AD1865 the best DAC

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ad 1865 the best dac

I don t see anything revolutionary in rubydac s design, he simply switched audio note version of sulzer with jung regulators, tube output with tube rectification. Identical approach to a glue logic, as old romans used to say: nihil nove sub sole.
I tried lundahl 1636 passive, fets, but sole tungsol 5687 kick *** to all of them. :dead:
 
At first to explain my dac, I used dsavit s boards ad1865/5687 with ccs, but I used power supplies like audio note does it for digital board, and I used 220R audio note tantalum resistor on I/V conversion. Putting LL1636 on the output looked nice with some bass restriction, and lack of punchy - solid state kick. Sound with lundahl is very neutral across the whole audio spectrum but I feel that I miss some "action". Experiments with scope would probably solve problem of matching impedances which is crucial for the best ad output. Putting 5687 on the output of the dac changed sound and made it crispy, punchy with lot of detail, witihout any trace of treble harshness. Whole dac is in the inox case, with big power supply and 10H choke, clrcrcrcr...
(nothing new under the sun..:)))
I presume that would be interesting to see the values of audio note dac 5 interstage transformer (I think around 680R in primary), which replaces I/V resistor.
 
audiodesign said:
I have tested today a pair of LL7903 to increase the output level but the result was a bad sound.

The AD1865 since to be perfect with a caddock 200-250 ohm resistor and nothing else

I will try soon a ECC82/12AU7 stage after this passive I/V conv


did you terminate the secondary ?
if not, there will be ringing and it will sound ugly...
play a cd wth a square wave and watch it with a scope.
adjust with a 50kohm pot across sec. until ringing disappears.
 
robot said:
Sound with lundahl is very neutral across the whole audio spectrum but I feel that I miss some "action". Experiments with scope would probably solve problem of matching impedances which is crucial for the best ad output. Putting 5687 on the output of the dac changed sound and made it crispy, punchy with lot of detail, witihout any trace of treble harshness.

personally I am afraid tube output stages will always add some kind of coloration to the sound (?)
 
Any active component adds something to sound, that s obvious, but if I have to choose I prefer chain which consists of a few parts than a bunch of transistors, opamps and other stuff.... I wrote on other place rather poetically, that a dac with solid state output is electronic component, and with tube output is a musical instrument.
:angel:
For example, I m using for sound comparing, and testings my friend s rather old combination of meridian 200/203 which uses very good SAA r2r dac, but it has infamous ne5534 opamps behind famous meridian digital stuff, and I think with a decent tube output would make this oldboy a killer dac.
Anyway I think that combination with a transformer on I/V than tube is very promissing in this case.
Considering best transformer, aren t Lundahls now in Jeff Rowland s gear?
 
My test untin now are test:

1) only a 320ohm Caddock MK132 resistor connected to DACT 10k and to the amplifier

2) a 320ohm Caddock MK132 connected to LL7903 1:4 and to the DACT 50k and after to the amplifer

3) no resistor, connected to LL7903 1:8 and to the DACT 50k and after to the amplifer

case 1 play very good
case 2 play bad
case 3 play better but I not sure better than case 1

case 3 = audionote choice
 
There was a discussion a few years ago about this conception of I/V conversion on this forum, witihout any useful conclusion. Its obvious that audio note uses some transformer with silver wire behind dac very expensive indeed, but unknown specifications, so copying this witihout usage of their transformer is not effective, and probbably wasting time and money.
We all know about thorsten s try to copy an dac 4 signature, his adagio . It s obvious that he used I/V resistor, and some filtering before cf e182cc. Not an easy task I belive. I think the main difference between using transformer and tube output is lack of bass in first case, so combining those two approaches probably solves that problem.
 
Ad1865

My test untin now are test:

1) only a 320ohm Caddock MK132 resistor connected to DACT 10k and to the amplifier

2) a 320ohm Caddock MK132 connected to LL7903 1:4 and to the DACT 50k and after to the amplifer

3) no resistor, connected to LL7903 1:8 and to the DACT 50k and after to the amplifer

case 1 play very good
case 2 play bad
case 3 play better but I not sure better than case 1

case 3 = audionote choice

Hi Audiodesign !
I design you cricuit DAC to layout,
The soud is very good, i like it, But I want output by tube not use tranformer. You can show for me exaple what tube can use for thi DAC!
Thank you very much
You can se my layout
 
Im layout this DAC!
You can see here:
 

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