• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

DAC-END R (ES9018) full assembled board

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Power supply little oscillation on 1.2 analog

Here the plot of the 1.2V analog after adding a 47uF OS-CON in parallel to the 47uF smd (total about 100uF).

Changing the cables on my table I have reduced also the 50Hz coming from the air.
 

Attachments

  • Noise_1_2Vana_100uF.gif
    Noise_1_2Vana_100uF.gif
    26.1 KB · Views: 338
Last edited:
Twisted pear had similar problems and bigger caps on output helped.
That's better :)

If you add a 100uF 6.3V in parallel to the 47uF smd this oscillation stop and the new measurement give -78dB.
OK, I'll add a 47-100uF cap in parallel for the two 1.2volt analog shunts.

Changing the cables on my table I have reduced also the 50Hz coming from the air.
Yep, I think that the Amanero/ES9018 is very sensitive to RFI/EMI.
The following are on my ToDo list:
1. Put the DAC in a case
2. twist all the ac wiring, keep it short and far away from the DAC
3. Add some shielding to the Amanero and the ES9018
 
Last edited:
What is the max value of filter cond. to put in parallel with 47uF / 6V

Can I put bigger then 100uF ? Safe for SHUNT ?

I have some 1500uF/10V with vary low ESR measured. Is this too much ?

In theory the capacitor on shunt output terminal should be little to get a fast transient response on load variations.

In practice a shunt with low output capacity on output could be unstable and on my experience sounds bad.

In theorry there is no limit on the value of output capacitor because the CCS of the shunt prevents that pass high current peaks during the charging of the capacitor.

I think 47uF or 330uF are good values.
 
I am using OPA 1612 :)

The quiescent Current (bias) of 2 x OPA1612 op-amp should be about 20mA so it is strange this high temperature on shunt.

If you are using the original transformer you should have 21V on 2200UF capacitor and 14-15V after shunt.

You can reduce the current on shunt chaging R4 and R5 from 10 ohm to 15 ohm or adding a resistor of 33ohm 1W in series to the transformer secondary.

I suggest you to eliminate also R9 and R10 in the shunt.

I suggest to desolder a component smd put the soldering iron on the contact side with the larger pcb wire and after few seconds with a screwdriver moved by the component.
 
The quiescent Current (bias) of 2 x OPA1612 op-amp should be about 20mA so it is strange this high temperature on shunt.

If you are using the original transformer you should have 21V on 2200UF capacitor and 14-15V after shunt.

You can reduce the current on shunt chaging R4 and R5 from 10 ohm to 15 ohm or adding a resistor of 33ohm 1W in series to the transformer secondary.

I suggest you to eliminate also R9 and R10 in the shunt.

I suggest to desolder a component smd put the soldering iron on the contact side with the larger pcb wire and after few seconds with a screwdriver moved by the component.

It is not my shunt. It is what I am told by another member. My dac is not finished. I am waiting for the green light ! :) Anyway I have changed 50 components allready because I do not like minimelf and ceramic caps. Everything with magnetic leads must go. 33 ohm in series with transformer. I like that. I use that trick a lot.
 
Last edited:
ATTENTION: corrections on op-amp module and DAC module

1) It is necessary reduce the current on shunt changing R4 and R5 from 10 ohm to 15 ohm because now the temperature of the second smd transistor is very high. Quanghao can send you the 4 x 15ohm smd resistors to make this simple correction.

2) Eliminate also R9 and R10 in the +15V and -15V shunt.

3) Add a 47uF or 100uF capacitor in parallel to the original 47uF on the 1.2V analog (L & R) near the jump to eliminate the little oscillation.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.