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Post by Deleted on Apr 4, 2018 16:03:04 GMT
Hi Stu, I was interested to read that you are the guy whose Naim CD modding threads I read on PFM some time ago. I was inspired but I lacked the sort of soldering skills that you'd need to do anything really intricate. I don't understand a great deal about electronics either, but I can replace caps, resistors etc on a circuit board.
Is there anything I can do to my Naim CD3 that would make a sizeable improvement within the limits of my abilities? I have owned a few Naim players in my time and all have been good. The area I would most like to add too on the CD3 is weight, pace and drive. The CDI was a real favourite of mine and moving in that direction would be my aim. If I'm expecting too much from the sort of mods I can do myself, I can always sell it on and buy a better Naim player.
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Post by karatestu on Apr 4, 2018 16:23:03 GMT
Hey Andrew. Yes it was me. I had a few including a very long one that ran for a couple of years. Still not finished messing about with it yet  I will have to have a think about it and reply later. I am not entirely sure what level you are at as regards diy audio. Thinking hat on but its kids tea time and i'm a cooking. Stu |
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Post by Deleted on Apr 4, 2018 16:31:42 GMT
Cheers, Stu. My level is definitely "ground floor". I've replaced failed components and switches, recapped amps and messed about with crossovers. That's about it. No problem if my limited skills mean I'm best off leaving it alone Your threads on PFM were amazing and I'm sure they were responsible for setting quite a few people on a voyage of discovery. I hope you get to do the same here and wherever else you post with your speaker escapades. I'm a big fan of semi-omnis and I really enjoyed building my own variation on the Cubettes. If I hadn't moved out of the U.K. (Which makes getting hold of bigger stuff more expensive) I would've loved to build an isobaric version with two boxes stacked on top of each other. I still use my semi Omnis every day and never tire of them. |
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Post by karatestu on Apr 4, 2018 18:39:17 GMT
Hi Andrew. I will try and advise you accordingly. The CD3 & CD3.5 (which i have) are very different. The 3.5 runs on a single rail positive voltage psu whereas the 3 runs on a split rail psu (positive and negative). I dont know loads about the 3 but i do know it has a very good dac chip which is the TDA1541. A very anolgue sounding dac chip which is why many like the CD3. It will have a similar output stage i should think but the opamps will have a split rail supply unlike the 3.5. I do know that Naim improved the power supplies as they went up the range. Your 3 will probably have a smallish (around 200VA) toroid transformer that powers everything in the player. There is not an option to add an external psu for the anologue stage like the 3.5 as there is no din socket to enable hook up. This does not mean that you cant do it. I think the key thing that you could do is improve the psu. Bigger toroid to replace the original but it will have to be off boarded as there is not room in the case. You could go even further like i did by adding a psu for the anolgue stage and another for the dac. I also have a fourth powering a pfm flea powered clock with tentlabs oscillator. That last one is a bit hardcore though. You would need to trace the power supply lines and know which ones lead to the output stage and dac. Those lines would need to be severed and your new psu wiring introduced. Big VA transformers are what is needed but dedicated ones for each purpose rather than what Naim did and put several secondary windings on one core. Big and more transformers would not fit in the case so you would have to build your psu in an external box. If all that is too much for you then adding regulators is the way forward as providing chips with their own regulator where previously they shared a regulator with other chips is a big win win. You could also improve the LM317 regs with some of the mods for 3 pin regulators found on the acoustica website. There are loads of other things but i dont think swapping resistors or caps is going to get you what you are looking for. The power supply caps could probably do with changing by now though. So in conclusion i think the way forward for makinng a cdi killer is with the psu. Bigger VA (lower impedance) toroid transformers and more of them to power different parts of the player independently. More music |
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Post by Deleted on Apr 4, 2018 20:08:50 GMT
Thanks, Stu. I think more and bigger power supplies are a good way for me to go. I have a mate who is more savvy a thin I will be with tracing the power supply tracks. I can send him some detailed pics if I get stuck.
I will be packing it up and moving very soon but this will be a nice project for me to attempt.
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Post by dsjr on Apr 5, 2018 16:57:01 GMT
The CD3 can be better sent to Avondale for updates and I trust Les's ears to do the right thing by it. The old 1541 chipset as a whole isn't perfect by any means, and complete players of the times had uhf noise and general shit issues up and down the mains and signal cables in my experience of a good few different models including my own heavyweight Micro Seiki which is based on the generic Philips/Marantz chassis as used in the Marantz CD94. I suspect Naim's proprietary analogue output would naturally filter a lot of this away?
The 3.5 deserves a better supply and that's where the Flatcap of old came in, benefitting sonics no end I recall.
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Post by karatestu on Apr 5, 2018 18:30:01 GMT
The CD3 can be better sent to Avondale for updates and I trust Les's ears to do the right thing by it. The old 1541 chipset as a whole isn't perfect by any means, and complete players of the times had uhf noise and general shit issues up and down the mains and signal cables in my experience of a good few different models including my own heavyweight Micro Seiki which is based on the generic Philips/Marantz chassis as used in the Marantz CD94. I suspect Naim's proprietary analogue output would naturally filter a lot of this away? The 3.5 deserves a better supply and that's where the Flatcap of old came in, benefitting sonics no end I recall. Hi Dave, thanks for popping in. I am not sure Les still does the cd3 conversion anymore. I think from memory naim use a 7 pole bessel filter in the anologue output stage. The 3.5 uses a tda1305 dac chip which quite honestly is a poor choice (cheap) and is the weakest part of the player. The flatcap for the price is a complete joke. I have 4 diy psu's on mine. 1 for digital, 1 twin rail for anologue stage , 1 triple secondary EI on the dac (one secondary per dac power pin and another EI psu for the fancy pfm flea powered tentlabs clock. It seems to breed power supplies |
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Post by MartinT on May 27, 2018 19:31:32 GMT
Hi karatestu, any updates on your system? Have you found a solution to having no volume control? I couldn't do without one, personally. The disparity in levels between recordings is too high and classical nearly always needs winding up more. |
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Post by karatestu on Sept 16, 2019 12:59:28 GMT
Hi karatestu , any updates on your system? Have you found a solution to having no volume control? I couldn't do without one, personally. The disparity in levels between recordings is too high and classical nearly always needs winding up more. Hello martin. Sorry for a very late reply to your question. My apologies, this is my first visit here for a long time. Still got the volume set by two resistors in a potential divider. I have chosen the values so that it is never too loud or too quiet even with the variability of level between CD's. I don't often listen to classical but when i played The Planet Suite & Dvorak symphony no.9 the other day it was a bit lacking in volume. Not a big problem but i will be fitting a stepped attenuator at some point in the future. I just know though that it will sound inferior  |
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Post by MartinT on Sept 16, 2019 13:18:53 GMT
Hi Stu, it's nice to have you back! What I am finding is still a big variation in volume with older recordings (e.g. most prog) tending to be quieter on average with room for big swings and more modern recordings varying between 'loudness wars' (e.g. Coldplay) and excellent dynamic range material (e.g. Alt-J). I vary my volume on just modern music between around 54 and 60, which is a 6dB difference - quite significant.
You could maybe make a stepped attenuator covering just a small range using excellent switches and the same resistors as you use currently?
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Post by karatestu on Sept 16, 2019 13:45:19 GMT
Hi Stu, it's nice to have you back! Thanks Martin. I thought i should come back and see what Slinger is up to  |
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Post by MartinT on Sept 16, 2019 14:37:49 GMT
Great! Do please keep him in check...  |
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Post by karatestu on Sept 16, 2019 15:44:55 GMT
Anyway back to stepped attenuators. You are correct that i am planning a high quality switch with just a few chosen values only going up to the volume that i will need and no more. My kids can't then turn it right up and have an amp and speaker killing party.
I have been using the shunt method but the series method also interests me although i have not tried it. The shunt was always more attractive with only one resistor in the signal path at any one time. Only bad thing is the resistance to ground changing.
I had an idea to have a volume control for each of the six channels of amplification. That is getting a bit complex, expensive and hard to use. The idea was that i could have balance control (even though i have never needed it) and the volume of each driver in my 3 way speakers could be independently controlled. I might just give it a go with more fixed resistor potential dividers to see if it works with all those power amp input impedances in parallel.
Speakers are due for a revamping in to something more aesthetically pleasing. I am currently playing with isobaric 12 inchers firing in different directions. Forward, down, up and side. I have already ruled out side firing - just not right somehow. Ideally i would like the bass down firing with the mid up firing and tweeter front firing as usual but not sure of the exact outcome just yet. Another prototype on the way. Concrete cube bass cab with a wooden mid cube sat on top with some decoupling in between. If i can decouple the tweeter from the vibrations of the mid driver cabinet i will try.
Oh and i need to try the drivers with magnets facing out to see how they sound like that. With the dust caps pointing inwards i might get some useful attenuation of higher frequencies as i don't use a crossover, just cone doping and pointing bass and mid in interesting directions.
If i ever get my system finished and beyond experimentation stage it will be a miracle. I have a diy over load from time to time and revert back to just listening for a while and enjoying the music. The urge to get the soldering iron out again comes back eventually and then i have another frenzied period of activity.
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