miklos said:
Thomo said:
Well this is an interesting point: why bypass the HDAM circuit only to build another buffer?
I think the point is that the pre-amp buffer circuit comes after the volume pot and so provides the best interface with the power amp. A low output impedance to go with the high input impedance of the power amp. Someone please correct me if I'm wrong
So if you put a volume pot after the opamps in the CD63 and before the HDAM you'd get a CD player with volume control that might work well into a power amp directly. I don't know if it's a good idea but it's a thought.
Also, as Lee says, this buffer he's made is going to be a bit of a no-compromise project, whereas the HDAM was only part of a modest CD player and is, perhaps, nothing special. At least it's nothing special when you're also putting the signal through TWO op-amps beforehand. The CD63 only sounds its best when the opamps and HDAM are removed and replaced with something better.
Simon
SimontY said:
Well this is an interesting point: why bypass the HDAM circuit only to build another buffer?
I think the point is that the pre-amp buffer circuit comes after the volume pot and so provides the best interface with the power amp. A low output impedance to go with the high input impedance of the power amp. Someone please correct me if I'm wrong
So if you put a volume pot after the opamps in the CD63 and before the HDAM you'd get a CD player with volume control that might work well into a power amp directly. I don't know if it's a good idea but it's a thought.
Also, as Lee says, this buffer he's made is going to be a bit of a no-compromise project, whereas the HDAM was only part of a modest CD player and is, perhaps, nothing special. At least it's nothing special when you're also putting the signal through TWO op-amps beforehand. The CD63 only sounds its best when the opamps and HDAM are removed and replaced with something better.
Simon
Don't forget that the HDAM was also to some extent, a marketting gimmick.
It was sold as an improvement when actually what was required was upgrading of the filter stages.
(edit: as we have seen on this thread)
Andy
Indeed!
I'm having a crack at upgrading my output coupling caps tonight. So far I've had to remove the remote control sockets and the digital outputs, and remount the discrete board in order to create enough space to squeeze the big Epcos MKV caps in.
I seem to have disrupted something critical in all that moving and pcb bending... this is proving to be quite a task!
Simon
I'm having a crack at upgrading my output coupling caps tonight. So far I've had to remove the remote control sockets and the digital outputs, and remount the discrete board in order to create enough space to squeeze the big Epcos MKV caps in.
I seem to have disrupted something critical in all that moving and pcb bending... this is proving to be quite a task!
Simon
I probed some voltages and it started playing again, so no real problems there 
I drilled the rear panel to mount the new caps, repaired the connections from the muting circuit and discrete board that broke off. Then I wired in the new caps and put things back as they should be...
It still plays but there's no sound yet. The new caps barely fit, looks quite cool. Pics to follow soon.
Simon
I drilled the rear panel to mount the new caps, repaired the connections from the muting circuit and discrete board that broke off. Then I wired in the new caps and put things back as they should be...
It still plays but there's no sound yet. The new caps barely fit, looks quite cool. Pics to follow soon.
Simon
poynton said:
I guess it had to be something 'simple'.
There are no pads left to be lifted
Andy
I've lifted two tracks from my discrete pcb. I previously weakened it by drilling the pads out to accommodate very large cap leads (old 22uF WIMA films), and the repair-work was hard to do with all the short, thin silver leads attaching the DAC at one end and muting cct at the other!
I did another small tweek whilst I was in there:
Attachments
Looking good indeed.SimontY said:
Hi Brentrowemeister said:And guess who's looking at it today?
This weekend I will place the C1 on the servo.
As yesterday I broke the connections for the 10.000uF placed after the +-12v sregs, I will replace these by 470uF BG. (Size matters)
Hope this modd does not compromise the sound in any way.
Also hope I will not need to send you my player so you can look at it also.
Regards
Ricardo
Thank you Brentrowemeister said:I'm sure it will all be fine
I am sharpening my hammer right now
Another question:
What should yield better results:
Replace C805 / C806 by 470uF BG or something bigger like 4700uF Pana FC ?
Or should I remove these and place the 470uF nearer the opamps U208 / U209 ??
As you know I had linked in C805/806 a pair of 10.000uF but the wire connections broke last night.
Actually the sound was quite good with the 10.000uF but the wiring is horrible.
Please advise.
Ricardo
Chivvyp said:
That's a good idea Pete! I wouldn't do the drilling on something like the discrete board again, it just doesn't allow for easy component swapping.
Well of course the player it working sweetly again (I'll say no more about that) and I've just really hooked it up and am letting it warm up now.
The first impression with these Epcos MKVs is that they're very bass-light. Perhaps as a side-effect of the lacking bass weight is a clean, detailed presentation.
The difference in bass is so obvious (and it's very obvious when you connect another cap, say Mundorf MKP, in parallel - loads more bass) that I almost wonder if there's a roll-off problem. Or it could just be burn-in time. These caps worked wonders in my preamp, and weren't much different to DC coupling / no cap. This is odd
Simon