Hmmmm. I am still fussing with the ground resistors in the RCA out circuit. I have checked again the resistance from the out pad of the 3rd set of caps and I still find 1k to ground. From the same pad, indeed, 1k and 100R to to the RCA and the muting resistor connects in between. I still cant find a 100k as in the AV out. It seems that back finds the same. But that would be a corner frequency of 16 Hz (with the 10uF cap). Where am I going wrong?
Dragonmaster, it also seems that two caps going from the output to ground, just as for the AV out, should be added to your schematic. On the board they are located close to the strange thing Jives has located just before the RCa jacks. I have measured 250pF for each.
Mick
Dragonmaster, it also seems that two caps going from the output to ground, just as for the AV out, should be added to your schematic. On the board they are located close to the strange thing Jives has located just before the RCa jacks. I have measured 250pF for each.
Mick
Mick_F said:
mick i can`t help much because my ps1 dosn`t have rca but
i will explain a few things i figured out.
first off all desolder completely the muting transistors because
you measure a part f their resistance which is between the outputs and the ground.
after that if you follow the output off the dac a little before the caps there is a split and there are two resistors 500 ohms each.
one is going to one off the muting transistor`s leg and the other
one is in series with the signal and next to it in series again is the 100 ohm you found.
there is no 100k around.
after that the signal goes to the output (assuming the caps are bypassed) and at the end near the output there are 2 resistors
in parallel with the output 1k and two caps again in parallel (250pf
you said it i didn`t measure them)with the output.
when i desolered the 1k resistors (that`s what you measure) i measured 100k to the output which i guess is the internal resistance off the dac but the sound was bad so i soldered them back on.
after that i desoldered the two 250pf caps which gave me a bit improved highs but very small difference and i don1t know if it will be audible with other speakers since mine go up to 40khz.
but you can desolder them anyway it`s easy.
p.s. 1why don`t you remove the 10uf cap two?
no cap is better than good cap unless you don`t have a dc blocker to the next stage but you still can replace it with a 22uf
if the 16hz isn`t enough for you.
p.s.2 don`t desolder the 1k resistors because it`s very hard to solder them back they are too small.
Look at the left of this attachement, there is one. It's marked 104.
http://www.diyaudio.com/forums/attachment.php?postid=783144
BTW, do you have PU-8 PCB?
I'm not following the topic much as I don't have much time to work on the PlayStation. (I have to build speakers before Christmas.
) I do check the replies but I read fast. Be sure to include my username (Mick, you already do this) if you want ask me something. A trick to work with the circuit is to take pics. It's easier to read everything.OK I'll have to add the caps to the RCA circuit too. That's what I thought, AV and RCA have the same circuit at the opamp output.
Mick_F said:
Mick - is it not possible that the corner frequency IS 16uF. This device was not intended as an audiophile unit originally. Perhaps for space/cost/least offensive sound reasons there is some bass loss. It would be minimal I guess as CD has a wall at 20Hz. If you decide to go for bigger caps I have a few spare 100uF Nitais can forward as an early Christmas present if you like. Drope me a private email if you're interested.
As for the mystery device in the circuit path, I took some better pictures and was surprised by the result:
http://cecelia.physics.indiana.edu/life/video/2001/monolith.JPG
Still don't know what it's purpose is. If it's a filter for EMC regulations then why only implement on the RCA circuit tracks and not the AV ?
I favour that it is some form of switch that is engaged when the external VHF/UHF Modulator conector is plugged in. This appears to get a summed mono signal through the left audio channel only
Thanks a lot, my friends, for your answers. Let me say that it is a big pleasure to work together with you on this mod of the PS1.
Back, on the PS1 I was working with yesterday, I have soldered all six caps out and the muting resistors are tilted as shown by Dragonmaster. I will take them out completely tonight and look if I can verify what you wrote. I have also desoldered the 250 pF caps.
In my final configuration (which I did not find yet) I will have to include a DC blocker cap as I have an amp without.
Dragonmaster, I have noticed these resistors labelled 104 and found four of them on the board. I was however not able to conclude on their position in the schematic by following the traces on the PCB. What irritated me is that when I simply measure the resistance from the output of the 3rd cap to ground with a DMM I get 1k. On both channels. And if I do the same for the AV circuit (i.e. from the 2nd pair of caps to ground) I measure 100k.
Yes, I have the PU-8 board.
Jives, sure you are right, it may be that they found 16 Hz sufficient. And of course I am interested in those Nitais, I'd love to try them. I will write you a personal mail.
Indeed your findings concerning the unknown component are striking. Maybe it is a transmitter who taps our audio signals and sends them directly to an alien species somewhere out there. By listening to our music they nourish on our human emotions - and yes, I feel mentally empty today...
Mick
Back, on the PS1 I was working with yesterday, I have soldered all six caps out and the muting resistors are tilted as shown by Dragonmaster. I will take them out completely tonight and look if I can verify what you wrote. I have also desoldered the 250 pF caps.
In my final configuration (which I did not find yet) I will have to include a DC blocker cap as I have an amp without.
Dragonmaster, I have noticed these resistors labelled 104 and found four of them on the board. I was however not able to conclude on their position in the schematic by following the traces on the PCB. What irritated me is that when I simply measure the resistance from the output of the 3rd cap to ground with a DMM I get 1k. On both channels. And if I do the same for the AV circuit (i.e. from the 2nd pair of caps to ground) I measure 100k.
Yes, I have the PU-8 board.
Jives, sure you are right, it may be that they found 16 Hz sufficient. And of course I am interested in those Nitais, I'd love to try them. I will write you a personal mail.
Indeed your findings concerning the unknown component are striking. Maybe it is a transmitter who taps our audio signals and sends them directly to an alien species somewhere out there. By listening to our music they nourish on our human emotions - and yes, I feel mentally empty today...
Mick
Summary?
OK guy's, I've been trying to follow you on your quest but I'm getting lost in the detail. I have a couple of original PS1's and would love to use it with my modded T-amp but I lack the appropriate knowledge to follow just the words.
Do you think you could create a summary with some pic's to help us 'beginners' out?
Thanks
Lee
edit: it is a 1002...and a 1002b as well
OK guy's, I've been trying to follow you on your quest but I'm getting lost in the detail. I have a couple of original PS1's and would love to use it with my modded T-amp but I lack the appropriate knowledge to follow just the words.
Do you think you could create a summary with some pic's to help us 'beginners' out?
Thanks
Lee
edit: it is a 1002...and a 1002b as well
Re: Summary?
Well there are some mighty fine pictures in this thread and at
http://dogbreath.de/PS1/index.html
Two things first :
1) Are you compfortable dismantling the PS1 ? It's not that hard and most of us now can do it with the lights turned off but the first time it is quite daunting, especially the ribbon cable which joins the transport to the motherboard.
This slots into a plastic fitting. A rectangular collar slides down to lock it tight . You have to ease the collar up a little to release the ribbon. I broke thend end off mine the first time, but it still works. I now only use my fingers so as not to exert too much force.
2) The PS1 motherboard uses tiny (and I mean tiny !) surface mount components. In most cases it's just a case of desoldering them, but you need a fine point soldering bit and steady hands. I have the former but not much of the latter, but was able to cope.
If these sound too much you can achieve quite a lot of the benefit by using the AV output. Strangely you can access the Audio L & R in two ways :
1) Via the RCA sockets on the back
2) Via an adaptor cable which plugs into the AV socket.
The circuit path for 1) passes through 2 caps and an Opamp, whereas for 2) it only passes through 1 cap.
So ....If you have a cable with a PS1 AV connector on one end and yellow, red & white RCA plugs on the other, this gives you some of the benefit (shorter circuit path) for less of the hassel (dismantling & nano surgery) .
If you do want to operate and have taken the motherboard out you need to decide wether you want to use the AV circuit or the RCA circuit and how much extra wiring you want. I went for RCA's and minimal internal wiring. I just removed the 6 DC blocking caps near the DAC, jumpered a new better DC blocking cap across these and removed the Mute transistor.
BUT you do need to learn the terrain of the board first as the DAC is about the size of a dual opamp, and the caps even smaller.
Lostcause said:
Well there are some mighty fine pictures in this thread and at
http://dogbreath.de/PS1/index.html
Two things first :
1) Are you compfortable dismantling the PS1 ? It's not that hard and most of us now can do it with the lights turned off
but the first time it is quite daunting, especially the ribbon cable which joins the transport to the motherboard.This slots into a plastic fitting. A rectangular collar slides down to lock it tight . You have to ease the collar up a little to release the ribbon. I broke thend end off mine the first time, but it still works. I now only use my fingers so as not to exert too much force.
2) The PS1 motherboard uses tiny (and I mean tiny !) surface mount components. In most cases it's just a case of desoldering them, but you need a fine point soldering bit and steady hands. I have the former but not much of the latter, but was able to cope.
If these sound too much you can achieve quite a lot of the benefit by using the AV output. Strangely you can access the Audio L & R in two ways :
1) Via the RCA sockets on the back
2) Via an adaptor cable which plugs into the AV socket.
The circuit path for 1) passes through 2 caps and an Opamp, whereas for 2) it only passes through 1 cap.
So ....If you have a cable with a PS1 AV connector on one end and yellow, red & white RCA plugs on the other, this gives you some of the benefit (shorter circuit path) for less of the hassel (dismantling & nano surgery) .
If you do want to operate and have taken the motherboard out you need to decide wether you want to use the AV circuit or the RCA circuit and how much extra wiring you want. I went for RCA's and minimal internal wiring. I just removed the 6 DC blocking caps near the DAC, jumpered a new better DC blocking cap across these and removed the Mute transistor.
BUT you do need to learn the terrain of the board first as the DAC is about the size of a dual opamp, and the caps even smaller.
I am working on a summary of all this. Here is a preview.
The pictures showing the modified board are still in my camera at home. I will try to update soon.
Dragonmaster, Jives and back, please let me know if you whish to be quoted by your full name instead of your username. If you agree I would prefer to do so. Just send me an email to mick at feuerbacher dot de
Mick
The pictures showing the modified board are still in my camera at home. I will try to update soon.
Dragonmaster, Jives and back, please let me know if you whish to be quoted by your full name instead of your username. If you agree I would prefer to do so. Just send me an email to mick at feuerbacher dot de
Mick
extra DAC PSU decoupling
Hi , I noticed Dommi that you put in some extra ceramic decoupling caps across the two 10uF DAC decoupling caps.
Looking at Micks amazing photographs I wonder if there are any places underneath the board we could use the place some extra cermics VERY close to the caps or the pins of the DAC ?
Hi , I noticed Dommi that you put in some extra ceramic decoupling caps across the two 10uF DAC decoupling caps.
Looking at Micks amazing photographs I wonder if there are any places underneath the board we could use the place some extra cermics VERY close to the caps or the pins of the DAC ?
jives11 said:
if you disconect the collector they are out of the signal path
but the emiter-base throught a 500R resistor and ground influence impedance measurements (not the sound) from output to ground.
mick i didn`t understand your email i will send you a p.m.
no problem to let you know my name.
Hi @ all,
can you please report your experiences with a tube output stage ?
For me it's interesting if the differences in spacial information are better with the tube stage. Maby it's a question about the capacity of the wire to the Preamp, if a tube stage is better or not.
Any ideas ??
Thanks
Dommi
can you please report your experiences with a tube output stage ?
For me it's interesting if the differences in spacial information are better with the tube stage. Maby it's a question about the capacity of the wire to the Preamp, if a tube stage is better or not.
Any ideas ??
Thanks
Dommi
Well, Michael Methe describes on his site http://www.methe-family.de/cd.htm that he has implemented a tube output stage. And (of course) he reports that it is very good. You can contact him directly, I have experienced him as a very communicative person.
Mick
Mick
This one is for Jives.
These are the flat cable connectors I use for the connection of the umbilical to the mainboard and the PSU board. For the mainboard use a connector with 2mm pitch, for the PSU 2.5mm (1/10 inch). These are standard values. You can easily cut them to length and solder the leads to the pins.
Hope this helps.
Mick
These are the flat cable connectors I use for the connection of the umbilical to the mainboard and the PSU board. For the mainboard use a connector with 2mm pitch, for the PSU 2.5mm (1/10 inch). These are standard values. You can easily cut them to length and solder the leads to the pins.
Hope this helps.
Mick