Tweaks to NAIm CDS -Part 2- valve output stage
- Thread starter audiojoy
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sideshowbob
Champagne fascia aficionado
Splendid. What next, MOSFETS in a pair of Quad IIs?
-- Ian
-- Ian
teddy_pardo
Trade: Teddy Pardo
BTW has anyone tried or considered using the naim TA729 boards at the CD output? By changing some capacitors/resistors this should provide same filtering capabilities but with discrete components.
Thanks everyone for your replies.
Firstly, small triode tube circuits and power supplies are VERY SIMPLE to build. Noise, vibration tube life etc etc do niot seem to be a problem with these very small valves.
In the end what matters is the sound , regardless if we use tubes, solid state devices, krypton powder or what other weird or wonderful idea we want to try. If the sound improves in the right direction, which by this i like to mean the 'Naim sound' then who cares what method was used.
I believe there are far more valve DIY'ers than solid state, as valve circuits and their power supplies really are very simple with only a handful of components in each circuit. Try it, you never know you might be smitten by it!!
I love the simplicity of the Naim 62 cannot wait to get started. As for using valves in it - may be not, no major filter circuit with lots of IC components needs to be overcome as with the CDS.
Firstly, small triode tube circuits and power supplies are VERY SIMPLE to build. Noise, vibration tube life etc etc do niot seem to be a problem with these very small valves.
In the end what matters is the sound , regardless if we use tubes, solid state devices, krypton powder or what other weird or wonderful idea we want to try. If the sound improves in the right direction, which by this i like to mean the 'Naim sound' then who cares what method was used.
I believe there are far more valve DIY'ers than solid state, as valve circuits and their power supplies really are very simple with only a handful of components in each circuit. Try it, you never know you might be smitten by it!!
I love the simplicity of the Naim 62 cannot wait to get started. As for using valves in it - may be not, no major filter circuit with lots of IC components needs to be overcome as with the CDS.
In terms of relative merit of each mod, difficult to say, because I did not revert a mod before trying another. But i can try and give you the improvement after the addition of each mod and in chronological order as follows:-
using scale 1-10 1 very minimal improvement 10 huge improvement completely changing the way you hear your old familiar cd's.
1)Adding 15000 uF ELna Cerafines to cdps......... 2
2)Change all Tantalums in power supply regulators, Regulators in cd player and all signal caps .............9-10
3) Change power supply umbilical to pure silver in polyethylene sleeves... 5.5
4) adding silver litz wired inductors to power supply lines....6.5
5) changing polystyrene filter caps with teflon caps....5.5
6) valve output ........7.5
7) Solid State Buffer ..8.5
Hope this helps. But the sum is far greater than the individual changes which on my scale would ghit an easy 10.
Chrism in terms of transparency I would say without a shadow of a doubt the cap changes and the valve output stage and solid state buffer improve transparency most. The cap changes provide about 70% of the transparency changes.
BUT PLEASE NOTE THE 'Musicality Thingy' only improved after the valve stage was added.
using scale 1-10 1 very minimal improvement 10 huge improvement completely changing the way you hear your old familiar cd's.
1)Adding 15000 uF ELna Cerafines to cdps......... 2
2)Change all Tantalums in power supply regulators, Regulators in cd player and all signal caps .............9-10
3) Change power supply umbilical to pure silver in polyethylene sleeves... 5.5
4) adding silver litz wired inductors to power supply lines....6.5
5) changing polystyrene filter caps with teflon caps....5.5
6) valve output ........7.5
7) Solid State Buffer ..8.5
Hope this helps. But the sum is far greater than the individual changes which on my scale would ghit an easy 10.
Chrism in terms of transparency I would say without a shadow of a doubt the cap changes and the valve output stage and solid state buffer improve transparency most. The cap changes provide about 70% of the transparency changes.
BUT PLEASE NOTE THE 'Musicality Thingy' only improved after the valve stage was added.
teddy_pardo
Trade: Teddy Pardo
Audiojoy,
In #2 you replaced the tantalums by Silmics, right? Which silmic capacitor values did you use? Did you stay with 10uF or increased it?
How old is your CDS? Is it possible that your tantalums were simply old and replacing them with new ones would have made the same improvement?
For the signal caps, have you tried film capacitors?
Teddy
In #2 you replaced the tantalums by Silmics, right? Which silmic capacitor values did you use? Did you stay with 10uF or increased it?
How old is your CDS? Is it possible that your tantalums were simply old and replacing them with new ones would have made the same improvement?
For the signal caps, have you tried film capacitors?
Teddy
Hi Teddy,
good points. Not sure how old the units are. Remember I have two CDS units both with the same unmodded sound. Furthermore, the sound of the unmodded versions were more typical of the Naim sound as I know it, not hinting at a problem from the outset. Chrism was quick to point out that one of the CDS's weaknesses was a lack of transparency and that is exactly where the majority of improvements have occurred. I must confess I have now created a sound more akin to audionotes, which is no bad thing.(NAimies all go cringe)
The values i used were 4.7uf not 10uf. The signal line caps are still slimics, and yes it might be time to use film. But quite frankly i have reached that rarity of situations (for me anyway), where i feel I have reached a certain level of performance that i am very happy with for the time being. I will go back and tidy everything up, before I look at the regulators and the clock, but i really cannot see how much more i will be able to get out of it, it is that good to my ears. But you never know.
Luke
good points. Not sure how old the units are. Remember I have two CDS units both with the same unmodded sound. Furthermore, the sound of the unmodded versions were more typical of the Naim sound as I know it, not hinting at a problem from the outset. Chrism was quick to point out that one of the CDS's weaknesses was a lack of transparency and that is exactly where the majority of improvements have occurred. I must confess I have now created a sound more akin to audionotes, which is no bad thing.(NAimies all go cringe)
The values i used were 4.7uf not 10uf. The signal line caps are still slimics, and yes it might be time to use film. But quite frankly i have reached that rarity of situations (for me anyway), where i feel I have reached a certain level of performance that i am very happy with for the time being. I will go back and tidy everything up, before I look at the regulators and the clock, but i really cannot see how much more i will be able to get out of it, it is that good to my ears. But you never know.
Luke
Hi Teddy,
'BTW has anyone tried or considered using the naim TA729 boards at the CD output? By changing some capacitors/resistors this should provide same filtering capabilities but with discrete components'
Your idea of a discrete output stage somewhat akin to Marantz's HDAM modules, might be a neater and much simpler solution than mine, you might have a winner here, simpler to implement for all others to use, are you going to try it?
Luke
'BTW has anyone tried or considered using the naim TA729 boards at the CD output? By changing some capacitors/resistors this should provide same filtering capabilities but with discrete components'
Your idea of a discrete output stage somewhat akin to Marantz's HDAM modules, might be a neater and much simpler solution than mine, you might have a winner here, simpler to implement for all others to use, are you going to try it?
Luke
teddy_pardo
Trade: Teddy Pardo
audiojoy said:
Yup, I remember myself saying exactly the same words to Avi about six month ago, then I listened to HIS system, went back home and opened everything again... The funny part is that my system is closed again now, and I'm saying the same things again... (but my system is far better than it was)
I think that hi-fi is like good wine, when you are not used to good ones you can't make the difference, but when you start appreciating the good ones...
S-Man said:
The trouble with those discrete line stages is that they are actually not that refined. For a start, we need only look at the poor PSRR and the complex power supply arrangements needed to get decent levels of performance out of them. Then there is the shared signal/power in the grounding right at circuit level, which causes just as many problems as the poor PSRR. The CDS-II saw the introduction of split-rail discrete circuits as a way past these inherent limitations.
Mr Tibbs
S-Man said:
Indeed. In the past I've played about with some opamp based home-brewed preamps and found it was possible to very closely mimic the sound of my Naim 42.5, just by using the Naim RC input filter in front of the opamp.
I agree, but think the difference is quite marginal. There are some seriously good preamps out there that rely solely on opamps.
Mr Tibbs
S-Man
StrivingON
Mr Tibbs said:
Doesn't the RC filter interact with the variable source impedance caused by the volume pot and vary the frequency response according to pot position?
Mr Tibbs said:
Please could you name some - I would be interested to see how they get them to sound really good.
I have tried most of the raved about opamps + Jung's nested feedback scheme and although some are good, I have never got to "excellent" with opamps (or valves for that matter).