API 312 Thread!

[jsteiger]

...the colors are correct on the PCB than API 2503?...

IIRC from a previous post, yes.

Did you parallel the primaries on the 2622? I forget what Bob's boards are set up for in regards to the input trafo.

This probably would not be your problem but if you have old, original 2503's some of the leads can be very faded and throw off your lead color scheme.

 

[ilfungo]

Thanks jsteiger

Sorry for the stupid question
I have a doubt about how I oriented the transformer ...
the white dot on the API 2622 is the white dot on the card?
thanks

 

[mikefatom]

ilfungo:

Check your ground connections.  I have experienced the same symptom in one of my builds (low signal + low cut effect) and it was caused by an faulty ground connection on the board IIRC.

good luck,

Mike

 

[jsteiger]

Thanks jsteiger

Sorry for the stupid question
I have a doubt about how I oriented the transformer ...
the white dot on the API 2622 is the white dot on the card?
thanks

Typically indicates pin 1 for both things. Is it an original AP2622 or one of our EA2622's?

 

[ilfungo]

Thanks jsteiger

Sorry for the stupid question
I have a doubt about how I oriented the transformer ...
the white dot on the API 2622 is the white dot on the card?
thanks

Typically indicates pin 1 for both things. Is it an original AP2622 or one of our EA2622's?

is your EA2622

 

[ilfungo]

Hello
I just finished 2 x 312 with your card
I have a problem of ground
a question: I have to connect all ground points with PSU Ground? (bob schwenkler PCB)
1 pin XLRM - XLRF to chassis?
Is there anything to be connected to ground?
Thanks

 

[mikefatom]

Hello
I just finished 2 x 312 with your card
I have a problem of ground
a question: I have to connect all ground points with PSU Ground? (bob schwenkler PCB)
1 pin XLRM - XLRF to chassis?
Is there anything to be connected to ground?
Thanks

If you're using my PSU, connect all XLR-PIN1 to the point marked STAR POINT on the PSU PCB.
The star point can then be connected to the chassis via the standoff underneath it.  Just make sure that there is a good connection between the start point/standoff/case. Remove paint/powder coat if needed.

Good Luck,

Mike

 

[mikefatom]

BTW, what tells you that you have a ground problem?

 

[ilfungo]

I'm using is your PSU
low frequency noise and hiss...
I just tried to connect pin 1 of XLR in - out to Star Ground on PSU and a lot of noise is gone ...
I still have a doubt
3  ground  points on 312 must be connected to the star ground? (I had them connected to the PSU out (-16  +16 Ground  +12 +48)

Thanks Mike

 

[mikefatom]

I'm using is your PSU
low frequency noise and hiss...
I just tried to connect pin 1 of XLR in - out to Star Ground on PSU and a lot of noise is gone ...
I still have a doubt
3  ground  points on 312 must be connected to the star ground? (I had them connected to the PSU out (-16  +16 Ground  +12 +48)

Thanks Mike

Give me a moment. I will look up Bob's 312 schemo and get back to you on that.

mike

 

[Sredna]

To get phantom power to work, youll have to connect pin 1 on IN to (psu) ground!

 

[mikefatom]

I'm using is your PSU
low frequency noise and hiss...
I just tried to connect pin 1 of XLR in - out to Star Ground on PSU and a lot of noise is gone ...
I still have a doubt
3  ground  points on 312 must be connected to the star ground? (I had them connected to the PSU out (-16  +16 Ground  +12 +48)

Thanks Mike

Ok, I just got a look at Bob's schematic and it looks like he provides 3 connections for signal ground on the power header.  According to the schemo, they should all be the same ground node.  Take a quick look at the PCB to confirm that this is the case.  If that is correct, you can use a single ground connection from the power header to the PSU.

Try and report back.

Cheers,

Mike

 

[ilfungo]

thanks mike for your help!!!
the noise is much lower ...
Now I will test in my studio
last question
Could you tell me where to put a stop to Grayhill?
THANKS !!!!!

 

[mikefatom]

thanks mike for your help!!!
the noise is much lower ...
Now I will test in my studio
last question
Could you tell me where to put a stop to Grayhill?
THANKS !!!!!

Pop the pin at the 12 o'clock position. Make sure it's all the way in and flush.

Btw, do you have the power transformer in the same case as the pres?  You may be able to improve further on the noise by shielding it or taking it out of the case.

Glad I could help!

Cheers

Mike

 

[mikefatom]

Check page 17 of Owel's fantastic manual here: http://www.fivefishstudios.com/pdf/X12Assembly.pdf

I hope he doesn't mind  :-[

Cheers

Mike

 

[ilfungo]

thanks Mike
the power transformer is on external case...

 

[mikefatom]

Well then, there is only one thing left to do:

Put a lid on that thing and go record some kick ass tunes! ;D

 

[ilfungo]

hello thank you all for your help ...
I tried everything you told me
something has improved, but there is always low signal and noise ...
At this point I think my problem is on GAR2520
How can I test them?
There are reference voltages?
help!
thanks

 

[mikefatom]

hello thank you all for your help ...
I tried everything you told me
something has improved, but there is always low signal and noise ...
At this point I think my problem is on GAR2520
How can I test them?
There are reference voltages?
help!
thanks

Could you record a sample of the noise and send it to me or post it somewhere?

Is the noise present regardless of the gain setting?

 

[ilfungo]

Hello Mike
Tomorrow I try to record sample ...
the problem is constant, but I think it is a problem on  GAR2520 because  the signal very low ...
Then I read that GAR2520 should warm up, while mine is cold
THANKS!!!!
sorry for my english....