stefanobilliani said:
Interestingly the RCEZ32 uses an actual LM7808...
FWIW I tried a 50VA transformer today and switched back to the stock transformer which is probably no more than 15VA estimated from looking at it.. I did not hear any significant difference between the two in my set up.
I will re-evaluate the higher rated transformer at some point, but I think the stock transformer may actually be more than adequate in view of the considerably lightened load. (And my space/budget constraints.)
Indeed, a nice project! A very good sounding transport, very modular.
The weekend was to short, to make the finish as I want to have it.
Here my first "rough" version playing:
The clamp with the magnet to fix the CD is imho the weakest point of the transport.
It is nearly impossible, to mount the magnetic ring exactly centered. The resulting centrifugal force must be horror for the motors bearing.
I just used for the first test small pieces of double sided tape to stick the CD to the spindle.
Franz
The weekend was to short, to make the finish as I want to have it.
Here my first "rough" version playing:
An externally hosted image should be here but it was not working when we last tested it.
The clamp with the magnet to fix the CD is imho the weakest point of the transport.
It is nearly impossible, to mount the magnetic ring exactly centered. The resulting centrifugal force must be horror for the motors bearing.
I just used for the first test small pieces of double sided tape to stick the CD to the spindle.
Franz
On the cd clamp thing, I used a little blue tack and carefully centered the magnetic and put the top back on when I was sure it was centered ok.. Seems to work ok..
I also added a safety ground to the chassis plate, and tied this to the supply ground through a 10 ohm resistor. Oddly enough this seems to have helped the overall sound significantly, it is less artificially wet than it seemed last night.
I am going to work on cleaning up the spdif connection and getting some good quality resistors next. (My originals are not appropriate due to the higher than expected output voltage.)
For those of you using non standard spdif connections you might really want to think about that - there is a limit to the amount of current the port can source, and running directly into less than a couple of hundred ohms is asking the port to source a lot of current. A 100 ohm load will require 50mApk from that port. Direct drive to an external dac places 75 ohms directly across the spdif driver output for 67mApk load current.. Safe values are probably somewhere around 20mA..
I also added a safety ground to the chassis plate, and tied this to the supply ground through a 10 ohm resistor. Oddly enough this seems to have helped the overall sound significantly, it is less artificially wet than it seemed last night.
I am going to work on cleaning up the spdif connection and getting some good quality resistors next. (My originals are not appropriate due to the higher than expected output voltage.)
For those of you using non standard spdif connections you might really want to think about that - there is a limit to the amount of current the port can source, and running directly into less than a couple of hundred ohms is asking the port to source a lot of current. A 100 ohm load will require 50mApk from that port. Direct drive to an external dac places 75 ohms directly across the spdif driver output for 67mApk load current.. Safe values are probably somewhere around 20mA.. kevinkr said:
That is very important expecially if : none ot the the other elements of the chain ...say dacs and amps , has a decent earth connection .
and if the ps arrangements are different to each component of the chain .
I currently have all my gear with the same PS arrangement ( bridges/ diodes for instance ) and the amp with a good ground/earth connection .
I connected the SPDIF ground to the earth through a little capacitor .
I dont mean this has to be a rule , but helps a lot .
Hi Kevin.
Regarding the SPDIF resistors - I'm currently running without any so need to rectify this - are you going to go along with the 291 / 100 ohms combination mentioned a few pages back?
Regarding the puck, I've found you can use the bare magnet as a clamp instead - it grips the disc far more firmly, and you can center it exactly to reduce the strain on the motor from wobbling. On the negative side I guess the servos for tracking have a harder time battling against the magnetic field of the magnet.
Looking forward to Okap's clamp - should solve all the clamping problems in oen stroke
Regarding the SPDIF resistors - I'm currently running without any so need to rectify this - are you going to go along with the 291 / 100 ohms combination mentioned a few pages back?
Regarding the puck, I've found you can use the bare magnet as a clamp instead - it grips the disc far more firmly, and you can center it exactly to reduce the strain on the motor from wobbling. On the negative side I guess the servos for tracking have a harder time battling against the magnetic field of the magnet.
Looking forward to Okap's clamp - should solve all the clamping problems in oen stroke
johnm said:Hi Kevin.
Regarding the SPDIF resistors - I'm currently running without any so need to rectify this - are you going to go along with the 291 / 100 ohms combination mentioned a few pages back?
Regarding the puck, I've found you can use the bare magnet as a clamp instead - it grips the disc far more firmly, and you can center it exactly to reduce the strain on the motor from wobbling. On the negative side I guess the servos for tracking have a harder time battling against the magnetic field of the magnet.
Looking forward to Okap's clamp - should solve all the clamping problems in oen stroke
Hi John,
I'm planning on 392 ohms and 93.1 ohms as this will give me a 75 ohm source and ~1Vpp unloaded and ~500mVpp into my dac per current EIC 60958-3 specifications. The other values will work, but 500mVpp is a fairly healthy level and assures that my low voltage receiver will not have issues with it. These values and signal levels are relatively standard when you look at spec sheets or measure the spdif outputs of typical consumer digital audio gear.
Believe me I am always amazed at how different things sound depending on whether I am using a good digital interconnect or something just lying around. I don't get it, and there probably is not a rational explanation either.
I'm on the list for one of Okapi's clamps.. However in the meantime I used a little blue tack on the better of my two clamps to hold the magnet in place after I centered it. It is probably my imagination, but I think I heard a real improvement.
On the ground issue, all of my components except the new dac and transport are grounded exactly the same way. I have now done that to the transport with the noted improvements which seem real enough. The dac awaits that little tweak.
All in all I am pretty happy with the peformance of this thing, if not for the theft and blown controller I would have gotten off for less than $100. It is NOT perfect, OTOH it is far better than it has any right to be - and I have a tweaked SCD-777ES to compare it to and a media server I worked on a lot to get it to sound good for comparison. It is holding its own.. I think additional mass, a better clamp and few more BG caps and I will be done. I then plan to stick it in a sescom cabinet that matches my dac.
Kevin,
One other question from your Power Supply schematic. I notice you switched to 6V (7806) on the microprocessor supply. Did you remove parts that made that move necessary? Is it necessary? Any reason for 6V rather than 5V? Not trying to be critical, just trying to understand and make sure I don't make a bad move while I wean the boards from their native supply.
Thanks,
Craig
One other question from your Power Supply schematic. I notice you switched to 6V (7806) on the microprocessor supply. Did you remove parts that made that move necessary? Is it necessary? Any reason for 6V rather than 5V? Not trying to be critical, just trying to understand and make sure I don't make a bad move while I wean the boards from their native supply.
Thanks,
Craig
Hi Hayenc,
I'm a little confused by your comments on the supply issue..
I deleted the entire audio board which amongst other things contains lots of power control circuitry and a 6V regulator that powers the mpu continuously whether battery or AC operated.
(This regulator was a micro-power and LDO type.) Incidentally the mpu is rated for normal operation to 6V, although the voltage powering it is significantly less.
The power supply I designed replicates some of that functionality using parts I had on had, and that are readily available.
The 6V regulator runs the mpu and some other circuitry on the controller pcb. (I originally used LM317 because that is what I had on hand at the time.)
The 8V regulator runs only the mechanism and its board.
I went to regulated 12V from the unregulated "12V" of the original design, because in the original the transformer was heavily loaded and at high line the voltage did not exceed 14V, with my mods it was over 16V under the same conditions. I was concerned about the life of some components under the excessive voltage, and accidents like the one I had previously.
Also in the original design the LED was powered by the 6V regulator through some circuitry that both sensed the presence of AC power and a valid power control signal from the mpu.. In mine I wanted to avoid additional circuitry and decided to run it from the unregulated supply, but this did not work that well as every time the spindle motor started or accelerated the LED would flicker.
I'm a little confused by your comments on the supply issue..
I deleted the entire audio board which amongst other things contains lots of power control circuitry and a 6V regulator that powers the mpu continuously whether battery or AC operated.
(This regulator was a micro-power and LDO type.) Incidentally the mpu is rated for normal operation to 6V, although the voltage powering it is significantly less.
The power supply I designed replicates some of that functionality using parts I had on had, and that are readily available.
The 6V regulator runs the mpu and some other circuitry on the controller pcb. (I originally used LM317 because that is what I had on hand at the time.)
The 8V regulator runs only the mechanism and its board.
I went to regulated 12V from the unregulated "12V" of the original design, because in the original the transformer was heavily loaded and at high line the voltage did not exceed 14V, with my mods it was over 16V under the same conditions. I was concerned about the life of some components under the excessive voltage, and accidents like the one I had previously.
Also in the original design the LED was powered by the 6V regulator through some circuitry that both sensed the presence of AC power and a valid power control signal from the mpu.. In mine I wanted to avoid additional circuitry and decided to run it from the unregulated supply, but this did not work that well as every time the spindle motor started or accelerated the LED would flicker.
Hi Hayenc,
Something else I should mention, while the RCEZ32 uses a similar chipset none of the chips used are exactly those found in the RCEZ31 and perhaps some of your confusion stems from that fact. There is nothing in anyone else's mods that is directly applicable to the '32, although general hints are there.
The '32 as you are finding out is much more complex. I have no schematics and laboriously analyzed all of the circuitry I needed to replace. I left a lot of things out deliberately...
You're pretty much on your own for anything beyond what I have posted.. I do recommend you not take anything at face value and try to figure things out on your own if possible. It's better to replicate my results than to blindly clone them...
And be careful!
Now I'm going to focus on tweaking the electronics directly associated with the mechanism, and getting it into a box.
Something else I should mention, while the RCEZ32 uses a similar chipset none of the chips used are exactly those found in the RCEZ31 and perhaps some of your confusion stems from that fact. There is nothing in anyone else's mods that is directly applicable to the '32, although general hints are there.
The '32 as you are finding out is much more complex. I have no schematics and laboriously analyzed all of the circuitry I needed to replace. I left a lot of things out deliberately...
You're pretty much on your own for anything beyond what I have posted.. I do recommend you not take anything at face value and try to figure things out on your own if possible. It's better to replicate my results than to blindly clone them...
And be careful!
Now I'm going to focus on tweaking the electronics directly associated with the mechanism, and getting it into a box.
Kevin,
Thanks for your help. Your decisions make complete sense. I am quite aware the 32 is more complicated than the 31 and was only trying to take advantage of the road you already plowed. I don't think we will ever match the smd's that were removed from the 31 boards.
I had not had time to check for a regulator on the audio board so thought I would ask first. I will continue ringing through the board to make sure I understand both what you did and what I need to do to move beyond the stock supply and get rid of the audio board.
I also agree, it is best to get past the power supply issues and move on to what else will help it sound better and to some packaging. I appreciate your sharing what you have found out through trial and error and allowing me some comfort in knowing I am on the right path. I look forward to your pictures when packaged.
I did manage to avoid one issue you had. My second unit was sitting on the mail truck with the delivery person sitting inside long after they had left an attempted delivery notice on my door. I was able to retrieve it from the truck rather than stand in line at the post office. Too much work to make USPS mean Service.
Again, appreciate your blazing the trail with the 32.
Craig
Thanks for your help. Your decisions make complete sense. I am quite aware the 32 is more complicated than the 31 and was only trying to take advantage of the road you already plowed. I don't think we will ever match the smd's that were removed from the 31 boards.
I had not had time to check for a regulator on the audio board so thought I would ask first. I will continue ringing through the board to make sure I understand both what you did and what I need to do to move beyond the stock supply and get rid of the audio board.
I also agree, it is best to get past the power supply issues and move on to what else will help it sound better and to some packaging. I appreciate your sharing what you have found out through trial and error and allowing me some comfort in knowing I am on the right path. I look forward to your pictures when packaged.
I did manage to avoid one issue you had. My second unit was sitting on the mail truck with the delivery person sitting inside long after they had left an attempted delivery notice on my door. I was able to retrieve it from the truck rather than stand in line at the post office. Too much work to make USPS mean Service.
Again, appreciate your blazing the trail with the 32.
Craig
Hi Craig,
I'm relieved to hear that your 2nd unit did not go astray, it was quite a bummer when my first one was stolen. Score: Hoodlum - 1, Kevin - 1, place where dead electronics goes - 1.
The key to not repeating my experience is mostly to take your time, not work late at night on it, and avoid excessive handling - those ribbons are fragile..
I forgot to mention the big cap/battery on the mpu board, treat that with care.. (Keeps the clock alive in the absence of any other source of power.)
I think there are analogs for a lot of the changes Peter made to the '31 board, and I may go to some trouble to match those up, however the board is different and the same tweaks may not give the same good results. I plan to just continue trying things one at a time.
The sonics have come a long way, but there is still a hint of "Technicolor" I find objectionable, it has diminished considerably. It no longer sounds "mechanical" as I alleged in an earlier post. Low level detail recovery is really good, but so much has changed recently in my system that it is hard to judge how much is due to this "transport" and how much is due to other things. The changes have been sequential, but relatively close together making it hard to judge. I have made large improvements in the digital side of my system and speaker x-o design since Christmas and some of this stuff is still burning in.. (Building and design blitz + 1 Sony SCD-777ES.)
I'm relieved to hear that your 2nd unit did not go astray, it was quite a bummer when my first one was stolen. Score: Hoodlum - 1, Kevin - 1, place where dead electronics goes - 1.
The key to not repeating my experience is mostly to take your time, not work late at night on it, and avoid excessive handling - those ribbons are fragile..
I forgot to mention the big cap/battery on the mpu board, treat that with care.. (Keeps the clock alive in the absence of any other source of power.)
I think there are analogs for a lot of the changes Peter made to the '31 board, and I may go to some trouble to match those up, however the board is different and the same tweaks may not give the same good results. I plan to just continue trying things one at a time.
The sonics have come a long way, but there is still a hint of "Technicolor" I find objectionable, it has diminished considerably. It no longer sounds "mechanical" as I alleged in an earlier post. Low level detail recovery is really good, but so much has changed recently in my system that it is hard to judge how much is due to this "transport" and how much is due to other things. The changes have been sequential, but relatively close together making it hard to judge. I have made large improvements in the digital side of my system and speaker x-o design since Christmas and some of this stuff is still burning in.. (Building and design blitz + 1 Sony SCD-777ES.)
kevinkr said:
RCEZ32 and RCEZ31 have different output ports, RCEZ32 is capable of more output current and has less internal resistance.
So i'd say;
RCEZ32: 392 / 93.1 Ohm
RCEZ31: 291 / 100 Ohm (rated output current is 12mA)
Bad impedance matching or overloading the output will induce jitter and heavily influence the sound.
