With 30V input you need a heatsink indeed...
I don't think the LEDs are faulty, probably just thermal shutdown.
The cap and resistor are only for testing purposes.
Ray
I don't think the LEDs are faulty, probably just thermal shutdown.
The cap and resistor are only for testing purposes.
Ray
Ray6h5c said:
I have succefully built a "normal" regulator with two red leds that can output 5.01V steady (with 1k5ohm 2200uF load).
Now I am restarting the super regulator (same as before but adding a capacitance multiplier).
I am using a BC550C and the results are:
When using a 120uF pana in the cap amplifier 4.97v
When using a 10uF OsCon I get 4.96v
When using a 2200uF Pana I get 4.94v
Are these values ok?
Should I use a big cap or a small one with very high ESR?
Regards
Ricardo
Hi Ricardo,
Those voltages look fine. Don't worry about a few digits difference, remember you are taking about tens of millivolts here!
I would not take a too big cap, as the voltage will come up very slowly at power-up. This could cause problems. A good small cap is better than a big bad one.
Regards,
Ray
Those voltages look fine. Don't worry about a few digits difference, remember you are taking about tens of millivolts here!
I would not take a too big cap, as the voltage will come up very slowly at power-up. This could cause problems. A good small cap is better than a big bad one.
Regards,
Ray
SimontY said:
LMAO! By comparison there I am rejoining diodes with random scraps of wire where the pads have come away from the PCB...
I aim to be neater in future
LOL maybe the new tip on the iron will help
Brent
Thomo said:
Me too. About five of my dac pins are connected with wire to the circuit. I did have to replace the chip though, after that vase of water cleaned the inside for me
Lee.
Tell people it was de-ionized water and it makes it sound better 😀
Brent
rowemeister said:
Indeed sir, indeed!
As you know, Brenton, I've been having a fiddle with my power supplies and ground switch to try and learn more about my noise issues.
I disconnected all of my external supplies and ran all my extra regulators off the +20v. This sounded quite poor, had very little noise, and played only some discs. The rail was sagging to about 18vdc.
I then connected just the servo clock circuit to my external supply and this cured the reading trouble, and let the 20vdc climb to 19v. This sounds decent enough, but I'm definitely missing some of the magic.
There's not much noise, however, which is a welcome relief. There's just a slight buzz, virtually no hum, and some "tape" hiss. If I don't ground to safety earth I get an AC hum. The tape hiss, as we know, comes from using fast regulators on the discrete buffer. This is not loud enough to be troublesome but can be fixed anyway by making an adjustment to the S Power regs.
I obviously have a problem I've yet to pin down regarding my external supplies. I'll connect them one by one to see where it really kicks in.
I'd also like to know where the slight buzz is coming from. This one is very mild and only really audible when listening with headphones, which I jerry-rigged to my preamp.
Simon
I would change those inductors on the discrete first and foremost.
See what that does, I have a feeling they maybe contributing to some of the noise.
Brent
See what that does, I have a feeling they maybe contributing to some of the noise.
Brent
I have just installed a discrete into a mates cd67, and there is a huge hiss again. I also experienced this in my cd67 and cured it by changing the dac ic.
Has anyone else had this problem with the cd67? I tried my discrete in a cd63 first and had no problems. Only when I put it into the cd67 did I get huge hiss.
Hopefully Simon, this isn't part of your problem cos that chip is a pain in the bum to change.
Lee.
Has anyone else had this problem with the cd67? I tried my discrete in a cd63 first and had no problems. Only when I put it into the cd67 did I get huge hiss.
Hopefully Simon, this isn't part of your problem cos that chip is a pain in the bum to change.
Lee.
Thomo said:
It still makes me chuckle, but just how long will this line of comedy continue???
Probably until I do something else equally stupid.
Brent, do you think I could improve things further by adding another tx for the driver ic's? Would LM317 or LT1086 based Raygulators with 30va tx make much difference?
Lee.
Brent, do you think I could improve things further by adding another tx for the driver ic's? Would LM317 or LT1086 based Raygulators with 30va tx make much difference?
Lee.
Hi Lee
I of course had a big improvement using SPower over 7809, but the 7809 improved over the standard set up.
I got a little voltage sag on the input to the regs using 7809 and even more sag using the SPower.
Thats why I added a 15V 30VA tx to do the job properly.
Firstly slap the regs in place, get large caps on the inputs to the regs. Measure the +/-12V (ish) when it is running and see how much the V drops when tracking the disc. You could see quite a big drop. Now remove the fuses and short then out, you will have 80% less V sag.
The + rail is the one that suffers.
Basically if the 9V after the regs is stable you are ok
Brent
I of course had a big improvement using SPower over 7809, but the 7809 improved over the standard set up.
I got a little voltage sag on the input to the regs using 7809 and even more sag using the SPower.
Thats why I added a 15V 30VA tx to do the job properly.
Firstly slap the regs in place, get large caps on the inputs to the regs. Measure the +/-12V (ish) when it is running and see how much the V drops when tracking the disc. You could see quite a big drop. Now remove the fuses and short then out, you will have 80% less V sag.
The + rail is the one that suffers.
Basically if the 9V after the regs is stable you are ok
Brent
Cheers for the advice Brent. I am using a cd67 and the three tda7073a's that are the ic's in question have only one +5v input each. I think the ic's in the cd63 are different, requiring +&- inputs. I reckon I'll stick a separate reg on each and monitor what happens after. I do have the tx ready and waiting, so if it'll bring improvements I'll just bung it straight in.
Lee.
Lee.
rowemeister said:
That's not a very wise thing to do, unless you add the right primairy fuse before the transformer. Otherwise, your insurance company will not pay if your house catches fire
😉. Let's keep things safe!The best solution is: get some low-drop regs and make the +/- 10V driver voltage regulated. Or get a CD67 😀.
Ray
I have looked at this in more detail and measured the voltage. During playback, skipping tracks etc the voltage never dropped below 12.5v. As it is a cd67, the driver ic's are already regulated and I have upgraded all caps, the main smoothing cap for this part of the circuit is 3300uF and all the caps at the chips are upgraded also.
Would adding separate regs for each ic bring any benefit?
Ray, have you had any problems with adding discrete output stages into cd67's?
Lee
Would adding separate regs for each ic bring any benefit?
Ray, have you had any problems with adding discrete output stages into cd67's?
Lee
Thomo said:
No, I don't think so. The voltage regulator is able to deliver plenty of current, so if you have a solid 5V, it should be o.k. If you have added some local electrolytics to each driver, they can draw the needed peak currents from that.
I haven't had any problems with the discrete stage up till now. I have modded four players with it so far (3xCD67 and SA8400), and no hum or other strange phenomena occurred. Due to the architecture of the DAC of the CD63/67, there is a bit of HF noise on the analog outputs, that's more audible because of the more relaxed slope of the passive filter, but I have to put my ear on the tweeter and the volume to max. to be able to hear it. But it's there. Hum could also be caused by the ground lay-out and how you've connected the various grounds of the discrete PCB and the PSU's together. Using a star-point usually gives the best results.
Regards,
Ray
I've fitted a few now with no problems but not on a 67. The dac onwards is pretty much identical so there is no reason why the noise would occur on a 67 unless as Ray says a bad gnd etc was causing it.
Brent
Brent
Re: Next mod, more regs!
http://www.diyaudio.com/forums/showthread.php?postid=1242556#post1242556
Hi, back again, player still in bits after over a year, pending reg completion. Wife will make the board and I have a dedicated transformer. Does anyone have simple close-ups pics and or simple schematics of where the wires leading from this reg board are soldered into? I just want to get this done, clock in (also with Tranny) and the HDM bypass and close her up, it's gathering dust :-(
Ta!
k.
Joe-HT said:
http://www.diyaudio.com/forums/showthread.php?postid=1242556#post1242556
Hi, back again, player still in bits after over a year, pending reg completion. Wife will make the board and I have a dedicated transformer. Does anyone have simple close-ups pics and or simple schematics of where the wires leading from this reg board are soldered into? I just want to get this done, clock in (also with Tranny) and the HDM bypass and close her up, it's gathering dust :-(
Ta!
k.