I'm not quite sure. And after frying the SMPS I don't really look forward to play around with it at all.
In the schematic I posted here some time ago, there are just 3 leads following the transformer. I thought that was great. For me, 3 leads are a lot better than 7. Then it turned out you need 5. Not as interesting anymore.
Well, I like the idea of keeping the transformer and especially the voltage regulator away from the PSX. But I also like to keep the power button as well as keeping the PSU close to the board.
If this is a good idea, I don't know. I'm not the engineer here. So Greg, you know better than me about any inductance. But I just ordered an SMPS and will report here once I have tried it. Again, after my mishap, I'm not that overly confident.
I have more reasons for this. Those are farfetched. So until I know I won't tell. If it does work, I'll let you in on it. Otherwise there's nothing to know.
In the schematic I posted here some time ago, there are just 3 leads following the transformer. I thought that was great. For me, 3 leads are a lot better than 7. Then it turned out you need 5. Not as interesting anymore.
Well, I like the idea of keeping the transformer and especially the voltage regulator away from the PSX. But I also like to keep the power button as well as keeping the PSU close to the board.
If this is a good idea, I don't know. I'm not the engineer here. So Greg, you know better than me about any inductance. But I just ordered an SMPS and will report here once I have tried it. Again, after my mishap, I'm not that overly confident.
I have more reasons for this. Those are farfetched. So until I know I won't tell. If it does work, I'll let you in on it. Otherwise there's nothing to know.
phn said:
Actually I didn't, it was a good educated guess, but I spent a little time learning a bit more about SMPS's today. Figure 4 on this site looks to describe a SMPS scheme that 's very close to the SCPH-7500 PSU schematic posted a few pages back:
http://www.steve-w.dircon.co.uk/fleadh/mphil/history.htm
Based on how that functions, you're extending the path for the regulator's feedback loop... it might cause problems, honestly I am not sure here, but DO have a good fuse in the unit and if it blows, trust that it is telling you something you don't want to ignore.
Let us know the outcomes!
Greg in Minneapolis
Greg, nice link. Yeah, I like figure 4. Now the only thing that remains is to find out what the inductance will do to the circuit.
I can't say I like this: "The linear is also preferred where a virtually noiseless supply is required." Does that mean a traditional PSU could be an alternative? You don't have to answer that. It's just that I was really banking on the SMPS. To me it seems like the choice between SMSP and linear PSU isn't that clear cut as I hoped. This isn't necessarily a bad thing. Transformers may be costly, but at least they are simple to work with.
I can't say I like this: "The linear is also preferred where a virtually noiseless supply is required." Does that mean a traditional PSU could be an alternative? You don't have to answer that. It's just that I was really banking on the SMPS. To me it seems like the choice between SMSP and linear PSU isn't that clear cut as I hoped. This isn't necessarily a bad thing. Transformers may be costly, but at least they are simple to work with.
Which is why I suggested a linear supply from the start and not to bother with the SMPS.
Not the only thing, SMPSes make more than line noise, they also make RFI. Turn on your PlayStation near an AM tuner on ~890kHz...
They also act strange when you play with them.
A transformer for the PlayStation would not need a lot of power / would be cheap. The 1001's SMPS uses 17w. (And I'm sure a lot of them are waisted in heat)
A small 20-30VA toroid is cheap.
Mick_F said:
DragonMaster said:
I keep forgetting to mention... that IC is just 4 diodes in a bridge configuration, exactly the same as the four individual diodes in the other PSU's.
The high heat dissipation is another thing, but having the diodes in a monolithic bridge (as opposed to 4 individual diodes in a bridge) is not a bad thing for those early PSU's.
Greg in Minneapolis
DragonMaster said:
Antoine,
I totally agree with you on a linear supply being the ultimate good-sonics solution for the PS. That will be one of my next steps.
The reason I'm trying some modifications to the SMPS is to learn what works and doesn't here... I've seen that several companies perform mods to SMPS's, but I don't have any direct experience doing that myself. As more and more units use SMPS's, I'd like to know what works and makes a sonic difference in modifying them. The PS-1 is a great unit to do this on as the SMPS is very accessable when you run it with the top off like I do, the SMPS is a pretty simple unit compared to some others I've seen, and the overall unit is available used for cheaps, so if I fry one, I'm not out much.
But honestly, I don't like the idea of the SMPS... as you say, they do create a lot of electrical noise as a by-product of how they work. I've seen good-sounding units that use them (including some of the Berning tube preamplifiers and amplifiers as far back as the early 1980's), but I know that it takes a lot of care to make a good-sounding SMPS and use it to power a unit.
DragonMaster said:
One trick used by PS Audio back in their first incarnation was to offer oversized external power supply units for better sonics... mostly oversized transformers (using amplifier-sized transformers for their preamplifiers). Naim does something like this too, but their upgrad PSU's are also fairly complex units with multiple levels of regulation. I like both of these strategies.
I'm thinking a 2-transformer linear supply solution... two entirely separate power supplies, enclosed in one box and sharing only the ground connection, with basic regulation on the high-voltage supply and more sophisticated regulation on the low-voltage supply. Both will be oversized for the current needs of the PS-1,
Greg in Minneapolis
That can be done, but there's no limit to improvements. You could use separate transformers and regulators for the DSP, DAC and clock, buffer the clock, remove the video ICs, and you end up with something that isn't a PlayStation anymore.
IMO, 50VA is more than the PlayStation would ever need.
IMO, 50VA is more than the PlayStation would ever need.
DragonMaster said:
Funny... I was thinking of eventually doing separate regulation for the DAC, but for the rest, I'd need a service manual and I haven't seen them around yet.
Greg in Minneapolis
P.S. Mine is not really a Playstation anymore anyway... not only is it running with the top off, but with the SMPS mods, I can't even put the top on. My coupling caps are tacked onto the top of the metal shield with their own RCA jacks. It is beginning to become a custom CDP based on a Playstation.
I'm at a loss here. My main concern was to get away from long leads at the output. Now, my fears should not be exaggerated, but I do have some worries because of those hateful surface-mount fuses on the main board.
I will cut the SMPS, if just for the hell of it. But I will also look into using a transformer. And one thing. I have only one PSX. I will not test these things until I have found another. The one I have is very nice and has never been tampered with. I will not risk losing that one until I have an equally nice spare.
I will cut the SMPS, if just for the hell of it. But I will also look into using a transformer. And one thing. I have only one PSX. I will not test these things until I have found another. The one I have is very nice and has never been tampered with. I will not risk losing that one until I have an equally nice spare.
phn said:
My slightly-educated guess, knowing a little bit more about SMPS's than I did a couple of days ago, is that leads at the output of the SMPS are going to be better than splitting it.
You can think of it this way... most electrical circuits have a beginning and end to them... the beginning is of course where the input is applied (signal or power, depending on whether it's a signal or power circuit) and then the end is where the output is taken from. Both of these points are generally configured for easy interfacing to the upstream/downstream circuits and this is where you can hook up a wire (power or signal and ground in many cases) to connect it to the upstream/downstream circuit with little impact on how the circuit actually functions.
In the case of the PS-1 SMPS, where you are looking to split it is not at an input point or output point... and actually is in the middle of the circuit processing (regulator control feedback loop). By cutting it here, you will likely change how the circuit functions... sorta like splitting an amplifier between the input/driver stage and the output stage and running a 1 meter cable between them... it can be done, but may easily mess up phase relationships and cause unwanted oscillations, introduce or induce noise pickup, etc.
But OTOH, as I noted in one of my previous posts, the PS-1 is a great experiemental platform... and maybe, just maybe, splitting the SMPS will be a very good modification. So I think you should do it... just take care (as I noted), make sure you have a spare (as you noted), and listen for the changes and report back.
And I think we'll get the best sound with good linear power supplies (battery will be interesting!).
Greg in Minneapolis
Break-in is happening...
And that's a good thing. After listening to my SMPS mods each day since I did them a week ago, I could hear promise, but the sound never hung together like it did with the stock SMPS. While I heard promise in the sound, I was ready to admit that maybe I shouldn't have poked around in them. I gave up listening a couple of days ago to let them break-in more.
They did.
I listened again this afternoon and heard the greater detail and delineation I'd heard from the beginning, but now the bass was back and things were 'coherent', 'dynamic', and 'hung together'. So I've been listening tonight and finally really liking what I hear.
I'll give things another week of break-in (they'll be up to about 400 hours) and then compare the modified PSU's to a stock one... but my impressions tonight are that the mods are a fine success.
Greg in Minneapolis
<---(finally smiling again!)
And that's a good thing. After listening to my SMPS mods each day since I did them a week ago, I could hear promise, but the sound never hung together like it did with the stock SMPS. While I heard promise in the sound, I was ready to admit that maybe I shouldn't have poked around in them. I gave up listening a couple of days ago to let them break-in more.
They did.
I listened again this afternoon and heard the greater detail and delineation I'd heard from the beginning, but now the bass was back and things were 'coherent', 'dynamic', and 'hung together'. So I've been listening tonight and finally really liking what I hear.
I'll give things another week of break-in (they'll be up to about 400 hours) and then compare the modified PSU's to a stock one... but my impressions tonight are that the mods are a fine success.
Greg in Minneapolis
<---(finally smiling again!)Hi Greg,
maybe that the PS now sounds better because you've listened in the evening on a weekend ? There are some theories that the power is better at night and on weekends because the great indusrtrials don't contaminate the power with high frequency etc. Do you inplemented any kind of filter ? Can you please show us the schematic ?
Another question. What is the meaning of SMPS ?
Thanks and a happy easter
Dommi
maybe that the PS now sounds better because you've listened in the evening on a weekend ? There are some theories that the power is better at night and on weekends because the great indusrtrials don't contaminate the power with high frequency etc. Do you inplemented any kind of filter ? Can you please show us the schematic ?
Another question. What is the meaning of SMPS ?
Thanks and a happy easter
Dommi
Dommi,
Absolutely my system sounds better listening in the evening on a weekend... this has been my experience with my stereo for over 30 years with this hobby (and realizing that was one of the first 'Ah Ha' moments I had where I understood there were things that affected the sound of my system and I could do something about them).
I've tried to take that into account.
In my experience with my system here in this part of Minneapolis, the best time to listen is weekend nights, followed by weekday nights, then weekend days, then weekday days, with the worse being weekday early evenings (5pm - 11pm or so).
Because of the timing of when it sounds worse, I suspect nowadays it is the kids and families watching TV, cooking dinner, and playing on their computers and video games that causes most of the degradation, not industry (as it used to be... years ago, during the day sounded almost as bad as the evenings before 11pm, but that is lessened nowadays).
This week when I listened to my modified PS-1, I did so either in the midday or at night (after 11pm), when it should have sounded at least OK. I'd expect what I'm hearing tonight to be better than either of those times, but not by the margin I heard.... and I also heard the qualities I'm hearing tonight while I listened during the day today. The sound quality was distinctly better during the day today than any other time I've listened since I did the power supply mods... and even better this evening! (Note, I purposefully didn't listen to it on Thursday and Friday... I was just too discouraged about how it sounded then.)
As for AC line filtering, I'm using very little of that... only some capacitors across the hot to the neutral of the AC of my amp and the PS-1 (and the ones in the PS-1 are just upgraded versions of the ones that are there in the stock SWITCH-MODE POWER SUPPLY... SMPS... sorry about that).
AC line filtering is an area I need to spend some time working on... I suspect I can reduce the amount of change in the quality of my system based on the the time of day and day of the week with some attention here.
Very welcome... and thanks for asking... and a happy Easter to you too!
Greg in Minneapolis (who was only going to listen to one last song... 3 1/2 hours ago!)
P.S. That's really the thing that has let me know the PS-1 as a CD player is special... I've started 'listening' to CD's again, actually sitting down in the sweet spot and focusing on the music. I used to only 'listen' to my vinyl setup! And I've even started buying more CD's (and I have way too many of them already... and way too many more records) because I WANT to listen through the PS-1! That's the highest praise I can give any piece of stereo gear.
Absolutely my system sounds better listening in the evening on a weekend... this has been my experience with my stereo for over 30 years with this hobby (and realizing that was one of the first 'Ah Ha' moments I had where I understood there were things that affected the sound of my system and I could do something about them).
I've tried to take that into account.
In my experience with my system here in this part of Minneapolis, the best time to listen is weekend nights, followed by weekday nights, then weekend days, then weekday days, with the worse being weekday early evenings (5pm - 11pm or so).
Because of the timing of when it sounds worse, I suspect nowadays it is the kids and families watching TV, cooking dinner, and playing on their computers and video games that causes most of the degradation, not industry (as it used to be... years ago, during the day sounded almost as bad as the evenings before 11pm, but that is lessened nowadays).
This week when I listened to my modified PS-1, I did so either in the midday or at night (after 11pm), when it should have sounded at least OK. I'd expect what I'm hearing tonight to be better than either of those times, but not by the margin I heard.... and I also heard the qualities I'm hearing tonight while I listened during the day today. The sound quality was distinctly better during the day today than any other time I've listened since I did the power supply mods... and even better this evening! (Note, I purposefully didn't listen to it on Thursday and Friday... I was just too discouraged about how it sounded then.)
As for AC line filtering, I'm using very little of that... only some capacitors across the hot to the neutral of the AC of my amp and the PS-1 (and the ones in the PS-1 are just upgraded versions of the ones that are there in the stock SWITCH-MODE POWER SUPPLY... SMPS... sorry about that).
AC line filtering is an area I need to spend some time working on... I suspect I can reduce the amount of change in the quality of my system based on the the time of day and day of the week with some attention here.
Very welcome... and thanks for asking... and a happy Easter to you too!
Greg in Minneapolis (who was only going to listen to one last song... 3 1/2 hours ago!)
P.S. That's really the thing that has let me know the PS-1 as a CD player is special... I've started 'listening' to CD's again, actually sitting down in the sweet spot and focusing on the music. I used to only 'listen' to my vinyl setup! And I've even started buying more CD's (and I have way too many of them already... and way too many more records) because I WANT to listen through the PS-1! That's the highest praise I can give any piece of stereo gear.
PS-Power Booster
Hi you all,
I am afraid this is a little bit off topic...I built a flee power SE amp that delivers 2,5W into a 4 Ohm load. My PS is directly connected to this little amp. Realy good sound with my highly efficient ESS-bookshelf speakers.
Nice Easter Holidays and happy listening!
Peter
Hi you all,
I am afraid this is a little bit off topic...I built a flee power SE amp that delivers 2,5W into a 4 Ohm load. My PS is directly connected to this little amp. Realy good sound with my highly efficient ESS-bookshelf speakers.
Nice Easter Holidays and happy listening!
Peter
