In fact 1uF and then the L/R another 1uF could be enough.
The mkt filters spikes from DC, as the bead. The bigger oscon buffers it also for current dips, so then prefarably keep it from 22uF or so.
The cd304 is very well built, much more solid then the 650/60. Alu base, rock-solid alu CDM1, rubber suspended (660 springs)
Imo it has a rather logical pcb layout too for the decoder pcb. And some compartiments in the aluminium case to put clocks in
grabbed some pics from the net:
http://www.lampizator.eu/lampizator/REFERENCES/Philips Cd-304 MK-II/IMG_1255.jpg
http://www.lampizator.eu/lampizator/REFERENCES/Philips Cd-304 MK-II/IMG_1256.jpg
The glass is clear now in my player, made a new one
The mkt filters spikes from DC, as the bead. The bigger oscon buffers it also for current dips, so then prefarably keep it from 22uF or so.
The cd304 is very well built, much more solid then the 650/60. Alu base, rock-solid alu CDM1, rubber suspended (660 springs)
Imo it has a rather logical pcb layout too for the decoder pcb. And some compartiments in the aluminium case to put clocks in
grabbed some pics from the net:
http://www.lampizator.eu/lampizator/REFERENCES/Philips Cd-304 MK-II/IMG_1255.jpg
http://www.lampizator.eu/lampizator/REFERENCES/Philips Cd-304 MK-II/IMG_1256.jpg
The glass is clear now in my player, made a new one
Here is a shot of the two shunt regs for 7210/7220 on my CD880. The LM317 regs are behind the custom clamp on the original coolsink. The aluminium rod on the right have i added to cool the BD's and holds extra pcb's from clock/shunt in the cdp
The shunts must be wired, will do that tonight.
Yes thats all. Only 7 parts, 9 with the LM added.
The shunts must be wired, will do that tonight.
An externally hosted image should be here but it was not working when we last tested it.
Yes thats all. Only 7 parts, 9 with the LM added.
Thnx Simon.
I dont't want to ruin the nice CD880 with home-fried stuff.
Well, not everywhere as neat:
http://www.zelfbouwaudio.nl/forum/download.php?id=15688
THS4031 soic on homebrew heatsinks
I dont't want to ruin the nice CD880 with home-fried stuff.
Well, not everywhere as neat:
http://www.zelfbouwaudio.nl/forum/download.php?id=15688
THS4031 soic on homebrew heatsinks
Hi Guys. I have been tweaking my Marantz cd94 today.
I have used a variant of the I/V stage shown in the AD797 datasheet (page 14, fig 39).
Datasheet here.
I have a couple of questions regarding the components Cs & Rs. Does anyone have an idea which value cap and res to use please? At the moment that pin is left unconnected, but it seems to work fine.
Also, how do I know what value feedback cap to use? I just used 30pF as it's what I had.
The player now sounds better than ever, but it would be nice to get the best from it, and I thought it may benefit Simon's player as it is a simple cct to build on veroboard.
Cheers, Lee.
I have used a variant of the I/V stage shown in the AD797 datasheet (page 14, fig 39).
Datasheet here.
I have a couple of questions regarding the components Cs & Rs. Does anyone have an idea which value cap and res to use please? At the moment that pin is left unconnected, but it seems to work fine.
Also, how do I know what value feedback cap to use? I just used 30pF as it's what I had.
The player now sounds better than ever, but it would be nice to get the best from it, and I thought it may benefit Simon's player as it is a simple cct to build on veroboard.
Cheers, Lee.
Hi Lee,
I don't know why, but I thought the AD797 was a specific type of op amp that uses current feedback or something that makes it ideal for IV conversion, but looking at the datasheet it seems like a just a nice op amp. Have I missed something there?
The typical IV converter has just a resistance in parallel with the capacitance in the feedback loop (like in the TDA1541A datasheet). This one seems a bit more exotic. I suspect the capacitor across the inputs is to filter out high frequency noise?
From my experience, I think something 30pF is probably okay. I can't remember what I used, I think its of the order of 20pF.
The bigger it is, the more the hf is attenuated, but I suspect this is still well out of the audio band.
So, do you follow this with a buffer stage on the CD94? Or any other filtering?
Simon, how's the CD650 going, this thread seems to have slowed awfully. Can't you at least come up with something off topic - just to keep the thread alive?
Cheers,
Phil
I don't know why, but I thought the AD797 was a specific type of op amp that uses current feedback or something that makes it ideal for IV conversion, but looking at the datasheet it seems like a just a nice op amp. Have I missed something there?
The typical IV converter has just a resistance in parallel with the capacitance in the feedback loop (like in the TDA1541A datasheet). This one seems a bit more exotic. I suspect the capacitor across the inputs is to filter out high frequency noise?
From my experience, I think something 30pF is probably okay. I can't remember what I used, I think its of the order of 20pF.
The bigger it is, the more the hf is attenuated, but I suspect this is still well out of the audio band.
So, do you follow this with a buffer stage on the CD94? Or any other filtering?
Simon, how's the CD650 going, this thread seems to have slowed awfully. Can't you at least come up with something off topic - just to keep the thread alive?
Cheers,
Phil
I can try on-topic Phil!
I took my player to Sercal today and dropped in another couple of op-amps...
We played heavily modified CD17KI and CD85s first for a reference. Then mine with the "standard" LM4562.
We swapped these for the metal can "HA" variant. These sounded better - more detailed, calmer, more musical, with better dynamics and bass. There's a thread about metal can versions somewhere on here now...
We then tried the Burson discrete op-amps - these blew even the metal cans out of the water, with more openness, detail, dynamics and a far less harsh sound.
Still the player sounded very bass-light and raw next to a CD85 (7-8x S Power & single crown) and CD17KI (quite a few mods and by far the best of the bunch).
I'll be buying some of those Bursons when I can afford it but they're nearly £50 each it seems.
Simon
I took my player to Sercal today and dropped in another couple of op-amps...
We played heavily modified CD17KI and CD85s first for a reference. Then mine with the "standard" LM4562.
We swapped these for the metal can "HA" variant. These sounded better - more detailed, calmer, more musical, with better dynamics and bass. There's a thread about metal can versions somewhere on here now...
We then tried the Burson discrete op-amps - these blew even the metal cans out of the water, with more openness, detail, dynamics and a far less harsh sound.
Still the player sounded very bass-light and raw next to a CD85 (7-8x S Power & single crown) and CD17KI (quite a few mods and by far the best of the bunch).
I'll be buying some of those Bursons when I can afford it but they're nearly £50 each it seems.
Simon
I'm still waiting for an order to arrive but when it does I'll put the clock regulator on its own power supply. I'll report any changes here.
And for laughs... I soldered the D-pak output transistor that melted itself off my Super Regulator back on today. Incredibly, the reg still works!!!
I may also drop a 5V Audiocom Super Reg on the 1541, but they're quite a fragile design and I don't know if it could deliver the current for this old beast. I'll look at specs at some point and try to find a suitable heatsink and transformer!! I've learned that small heatsinks and too high voltage transformers have to be avoided when supplying old-school chips.
Simon
And for laughs... I soldered the D-pak output transistor that melted itself off my Super Regulator back on today. Incredibly, the reg still works!!!
I may also drop a 5V Audiocom Super Reg on the 1541, but they're quite a fragile design and I don't know if it could deliver the current for this old beast. I'll look at specs at some point and try to find a suitable heatsink and transformer!! I've learned that small heatsinks and too high voltage transformers have to be avoided when supplying old-school chips.
Simon
Cool!
Sounds like you're still going then.
In general, its more efficient to use transformers to get a more sensible voltage - just a few volts above what you want (unless its high current {read class a amp or similar} - you might pull the transformer secondary voltage down by that much). The regulator is dissipating the current through it by the voltage it has to drop essentially as heat. So the smaller the voltage drop, the less heat.
I don't think its important specifically for older chips. The regulated voltage would be the same either way.
Sounds like you're still going then.
In general, its more efficient to use transformers to get a more sensible voltage - just a few volts above what you want (unless its high current {read class a amp or similar} - you might pull the transformer secondary voltage down by that much). The regulator is dissipating the current through it by the voltage it has to drop essentially as heat. So the smaller the voltage drop, the less heat.
I don't think its important specifically for older chips. The regulated voltage would be the same either way.