    Keep the updates coming Ken

  6. #236
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

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    Thanks for the input Alan, I will remember that one.
    Of course the other reason I changed to the single channel is the monetary saving £40/opamp so £80 less for the pair of single channels.

    I'm spread a bit thin at the moment, with my semi active three way project taking most of my time and funds.

    Hope to get back to the NS-1000M soon. I'm considering going over to the dark side and looking at DSP. After hearing Ali's 401/slate turntable and Benz Gullwing cartridge through a miniDSP, my concerns about degrading the analogue sound through an ADC/DAC have evaporated.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  7. #237
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

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    Apart from making small tweaks to the components in the analogue active crossover, which will make only small changes to the sound, the NS-1000M are about as good as I will get them with the stock crossover points.

    I have been experimenting with other speakers, but I keep coming back to the Yamaha's and their exceptional mid range clarity and imaging.

    They are not without their faults, as I have mentioned before, the bass falls off early, with an F3 above 50Hz. It's all about that fabulous 3 1/2” Beryllium Mid Dome, it certainly dominates the voicing. It has a high upper crossover point of 6kHz and with the shallow roll off from the simple passive second order circuit, it will still be contributing at 10kHz and beyond. The tweeter has a bit of a ragged response at its lower end and drops off quickly at the top (15kHz). The dominance of the mid dome can be verified by switching the tweeter off. I can do this easily on my active system with the flick of a switch. It really doesn't contribute much, other than a sparkle to symbols etc. Having said all that, I keep coming back for more, so there is something fundamentally right about the sound.

    I've been asking myself the question, as to what would happen if the tweeter crossover point was lowered and/or a steeper slope was introduced. This and maybe replacing the tweeter with a modern ribbon tweeter, I have been very impressed with the Fountek NeoX 1.0 I've been working with. Then there is the bass, keep it as a sealed box, but use a driver that goes a bit deeper?

    There are lots of variables, I certainly wouldn't want to loose the signature sound, but maybe loosing some of the steely sharpness at the top might be a good thing. This might make them more Amp friendly, as they do need a bit of care when matching?

    They obviously would no longer be an NS-1000M, but maybe a modern take on the theme? This is an image of the kind of thing I have at the back of my mind. “NS-1000 Revisited”



    It would need a lot of experimenting with crossover points and slopes, so a minidsp would be used to help achieve this. I have had concerns in the past about using a DSP with my Turntable, but after hearing Ali's very good TT recently, through just such a set up, I am less worried, as the results were excellent. I would love to at least try this at some point and see what can be done, we all aim for that audio Nirvana, I think mine is based somewhere around the NS-1000M Mid Dome.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  8. #238
    Join Date: Feb 2012

    Location: Falun, Sweden

    Posts: 2,138
    I'm Mike.

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    This looks really intriguing Ken! Looking forward to reading more on your adventures in NS-land!
    And i might add, my bog standard NS1000M were used as discotheque speakers on new years eve! I had my doubts wheter they would survive the heavy pounding they took from several hundred watts and disturbingly loud SPL's!
    But they sailed through, with several compliments on sound quality from the dancing guests!
    Cheers /Mike

  9. #239
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

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    I once took some big wharfedale speakers to a party, they were played so loud no one could hear one of the tweeters had failed, blew a cap in the crossover, so an easy fix.

    I've got lots of ideas floating round in my head for the Yamahas, I am getting the Scanspeak bass drivers for another project, and I want to experiment with a DSP set up, so I might get to try a lash up similar to the one in my picture.

    Don't ask me when though

    I will keep adding my findings to the thread.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

  10. #240
    Join Date: Jan 2013

    Location: Durham - UK

    Posts: 1,232
    I'm Ken.

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    I didn't take this picture, but it's of the Scanspeak 30W/4558T00 12" Subwoofer.
    It's featured in my sketch and I think it would make a good replacement for the Yamaha 12" Woofer and add some missing depth to the bass.
    It's a fairly substantial driver as can be seen.




    I think, because it has a low Fs of 17Hz, a reasonably large XMax and power handling, Scanspeak decided to place it in the Subwoofer category, it certainly gets used a lot for that application. But DIY builders including Troels Gravesen have used it as a straight Woofer in a three way. Below is Scanspeaks own frequency sweep for this driver.

    Edit: It's worth pointing out this would be best implemented in an active set up, as this driver is 4ohm and also 4dB less sensitive than the 8ohm mid dome.




    Don't be too alarmed by the peaks and troughs in the lower section, Scanspeak plots always look like this. Where most manufacturers use smoothing on the plot, or include nearfield response at the lower end, to make it look better, Scanspeak prefer to give you the true results warts and all, they have to be applauded for doing so.

    The thing that struck me about this plot, was how flat it is in the upper bass and how far it extends up the range, definitely a response more like a Woofer than a true Sub, with its typical hump back curve.

    This driver has an Efficiency Bandwidth Product (EBP) of 49 making it best suited for a sealed enclosure.

    Taking the standard Qtc figure for a flat response of 0.707 this computes as an F3 of 38Hz in an ideal 55L (Net) sealed box.

    So, by keeping the same footprint for the cabinet, it would only be around 100mm taller than the 50L NS-1000M. It would probably perform well, if not ideal, in the Yamaha cabinet. Sealed cabinet pairings are less fussy about exact volumes, compared with tuned ported cabinets.

    It certainly ticks a lot of boxes for the Yamaha's, so not surprisingly, the spec grabbed my attention when I was checking out drivers for my other project.
    Last edited by Qwin; 15-01-2017 at 11:58. Reason: Sensitivity note added.
    Ken

    http://www.jkwynn.co.uk/
    DIY Technics/ProJect based Turntable + Terminator linear tracker + Ortofon MC20 Supreme / Pro-Ject Phono box & Pre Box RS / KMTech Active X-Over / Nakamichi AVP1 Power / DIY Sealed Three Way Speakers / Stello CDT100 Transport / DAC Magic.

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