Another DOS! Any idea how many are out there, Ray?
Fortunately I got my Black Gate FKs in the right way round first time
Actually most of these parts were hard to come by. The transistors are matched pairs from France, the 1% silver micas were special order from 2 sellers in the US, the 5% inductors were from the UK... There was a lot of searching involved.
Fortunately I got my Black Gate FKs in the right way round first time
Actually most of these parts were hard to come by. The transistors are matched pairs from France, the 1% silver micas were special order from 2 sellers in the US, the 5% inductors were from the UK... There was a lot of searching involved.
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I've had a standard 63 since they first came out as I couldn't afford anything better at the time.
I've just bought a K1 signature off Ebay. In the advert it stated:-
"Level 1 upgrade
New laser transport
HDAM Audiophile OP AMPS
Schotky Resistors in all important signal paths
Extensive sound damping"
I've no idea what has actually been done. I have taken the cover off and the lid does have a very heavy material stuck on the inside.
It sounds pretty good and much, much better than my standard 63.
I have been trawling through this great thread looking for simple cheapish mods.
Tonight I added an IEC mains socket and replaced C505 with a Polystyrene (because we had one of the right value lying around at work)
It still sounds great but I do wonder how you guys pick up on improvements? In most cases it's not easy to do a before and after, and then before again, comparison.
Dare I say it, but could it be a case of the Kings new clothes sometimes (not trying to offend) where having done a mod and maybe paid for it you believe it sounds better with no real proof.
Any comments?
I've just bought a K1 signature off Ebay. In the advert it stated:-
"Level 1 upgrade
New laser transport
HDAM Audiophile OP AMPS
Schotky Resistors in all important signal paths
Extensive sound damping"
I've no idea what has actually been done. I have taken the cover off and the lid does have a very heavy material stuck on the inside.
It sounds pretty good and much, much better than my standard 63.
I have been trawling through this great thread looking for simple cheapish mods.
Tonight I added an IEC mains socket and replaced C505 with a Polystyrene (because we had one of the right value lying around at work)
It still sounds great but I do wonder how you guys pick up on improvements? In most cases it's not easy to do a before and after, and then before again, comparison.
Dare I say it, but could it be a case of the Kings new clothes sometimes (not trying to offend) where having done a mod and maybe paid for it you believe it sounds better with no real proof.
Any comments?
Yes, I have a pretty good idea! There are about 60 DOS'ed players or DAC's out there.
I'm into the third batch of 25 DOS boards at the moment, and I have about 15 left in stock
Ray
Plus the once done several years ago - when the threat was young and the boards was home-etched
From your description it appears there isn't many "upgrades" being done.
i. New laser transport - this is not an upgrade.
ii. HDAM Audiophile OP AMPS - If OPAMPs are changed with audiophile ones HDAM should be removed.
iii. Schotky Resistors (?) in all important signal paths - If the diodes are changes to Schotky then this is an upgrade but changing these diodes alone will not change the SQ by much.
iv. Extensive sound damping - This may be regarded as improvement to damp out vibrations.
I would say the cost of these "upgrades" would cost about £30 and the KI normally sold for £110-120 and you should have bought the whole CDP for around £150.
Changing C505 with MKT caps will certainly have noticeable improvement in SQ.
When you have done all major upgrades such as changing the stock TX with bigger capacities; change all critical caps with audiophile caps; change the clocks for DAC and servo with very low jitter clocks; and use very low noise voltage regulators to supply independent power to the servo, the DAC and the decoder circuits you will certainly hear a BIG BIG improvements and it is not a case of the Kings new clothes as you have mentioned.
If there is no improvement in SQ six of my friends would not beg me to carry out the modding work that I had done for them. As to myself I modded two CD63 (one KI and one SE) for my own use.
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Thank you Highlander. I paid £118 delivered so I think I did ok, mods or no mods.
I am an Electronics Engineer so I know that there are no such things as Schotky Resistors, hahah.
How can I tell if HDAM has been removed ?
I'm sure in this thread there are extensive details on changing the clocks but do you have again please?
Thanks.
£118 is about right.
As a start I suggest you first go through Ray's web
http://www.raylectronics.nl/index_en.html
As a start I suggest you first go through Ray's web
http://www.raylectronics.nl/index_en.html
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So my +and- 12v Class-A shunt regs for the DOS board turned up today. Funky little things I'm just going to use 1 of each for both channels.
Got them from here: Audio-GD PSU-A - class A design PSU
turned up in 4 days to the UK and worked out as £17 each inc delivery
Won't get to install them for a few days, but I'm excited to hear the results
I'm just going to use 1 of each for both channels.
Got them from here: Audio-GD PSU-A - class A design PSU
turned up in 4 days to the UK and worked out as £17 each inc delivery
Won't get to install them for a few days, but I'm excited to hear the results
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So my +and- 12v Class-A shunt regs for the DOS board turned up today. Funky little things
Got them from here: Audio-GD PSU-A - class A design PSU
turned up in 4 days to the UK and worked out as £17 each inc delivery
Won't get to install them for a few days, but I'm excited to hear the results
They are Good stuffs but don't short circuit them as there is no protection circuits fitted. Will cause damage when short !!!
Thanks, that's good advice. I think I'll insulate the underneath of them with my hot glue gun to be sure they're safe
No, it's not a typo. The 806 ohm is a standard E96 value for precision resistors. The values for these resistors are based on my simulations with the DOS-circuit to give 2V rms output voltage. I simply picked the closest E96 value for the correct output. This is not very critical of course, you can use 820 ohm and have slightly less output signal, this is not a problem in most cases.
I got Takman resistors for my CFP DOS board from hificollective Hifi Collective Hifi Components - Hifi Collective
Hey guys, I'm sure this has been answered before, but I have startup issues from a cold start - the servos go crazy - but my clock PSU smoothing caps are 1 tenth of the other rails, which are all the same. I wonder, could it be because my servo PSU has huge VA and so charges up the servo rail cap far faster than all my smaller chip supplies?
I think it's the other way around, your clock supply is probably coming on too slow, so the player doesn't see a stable clock at startup. But the smoothing cap is already a lot smaller, and this should give it a faster startup.
You can try this: power the clock from a stable source outside the player, like a bench supply, and leave this on. See if the problem is gone. If not, it's not the clock
Ray
You can try this: power the clock from a stable source outside the player, like a bench supply, and leave this on. See if the problem is gone. If not, it's not the clock
Ray
I will proceed to debug as suggested
Hey Ray, the DOS is a revelation. It took a couple of hours to really open up (those Black Gates had been sitting a while) but it's just gorgeous now. The stereo imaging is dead centre and it's just got all this detail and bass/mid coherence that wasn't there before. I'm only on standard regulators too, but I'll be happy with this for a while.
Hey Ray, the DOS is a revelation. It took a couple of hours to really open up (those Black Gates had been sitting a while) but it's just gorgeous now. The stereo imaging is dead centre and it's just got all this detail and bass/mid coherence that wasn't there before. I'm only on standard regulators too, but I'll be happy with this for a while.
Ok, I hope you can find the cause. One other option would be to increase the reset-time of the player. There's a small reset-IC that generates the RESET signal (QF02). If the player needs some more time to stabilize you can increase CF03 to make the start-up delay longer.
Good to hear you like the DOS
It usually needs some time to settle down soundwise, depending on the parts that you used. Polystyrenes can take some time as well. Great result, considering you're running with 78xx/79xx regs.
Good to hear you like the DOS
It usually needs some time to settle down soundwise, depending on the parts that you used. Polystyrenes can take some time as well. Great result, considering you're running with 78xx/79xx regs.