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Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Tue Nov 27, 2018 6:58 pm
by nige2000
Right I've tried the direct supercaps on board reg bypass with success
This is the equivalent sound of the finished product
If we don't change anything

After listening to it I can't imagine changing much
It's clean, refined and dynamic

I don't think anyone will be disappointed with the sound

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Tue Nov 27, 2018 9:10 pm
by Derek
Good enough for me. You're puttin' the hours in this week, fair play!

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Tue Nov 27, 2018 9:23 pm
by Fran
Excellent news Nigel, it's really great that the bypass worked out.......

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Thu Nov 29, 2018 5:12 pm
by Sligolad
Got me interested in finding out about Super or Ultra capacitors today....turns out i learned a bit about Estonia as well!!
https://youtu.be/KQ2Eo6wl5r0
https://www.skeletontech.com/ultracapacitor-webstore

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Fri Nov 30, 2018 1:46 pm
by jkeny
Well done Nige - I didn't see this thread before - Fran mention something about your DAC & I guessed it was the PCM1794 but I didn't know you were doing another Group effort

Never say never again - I'm told it's like childbirth - you forget the pain of the last birth & go ahead with another one :)

What do you think of the Supercap sound - more dynamic than batteries.

Look forward to hearing one - remind me again, what was the final CCS IC that we found best?

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Fri Nov 30, 2018 3:03 pm
by nige2000
jkeny wrote: Fri Nov 30, 2018 1:46 pm Well done Nige - I didn't see this thread before - Fran mention something about your DAC & I guessed it was the PCM1794 but I didn't know you were doing another Group effort
several months ago i was looking at the rather large pile of dead 1794 chips in the shed, and regretted i never built anything permeant with that design.
Never say never again - I'm told it's like childbirth - you forget the pain of the last birth & go ahead with another one :)
yes its definitely something like that, although this is substantially smaller project

What do you think of the Supercap sound - more dynamic than batteries.
i think its likely better ive done little testing yet, only tried batt vs supercap pre regulators. in which i thought its substantially better
Look forward to hearing one - remind me again, what was the final CCS IC that we found best?
2sk208
ive got both "r" versions and "o"
so "which" needs to be tested too
might not make much difference

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Fri Nov 30, 2018 8:30 pm
by Sligolad
Finally took up the challenge of a front panel with no screw heads and added adjustable tilt just to make life difficult :-(
Posting some renderings below just for the concept and do not mind the colours since we can spray paint in any colour.
Will start some test prints to see if this will work. Ideas and feedback welcome.

Image

Image

Image

Image

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Fri Nov 30, 2018 10:48 pm
by jkeny
Nige
Are you using regulators on the DAC board or how are you keeping the voltage steady?
From what I can understand, you are not concurrently charging supercaps while playing DAC, are you?
Have you found the sound better when not concurrently charging?

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Fri Nov 30, 2018 11:22 pm
by nige2000
jkeny wrote: Fri Nov 30, 2018 10:48 pm Nige
Are you using regulators on the DAC board or how are you keeping the voltage steady?
From what I can understand, you are not concurrently charging supercaps while playing DAC, are you?
Have you found the sound better when not concurrently charging?
We're using the amp power supply system
Nothing completely set in stone though
This is the way i envisage it
Five supercaps
Set to 1.65,1.65,2.35,2.35,2.35
So we have 3.3v 8v and 10 odd volts
The dac has on board regs 10v for that
That manages power up then there's the direct supercap power that bypasses that as soon as the voltages are correct
We're going to use a comparator and relay system to manage that probably on the 8v rail
Supercaps are been charged constantly

There's an interesting difference with the bypass

Re: NOT QUITE NEVER AGAIN, THE GROUP BUY DAC BUILD

Posted: Fri Nov 30, 2018 11:51 pm
by jkeny
nige2000 wrote: Fri Nov 30, 2018 11:22 pm We're using the amp power supply system
Nothing completely set in stone though
This is the way i envisage it
Five supercaps
Set to 1.65,1.65,2.35,2.35,2.35
So we have 3.3v 8v and 10 odd volts
The dac has on board regs 10v for that
That manages power up then there's the direct supercap power that bypasses that as soon as the voltages are correct
We're going to use a comparator and relay system to manage that probably on the 8v rail
Supercaps are been charged constantly

There's an interesting difference with the bypass
Ok, so during startup period DAC board is running off it's on board voltage regs (powered by the amp PS system + supercaps they are charging)
When supercaps reach their assigned voltages then on-board voltage regs bypassed & DAC board is powered by Supercaps being kept charged by the amp PS system.

How long does it take for supercaps to come to assigned voltage when starting from 0V - I would imagine it's very quick with that amp PS charging system?

Yes, I would expect an audible difference between Supercap direct power to DAC board & supercap power through voltage regulators on DAC board