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OLD THREAD DAC End by Andrea Ciuffoli

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#1,101
*with LED bias* its more natural than the dacmagic, the depth of the soundstage is greater and it makes the dacmagic sound a bit false (mids / highs too forward).

The dacmagic is brighter, so detail is more in your face, but its all there with the dacend, and i prefer the natural quality.

For me, without the led bias i found the bass to loose. IT was too warm and cuddly and a little confused in complex bass passages.

I have had a play with a css, and am unsure so far as to whether i like it or not. It tightens the bass further, but you do loose some of that lovely valve sound (for the scientists you probably read that as 'valve distortion'). Its more clinical and detailed, but not sure if i like it or not yet. The CSS also needs a lot of heatsinking, its dropping a lot of volts!
 
#1,102
adamus said:
*with LED bias* its more natural than the dacmagic, the depth of the soundstage is greater and it makes the dacmagic sound a bit false (mids / highs too forward).

The dacmagic is brighter, so detail is more in your face, but its all there with the dacend, and i prefer the natural quality.

For me, without the led bias i found the bass to loose. IT was too warm and cuddly and a little confused in complex bass passages.

I have had a play with a css, and am unsure so far as to whether i like it or not. It tightens the bass further, but you do loose some of that lovely valve sound (for the scientists you probably read that as 'valve distortion'). Its more clinical and detailed, but not sure if i like it or not yet. The CSS also needs a lot of heatsinking, its dropping a lot of volts!
Click to expand...

Thanks for the feedback.
Appart the output stage mods, we also have to consider the Salas suggestion regarding the bypass of the 431, if anyone has the knowledge to apply it correctly.
 
#1,104
CustomHT said:
So where to now??

Are you gonna try and upgrade this dac or I/V tube stage to improve its performance?
Click to expand...

First I'm gonna cross the two DACs. New DAC with old tube stage, and old DAC with new tube stage. This way I can identify where is the major issue.

Adamus, if you can help me with your experience: my friends told me that the new DAC comparing to other two already has less bass. If I apply your mod am I going to loose more bass?

Tell me if you need to know all the parts in the circuit. Sometime oscon are responsible of bass.

Do you use the passive filter before I/V?
 
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#1,106
apelizzo said:
First I'm gonna cross the two DACs. New DAC with old tube stage, and old DAC with new tube stage. This way I can identify where is the major issue.

Adamus, if you can help me with your experience: my friends told me that the new DAC comparing to other two already has less bass. If I apply your mod am I going to loose more bass?

Tell me if you need to know all the parts in the circuit. Sometime oscon are responsible of bass.

Do you use the passive filter before I/V?
Click to expand...

Passive filter installed (bourns 120uf)

you wont loose bass, it will be more controlled and the low mids will be better resolved, i found it 'wooly' messy if you like pre mod.

Everything is was slightly better resolved for me. i find a lto of people describe wooly bass + low mid as warmth, so you will loose a little 'warmth'.
 
#1,107
Low distortion tube stage

Tube stage with 5670 or russian 6N23P designed and used in my old DAC considered having better sound. Gain to be adjusted.
Also added shunt tube regulator on +/-85V
 

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#1,111
What about the digital bypass mod done by mister lampizator?

ad1865

"The digital input RCA is installed with a complete bypass of digital input transformer as well as the input buffer chip. I went directly by silver wire - from RCA hot to CS pin 9 (Rxp) , and from cold RCA to CS8414 pin 10 (Rxn)"

"The digital bypass. It is so audible - I can tell you - it is a real thick blanket being removed."
 
#1,112
torsken said:
What about the digital bypass mod done by mister lampizator?

ad1865

"The digital input RCA is installed with a complete bypass of digital input transformer as well as the input buffer chip. I went directly by silver wire - from RCA hot to CS pin 9 (Rxp) , and from cold RCA to CS8414 pin 10 (Rxn)"

"The digital bypass. It is so audible - I can tell you - it is a real thick blanket being removed."
Click to expand...

I think there are some great experiments to be performed.

I am away from my house and projects for about 3 weeks.

My plan is to remove the fiter from DAC board and put it on a separate perf board so that I can easily try other IV set-ups.

These will include Oliver's board
http://www.diyaudio.com/forums/group-buys/156149-tube-i-zator-professional-pcb.html
This is the Lampizator's set-up in which I will try the 6N2p

I will also try raindrop hui's (AD1865 ref above) tube output (miniature Raytheons)

I also have Welborne's Borbely hybrid which is set-up as a differential output. Depending what I hear with the original board and the two others I may mod it for the AD1865. It uses the 6G8M at 24V. I have also used the 6H6P at 24V in the same board but set up as line stage. Quite interesting.

I will be about 3 weeks behind all of you but will report when I am back to my home.

Thanks to all for their comments.

Best

Bob
 
#1,113
I desperately need a CS8414 on DIP. I bought one from ebay, being told it was soldered, which it wasn't to the converter board.
I attempted to solder it myself, but wrecked the tracks as i have no patience.
Can anyone recommend me a place, or even solder another up for me?

Thanks
 
#1,114
agithegreat said:
I desperately need a CS8414 on DIP. I bought one from ebay, being told it was soldered, which it wasn't to the converter board.
I attempted to solder it myself, but wrecked the tracks as i have no patience.
Can anyone recommend me a place, or even solder another up for me?

Thanks
Click to expand...

Yes it's hard to solder. I've got this one from ebay and asked to solder and test for me. They done it, mounted and works.

CS8414 CS8414CS to DIP28 (PCB adapter- SOIC28) - eBay Other, Electronic Components, Electrical Test Equipment, Business Industrial. (end time 13-Apr-10 03:54:58 AEST)

Ask to solder and test it for you.
 
#1,118
apelizzo said:
Yes it's hard to solder. I've got this one from ebay and asked to solder and test for me. They done it, mounted and works.

CS8414 CS8414CS to DIP28 (PCB adapter- SOIC28) - eBay Other, Electronic Components, Electrical Test Equipment, Business Industrial. (end time 13-Apr-10 03:54:58 AEST)

Ask to solder and test it for you.
Click to expand...

I proberly should have asked them to solder mine for me aswell being my first diy project and all, I just did it myself tho, seemed to turn out alright, guess wont know till dac is finished and its time to test it..
 
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