[Bojamijams]

Damn. That's almost certainly a fake then

 

[purrin]

Or rejected chips by BB/TI that were otherwise headed to the trash bin that someone picked up and is now selling in China.

 

[Mong0]

Hello
 
I have a question as i know nothing about opamps. I am removing the OPA627 class A package from my amp. I intend to to buy a LME49720NA to replace it. I should just remove the 627 on the "extender" from the socket that goes into the board and i then with no further ado insert the 49720 directly into the socket as long as it is aligned with the marker thing on the edge pointing in towards to back of the amp. Or do i need to take the socket thing out and plug the opamp directly onto the board?
I assume all that talk about resistence UF or whatever it was about, was being handled by the soldering thingie and not some setting or something that i physically need to change.
 
Short version: Bought the class A mod, want to remove and insert LME49720NA. What to do to make sure I wont destroy anything.

 

[r3791]

Hello wich the best the matrix M-Stage or the old Gilmore lite ?

 

[purrin]

Quote:

Hello
 
I have a question as i know nothing about opamps. I am removing the OPA627 class A package from my amp. I intend to to buy a LME49720NA to replace it. I should just remove the 627 on the "extender" from the socket that goes into the board and i then with no further ado insert the 49720 directly into the socket as long as it is aligned with the marker thing on the edge pointing in towards to back of the amp. Or do i need to take the socket thing out and plug the opamp directly onto the board?
I assume all that talk about resistence UF or whatever it was about, was being handled by the soldering thingie and not some setting or something that i physically need to change.
 
Short version: Bought the class A mod, want to remove and insert LME49720NA. What to do to make sure I wont destroy anything.

You can plug the LM chip in the piggyback class A adapter no problem. I assume that it is the class A adapter and that you don't have the resistors soldered directly on the OPA627.

 

[Mad Max]

What I circled in green there seems to be throwing interference into the left channel of input 1.  How can I shield the inputs from those red cables?
 
 

 

[Mong0]

Quote:

Quote:

Hello
 
I have a question as i know nothing about opamps. I am removing the OPA627 class A package from my amp. I intend to to buy a LME49720NA to replace it. I should just remove the 627 on the "extender" from the socket that goes into the board and i then with no further ado insert the 49720 directly into the socket as long as it is aligned with the marker thing on the edge pointing in towards to back of the amp. Or do i need to take the socket thing out and plug the opamp directly onto the board?
I assume all that talk about resistence UF or whatever it was about, was being handled by the soldering thingie and not some setting or something that i physically need to change.
 
Short version: Bought the class A mod, want to remove and insert LME49720NA. What to do to make sure I wont destroy anything.

You can plug the LM chip in the piggyback class A adapter no problem. I assume that it is the class A adapter and that you don't have the resistors soldered directly on the OPA627.

 
The resisters is soldered directly onto the opamp which was soldered or otherwise stuck to an adapter. And that adapter with the opamp was then in another adapter which was inserted into the board. So it was basically running class a modded on the opamp into 2 adapters. I have removed everything but the last adapter and I think i will skip class A for now as I don't own a soldering iron and buying one just for this task may be a bit too much. But I assume I could just plug it into the socket then, cheers.

 

[castlevania32]

for those of you who have a dt880 600 paired with the m-stage which gain do you use ?

 

[Jibbie]

When I had the DT990/600ohm I used a gain of 20.  18 might work, but nothing lower.

 

[Sganzerla]

 I use gain 20 too with my DT880/600.

 

[castlevania32]

Thanks that's what i thought. With 10dB it sounds thin.

 

[purrin]

Quote:

What I circled in green there seems to be throwing interference into the left channel of input 1.  How can I shield the inputs from those red cables?
 
 

 
Can you explain more? Are you sure the wires are the culprit? Do you get buzzing or noise if you move those wires? I don't have my M-Stage anymore, but I believe those are just from the AC into the transformer. Shouldn't cause interference considering how far away they are from the input #1 trace on the PCB. There are a couple of things you can check:
 

1. Make sure the individual wires are seated properly in the plug to the PCB
2. Make sure the screw that fastens the transformer on the bottom side of the unit is securely fastened

 

 

[Mad Max]

 
Quote:

Quote:

What I circled in green there seems to be throwing interference into the left channel of input 1.  How can I shield the inputs from those red cables?
 
 

 
Can you explain more? Are you sure the wires are the culprit? Do you get buzzing or noise if you move those wires? I don't have my M-Stage anymore, but I believe those are just from the AC into the transformer. Shouldn't cause interference considering how far away they are from the input #1 trace on the PCB. There are a couple of things you can check:
 

1. Make sure the individual wires are seated properly in the plug to the PCB
2. Make sure the screw that fastens the transformer on the bottom side of the unit is securely fastened

 

I was tinkering with parts of the amp to make sure I didn't miss something or if something looks messed up (checking for the source of the buzz) and when I completely covered those wires with my hand, the buzzing stopped.
I was able to push that connector down slightly more and the buzz is quieter now, but still there.  Perhaps the connector is a bit faulty?
 
I noticed an additional very low hum in both channels with my IEMs.  I wonder if that is the RK27-related hum I read about in the LC thread?  It is different from the buzz I've heard that originates from a ground loop between different equipment (if that is the right way to call that).

 

[purrin]

Loosen the transformer bolt and tighten again. I recall I had a similar problem and this did the trick.
 
You could use aluminum foil to shield - tape a wire to it and fasten to a screw (ground). It's not a very elegant solution so I didn't want to suggest it in the first place. Tape down the aluminum foil and make sure none of it every touches the hot wires.

 

[Mad Max]

Messing with the transformer bolt didn't help.
 
I'll try the improvised shielding once I find some tape, lol.
 
Thanks!