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Thread: Yamaha NS1000M - Tweaks

  1. #41
    Join Date: Mar 2008

    Location: Galashiels

    Posts: 13,669
    I'm inthescottishmafia.

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    Aye, it sounds pretty good, shame he's only got 5m left, I could have rewired the OB's internally.
    “Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”

    Hunter S Thompson

  2. #42
    Join Date: Feb 2012

    Location: Falun, Sweden

    Posts: 2,245
    I'm Mike.

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    Give single strand installation cable a try! Preferably with a similar twist to ones you show pictured. That, will give you an eye opener

  3. #43
    Join Date: Feb 2012

    Location: Falun, Sweden

    Posts: 2,245
    I'm Mike.

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    And as an extra tweak, try one twisted pair per conductor. (In total two twisted pairs per speaker connection)

  4. #44
    Join Date: Aug 2012

    Location: Hartlepool UK

    Posts: 1,640
    I'm Alan.

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    Turntable - Garrard 401/Jelco 750L/Ortofon Kontrapunkt B, Pioneer PLC 590, Micro Sieki MA505 , Denon DL103R - DIY Paradise Phono stage - Reel 2 Reel Studer A810, Otari MX55,Tascam BR20, Revox A77, B77, PR99, TEAC X1000 & 3440, Digital HTPC / Young Dac - Preamp - DIY B4, 821, Power Amp's DIY Avondale NCC300 Mono Block, Speakers Wilmslow Kit Volt BM220.8 / Scanspeak D2905/9500

  5. #45
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    Quote Originally Posted by Qwin View Post





    I decided to replace the wiring inside the cabinets. I found many great reviews for the Belden 9497 (top picture) and it was used by Shindo Labs. Trouble is it is thin and only good for low powered valve amps into efficient speakers, it just wont handle larger current. I decided to make my own beefier version of this cable and purchased some 2.5mm square, marine, tinned, thin wall cable. I twisted this together using a cordless drill and as you can see from the two specs it is very similar, using similar diameter strands just more of them. I tried this out as a speaker cable running from the amp and it is very natural sounding with phenomenal bass, so I replaced the stock internal cables with this and while I was at it, bypassed the level controls and ran the cables along neater paths and not bunched together which could result in crosstalk.
    As it turned out I didn't like this cable as it high lighted some distortion I was hearing in the upper mids. It works very well for bass and lower mids so in another set up it might shine.

    I took it out and replaced it with plain 2.5mm OFC I stripped out of some old Van Damme tour grade cable that I had lying around. This was much better at concealing some of the distortion.

  6. #46
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    I've never been completely happy with the passive cross over, either before or after the re-cap. I hear distortion around the mid to tweeter x-over point. I've heard it on other examples of the NS-1000M, I had it on my Celestion 66's and hear it to some degree on almost every passive three way I have come across. It's mostly noticeable on voices, especially Female. I decided to try a simple analogue active filter circuit in an attempt to get rid of this problem, I'm using the ready made modules by KMTech. The passive is a simple circuit without any notch filters or zobel networks so a simple analogue filter using Op-Amps might work without the need for any frequency equalisation etc. The PDF file linked here: http://www.jkwynn.co.uk/Project_Imag...ver_Layout.pdf
    shows the layout I drew up, it has a power supply, also by KMTech, you just need to add a Transformer. The 30VA I used is overkill and one of 15 to 20VA would have done the job if I could have found one. I've tried to keep the AC path well away from everything else and to avoid the DC tracks crossing the signals, which I have kept as short as is practical. I am building high quality volume pots into the outputs to allow channel matching for amplifiers of different power ratings and sensitivity. The standard PCB mounted RCA sockets will be removed from the boards, I just used library pictures of the products for the layout.





    It all fits into a 17" x 1U case which is 250mm deep, this is only marginally bigger than my Croft pre amplifier so it will sit under this on the shelf. I bought a ready made case and started work fitting the power supply.









    This is the back panel and a trial fit of the fused IEC socket, the RCA sockets and the label I made to help identify the inputs/outputs. I went for a traffic light system, Red for Tweeters normaly at the top, Amber for Mids and Green for Bass normaly at the bottom. These all have Left and Right channel variants which are indicated by Red and White RCA sockets/plugs as normal. I will colour code the leads and amp channel inputs, also the speaker outputs to make it all fairly idiot proof. I don't want to accidentally plug a channel with power and frequency tailored for a bass driver into a tweeter, not if I can help it, so the clearer the better.
    Last edited by Qwin; 28-05-2015 at 18:23.

  7. #47
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    I fired up the power supply to test the "Power On" LED. I put a standard LED across the whole of the dual voltage output (-9.8/0/+9.8) so about 19.5 volts dc. This will allow it to discharge both pairs of capacitors in the PSU when switching off. This calculates to approx 750R for the anode resistor, but with the 20 mcd LED used I thought this was too bright, and I don't like really bright lights on my gear. As can be seen in the centre of the picture I used a very small pot on the LED and turned it down till it was the brightness I wanted. I then measured the pot resistance (1k2) and soldered a resistor of that value on the long leg.

  8. #48
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    The crossover modules arrived from KMTech. The Yammies cross at 500 and 6000 Hz, these boards cross at 501 and 6090 Hz which is the closest match using standard resistor/cap values. I'm not using the stock PCB mounted RCA sockets, so I've added extension wires to the boards made from wires I stripped out of some Klotz MC-5000. The input cables are made from the same, but I just stripped off the outer jacket and copper shield on these. As I will probably be using interconnects made from Klotz MC-5000 it made sense to use this on the internal connections.

  9. #49
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    Got all the wiring done, crossover boards now have power to them and I have wired a couple of cheap 10k dual gang volume pots into the output to control mid and tweeter levels. I didn't see the point in splashing out on expensive pots till I have an idea of how good the crossover is. Must say I am a bit concerned about all those wires and the possibility of crosstalk.

    I managed to do a basic check that things are working. I played each pair of outputs in turn through a stereo amp and a pair of passive speakers. This confirmed HF/Mid/LF output from the boards and that the level pots were wired up correctly.

    I now have to construct some new rear panels for my Yamaha speakers with three sets of speaker connectors, I want to keep the existing panels with the passive crossovers attached un-altered, in case I ever want to revert to original spec.

  10. #50
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    Made the rear panels for the speakers, the camera has made them look crooked and a bit scruffy but they are square and straight in the flesh and look much smarter.

    I made suitable laminated labels for the panels and mounted the connecting sockets.

    I only ever use "Z" type 4mm Banana plugs, so I'm not a fan of bulky multi function binding posts. The panel sockets I used (inset) stand only 5mm off the surface and are high quality items from "Hirschmann" they are solid Brass, Gold plated and rated at 32Amp. RS do them at £2.04 each with free delivery.

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