After about three years I decided to recase my DAO. As it was the Beta build I had used a generic case that left
a little to be desired compared to some of my other builds....
I only retained the heatsinks of the original case since they were about ideal for the layout and were already drilled
and tapped. The new case is a little bit wider but mostly just for the good proportions
The custom front plate
was modelled in CAD and cnc cut by Protolabs ($$) All the other case parts were done at a local company (Schaeffer).
Of course I retained the layout but tried myself in better and more proper wiring, and added one of P's SHPP boards
for headphone protection. I also used the LEMO connector at the front that is ever so precise.
Now only the top cover has to be added (the jury is out whether it will be acrylic as CeeVee's case or aluminum, with a
corresponding opening above the blue heat spreader)...
And btw... she's sounding as glorious as ever.
a little to be desired compared to some of my other builds....
I only retained the heatsinks of the original case since they were about ideal for the layout and were already drilled
and tapped. The new case is a little bit wider but mostly just for the good proportions
The custom front plate was modelled in CAD and cnc cut by Protolabs ($$
) All the other case parts were done at a local company (Schaeffer).Of course I retained the layout but tried myself in better and more proper wiring, and added one of P's SHPP boards
for headphone protection. I also used the LEMO connector at the front that is ever so precise.
Now only the top cover has to be added (the jury is out whether it will be acrylic as CeeVee's case or aluminum, with a
corresponding opening above the blue heat spreader)...
And btw... she's sounding as glorious as ever.
Attachments
I am late to the party. Too late?
I am looking for a new headphone amp for my low-impedance headphones (16 Ohm). I want balanced inputs. The crossfeed option would be nice to have, but is not mandatory (I mostly use a digital crossfeed filter before the DAC).
I started reading this thread. It's too long to read everything, but from looking at EUVLs PDF docs (parts 1-4) I believe the DAO would fit my needs quite nicely.
Sooo... Is the DAO available in any form? PCBs, full kit, enclosure, etc.? Is it still possible to find the "difficult" parts? I might even consider a fully built unit.
I am looking for a new headphone amp for my low-impedance headphones (16 Ohm). I want balanced inputs. The crossfeed option would be nice to have, but is not mandatory (I mostly use a digital crossfeed filter before the DAC).
I started reading this thread. It's too long to read everything, but from looking at EUVLs PDF docs (parts 1-4) I believe the DAO would fit my needs quite nicely.
Sooo... Is the DAO available in any form? PCBs, full kit, enclosure, etc.? Is it still possible to find the "difficult" parts? I might even consider a fully built unit.
I am confused... The above link does not take me to the schematic of the DAO SE. Can someone provide the schematic or a correct link to it?
Well, that's what I did, but I am too stupid.
I guess the circuit is somewhere in the PDFs:
Part 1 is background.
Part 2a is about the basics of the circuit.
Part 2b adds the Taylor current source. The circuit on page 3 of this PDF looks a bit like a rather detailed schematic, but the caption says "Simplified Schematics, Q1, Q2 to be replaced by the JFET triode cell", so I guess this might not be what I am looking for. Oh, the circuit is also missing a GND, but I guess this is implicitly hiding as the center tap between +Vs and -Vs.
Part 3 is about the crossfeed and voltage gain stages.
Parts 4 and 5 are about construction and some tweaks for difficult loads.
Sooo, which is the circuit schematic?
> The circuit on page 3 of this PDF looks a bit like a rather detailed schematic
This is the one to use in the public domain.
> the circuit is also missing a GND
A buffer will follow the input, also in DC.
See examples.
Patrick
.
This is the one to use in the public domain.
> the circuit is also missing a GND
A buffer will follow the input, also in DC.
See examples.
Patrick
.
Attachments
Ha!
Must also thank you for alerting me (elsewhere on the forum) on the 3324 / 1312 combo and other Toshiba goodstuff that has been discontinued in through hole.
Seems prudent to go for the multiplier instead of trying my luck on the multiplicity of TL431 variants within the onSemi range alone.
cheers
cv
Must also thank you for alerting me (elsewhere on the forum) on the 3324 / 1312 combo and other Toshiba goodstuff that has been discontinued in through hole.
Seems prudent to go for the multiplier instead of trying my luck on the multiplicity of TL431 variants within the onSemi range alone.
cheers
cv
Hi all,
Just wondering if any one had compared the HAGS to the 4 Mosfet UTHAiM front end when it comes to driving DAO SE?
My spice sims suggest that one can tweak the overall amp distortion spectrum with the latter to yield a touch of 2nd and everything else negligible.
They both strike me as exceptionally elegant topologies but the UTHAiM is far less needy when it comes to the Toshiba stash.
On that basis, easier to try the UTHAiM first I suppose!
Cheers
cv
Just wondering if any one had compared the HAGS to the 4 Mosfet UTHAiM front end when it comes to driving DAO SE?
My spice sims suggest that one can tweak the overall amp distortion spectrum with the latter to yield a touch of 2nd and everything else negligible.
They both strike me as exceptionally elegant topologies but the UTHAiM is far less needy when it comes to the Toshiba stash.
On that basis, easier to try the UTHAiM first I suppose!
Cheers
cv
One is a conveyor, the other uses mirrors.
And you can check out Pavel's webpages on the distortion of JFETs, especially the 4 JFET version.
Distortion in JFET input stage circuits
Patrick
And you can check out Pavel's webpages on the distortion of JFETs, especially the 4 JFET version.
Distortion in JFET input stage circuits
Patrick
Uthaim front end
So I lashed up a k170/j74 BL front end with ZVx3306 mirrors. 3k6 iv and 500R degeneration
What a delightful little circuit!
4v rms out I got -86db / -102db 2nd and 3rd harmonic respectively
2v rms was -92 / -112
Astonishingly, this was with no attention to matching. I did notice a steady decrease in distortion as the rail voltages were increased and the above were at +/- 30V. Spice says it shouldn't matter and I imagine the discrepancy is due to using unmatched mosfets. Would be good to keep jfet voltage down for noise.
I was going to try the hags / blowtorch topology next but I'm going to build this one out properly and see how far performance can be pushed by matching,twiddling the key resistors and poss degenerating the p channel.
Patrick - how does hags compare?
Anyway I will investigate further and publish findings (in the right thread too) ,might make a great gain stage for MoFo fans.
Thanks again Patrick for sharing your work on conveyors. Hard to imagine a more elegant, parsimonious topology.
So I lashed up a k170/j74 BL front end with ZVx3306 mirrors. 3k6 iv and 500R degeneration
What a delightful little circuit!
4v rms out I got -86db / -102db 2nd and 3rd harmonic respectively
2v rms was -92 / -112
Astonishingly, this was with no attention to matching. I did notice a steady decrease in distortion as the rail voltages were increased and the above were at +/- 30V. Spice says it shouldn't matter and I imagine the discrepancy is due to using unmatched mosfets. Would be good to keep jfet voltage down for noise.
I was going to try the hags / blowtorch topology next but I'm going to build this one out properly and see how far performance can be pushed by matching,twiddling the key resistors and poss degenerating the p channel.
Patrick - how does hags compare?
Anyway I will investigate further and publish findings (in the right thread too) ,might make a great gain stage for MoFo fans.
Thanks again Patrick for sharing your work on conveyors. Hard to imagine a more elegant, parsimonious topology.