Thanks for looking at the 1st diagram, I have included a 2nd update, is this what you mean??
Thanks for the tips. I'm only 100 posts in the thread, more tonight!! I'll leave the HDAM alone then but at least I can now do it. 😀 I'll probably have a better understanding of which op-amps, filter-caps and PSU caps when I get further into the thread. There seems to be some many suggestions it's extremely difficult to keep up!
Attachments
If that can help, don't remeber for wich player I've done it but here it is.
Note that it's for HDAM and OEM's caps bypass, parts removed as you did on your drawing.
http://img194.imageshack.us/img194/6784/image3icn.png
Note that it's for HDAM and OEM's caps bypass, parts removed as you did on your drawing.
http://img194.imageshack.us/img194/6784/image3icn.png
Hi guys, I'm looking for a nice (free) tweak to do next while I wait to get DOS parts. Does the following make sense?
I currently have 2 transformers in my player: a 50VA 2x12v that buzzes very slightly in proportion to the load, and a 30VA 2x15v for the output section that is absolutely fine. I bought a display tx but it was DOA.
My driver ICs are currently regulated to 9v with 7809/7909s fitted to the rails in place of the dropping resistors.
I'd like to:
1. Bring my display back
2. Raise my drivers to 12v
3. Minimize the noise from that slightly buzzing transformer if possible
In my box of bits, I have:
- Original KI transformer
- 3x 7812
- 3x 7912
- A rectifier diode bridge
- 4x Elna "For Audio" 56v 12,000uF caps
- 6x Black Gate 16v 220uF
- Veroboard
Can I do the following:
- Disconnect the 50va transformer secondaries
- Reconnect the original KI transformer to all pads except the ones fed by the 30VA 2x15v output transformer (assuming it fits!)
- Build a dual regulated power supply on the veroboard with 3x12v regs in parallel per rail
- Remove the existing 9v driver regs, isolating the ICs
- Wire directly to the pins of the driver ICs with the 6 Black Gates on local decoupling duties (to the top screen?)
Can someone sanity check that for me? I'm hoping that either the buzzing from the transformer is caused by the way it's currently connected and that would go away in the new configuration.
Cheers,
Ben
I currently have 2 transformers in my player: a 50VA 2x12v that buzzes very slightly in proportion to the load, and a 30VA 2x15v for the output section that is absolutely fine. I bought a display tx but it was DOA.
My driver ICs are currently regulated to 9v with 7809/7909s fitted to the rails in place of the dropping resistors.
I'd like to:
1. Bring my display back
2. Raise my drivers to 12v
3. Minimize the noise from that slightly buzzing transformer if possible
In my box of bits, I have:
- Original KI transformer
- 3x 7812
- 3x 7912
- A rectifier diode bridge
- 4x Elna "For Audio" 56v 12,000uF caps
- 6x Black Gate 16v 220uF
- Veroboard
Can I do the following:
- Disconnect the 50va transformer secondaries
- Reconnect the original KI transformer to all pads except the ones fed by the 30VA 2x15v output transformer (assuming it fits!)
- Build a dual regulated power supply on the veroboard with 3x12v regs in parallel per rail
- Remove the existing 9v driver regs, isolating the ICs
- Wire directly to the pins of the driver ICs with the 6 Black Gates on local decoupling duties (to the top screen?)
Can someone sanity check that for me? I'm hoping that either the buzzing from the transformer is caused by the way it's currently connected and that would go away in the new configuration.
Cheers,
Ben
If it's the buzzing that annoys, try swapping round the secondaries, one at a time on the 50va. This sometimes can stop toroidals buzzing. But don't ask me why cos I can't remember.
Lee.
Lee.
Thanks, I already tried that and it seemed to make no difference. I'd also like to get my display back if I can while also getting my servo towards a more 'final' solution. I figured if I can get them running off an OK supply board from bits I have then I can swap another one in later using better components.
Fair enough Ben, I remember that I tried it before after some advice but it also made no difference.
Why not connect the KI TX in, but use its servo windings for other psu's such as the dac or clocks? Your 50va tx will be miles better than the original windings for servo duties.
The more separate supplies you add in, will relieve that 50va of more and more load and the buzzing should go away.
Lee.
Why not connect the KI TX in, but use its servo windings for other psu's such as the dac or clocks? Your 50va tx will be miles better than the original windings for servo duties.
The more separate supplies you add in, will relieve that 50va of more and more load and the buzzing should go away.
Lee.
Thanks Lee - yes, I was thinking of making the 50VA tx dedicated to feed just the servo drivers and put the original KI windings back in for the 5v supplies for now. The output secondaries would not be used, so I guess I could use them for something else - that's a good idea.
Ben
Ben
Definitely worth doing Ben. That driver ic psu upgrade won't be totally evident until everything else is isolated from it. I'd definitely concentrate on splitting off the rails as much as possible before worrying about the output stage. Many more gains are made by doing that than by adding a better output stage imho (as long as you have good opamps).
My cd63 is currently only a transport outputting spdif to my modded chinese dac. I currently have separate low-noise regs for pretty much everything. Every time I add in another psu or reg I can clearly hear the improvement, even through the dac which is not the ultimate in quality.
Sorry if I'm prattling on, I have no idea how much you've done and have missed large chunks of this thread recently.
Lee.
My cd63 is currently only a transport outputting spdif to my modded chinese dac. I currently have separate low-noise regs for pretty much everything. Every time I add in another psu or reg I can clearly hear the improvement, even through the dac which is not the ultimate in quality.
Sorry if I'm prattling on, I have no idea how much you've done and have missed large chunks of this thread recently.
Lee.
Oh, I wouldn't use those Black Gates as decoupling for the driver IC's. Rubycon ZLG are fine for that, and lets you use the BG's somewhere else😉
Lee.
Lee.
I removed the 50VA supply last night in preparation to build a standalone servo supply, reinstalling the original transformer The buzz is still there, so it must be something else. I just can't listen to it now - the bass weight has vanished and the top end is grating. I'm not sure if it's best to perservere with the servo PSU plan or just put the big torid back in! Will 50VA supply direct to driver ICs bring the bass back?!? 😕
A while ago I had also a humming torid (the original one) and that was because of a loose soldering contact on the PCB (the 10V supply, the most demanding). Maybe somewhere on the supply lines there's a bad contact? Try to move the wire a bit, to see if it disappears. I think your 9V servo chip supply must work on the standard toroid as well as the 50VA dedicated one without the buzzing.
I wimped out and crammed the servo PSU back in. The sound is back again. I left the KI tx connected for the display. I think I'm still out of my depth with the driver ICs. I'm going to look at driving my DAC and decoder 5v supplies off the unused KI tx output windings instead.
TIL: Clock mods without a big servo PSU makes my ears bleed.
TIL: Clock mods without a big servo PSU makes my ears bleed.
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Ben, where have you conneted the 50va tx? I thought you'd basically replaced the original tx with the 50va one for the main supply (+/-10v ish)
If that's what you've done then the driver ic's are running off that, which is what you want.
Lee.
If that's what you've done then the driver ic's are running off that, which is what you want.
Lee.
Yep, that's what I've done. I was thinking of building a separate supply for them, but I've just raised the driver regs to 12v instead. Next step will probably be to replace my 9x LM317 boards with super regs.
It's funny - since fitting the 12v regs, my sled motor goes mental when I switch on from cold, but it's fine subsequent times.
Lots of parts arrived for my DOS today. I got my FETs in matched pairs and some badass 1% silver micas 😀
Lots of parts arrived for my DOS today. I got my FETs in matched pairs and some badass 1% silver micas 😀
re regs
thanks simon alan😉
I know they run raw voltage but unsure to use 9v + and minus or 8v , I know i must use low drop out on pos rails am i correct. 6 in total 1pos 1 neg each ic.
thanks simon alan😉
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