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DAC ES9038 PRO Group Buys

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analog_sa

analog_sa

Member
Joined 2002
akltam said:
The bottom one is 'current mode'. Instead of a 10K resistor, the coil is connected directly to the ground instead. Each coil (of the LL1684) has a resistance of 41 ohm. Thus the output of the DAC will force current through the coil to the ground. Thus the coil is also acting like a resistor and performs an I-V.
Click to expand...


No. The resistance is immaterial for the I/V as it is a DC parameter.

The only consequence of the low resistance value is that the dc level at the dac output is now close to zero volts. There is no i/v conversion as the secondary of the transformer is unloaded.

So, what kind of load does the dac see at audio frequencies then? Not sure about this particular transformer but i have measured a similar Lundahl and the inductance of each primary was around 40-50H. Something like 500k @2kHz?

Again, nothing wrong with the circuit, just don't kid yourself it is somehow resembling current mode as it is not.
 
Last edited:
S

szczemirek

Member
Joined 2012
Hello Quanghao,
Sorry but because of lack answer on my private emails I must ask you on forum:
Could you inform me about progress with my orders?

23/03/17
Me:"Please confirm my payment for DAC controller and chassis. I'm confused.
Regards"
Quanghao:Yes, next week I will ship to you.
Thanks!"
 
T

Tuanqv58

Member
Joined 2017
Hi Quanghao, how would the schematic look like for balanced output? Thank you!
Tuanqv58.

Quote:
Originally Posted by quanghao View Post
Ok, now. New IV
I have tried to test a lot of IV for ES9038.

And finally I'm very happy with this design, that's my choice,
Combination LL1684 and electronic lights.

Yes, I specifically use Duelund output capacitors!

OHA ! Yes ! And great sound effects!
Thank you Mr. Duelund!
quanghao
 
D

dariedel2

Member
Joined 2013
quanghao said:
Ok, now. New IV
I have tried to test a lot of IV for ES9038.

And finally I'm very happy with this design, that's my choice,
Combination LL1684 and electronic lights.
You please take a look at it and test!

thanks
quanghao
Click to expand...

Andrea/Quanghao,
I'm definitely interested in the "T-Super I/V" as you described here. I want to wait to see how circuit will be set up for balanced output (no need to switch between balanced and unbalanced). Parts connextion has nice sale on film capacitors, and I want to order some parts. Will the output capacitors remain approximately 1.0 uF? Is there any reason to go any higher such as 2.2uF as you did with your Duelands or was that just because you had them?

Do you have any PCBs for your high voltage and heater power supply as pictured?

Thanks,
Doug
 
D

dariedel2

Member
Joined 2013
quanghao said:
Ok, now. New IV
I have tried to test a lot of IV for ES9038.

And finally I'm very happy with this design, that's my choice,
Combination LL1684 and electronic lights.
You please take a look at it and test!

thanks
quanghao
Click to expand...

Andrea/Quanghao,
I'm definitely interested in the "T-Super I/V" as you described here. I want to wait to see how circuit will be set up for balanced output (no need to switch between balanced and unbalanced). Parts connextion has nice sale on film capacitors, and I want to order some parts. Will the output capacitors remain approximately 1.0 uF? Is there any reason to go any higher such as 2.2uF as you did with your Duelands or was that just because you had them?

Do you have any PCBs for your high voltage and heater power supply as pictured?

Thanks,
Doug
 
T

Tuanqv58

Member
Joined 2017
Tuanqv58 said:
Hi Quanghao, how would the schematic look like for balanced output? Thank you!
Tuanqv58.

Quote:
Originally Posted by quanghao View Post
Ok, now. New IV
I have tried to test a lot of IV for ES9038.

And finally I'm very happy with this design, that's my choice,
Combination LL1684 and electronic lights.

Yes, I specifically use Duelund output capacitors!

OHA ! Yes ! And great sound effects!
Thank you Mr. Duelund!
quanghao
Click to expand...

Hi QH,
I hope that enjoy and great sound pefect. I wait feedback from you .
Brd,
Tuanqv58 .
 
S

szczemirek

Member
Joined 2012
"Quanghao,
Please confirm my payment for DAC controller and chassis.
I'm confused.
Regards
xxxxxxxxxxxx
Yes, next week I will ship to you.
Thanks!
xxxxxxxxxxxx
Any information?
Regards
xxxxxxxxxxxx
Hi,
Im sorry, I sent them to you on this week.
Thanks!"

...and still waiting from March! We paid 70USD just for delivery!
Please give me ANY information about delivery:
- DAC controller- Encorder + 4x20 LCD,
- Chassie.
 
Last edited:
quanghao

quanghao

Member
Joined 2009
quanghao.com/
Hello friends!

I know you are anxious!

We are taking the time to test the iv for 9038pro, we work very hard 12 hours a day.

So I did not go online. Looking forward to sympathy for me.

I have tested 10 different designs, however, we find the design below suitable and have the best sound.

It has a balanced output - directly from LL1684, but the amplifier is small, about once.

The output is not needed by using a large amplifier tube ~ about 3 VRMS

Please wait and pay for the DAC kit, and have fun waiting for the best results, please see the circuit diagram. The circuit diagram has a few points I did not publish.

thanks a lot!
 

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