awpagan said:Almost to 6000
It's all you fault Ray,
well almost, plus a few others
Wow, 6000 posts and counting...ok, I plea guilty...I admit fueling the irresistable urge of many to customize their equipment in search of the ultimate audio-experience
.poynton said:
Couldn't agree more, Andy! Thanks to all that contribute(d) for the good atmosphere here.
Here's the latest thing I've done to my SA8400
.Interesting discussion about the LM4562 BTW, it's not the ultimate opamp for me either. Indeed it gives a lot of extra detail and information to the music, but in the long run I find it too sterile and clean. I like my AD8610/AD8510 combo better, it involves me more in the music. Guess it must be the AD-sound.
Regards,
Ray
Attachments
Re: Re: Re: Zap Filter
News does travel fast.
15th from the right, row 237, i waved......
unfortuately the novelty of the bridge has pasted some time ago.
frequent user
there is still a law in place to herd sheep across the bridge between certain hours
some uni students tried years ago,,,,,,,,,,,
maybe it's just been used
allan
poynton said:
News does travel fast.
15th from the right, row 237, i waved......
unfortuately the novelty of the bridge has pasted some time ago.
frequent user
there is still a law in place to herd sheep across the bridge between certain hours
some uni students tried years ago,,,,,,,,,,,
maybe it's just been used
allan
martin clark said:Right here
Don't worry that shuld work OK.
The 17.6v figure is the lowest that is guaranteed to work with tolerances of parts - but not the raw PSU - taken into account:
7812 puts out 12.0v nominal, raised from ground by the LED - 1.95v actual, say 2V = 14.0v;
7812 dropout needs to be 2.2-2.5v min at low currents;
Gyrator portion drops 0.65v+ small amount through bias network to drive BC547. How much? well it's the output current - say 20mA - divided by Hfe, say 300 (pessimistic for a BC547C at 20mA). That's 67uA, or 0.67V across the 10K biasing resistor.
So we need (14.0+2.5+1.3v) input, 17.8V, to guarantee it will work. In fact, because the BC54x will have a Hfe of c.400 at these currents, most LM7812s are actually about 11.9v to avoid exceeding their rated voltage (and fwill work with 2.3v overhead at 10mA output) and the LED voltage reduces at -2mV/degreeC, 17.6 will work - always, but that's why it's given as 'minimum minimum'; it gives no allowance for variation in the output of the raw PSU.
If you're worried that your implentation is a bit marginal, then monitor the output from the 7812. It should be constant to two decimal places at (around 13.9v, +/- a little bit). If you see it wandering by 10mV or more over a few minutes then it has insufficient voltage input, and the fix is either more raw input, or reduce R1 (say to 5K ) and try again.
An externally hosted image should be here but it was not working when we last tested it.
Well, it seems there's also an "average minimum"...
My main dances from 225.00 to 226.00V -for now, as in minutes it can goes from 220 to 230!- while my PSU (20V raw, rectifiers, 1200µF, 7818, 47µf) dances from 18.85 to 18.89V, while the Flea's 7812 show 13.83 to 13.88. @L1 (wich is not there as the XO) it shows 5.05/.04. I have 15K at R1, as I have 2.2µF caps in filter...
Is it OK?
If no, may I change R1 even with 2.2µF?
Or may I remove the PSU's 7818 and let the 20V in?
About the opamps, as it seems it is the main debate on forums, is a ranking possible? I mean like 3 class, 3rd low cheap EOM ones, here JRC2114, a second class with not the best but still good sounding and enjoyed by some of us, and a 1st class, with the very best, maybe a top 5 where each of us may find happiness. Those this make sense? I think that may be a good help for newbies.
Have a good day!
Malefoda said:
Hi Matthieu,
Looks o.k. to me. Your Flea input voltage is above 18V and the output is a nice and stable 5.0V, so no worries here. As long as the first 7818 on the PSU has a minimum input of 20VDC then everything else behind it is o.k., it's all regulated.
15k for R1 is fine, there's hardly any current flowing there. The higher value nicely compensates for the capacitor being 2u2 instead of 3u3.
Regards,
Ray
6h5c said:
The very low noise and distortion of the LM4562 obviously contribute to it's ability to extract extra detail and information.
It would be interesting to see a circuit diagram but TI are keeping it secret (for now). I may get hold of some of the single chips and compare them to the LM6171/627 combo.
Andy
EDIT ...... There is a large thread on the LM4562.......
http://www.diyaudio.com/forums/showthread.php?s=&threadid=86276
poynton said:
6h5c said:
Me too, but I didn't want to mention it LOL
Ray
Ok I know this is me and one of my flaws...
Don't english people have the saying "Le mieux est l'ennemi du bien", standing for "better is the enemy of the good"... If I tell you I spend many long minutes to make the Epcos blue caps in line on the PCB...
Anyway, I order my X0 right now Thanks guys !Trying to switch the CD63KI TX into mij CD67 I get the suspision that something has gone (seriously ) wrong. The player doesn't turn on anymore.
at U311 and U312 I measure 29 volts???? at U305 'til U310 the voltages are according to the schedule...
Anybody any idea what has gone wrong, and what I should do?
(I hope this high voltage didn't destroy any sensible parts)
Thanks in advance
) wrong. The player doesn't turn on anymore.at U311 and U312 I measure 29 volts???? at U305 'til U310 the voltages are according to the schedule...
Anybody any idea what has gone wrong, and what I should do?
(I hope this high voltage didn't destroy any sensible parts)
Thanks in advance
the object is to keep this thread going until the last 63 and 67 have gone to dust Marantz never dreamed...Right, Time and Patience have to be metered so I'll get to the point. malefoda has kindly sourced some dip 4562's for me, and some caps to go with it. I'm assuming these have to be soldered underneath and assume there's space. Which means taking the whole damn player apart
gag... I would really appreciate two things; a pic. of the opamps in place so I don't screw up the direction again
(should be easy to do) and not so easy, if any of you have pics of the mods in progress so I can see exactly where the caps go and if they have a +-side. I would be too embarassed to get this wrong
Having been bitten by the diy virus (is it fatal? other than to equipment...), I wonder if you have seen or heard or used the Burson OPamp? Yes it's pricey but the work involved in making it gives me heartburn to think about.
http://www.bursonaudio.com/Burson_Promotion.htm.
Last but not least, my 67 came from Brent. It's not fully tricked out but sounds... well it should sound great. Trouble is it's got trouble. Even though it was shipped within the UK and carried to me by hand, "they" managed to give it a nice dent in the case. From day one it had the following issue; sometimes it will play and sometimes I have to give it a bang to start. othertimes it will start to spit and mistrack or give up altogether. This has nothing to do with what kind of cds I play. I assume the laser is out of allignment. Brent has of course agreed to take it in but that means serious shipping costs and the possibility that "they" do their mischief again. I would just as well change the whole sled/mechanism. It's easy to do and should cost less, I guess. Anyone know where I can get a new one and what it costs?
Marantz never dreamed...Right, Time and Patience have to be metered so I'll get to the point. malefoda has kindly sourced some dip 4562's for me, and some caps to go with it. I'm assuming these have to be soldered underneath and assume there's space. Which means taking the whole damn player apart gag... I would really appreciate two things; a pic. of the opamps in place so I don't screw up the direction again(should be easy to do) and not so easy, if any of you have pics of the mods in progress so I can see exactly where the caps go and if they have a +-side. I would be too embarassed to get this wrong
Having been bitten by the diy virus (is it fatal? other than to equipment...), I wonder if you have seen or heard or used the Burson OPamp? Yes it's pricey but the work involved in making it gives me heartburn to think about.
http://www.bursonaudio.com/Burson_Promotion.htm.
Last but not least, my 67 came from Brent. It's not fully tricked out but sounds... well it should sound great. Trouble is it's got trouble. Even though it was shipped within the UK and carried to me by hand, "they" managed to give it a nice dent in the case. From day one it had the following issue; sometimes it will play and sometimes I have to give it a bang to start. othertimes it will start to spit and mistrack or give up altogether. This has nothing to do with what kind of cds I play. I assume the laser is out of allignment. Brent has of course agreed to take it in but that means serious shipping costs and the possibility that "they" do their mischief again. I would just as well change the whole sled/mechanism. It's easy to do and should cost less, I guess. Anyone know where I can get a new one and what it costs?
shepperd said:
There has been a lot of discussion on the forum re Burson products. They even resorted to a little underhand self-promotion last year.
I think the general concensus was that they are OK but not exceptional. They are also sold as OEM by the manufacturer in China.
A search should find some threads.
If you consider going this far, the discrete output stage is by far better and easy for even a novice DIYer with reasonable soldering skills. (with care)
Andy
PS.....use www.bursonaudio.com