Hi Kevin.
Those caps at the top can be removed or linked out if you are using LM4572. They are for dc blocking and I pretty sure they're not needed.
The clock frequency is 16.93Mhz.
Also, I'm pretty sure that two really good quality 5v regs on the dac will make a massive difference. One for the dac digital and one for the dac analog.
Lee.
Those caps at the top can be removed or linked out if you are using LM4572. They are for dc blocking and I pretty sure they're not needed.
The clock frequency is 16.93Mhz.
Also, I'm pretty sure that two really good quality 5v regs on the dac will make a massive difference. One for the dac digital and one for the dac analog.
Lee.
Replacing the two 2200uF caps with Black Gates will be expensive. If you don't mind spending the cash, then just replacing with similar values would be good.
However, I would replace them with some Panasonic FC's or Rubycon ZLH's, then place Black Gates after the regs. This would give you similar results for much less cash.
Cheers, Lee.
However, I would replace them with some Panasonic FC's or Rubycon ZLH's, then place Black Gates after the regs. This would give you similar results for much less cash.
Cheers, Lee.
Hi Lee,
What is the value of the BG N cap you replaced on the right of the DAC?
I noticed the four caps you replaced next to opamps are 220uf 16v but on the 640c v2 Brent used 10uf 16v. So which one should it be?
Many thanks,
Kevin
What is the value of the BG N cap you replaced on the right of the DAC?
I noticed the four caps you replaced next to opamps are 220uf 16v but on the 640c v2 Brent used 10uf 16v. So which one should it be?
Many thanks,
Kevin
It's easier to use bigger caps on the V1 as there are so few, on the V2 you need to change 12 caps on the opamps. Use what ever value you like 22uF 47uF etc etc. I found the 10uF ideal as they fit nice and neat.
Brent
Brent
Yeah, I only used 220uF as they're what I had at the time. I shouldn't think there'd be much difference as opamps draw little current.
The bg nx I used is 100uF 6.3v and is on the clock buffer chip. I used 47uF BG Nx Hi-Q on the dac digital rail on the underside of the board.
Lee.
The bg nx I used is 100uF 6.3v and is on the clock buffer chip. I used 47uF BG Nx Hi-Q on the dac digital rail on the underside of the board.
Lee.
Lee brought his V1 to me to see if we can get the discrete output pcb running spot on with it so he won't be able to take any pics.
Brent
Brent
Erm..
Looks like I made a mistake, lol. There is a red BG Nx near the dac, I don't have the player here at the moment, but I'm fairly sure that will be on dac analog.
Latest pic I have is here
The big black cap on the left is now the Nx.
Mods List
I think that list is ok, but I haven't checked it thoroughly yet.
Cheers guys, Lee.
Looks like I made a mistake, lol. There is a red BG Nx near the dac, I don't have the player here at the moment, but I'm fairly sure that will be on dac analog.
Latest pic I have is here
The big black cap on the left is now the Nx.
Mods List
I think that list is ok, but I haven't checked it thoroughly yet.
Cheers guys, Lee.
Well I got the discrete running on the V2 by bypassing the onboard filter and attenuating the input to it and it had more detail and depth more apparent at louder volumes.
The V1 however will be fed direct from the dacs outputs and will therefore require a tweak of the filter.
Brent
The V1 however will be fed direct from the dacs outputs and will therefore require a tweak of the filter.
Brent
🤐 When you pop round to ours for the listening session (of the mildly modded 63ki 
) tomorrow i'm going to beat you with the CA LOL
Just the filter to work out.
Brent
) tomorrow i'm going to beat you with the CA LOLJust the filter to work out.
Brent
lol. I'm looking forward to hearing your system. I'm very curious about those ATC speakers.
Lee.
Lee.
Has anyone looked at the servo board in the CA in any detail? The Marantz players really benefited from tweaks to the servo, can two clocks be used here also?
Lee.
Lee.
I'm very interested in modding the CA. There's loads to do, and loads of space inside the case for extra tx's etc, which is a problem with the Marantz players.
I reckon it could sound very nice with the right mods etc.
Lee.
I reckon it could sound very nice with the right mods etc.
Lee.
Well your heard the V2 briefly at my work last week and it sounds pretty good. Especially when you listen to it properly rather than testing for differences. It sounds even better on the system at home.
Brent
Brent
Hi Guys,
Whats the Srevo acually doing then? Dosent it just control the mech, and how does it effect the sound?
Cheers,
Mike
PS, 640C V2 Service manual available, just PM me your email address. Mike
Whats the Srevo acually doing then? Dosent it just control the mech, and how does it effect the sound?
Cheers,
Mike
PS, 640C V2 Service manual available, just PM me your email address. Mike
In it's simplest form the servo section primarily controls the laser and all of its workings, the RF signal/data from the laser is then passed onto the decoder section that 'decodes' lol this info and then that is sent onto the dac. All these sections work in a loop to keep things working well.
I clocked my servo and uprated all the regs to for the motor control in my 63 and the gains were quite impressive.
Brent
I clocked my servo and uprated all the regs to for the motor control in my 63 and the gains were quite impressive.
Brent
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