Mike P
Trade: Pickwell Audio
Yes that's correct, I'm in Stocksbridge near junction 35A of the M1.
I do too and subjectively I find them very pleasing to the ear for opamp power supplies.
Naim CD3.5 mods (not on Acoustica)
- Thread starter mega lord
- Start date
Yes that's correct, I'm in Stocksbridge near junction 35A of the M1.
I do too and subjectively I find them very pleasing to the ear for opamp power supplies.
mega lord
Centre tapped
Martin - the resistor and cap to ground has definitely had an effect making the treble not so harsh.
I have experimented with a number of things over the last few days.
1) removed chock blocks, all regs tried are now soldered to a naked din plug with very short connections
2) removed alwsr and inserted an Avondale TPR4
3) powered all the opamps from one alwsr (tpr4 in hicap)
The chock blocks were a bad idea i now think. It is very easy to swap regs when they are soldered to a din plug. The extra bit of wiring helps i think by adding a small amount of resistance between reg and opamps.
I cannot decide which regulator i like the best ! Need to swap them in and out alot more. All i can say is that i did not miss the alwsr when i replaced it with a tpr4. les has done a magnificent job with this regulator.
When powering all the opamps from one alwsr i could not tell any difference between that configuration and using two ! It was only a brief listen though. I need to more extensive listening in each configuration before moving on.
A bit of close attention to the dac and psu is needed now, especially the flea on dac pin 28 as i removed the series resistor on the motherboard between the reg and dac. Maybe i will try reinserting 1R and see what happens.
Does the flea have an output which is synthetically inductive?
Stu
I have experimented with a number of things over the last few days.
1) removed chock blocks, all regs tried are now soldered to a naked din plug with very short connections
2) removed alwsr and inserted an Avondale TPR4
3) powered all the opamps from one alwsr (tpr4 in hicap)
The chock blocks were a bad idea i now think. It is very easy to swap regs when they are soldered to a din plug. The extra bit of wiring helps i think by adding a small amount of resistance between reg and opamps.
I cannot decide which regulator i like the best ! Need to swap them in and out alot more. All i can say is that i did not miss the alwsr when i replaced it with a tpr4. les has done a magnificent job with this regulator.
When powering all the opamps from one alwsr i could not tell any difference between that configuration and using two ! It was only a brief listen though. I need to more extensive listening in each configuration before moving on.
A bit of close attention to the dac and psu is needed now, especially the flea on dac pin 28 as i removed the series resistor on the motherboard between the reg and dac. Maybe i will try reinserting 1R and see what happens.
Does the flea have an output which is synthetically inductive?
Stu
mega lord
Centre tapped
Excess sibilance was more or less solved by putting my preamp back in its enclosure and tidying some wiring up.
Not much done on the 3.5 recently, however a few things were noted when playing around trying to track down the source of sibilance.
I changed the small 5VA EI i had on the dac (three secondary windings, one for each DAC pin) for an old NAP140 trafo with single secondary and psu for all three DAC pins. Definitely sounded worse after doing that. Small EI is back on the DAC now. I love how these tiny EI pcb transformers sound.
I decided to also put the digital psu down to 1 rail from the standard two rails. As the anologue, dac and clock duties have been lifted from the original transformer i thought it would be ok. One of the rails was only powering the decoder so i thought moving it to the other was a good idea to simplify things. Nothing bad happened and it sounds no worse for it.
Also whilst having a play around i decided to stick a PFM mosfet gyrator on the digital supply after the smoothing cap just to see what would happen. There are no start up issues with this and everything works just as before - laser motor is maybe fractionally slower at getting going than before but thats it. I couldn't say if the player sounds any better for it but it certainly is not any worse. the gyrator drops about 8V and gets quite warm so heatsinking was required. I just liked the idea of mopping up a load of noise and ripple before all the digital regs etc.
A few currernt draws i have measured recently (including local 317 regs)
DAC - about 60mA
Decoder - 70mA
Rest of digital gubbins - about 350mA (the meter was going up and down quite a lot but that was about the maximum i saw)
Anologue - 85mA (plus alwsr house keeping if you have them instead of 317)
More later
Stu
Not much done on the 3.5 recently, however a few things were noted when playing around trying to track down the source of sibilance.
I changed the small 5VA EI i had on the dac (three secondary windings, one for each DAC pin) for an old NAP140 trafo with single secondary and psu for all three DAC pins. Definitely sounded worse after doing that. Small EI is back on the DAC now. I love how these tiny EI pcb transformers sound.
I decided to also put the digital psu down to 1 rail from the standard two rails. As the anologue, dac and clock duties have been lifted from the original transformer i thought it would be ok. One of the rails was only powering the decoder so i thought moving it to the other was a good idea to simplify things. Nothing bad happened and it sounds no worse for it.
Also whilst having a play around i decided to stick a PFM mosfet gyrator on the digital supply after the smoothing cap just to see what would happen. There are no start up issues with this and everything works just as before - laser motor is maybe fractionally slower at getting going than before but thats it. I couldn't say if the player sounds any better for it but it certainly is not any worse. the gyrator drops about 8V and gets quite warm so heatsinking was required. I just liked the idea of mopping up a load of noise and ripple before all the digital regs etc.
A few currernt draws i have measured recently (including local 317 regs)
DAC - about 60mA
Decoder - 70mA
Rest of digital gubbins - about 350mA (the meter was going up and down quite a lot but that was about the maximum i saw)
Anologue - 85mA (plus alwsr house keeping if you have them instead of 317)
More later
Stu
mega lord
Centre tapped
I can't give you a link to one as the two i have were salvaged from my mum's old gas boiler.
I tried searching with part numbers as there are no names on them but no luck
All i know is they came out of an ideal isar gas boiler!
Sorry, i would have loved to have been able to tell you what they are. Surely some one sells 3 secondary 5VA EI transformers ?
Stu
I tried searching with part numbers as there are no names on them but no luck
All i know is they came out of an ideal isar gas boiler!
Sorry, i would have loved to have been able to tell you what they are. Surely some one sells 3 secondary 5VA EI transformers ?
Stu
Specul8tr
pfm Member
When you have separate PSUs with tx/rectifier/cap feeding individual regulators as we have here, what would be the most appropriate grounding scheme? As standard, each reg is ground planed back to the onboard smoothing caps but when we have independent l regulators, each being supplied by its own PSU, would it be better to separate the reg from the ground plane and instead return the ground back to its PSU, then star earth each PSU together at the PSU end? Or would it be better to keep the existing ground plane and connect each PSU ground to to a suitable point near its reg?
Or alternatively, perhaps it might be better to keep the ground plane for the regs feeding the digital side and have the analogue grounds returned to their source.
Any thoughts?
Or alternatively, perhaps it might be better to keep the ground plane for the regs feeding the digital side and have the analogue grounds returned to their source.
Any thoughts?
mega lord
Centre tapped
Trying to remember what I have done. I have no centre taps on the transformer windings feeding the clock or the three dac supply pins. This led to me to take the 0V connection to the added regualtors and then on to the 0V plane as close as I can to the powered chip.
I think that is what I have done - must check for you. Work has been so busy of late I have not even played a cd in 6 weeks. Not sure that is the best way but it sounds pretty damn awesome to me.
Stu
I think that is what I have done - must check for you. Work has been so busy of late I have not even played a cd in 6 weeks. Not sure that is the best way but it sounds pretty damn awesome to me.
Stu
Specul8tr
pfm Member
Hi Stu,
I'm at risk of showing my ignorance here... I feel the answer should be obvious but grounding is a potential minefield so I thought I'd at least ask the question. I should say that I have a 15-0-15 tx with both secondaries attached to a bridge rectifier/cap. I'm using the centre tap as 0v and not using the -ve half of the rectifier. A bit wasteful perhaps but keeps the voltage down. So the question still is where to connect these multiple grounds?
I'm at risk of showing my ignorance here... I feel the answer should be obvious but grounding is a potential minefield so I thought I'd at least ask the question. I should say that I have a 15-0-15 tx with both secondaries attached to a bridge rectifier/cap. I'm using the centre tap as 0v and not using the -ve half of the rectifier. A bit wasteful perhaps but keeps the voltage down. So the question still is where to connect these multiple grounds?
mega lord
Centre tapped
I guess it depends on what it is powering. Also how many regs is each transformer winding connected to ? With one reg on a transformer winding I tend to take the 0V connection from the caps negative to the reg and then on to the 0V connection of the decoupling cap for what ever I am powering. I have the psu & flea 0V on dac pin28 soldered to the negative leg of dac pin28's decoupling cap. I have done the same for dac pin 1 & 10 - all because each has its own transformer winding.
I have not been modding for a while now and things are getting a little hazy about exactly what I did.
I should think that if you have say the three dac supply pins powered from one transformer winding then the 0V connections should go somewhere near the dac and a little away from the main smoothers where the connection will be subject to the peaky charging currents.
What are you powering with this new transformer ? Hopefully Martin will look in and tell us all how it should be done !
Stu
I have not been modding for a while now and things are getting a little hazy about exactly what I did.
I should think that if you have say the three dac supply pins powered from one transformer winding then the 0V connections should go somewhere near the dac and a little away from the main smoothers where the connection will be subject to the peaky charging currents.
What are you powering with this new transformer ? Hopefully Martin will look in and tell us all how it should be done !
Stu
Specul8tr
pfm Member
Hi Stu,
The new transformer is powering the two analogue pins of the DAC, each of which are currently being fed by a gyrator/LM317 combination. My intention is eventually to replace these with Flea type regulators.
It may be that my concerns about grounding are of less importance here - after all, it makes sense to assume that Naim do have an inkling about what they are doing and therefore I should just stick to the original. But yes, I entirely agree that any connections need to be some distance away from smoothing caps.
The new transformer is powering the two analogue pins of the DAC, each of which are currently being fed by a gyrator/LM317 combination. My intention is eventually to replace these with Flea type regulators.
It may be that my concerns about grounding are of less importance here - after all, it makes sense to assume that Naim do have an inkling about what they are doing and therefore I should just stick to the original. But yes, I entirely agree that any connections need to be some distance away from smoothing caps.
mega lord
Centre tapped
Oh, very good- crack on!
Where are you going to power the dac's digital supply pin (no.10) from ?
Martin has highlighted the fussiness of the TDA1305 with start up times with the three supply pins. It says in the data sheet that they should all be powered from the same psu. I have never had any problems with this so there must be a little leeway.
Mine is still with lid off and wires all over the place. When I have finished modding it (when will that be ?) I will tidy it up. I found it really took over my life for a while and so am having a little rest. Too busy at work at the moment anyway.
Looking forward to hearing about the results of your new psu.
Stu
Where are you going to power the dac's digital supply pin (no.10) from ?
Martin has highlighted the fussiness of the TDA1305 with start up times with the three supply pins. It says in the data sheet that they should all be powered from the same psu. I have never had any problems with this so there must be a little leeway.
Mine is still with lid off and wires all over the place. When I have finished modding it (when will that be ?) I will tidy it up. I found it really took over my life for a while and so am having a little rest. Too busy at work at the moment anyway.
Looking forward to hearing about the results of your new psu.
Stu
mega lord
Centre tapped
How are you ģetting on with your 3.5 Stephen ?
Nothing done to mine recently but it is still playing music very nicely.
My sibilance wild goose chase was in fact for nothing. My own paranoia, tinnitus and god knows what else. Several other cdp's, amps (not rca based) and speakers have been tried and i get the feeling that it just exists on certain recordings and/or my ears are shot.
Stillmore to try on this much abused cdp, well it has survived so far.
Stu
Nothing done to mine recently but it is still playing music very nicely.
My sibilance wild goose chase was in fact for nothing. My own paranoia, tinnitus and god knows what else. Several other cdp's, amps (not rca based) and speakers have been tried and i get the feeling that it just exists on certain recordings and/or my ears are shot.
Stillmore to try on this much abused cdp, well it has survived so far.
Stu
Specul8tr
pfm Member
Hi Stu,
My CD3.5 is still working, which is a bonus. I haven't actually done much with it recently as I have been working on the other end of the chain, ie. Amp (which probably explains WHY it is still working!)
I think it's in roughly the same state of tweakdom as yours is. I suspect there is not much more that can be done without significant invasive surgery and with it the risk of invoking the word 'Oops!'
I'm curious to know what more you think may be possible though.
My CD3.5 is still working, which is a bonus. I haven't actually done much with it recently as I have been working on the other end of the chain, ie. Amp (which probably explains WHY it is still working!)
I think it's in roughly the same state of tweakdom as yours is. I suspect there is not much more that can be done without significant invasive surgery and with it the risk of invoking the word 'Oops!'
I'm curious to know what more you think may be possible though.
mega lord
Centre tapped
How about splitting the 6 opamps in the anologue stage to give each of them their own regulator, smoothers, rectifier and transformer winding. Not with super regs though.
Also I have always wondered what some bulk foil resistors would sound like in the critical positions of the anologue stage.
Stu
mega lord
Centre tapped
http://www.pinkfishmedia.net/forum/threads/best-cd-clock-upgrade.18014/
Hi Stephen,
Try this thread, I am pretty sure this is where the info is. A long thread (by Hacker of course) to trawl through with Martin and Andy Weekes very much involved.
Have fun
Stu
Hi Stephen,
Try this thread, I am pretty sure this is where the info is. A long thread (by Hacker of course) to trawl through with Martin and Andy Weekes very much involved.
Have fun
Stu
martin clark
pinko bodger
that was the start of the 'Flea'... nearly 13yrs ago!
laverda
pfm Member
that was the start of the 'Flea'... nearly 13yrs ago!
Ahh, those were the days....