Clearer, I wouldn't have thought that it could do this, but less hum, possibly. If you modded the PlayStation, there's no more muting transistor, so when the PSX is off, or the DAC isn't used, it's doing as if you left the cables unplugged - humming. Grounding the PSX case is simply cancelling the hum picked up by the cables. If the rest of your equipment is also double-insulated (No ground), the PSX is the path to ground, which isn't always a good thing. In this case, the amp should be also grounded.
I didn't think that this would make any difference either. The muting transistors are still hooked up, I forgot about this mod. The amp isn't grounded, and you're right- grounding everything through the Playstation isn't a good idea. I'm going to try a different power supply in it today, as I don't trust the one in it after hearing that wierd noise from it. I will try grounding the amp too, and see what happens.
OK, about whistling, there's no problem, it's an SMPS power supply, and they get noisy with time. (Insulation on the transformer dries and let the transformer resonate apparently. Are you sure the whistling came out of the speakers, and not from the unit itself?
Well, that mod, even if the muting transistors are still hooked, if you did the last mod on Mick's site, he bypassed everything, connecting 1st pair of caps directly to the outputs.
Well, that mod, even if the muting transistors are still hooked, if you did the last mod on Mick's site, he bypassed everything, connecting 1st pair of caps directly to the outputs.
That noise did come through the speakers- that's why I'm concerned about it. No problems, but no reason to take a chance either- I have 5 of them, so there's plenty to scrounge from. This player has Micks output mod, and I cut the plastic "tab" off the back of the transport to allow the suspension to float freely.
Put a different power supply into the Playstation yesterday. Hooked it up to the computer speakers again, this time no more funny noises, it worked fine. I also connected a ground wire to the amp. I was expecting to get a ground loop hum when the ground wire was connected to the shielding on the Playstation, but, surprisingly, no noise. The ground wire on the amp did clean up the sound, overall it seemed a lot less "noisy". Unfortunately, the Playstation doen't sound as good with this power supply though. Nevertheless, it still sounds better with the ground wire hooked up to the shield, though the difference isn't as pronounced. I wondered if this had something to do with the amp being grounded, so I also tried it with the ground on the amp disconnected, but the difference was the same. I'd guess from this result that the reason for the big difference in sound when I first tried the ground wire had something to do with the other power supply I'd first used.
I dont really understand what you are doing. If you close the connection of the main board and the PSU board, you automatically have a connection between the ground of the PSU and the main board shields, as the latter are connected to the ground of the main board. If you add an extra ground connection (this is what I understand you did), you create a ground loop. This may be the reason why the PS1 sounds worse then, which is not very surprising.
Or did I misunderstand something??
Mick
Or did I misunderstand something??
Mick
The little enclosure that I put the power supply in is grounded, but the power supply is not grounded to the enclosure. All I did was hook a ground wire up from the power supply enclosure to the shield around the main circuit board. There is no ground loop, as the circuit is only grounded to earth at one point- where the wire is attatched to the shield around the main PCB. As far as the difference in sound between the two power supplies goes, I don't know. It may have something to do with whatever problem the first supply has (that creates the whistling noise when its powered off). I do remember someone posting here who had tried different versions of the power supplies in their player, and found that the original one sounds the best. Unfortunately, the supply with the problem was the original.
Modifying the PS1
Hi,
Just finished reading the whole 113 pages
. Before I start trying to modify my 1002, I'm not sure if anyone followed up the above post by DragonMaster about making extra cuts etc to the one shown on Mick's website under "Modifiying the output stage of the Sony Playstation SCPH100x".
I'm going to cut the traces as per the photo below. Are there any additional cuts or jumpers to do on the board?
[/IMG]
cheers
DragonMaster said:
Hi,
Just finished reading the whole 113 pages
. Before I start trying to modify my 1002, I'm not sure if anyone followed up the above post by DragonMaster about making extra cuts etc to the one shown on Mick's website under "Modifiying the output stage of the Sony Playstation SCPH100x". I'm going to cut the traces as per the photo below. Are there any additional cuts or jumpers to do on the board?
cheers
I just got 2 Playstations, both of them japanese models, SCPH-1000 and SCPH-3000. When I opened both units, they actually have the same DAC and opamp. However, the only thing removed in the 3000 series was the S-video output, supposedly to cut cost. I'm playing the 3000 right now and didn't notice any audible difference with the 1000. Thus, I think its just fine to get the 3000 in case the 1000 is not readily available on you end. Both models have the audio and video rca outputs. Thanks
Need an advice from the modders, aside from actually cutting off the connection on the pcb, by scratching it off, isn't it better to just remove the 100k resistor that's in series with the (+) leg of the rca output? Is this resistor the last component actually attached in series? Where is this resistor located in case removing it is an option? I don't want to scratch off the connection so I can preserve the psx board. Thanks.
D0Hbert... scratching vs removing the 100 Ohm resistor
I wouldn't be too concerned about "cutting" the trace on the pcb board. A small piece of good quality solid core wire (like magnat wire), can always be used to solder from one side of the trace to the other or from one solder pad to the other.
have a look at Mick_F's website for complete mods, most of them documented here in this thread.
I wouldn't be too concerned about "cutting" the trace on the pcb board. A small piece of good quality solid core wire (like magnat wire), can always be used to solder from one side of the trace to the other or from one solder pad to the other.
have a look at Mick_F's website for complete mods, most of them documented here in this thread.
DOHbert, as far as I remember the 100k resistors are close to the caps or muting transtors, but there is other stuff closer to the RCAs, i.e. the small output caps and the unidentified "thing". I recommend to cut the traces, as Nanook said, they can be reconnected easy later on.
phn, I have no idea about your output transformers. Maybe you should ask in the tube section....
Mick
phn, I have no idea about your output transformers. Maybe you should ask in the tube section....
Mick
Hi chaps, just touching base to say that I've nearly completed my re-box with integrated t-amp. 
I also implemented Jurgen’s JFET buffer directly onto the board. I was a bit confused by the pin-out of the old NJM1200 though? It seems that the signal inputs are switched from the datasheet. Not that it matters but it did throw me when I went to find a grounding point!
I’ve also wired my remote receiver directly onto the motherboard and thrown all the front section
. I’ll post the pin-out and pictures if/when it’s all done and working???? 
TTFN
I also implemented Jurgen’s JFET buffer directly onto the board. I was a bit confused by the pin-out of the old NJM1200 though? It seems that the signal inputs are switched from the datasheet. Not that it matters but it did throw me when I went to find a grounding point!
I’ve also wired my remote receiver directly onto the motherboard and thrown all the front section
. I’ll post the pin-out and pictures if/when it’s all done and working???? TTFN
Hello to all in this great Forum!
I'am new here, and very interested at the sounds and modifications of the PS1.....at the moment i modify my PS with a lot of ideas that i found in this threat....when my tube out is built and ready i will describe what sounds i hear..
excuse my bad english, i try my best
greetings to all
Moonspell
I'am new here, and very interested at the sounds and modifications of the PS1.....at the moment i modify my PS with a lot of ideas that i found in this threat....when my tube out is built and ready i will describe what sounds i hear..
excuse my bad english, i try my best
greetings to all
Moonspell