I've not been 100% happy with the new dos sound. It still has less 'air' and hardness to the sound that I never had before.
Today I have swapped the BC550 (T5) for the current drive on the fets to a 2sc2240 as used on the older dos. The sound is now so much more composed, more linear, more composed and more 'air'.
I recommend people try this.
I am going to try a set of 2sa970 or 2sa1085 instead of the BC560 on the CFP
Brent
Today I have swapped the BC550 (T5) for the current drive on the fets to a 2sc2240 as used on the older dos. The sound is now so much more composed, more linear, more composed and more 'air'.
I recommend people try this.
I am going to try a set of 2sa970 or 2sa1085 instead of the BC560 on the CFP
Brent
I was at Brents place to witness this last change.
I have to say that the improvement is dramatic. There is much more clarity, smoothness and detail. The edge that was present in drums, cymbals, pianos etc is now massively better.
Pretty startling to be honest.
Lee
I have to say that the improvement is dramatic. There is much more clarity, smoothness and detail. The edge that was present in drums, cymbals, pianos etc is now massively better.
Pretty startling to be honest.
Lee
Nothing wrong with the new board as it's the same basic cct and you can mess around with it. Going to try the 2SA1085 in a while
Brent
Brent
Some have said that transistors can make the single biggest difference in terms of component selection.
I fully agree in this instance.
Fitted the 2SA1085 in place of the BC560 and it is now making music again!
Brent
Fitted the 2SA1085 in place of the BC560 and it is now making music again!
Brent
This is now my current configuration. The 2SA1085 and 2SC2240 have really improved the sound.
Brent
An externally hosted image should be here but it was not working when we last tested it.
Brent
hiya brent
being a bit of a noob is this mods to the cfp dos are the parts available at say rs ?
cheers alan
The old boards are 6 euros each at the mo cfps 12euros, Never gone discrete much improvement over lm4562s.
alan
alan
As long as you use good parts then yes it is better by quite a long way.
I have been tempted for quite some time to try a opamp based output pcb with filter from Dos and a single channel LME49710HA just to see what it sounds like. I suspect it will sound very good, better than a well fettled dos i'm not sure
Brent
I have been tempted for quite some time to try a opamp based output pcb with filter from Dos and a single channel LME49710HA just to see what it sounds like. I suspect it will sound very good, better than a well fettled dos i'm not sure
Brent
Swapped the Tacman carbon resistors on dos filter back to the Welwyn RC55Y 0.1% metal film from old pcb to see what difference there is between the two.
The accuracy and snap on snare drums is back to what I had before, they offer more ambiance to the upper mids and treble too. Strangely though the bass has become deeper as this was not expected. I am going to leave the metal films in.
Brent
The accuracy and snap on snare drums is back to what I had before, they offer more ambiance to the upper mids and treble too. Strangely though the bass has become deeper as this was not expected. I am going to leave the metal films in.
Brent
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Err do you mean did I use Takman carbons before swapping back to Welwyn metal films? If so the yes I did 
Brent
Brent
That cdp sounds annoyingly good again now, lol. Those component changes today have brought all the musicality and smoothness back.
The level of detail and reality it conjures up is really quite staggering. Really sinks home how far I still have to go with my own player.
Lee.
The level of detail and reality it conjures up is really quite staggering. Really sinks home how far I still have to go with my own player.
Lee.
With these tweaks I am leaning towards saying the Dos is now better than my old one! I of course have to run it at home for the proper test but i'm sure the CFP has made improvements to overall transparency and drive.
Brent
Brent
I could never figure this out for myself. I hope you don't mind me copying your parts list when you're done, Brent?
I put 2 regs on my servo control IC last night, separating analogue and digital lines. I listened at low volume for a couple of hours and never heard it skip, so fingers crossed. I also put one on the CPU. The improvement has been pretty staggering. I plan to do the driver ICs next.
Am I missing any good places for 5v regs? I built 2 more that I am not using. I have 4 on DAC, 3 on decoder, 2 on servo, 1 on CPU.
I put 2 regs on my servo control IC last night, separating analogue and digital lines. I listened at low volume for a couple of hours and never heard it skip, so fingers crossed. I also put one on the CPU. The improvement has been pretty staggering. I plan to do the driver ICs next.
Am I missing any good places for 5v regs? I built 2 more that I am not using. I have 4 on DAC, 3 on decoder, 2 on servo, 1 on CPU.
I'd put one on the hf amp and one on the transport ;-)
Looking forward to getting last bits to finish the dos. Hopefully they'll arrive tomorrow ;-)
Alan, one thing you will need with the dos is decent output caps. ;-)
Looking forward to getting last bits to finish the dos. Hopefully they'll arrive tomorrow ;-)
Alan, one thing you will need with the dos is decent output caps. ;-)
2SC2240 could be replaced with 2SC1841 or 2SC1845 and 2SA970 could be replaced with 2SA992. They are more modern devices and have a very low Cob.