Hi all, first post here, first CD player project I’m trying to improve a bit in the sunny UK 
I’ve gone through every thread about this and I’m still confused!
Firstly on a bit of a side note I apologise for the dumb question but does it matter if there is noise on the voltage input of a regulator? Will the regulator remove it in the process of “regulating” or will it affect the output in some way?
Secondly, a lot of people advocate a separate regulated supply for each voltage feed on each of the ICs, Thorsten Loesch on TNT Audio describes excellent results just from fitting chokes and ferrites to the voltage feeds to clean up the noise without going to the lengths of a separate clean supply. Anyone know whether the regs are worth the extra effort/wires in practice?
Thirdly I’m wondering the best way exactly to fit the regs, I was thinking a piece of stripboard with a row of LM340T5s on it all supplied from the 10v rail after the transformer and all connected to ground via a 500 ohm resistor - then wires from each reg to each voltage feed on the board. Any issues with this in practice with noise induced over the length of the wire for instance, or noise generated between the regs? Would shielded wires or a twisted pair make any difference?
The other way would be to fit the reg output physically at the voltage supply on the board and have a separate 10v feed to each one - this would be a bit messier and more difficult especially concerning the resistor between the reg and ground, but doable, easier if you build your own regs but that is going a little above my head as I can’t find a simple DIY for it!
I’ve gone through every thread about this and I’m still confused!
Firstly on a bit of a side note I apologise for the dumb question but does it matter if there is noise on the voltage input of a regulator? Will the regulator remove it in the process of “regulating” or will it affect the output in some way?
Secondly, a lot of people advocate a separate regulated supply for each voltage feed on each of the ICs, Thorsten Loesch on TNT Audio describes excellent results just from fitting chokes and ferrites to the voltage feeds to clean up the noise without going to the lengths of a separate clean supply. Anyone know whether the regs are worth the extra effort/wires in practice?
Thirdly I’m wondering the best way exactly to fit the regs, I was thinking a piece of stripboard with a row of LM340T5s on it all supplied from the 10v rail after the transformer and all connected to ground via a 500 ohm resistor - then wires from each reg to each voltage feed on the board. Any issues with this in practice with noise induced over the length of the wire for instance, or noise generated between the regs? Would shielded wires or a twisted pair make any difference?
The other way would be to fit the reg output physically at the voltage supply on the board and have a separate 10v feed to each one - this would be a bit messier and more difficult especially concerning the resistor between the reg and ground, but doable, easier if you build your own regs but that is going a little above my head as I can’t find a simple DIY for it!
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LOW NOISE REGULATORS
Just replace the existing regulators with the pin compatible ultra low noise switching types.
I've used ones from
http://www.ldovr.com
which use the LT 3045 chip.
Much noise is generated by the old school linear regulators so there is no point in replacing them with another linear regulator such as a LM340.
Just replace the existing regulators with the pin compatible ultra low noise switching types.
I've used ones from
http://www.ldovr.com
which use the LT 3045 chip.
Much noise is generated by the old school linear regulators so there is no point in replacing them with another linear regulator such as a LM340.
OK cheers for that. Might look into those then. The issue with the player as standard (apparently) is all the ICs polluting the 5v supply for the entire machine hence a separate regulated supply for each so they can’t interfere with each other.
As that would work out quite expensive for 10+ of them I might look into one to replace the 7805, one for the analogue and digital feeds of the DAC and then just inductors to filter the supply to the rest of the chips which is also apparently very effective (and looks much tidier)
As that would work out quite expensive for 10+ of them I might look into one to replace the 7805, one for the analogue and digital feeds of the DAC and then just inductors to filter the supply to the rest of the chips which is also apparently very effective (and looks much tidier)
Lets try and answer some of this without going to deep into theory...
The standard regulators generally do a pretty good job of keeping things clean. This is achieved not just by the regulator but also by the extra small decoupling caps added at various points on the output of the reg.
The chips supplied by the regulator in a typical CD player can superimpose internally generated noise onto the supply. This is where those decoupling caps come into their own in reducing that (by effectively 'short circuiting' the noise to ground).
Adding a separate regulator may seem to be a good tweak but beware... if you are having to wire it in then those very wires degrade the performance dramatically by virtue of their own resistance and inductance. The result is that while the voltage may be clean at the reg, it is still capable of being affected at the end of the wire.
I wouldn't go adding separate regulators to such a player, I would concentrate on improving what is there. Replacing any small electrolytic caps used for rail decoupling with parts known to have good characteristics designed for such use (such as low E.S.R.) could gain you a little in noise reduction on the rails. Do not replace any ceramic caps on the rails with film types in the belief they will be better... they wont.
You could research the exact regulators fitted (brand and full device number) with a view to searching out compatible but improved parts.
As with anything like this, first look at the noise with a good wideband scope correctly connected to measure the noise at the points of interest. Without doing that you have no way of knowing whether any change results in an improvement or not.
The standard regulators generally do a pretty good job of keeping things clean. This is achieved not just by the regulator but also by the extra small decoupling caps added at various points on the output of the reg.
The chips supplied by the regulator in a typical CD player can superimpose internally generated noise onto the supply. This is where those decoupling caps come into their own in reducing that (by effectively 'short circuiting' the noise to ground).
Adding a separate regulator may seem to be a good tweak but beware... if you are having to wire it in then those very wires degrade the performance dramatically by virtue of their own resistance and inductance. The result is that while the voltage may be clean at the reg, it is still capable of being affected at the end of the wire.
I wouldn't go adding separate regulators to such a player, I would concentrate on improving what is there. Replacing any small electrolytic caps used for rail decoupling with parts known to have good characteristics designed for such use (such as low E.S.R.) could gain you a little in noise reduction on the rails. Do not replace any ceramic caps on the rails with film types in the belief they will be better... they wont.
You could research the exact regulators fitted (brand and full device number) with a view to searching out compatible but improved parts.
As with anything like this, first look at the noise with a good wideband scope correctly connected to measure the noise at the points of interest. Without doing that you have no way of knowing whether any change results in an improvement or not.
Thank you very much for the post. I do plan on “going to town” on this player so low ESR decoupling caps are most definitely on the cards as well as many other mods.
By what you have said, I will be physically fitting the regulators as closely as possible, using the hole left by the existing supply to the chip. I have abandoned my plan to add a regulator to every feed on every chip (as some have done) instead using inductors combined with ferrites to reduce noise, but a separate reg for the DAC is a well known tweak for this particular player which is said to achieve very positive results even if using a 7805. I unfortunately do not own a scope but am basing my choices of mods upon the advice of others who have used a scope and have achieved hugely beneficial effects.
My plan now is to use one low noise reg (such as the ones listed) for the main regulator but to separate the 5v feeds to the DAC from the rest of the 5v rail using another one.
Again thank you all for the advice, it has cleared up most of the confusion I had surrounding this
Good luck with your project
Thank you!
I’ve had some great results out of it with the mods so far, hoping for more big improvements to come!Why not dig something out from this link on CD63 mod for sonic improvements:
Marantz CD63 & CD67 mods list
Marantz CD63 & CD67 mods list
I have either done or will be doing all of those in the next couple of weeks
Yeah I’ve seen that thread thanks, would take weeks to go through it all, have gained some ideas from there already, maybe I need to have another trawl through it... I’m basing my mods on this thread Marantz CD63 Basic upgrade overview / guide but with lots of extras
can’t wait to see what this bad boy can do...- Status
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