[Ivan TT]

I think mine are the same only silmic ii.

Crap.

My mod is ruined before it began, I was supposed to get Hi-Fi Audio SILMIC II, not a plain vanilla SILMICs

... and the op-amps I've ordered are most likely fake anyway, unless they have been salvaged from a written-off fax from mid-80's

Regardless, could anyone in the know put together some easy to follow mods instructions, it would be awesome and higly appreciated!

 

[Holypal]

Is there a simple way to measure the output impedance, with a multi-meter?

 

[knudsen]

Crap.

My mod is ruined before it began, I was supposed to get Hi-Fi Audio SILMIC II, not a plain vanilla SILMICs

... and the op-amps I've ordered are most likely fake anyway, unless they have been salvaged from a written-off fax from mid-80's

Regardless, could anyone in the know put together some easy to follow mods instructions, it would be awesome and higly appreciated!

I think some prefer silmic i to ii, so I think not to worry

 

[knudsen]

Got another z1 today, and have been comparing for an hour. Must say that with the combined effect of better caps + better opamp z1 is on another level.

To my ears the effect of other caps is on a similar level to a change of opamp.

Was a bit surprised that opa2604 besides more powerful bass has clearer mids than the stock 5532P (with caps being equal).

If you're already messing with the opamp I really recommend changing the 4 caps too.

 

[silverfishla]

Got another z1 today, and have been comparing for an hour. Must say that with the combined effect of better caps + better opamp z1 is on another level.

To my ears the effect of other caps is on a similar level to a change of opamp.

Was a bit surprised that opa2604 besides more powerful bass has clearer mids than the stock 5532P (with caps being equal).

If you're already messing with the opamp I really recommend changing the 4 caps too.

So you used Silmic II to replace all your caps in Z1? Same values? Were they the same physical size as the ones that were in there?

 

[groucho69]

What I'm hoping is that one day maybe you guys agree more or less on some optimal mod/mods, as currently it is a little experimenting and in different directions

That is not the engineering mind. Nothing is perfect, nothing is complete. Design is only released by external forces. Leave a designer alone with no deadlines, no requirements, no budget...it will never be completed.

 

[knudsen]

So you used Silmic II to replace all your caps in Z1? Same values? Were they the same physical size as the ones that were in there?

Still using the ones mentioned here, but I am not saying they are the definitive solution But I like them. They are more or less the same size, no problem fitting

 

[macky112]

In my Walnut V2, I reduced the output resistance. This really improves bass control even with 150 ohms headphones and increases the volume.
If you just put the jumper instead of the resistors were distortion. With 10 Ohm, everything is fine, but you also need to increase the capacitance of the output capacitors to 470 μF. It is also desirable to use an operational amplifier with a high output current. I use the LM6172 with 50mA and it works well with 32 Ohm headphones.
Then I found a way to remove the resistors and to avoid distortion I applied snubber (serial connection opamp output - resistor - capacitor - GND). I selected the components of the snubber by ear and the best result was obtained with 5 Ohm resistors and 0.22 μF film capacitors. The 32 Ohm headphones began to sound even better compared to the 10 ohm output.

For my V2 I think I am capable to attempt the 10ohm resister swap, the snubber part I am confused

Can you confirm if I use 10ohm resistor and 470uF output caps, there is no distortion? Thanks!

Ps I wonder if I can do the same to a Z1

 

[heraleks]

Btw, do you have an idea what kind of sound all 4 mods described by sanmiguel will result in (like removing all input and output capacitors)? A more sterile sound?

I think when switching to bipolar power and removing electrolytic capacitors, the sound will become less colored and more like a sound from a line output.

 

[DBaldock9]

In my Walnut V2, I reduced the output resistance. This really improves bass control even with 150 ohms headphones and increases the volume.
If you just put the jumper instead of the resistors were distortion. With 10 Ohm, everything is fine, but you also need to increase the capacitance of the output capacitors to 470 μF. It is also desirable to use an operational amplifier with a high output current. I use the LM6172 with 50mA and it works well with 32 Ohm headphones.
Then I found a way to remove the resistors and to avoid distortion I applied snubber (serial connection opamp output - resistor - capacitor - GND). I selected the components of the snubber by ear and the best result was obtained with 5 Ohm resistors and 0.22 μF film capacitors. The 32 Ohm headphones began to sound even better compared to the 10 ohm output.

Have you tried the OP275GPZ? It has 90mA /channel output capability (listed on the DigiKey site), and costs only $3.23 (on Mouser).
http://www.mouser.com/ProductDetail...=/ha2pyFadugpCK8MhBNXoFMwEe3gh5F6fCiXN00WKsQ=

 

[heraleks]

For my V2 I think I am capable to attempt the 10ohm resister swap, the snubber part I am confused

Can you confirm if I use 10ohm resistor and 470uF output caps, there is no distortion? Thanks!

Ps I wonder if I can do the same to a Z1

Yes. And there are people on player.ru who did this in Zishan.

 

[heraleks]

Have you tried the OP275GPZ? It has 90mA /channel output capability (listed on the DigiKey site), and costs only $3.23 (on Mouser).
http://www.mouser.com/ProductDetail/Analog-Devices-Inc/OP275GPZ/?qs=/ha2pyFadugpCK8MhBNXoFMwEe3gh5F6fCiXN00WKsQ=

I no try it. Not the best option for reduced output impedance. Look at the Circuit Protection section on page 7 of the datasheet. + -30mA is recommended.

 

[Nokizaru]

There should be another thread for Z1 modding haha

 

[endia]

Still using the ones mentioned here, but I am not saying they are the definitive solution But I like them. They are more or less the same size, no problem fitting

where did you order the caps, can you give the link? i'm in search for genuine silmics..

 

[macky112]

Yes. And there are people on player.ru who did this in Zishan.

Do you know if anybody recorded RMAA measurement for comparison?

Thank you again for the info!