I used parts that I already had available and ones I had tried and tested. I used a 2SA1085 instead of the 970
Brent
cd63
big caps on the psu 9 regs round the board good op amps.bout to have a go at a dos so i cant say .
alan
Have you clocked the dac and servo ben thats the biggest gain imho
big caps on the psu 9 regs round the board good op amps.bout to have a go at a dos so i cant say .
alan
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Hey Alan, I've not clocked anything yet but I'm moving up to it slowly. I bought a Flea PCB from Ray. Are two separate clocks preferred, or is it better to divide the DAC clock by two?
I have big caps on PSU and the 10 regs I mentioned, plus I'll be doing the driver ICs. I have good op-amps (LM4562HA bypassed with film caps).
Idle disc spinning is getting faster the more I take off the main 5v regulator... not really causing problems, but odd :-/
I have big caps on PSU and the 10 regs I mentioned, plus I'll be doing the driver ICs. I have good op-amps (LM4562HA bypassed with film caps).
Idle disc spinning is getting faster the more I take off the main 5v regulator... not really causing problems, but odd :-/
I've been gone a few days, just getting back now.
I see you are still going with the CFP configuration. Your comments back to me seemed directed to the current sink, which never seemed to matter much to me vs. the resistor. But the CFP does.
You have one of my boards, though I do not know if you are using it or one of Ray's, but my board is done with a Pin 1 Emitter on the CFP transistor, and not Pin 3 Emitter. This makes a big difference!!!!!!
Moving on, as you seem to be in experimental mode............
You are using 2mA thru the CFP. Have you tried going with 4mA, either paralleling the resistors or reducing them about in half. I use 4mA to feed the added transistor. I don't know if it all makes much difference, but thought I'd mention it.
That's all for now.
Yes it's the CS I've omitted due to the reasons mentioned earlier. It is Rays pcb I am using. The transistors I have fitted are now pin 3 emitters
I'm not really in experimental mode, just tuning the sound back to what I had with the old dos. I have not changed values to alter the current (yet) as I've been getting rid of the problems with the sound I had. I may try the resistors you mention as I want to fit metal foil there instead of the Takman carbon.
Brent
I'm not really in experimental mode, just tuning the sound back to what I had with the old dos. I have not changed values to alter the current (yet) as I've been getting rid of the problems with the sound I had. I may try the resistors you mention as I want to fit metal foil there instead of the Takman carbon.
Brent
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I'm using one of your boards which I got from Brent.
Do you have the schematic for this layout please? It'll make it easier for me to figure out what goes where.
Lee.
re clock
have fun alan
Best with two clocks if poss with own psus ,My clock is a cheap 16/8/4 mhz output taiwanese jobby but it works great.only 25gbp small torrdial 12v ac out job done. big cap after reg not good.
have fun alan
HI Ray,
I see what you mean with the extra Tx's needed for the valve output stages which is why I liked the idea of trying some of the professionally made (for the music industry - no less) products. They are priced very well considering they are fully built and all you need to do is apply a signel and away to go !!!
I have been looking at one in particular made by 'Studio Projects' called the VTB1. It costs €115 and is fully adjustable with Class A to B variable biasing, phase adjustment, gain adjustment and all the other functions expected of a professional grade tube pre-amplifier. Being a mono device though I would need two of these so the price then increases but the fact that it is already to go and would give an idea of what a 12AX7 valve output would be like and then maybe I could try one of my own. There are much cheaper makes available as €230 just to 'give an idea' is a bit pricey. Sorry guys, I know that it is not DIY but my thinking was to give an idea before I went out and DIY'ed.
In respect of the clock design Ray I have also discovered another couple of designs. One is a 4007 Complimentary MOS design, another uses a 74LSxxx Schmitt device and there are variations on these too. I have found out some books that I once used when I studied my Degree in Computing which is what I first studied when I left Secondary School twenty years ago and having passed the Degree I decide to look elsewhere for work and later studied Electrical Installation, after working ion the electronics industry for Pace satelite TV systems, (varied career here but all in the same sort of fields) to become an electrican no less (don't ask), so I have been re-reading some of my old textbooks to reacquaint myself with some digital techniques to hopefully put out a first rate clock. Some of what I have read regarding Bitstream techniques and PCM etc etc has been invaluable in ideas I have now regarding clocking techniques, dsign and construction.
Sorry if I am rambling here a bit and going slightly off-topic but i had previously promised to put up the circuit schematic for a clock based on the 4007CMOS and will do so along with some other designs to which I have the mathematics for.
Thanks for bearing with me and giving your time, designs to follow once I have got them all together and am confident.
Cheers
Gareth
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Hi Ben
No it is not too much.
I had the following combo there for some time:
580000uF Sprague powerlytic+470000uF NEC supercap+3600pF ERO KP1832 5% 1.2kv+2700pF NSF Styrofoam + 3u3 AVX Tantalum (This modd further improves transient response.)
For practical reasons this setup was replaced by a 10000uF BHC
When I had the 1Farad combo, after switching off the CDP, the CD spinned for more than 10 seconds at high speed.
Now, with the 10.000uF it does turn a bit but slowly and after two or three revolutions it stops
big cap after reg not good.
have fun alan
Is the idle spinning disc a known issue related to too large a value cap in C815? I have 4700uF there as per Ray's mods list, and Brent apparently has 10,000uF. What do you have there Alan? Thanks for your help.
Thanks for your reply, Ricardo. Wow, you really went to town there. My disc behaves normally when I turn the player off, but it turns slowly in stop mode. If I stop it with my finger then it will stay still, most likely due to friction, but then if I nudge it a little bit it will start turning again. It's not really causing problems, but I wondered if it might be indicative of some other problem elsewhere. Thanks all, I'll keep quiet about it now as it's not really a serious issue or of much general interest
Can't see any of those devices available from either RS or farewell in the UK!
Got all the bits to build up my dos now. I've not soldered much in yet because the 4700pF and 680pF micas will need some special attention to mount tidily!! Hopefully I'll get some bits done this weekend. ;-)
Hey Brent,
Looks like you've got the new DOS sorted now, that's good to hear! Thanks for all your hard work. Of course it had to be better in the end
I'll be doing some desoldering myself soon, to test the A970 and C2240. I have plenty of them left salvaged from 'old' HDAM sections
. In the meanwhile, feel free to experiment with it everyone, this is good stuff!Watch the pinning though, the BC550/560 are C-B-E and A970/C2240 are E-C-B.
Ray
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