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-   -   First run DAC End support (http://www.diyaudio.com/forums/quanghao-audio-design/169318-first-run-dac-end-support.html)

tassosk 25th June 2010 07:26 PM

First run DAC End support
 
5 Attachment(s)
I have just completed DAC End assembly. I’ve used LT1085 for the filament regulator, R8,R9 2.2R R11 560R. The supply I/V is 0- 250V and 0-9 V 3A. I was able to adjust for 6.3V and measured 268-274V for HV. I have also applied the LED mod. I did not apply yet SPDIF trafo and I use as SBDIF interface M2TECH HIFACE USB. Tubes are GE 7044. The sound is as described by adamus, sweet yet very detailed although it is not much forgiving for bad recordings.
However I experience an initial relay chattering for two or three seconds before it stabilizes and then the DAC runs with no problems. Also I can hear low frequency hum that becomes noticeable when the music is paused starting from pot position 11 o’clock on my MF X-CANv8 HeadAmp. I have no scope, only a multimeter.
Any hints for the relay chattering and mostly for the hum?

quanghao 26th June 2010 02:37 AM

Nice !
congratulations! noise can be filtered out by HV yet.

quanghao 26th June 2010 03:59 AM

3 Attachment(s)
some image my Firend is making DAC-end, and up dat

tassosk 26th June 2010 07:07 PM

Update
 
I’ve changed R8, R9 to 1.2R and no more relay chattering. Also while inspecting the I/V I found excess of solder on HV power connection that was very near the ground, removed it and no more hum. Now is dead quiet. This is a really great DAC.
Thanks Quanghao, Andrea and Sallas.

Jeffrey Davison 26th June 2010 09:57 PM

It is very good to see you back here in the forums.

For a little time it seemed that the DAC END thread was dead and gone. It was very suddenly cut off.

Jeff Davison

quanghao 27th June 2010 09:04 AM

Quote:

Originally Posted by Jeffrey Davison (Post 2228024)
It is very good to see you back here in the forums.

For a little time it seemed that the DAC END thread was dead and gone. It was very suddenly cut off.

Jeff Davison

Thank Jeff Davison!
Well I can work, Sorry you had to wait long
Please Update the list yourselves when you type here:
Hi quanghao, I've paid for my set through paypal. Thanks.

1. pathetic (1 set - PAID)
2. cchean ( 2 sets )
3. Lucylu (1 set)
4. Ulyses31 (1 set)
5. damohpi (1 set dac end 2 pcb)
6. mikvous (4 sets)
7. gipione ( 1 set)
8. flocchini (1 6h6P if done, 1 Salas HV)
9. belkoff (full set dac end 2 + 1 6h6P if done, 1 Salas HV) + schematic for each PCB
10. klaju1955 (1 set)
11. ben-jam-in (1 set)
12. morpheous
13. hotzman (2 x full set new dac end 2 pcb)
14. le´flu (one complete set of new DAC-pcb)
15. klie (1 set)
16. Yomanze (1 DAC PCB only)
17. Ferrari (1 full set + 1 extra I/V stage PCB)
18. Sugden (1 set)
19. rolotube (1 set - PAID)

le´flu 27th June 2010 09:08 AM

1. pathetic (1 set - PAID)
2. cchean ( 2 sets )
3. Lucylu (1 set)
4. Ulyses31 (1 set)
5. damohpi (1 set dac end 2 pcb)
6. mikvous (4 sets)
7. gipione ( 1 set)
8. flocchini (1 6h6P if done, 1 Salas HV)
9. belkoff (full set dac end 2 + 1 6h6P if done, 1 Salas HV) + schematic for each PCB
10. klaju1955 (1 set)
11. ben-jam-in (1 set)
12. morpheous
13. hotzman (2 x full set new dac end 2 pcb)
14. le´flu (one complete set of new DAC-pcb - PAID)
15. klie (1 set)
16. Yomanze (1 DAC PCB only)
17. Ferrari (1 full set + 1 extra I/V stage PCB)
18. Sugden (1 set)
19. rolotube (1 set - PAID)

Ferrari 27th June 2010 10:01 PM

1. pathetic (1 set - PAID)
2. cchean ( 2 sets )
3. Lucylu (1 set)
4. Ulyses31 (1 set)
5. damohpi (1 set dac end 2 pcb)
6. mikvous (4 sets)
7. gipione ( 1 set)
8. flocchini (1 6h6P if done, 1 Salas HV)
9. belkoff (full set dac end 2 + 1 6h6P if done, 1 Salas HV) + schematic for each PCB
10. klaju1955 (1 set)
11. ben-jam-in (1 set)
12. morpheous
13. hotzman (2 x full set new dac end 2 pcb)
14. le´flu (one complete set of new DAC-pcb - PAID)
15. klie (1 set)
16. Yomanze (1 DAC PCB only)
17. Ferrari (1 full set + 1 extra I/V stage PCB - PAID)
18. Sugden (1 set)
19. rolotube (1 set - PAID)

quanghao 28th June 2010 02:57 AM

3 Attachment(s)
and some image my friend make DAC-END updat

quanghao 28th June 2010 10:52 AM

pcb up dat is ok
 
2 Attachment(s)
PCB DAC-End (DAC+Salas shunt for DAC)

Material: FR4 – 1.6mm
Layers: 2
Board size: 118 x 230 mm
Surface finish: Immersion Gold
Soldermask: Both sides – RED
Silkscreen: Legend on top


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