martin clark said:
Please don't skimp on the horizontal rules!
<hr>
FWIW I really like your site regardless
Simon
martin clark said:
Hi Martin, I'm interested in your opinion here. My 1541 is seriously modded in every area! When I listened to the VRDS10 I was couldn't beleive how close it was in std form. I'm pretty certain with multiple low noise regs, Direct decet clock feeds and decent caps everywhere this combo can out perform the 1541. Just a hunch based on the starting point.
Can you give me your opinion on the differences. I'm particularly interested to know the state of tune of your kit.
I've started to look into adding a couple of 1547's to my 850MKII. It doesn't look too complicated. I've also studied the schema for the VRDS and a CD17MKII. I notice both of them use the voltage output and so use the inbuilt opamps. I had quite a long chat with Lee (Thomo) today about the I/V and possible options, and he ended up trying his DOS (based on Rays) to the current output on his 17. He said its very very good! I'm hoping he'll start a thread for the 17 for 1547 discussion (so we don't hijak Simons thread!)
Ian
UV101 said:
lol. 28 pages and probably ONE modified CD650 in total
I hope it's of some use to someone. I'm sure learning a lot.
Simon
These CD player threads are great as the principles are really useful for all similar players. Keep it up!
SimontY said:
lol. 28 pages and probably ONE modified CD650 in total
I hope it's of some use to someone. I'm sure learning a lot.
Simon
make that three I have two modded 650's.
keep it up!
amp-guy said:
Sorry amp-guy, in amongst all these pages I've lost track! Did you post about your mods on here?
Simon
Uh, actually I haven't posted any pics. but I have done basically what everyone else has bc poly caps on tda1541a, removed power supply dropper resistors to opamps, replaced output coupling caps with polyproylenes, replaced opamps with AD847 types . I find that I have been dissapointed with the sound of virtually any other players other than those that incorporate the tda1541 they are very "analog like" to my ears.
Good stuff, but you'll not hear much detail or transparency without separating some of these terrible power rails IME. Clocking seems ULTRA important too!
Simon
Simon
Iam sure you are right on that . Iam actually going out board with a p.c. board I picked up from www.analogmetric.com. Also have picked up a low jitter clock . Iam considering using a glass buffer stage using the 12B4A . But alas progress is slow it's boating season now!
This is only my opinion and something I once read but I don't feel the TDA1541 DAC needs any additional "warmth" from a tube stage, it's already such a euphonic and meaty sound. I may try the Pass Labs stage soon...
Simon
Simon
You are probably right on the tubes ,although the 12b4 does not really add warmth like most tubes it is clean and dynamic. But I dont relish adding the high voltage supply to the mix.
The pass I/V stage is also of interest to me. Jan diden had a discrete I\V stage back in TAA that would be worth trying as well.
Mainly though the idea is to get away from opamps.
The pass I/V stage is also of interest to me. Jan diden had a discrete I\V stage back in TAA that would be worth trying as well.
Mainly though the idea is to get away from opamps.
I'm guessing its too late then Simon, its already hijacked!! 😉
I think the general discussion based around other TDA1541 players is def on topic?!?!?!?!?!?!?!?!? (sort of)
Amp-Guy, I've got a modded copy MF tube stage acting as a buffer following Burson Discrete. I have been well impressed. I do however agree that the TDA is warm enough! I will play again without the stage just to do a like for like comparison (now the valve stage has settled). It will be intersting to do a level playingfield comparison now.
I've also got an analogue metric board that I'm building using all the principles learned here, seperate low noise regs, seperated clock feeds, ZA decoupling caps etc.... It should be very good when finished. I've also got a DIR9001 kit to replace the std CS8412. I also fancy trying to add an I2S input!
As Simon said, you should definately get seperate regulators. The most important being the supply to the 7220 chip. This is really noisy, its messes the 5v rail for the other devices and add noise to the std clock distribution! Once you have a decent clock, you should supply the clock direct to all chips (so its not via the 7220 anymore,loads about it on this thread). Implemented properly, 1 low noise reg and a decent clock (distributed well) will lift this player beyond anything you thought possible (imho)
Ian
I think the general discussion based around other TDA1541 players is def on topic?!?!?!?!?!?!?!?!? (sort of)
Amp-Guy, I've got a modded copy MF tube stage acting as a buffer following Burson Discrete. I have been well impressed. I do however agree that the TDA is warm enough! I will play again without the stage just to do a like for like comparison (now the valve stage has settled). It will be intersting to do a level playingfield comparison now.
I've also got an analogue metric board that I'm building using all the principles learned here, seperate low noise regs, seperated clock feeds, ZA decoupling caps etc.... It should be very good when finished. I've also got a DIR9001 kit to replace the std CS8412. I also fancy trying to add an I2S input!
As Simon said, you should definately get seperate regulators. The most important being the supply to the 7220 chip. This is really noisy, its messes the 5v rail for the other devices and add noise to the std clock distribution! Once you have a decent clock, you should supply the clock direct to all chips (so its not via the 7220 anymore,loads about it on this thread). Implemented properly, 1 low noise reg and a decent clock (distributed well) will lift this player beyond anything you thought possible (imho)
Ian
Mission progress
Thought I'd post up the progress on my Mission as it's been several months since I started this. Fortunately my Mission PCM4000 is a stripped down CD650 without the FTS/ additional filtering board - this gives me loads of room to fill the case with new power supplies.
i can only echo the preceding posts regarding a good supply for the 7220. I've build a kinda modular power supply system that allows me to mess about with the supplies easily.
2 extra transformers gives me 3 windings which in turn supply 3 seperate veroboards with all the 317/337's on. Board 1 has 2 x 317's for the 7210/7220 and a 7805 for the ram chip (😉 ). Board 2 does the opamps - 1 x 317 and 1 x 337 - Board 3 with it's dedicated transformer looks after the DAC - 1 x 317 and 2 x 337 with some fine adj.on the -15 to keep it and the -5 exactly 10v apart !!
This leaves the original supply looking after the servo and display ONLY!
Opamps are the mighty THS4032's - these bad boys are the business - i would heartily recommend them - detail, subtlety, power - it's all there!
some decent decoupling around the main board - Silmics and Wimas mainly - couple of big Mundorfs on the o/p and that's about it.
No fancy clocks yet - and an original TDA1541 too ( i have an S1 at hand to try one day 🙂 ) I did try the system clock direct to the DAC but didn't like it so went back to standard - might give it another go yet.
So how does it sound? - well it's seriously refined - it makes the original sound VERY rough indeed - which of course it wasn't at all. There are still things to sort out - it can sound a little soft on occasion - with a hint of sibilance at the top and some bloom at the bottom too. Vocals however are simply stunning. I ran out of 11DQ10's so went with BYV26's for the new supplies - i think that might be the cause of the softness - and the main smoothers are Panny ECA audios rather than FC's - could be a prob maybe?
everything was done with parts knocking around my bench really - nowt esoteric at all - with top results
anyway - great thread as always guys - it's been such inspiration - please keep it up
Thought I'd post up the progress on my Mission as it's been several months since I started this. Fortunately my Mission PCM4000 is a stripped down CD650 without the FTS/ additional filtering board - this gives me loads of room to fill the case with new power supplies.
i can only echo the preceding posts regarding a good supply for the 7220. I've build a kinda modular power supply system that allows me to mess about with the supplies easily.
2 extra transformers gives me 3 windings which in turn supply 3 seperate veroboards with all the 317/337's on. Board 1 has 2 x 317's for the 7210/7220 and a 7805 for the ram chip (😉 ). Board 2 does the opamps - 1 x 317 and 1 x 337 - Board 3 with it's dedicated transformer looks after the DAC - 1 x 317 and 2 x 337 with some fine adj.on the -15 to keep it and the -5 exactly 10v apart !!
This leaves the original supply looking after the servo and display ONLY!
Opamps are the mighty THS4032's - these bad boys are the business - i would heartily recommend them - detail, subtlety, power - it's all there!
some decent decoupling around the main board - Silmics and Wimas mainly - couple of big Mundorfs on the o/p and that's about it.
No fancy clocks yet - and an original TDA1541 too ( i have an S1 at hand to try one day 🙂 ) I did try the system clock direct to the DAC but didn't like it so went back to standard - might give it another go yet.
So how does it sound? - well it's seriously refined - it makes the original sound VERY rough indeed - which of course it wasn't at all. There are still things to sort out - it can sound a little soft on occasion - with a hint of sibilance at the top and some bloom at the bottom too. Vocals however are simply stunning. I ran out of 11DQ10's so went with BYV26's for the new supplies - i think that might be the cause of the softness - and the main smoothers are Panny ECA audios rather than FC's - could be a prob maybe?
everything was done with parts knocking around my bench really - nowt esoteric at all - with top results
anyway - great thread as always guys - it's been such inspiration - please keep it up
Attachments
Re: Mission progress
Nice work! 😀
I'm assuming the TDA pins 2 and 4 are still connected on the PCD?
If so they both need /2 (8.xxMhz) of the system clock.
If you seperate them, pin2 wants a /2 feed (8.xxMhz) and pin4 wants full sys clock (16.xxMhz).
You may also find that the std clock wont feed multple devices without buffering. Most hop up clocks can handle multiple feeds.
When you mess with the clock, you should also consider the DEM reclock.
You should try the S1. Its an easy swap!
Ian
herewegoagain said:
Nice work! 😀
I'm assuming the TDA pins 2 and 4 are still connected on the PCD?
If so they both need /2 (8.xxMhz) of the system clock.
If you seperate them, pin2 wants a /2 feed (8.xxMhz) and pin4 wants full sys clock (16.xxMhz).
You may also find that the std clock wont feed multple devices without buffering. Most hop up clocks can handle multiple feeds.
When you mess with the clock, you should also consider the DEM reclock.
You should try the S1. Its an easy swap!
Ian
Re: Re: Mission progress
yeah - I seperated them and fed the sys clock direct to pin 4 (strangely the pcb already has tracks all the way there from pin 9 of the 7220! - you just need to add a couple of links to finish it off) - pin 2 was left with the existing BCK from the 7220 - anyway i didn't get on with it - I thought it actually LOST some rhythm - so put it back to standard - ie. 2 & 4 connected.
regarding the S1 - I fitted a DIL socket a few weeks ago in preparation for fitting it - but wanted to see how things would progress with the standard chip first - each time the lid is off I'm tempted though!
The thing is this player cost me £11 and i really wasn't intending to do much with it apart from a spot of R&D - but it's compelling listening now and still hasn't cost me much over £30 in total - and despite having other players that would be more suited to modding - it's become a bit of a keeper this little Mission!
UV101 said:
yeah - I seperated them and fed the sys clock direct to pin 4 (strangely the pcb already has tracks all the way there from pin 9 of the 7220! - you just need to add a couple of links to finish it off) - pin 2 was left with the existing BCK from the 7220 - anyway i didn't get on with it - I thought it actually LOST some rhythm - so put it back to standard - ie. 2 & 4 connected.
regarding the S1 - I fitted a DIL socket a few weeks ago in preparation for fitting it - but wanted to see how things would progress with the standard chip first - each time the lid is off I'm tempted though!
The thing is this player cost me £11 and i really wasn't intending to do much with it apart from a spot of R&D - but it's compelling listening now and still hasn't cost me much over £30 in total - and despite having other players that would be more suited to modding - it's become a bit of a keeper this little Mission!
Attachments
herewegoagain,
Terrific work there with the Mission. The soft sound will largely be cured by a good clock solution. A bit more will come away (and you'll see nice gains in refinement) with the 1541A chip (being S1 could be a further bonus) and SAA7220 P/B digital filter.
Beyond that you may have to decide whether to bite the bullet on low-noise regs. There are some DIY alternatives, should you choose to pursue that path. Without them it won't reach its full potential.
The rail separation you've done is great already though! Glad you're enjoying it and I'd never have got to the level you're at with £30 in parts!
Another little tweak if you've not done it is to remove the ceramic SMD cap across the DEM pins of the DAC and replace it with something good like COG, PPS, PP, 'styrene or silvered mica. I used a 470pF polystyrene and it works a treat. The value seems unimportant but quality important! Superb value tweek!
Simon
Terrific work there with the Mission. The soft sound will largely be cured by a good clock solution. A bit more will come away (and you'll see nice gains in refinement) with the 1541A chip (being S1 could be a further bonus) and SAA7220 P/B digital filter.
Beyond that you may have to decide whether to bite the bullet on low-noise regs. There are some DIY alternatives, should you choose to pursue that path. Without them it won't reach its full potential.
The rail separation you've done is great already though! Glad you're enjoying it and I'd never have got to the level you're at with £30 in parts!
Another little tweak if you've not done it is to remove the ceramic SMD cap across the DEM pins of the DAC and replace it with something good like COG, PPS, PP, 'styrene or silvered mica. I used a 470pF polystyrene and it works a treat. The value seems unimportant but quality important! Superb value tweek!
Simon
UV101 said:
Hi,
If you ask the same question John Westlake (JohnW here), the answer is no...SAA7350 is one of the best dac ever made and it sounds even better without TDA1547. To get max. from SAA7350 you should do few things:
- bypass all internal opamps and use external ones (preferable discrete in smd with J-fet or M-fet input (BJT wan't do here) - discrete version on AD797 will do nicely or some sort of folded cascode, two stage discrete opamp)
- use a separate low noise, low impedance voltage regulator for Vref pin (search digital forum for Vref and SAA7350 and JohnW as author, you'll find simple solution from the man himself)
- use separate voltage regulator for SAA7350 and analog filter/opamps
aparatusonitus said:
Been looking at some threads on this subject. Looks really interesting. I will have a play with the 850MKII and see what that does for me, Thanks! 😉
SimontY said:
Indeed! No one would visit if it was too staight laced!
I'll stick some CD50 photo's on a bit later too! 😀
I'm up to 9 players now! Any more and I'll be trying to rival AndyP!
