Re: Access-312 Build Thread
« Reply #580 on: July 12, 2019, 07:32:22 PM »
OK

I did the measurements and the F2UEE push button switch is exactly 17.5mm apart from center of one switch to the next.

I bought the hardware chassis mounts for 17.5mm and it fits perfectly.


Re: Access-312 Build Thread
« Reply #581 on: July 12, 2019, 07:54:29 PM »
I am also wondering about the details regarding the input pad, because I would like to mod my input pad to be -10dB in attenuation.

In the Access 312 circuit, is the pad an H-Pad, a T-Pad, or a U-Pad?

I'd like to change the resistors to produce a -10dB pad.  I think right now the pad is about -19dB with resistors R8 = 120r, R9 = 470r, and R10 = 470r

The input Z of my input transformer is typically 1500 ohms.  And I think its typical for a mic output impedance to be 150 ohms, right?
So I am not sure a -10dB pad is possible with my given impedances?

I used a T-Pad / H-Pad calculator at http://www.nu9n.com/tpad-calculator.html
The calculator could not compute a -10dB pad with these impedances...
and the only way I got close to the current -20dB pad was by making both input and output impedances both 600 ohms...
The results from the T-Pad were R1 = 491, R3 = 491, and R2 = 121 (bridge power load resistance)

Just trying to figure this out. If any one knows please offer your understanding. Thank you


« Last Edit: July 13, 2019, 07:05:04 AM by talkieparade »

Whoops

Re: Access-312 Build Thread
« Reply #582 on: July 12, 2019, 11:19:02 PM »
I am also wondering about the details regarding the input pad, because I would like to mod my input pad to be -10dB in attenuation.

In the Access 312 circuit, is the pad an H-Pad, a T-Pad, or a U-Pad?

Read this page, the answer is there:

http://www.uneeda-audio.com/pads/

Re: Access-312 Build Thread
« Reply #583 on: September 02, 2019, 01:04:25 AM »
I’m having some trouble with my phantom power. Everything is grounded according to the diagram drawn out in the earlier replies and I’m using the collective cases external PSU. I’m getting ~ 50V in from my power supply to the phantom in screw terminal. LED on the switch is working. R1, R2 both  show ~ 40.5V and R3 shows 46V when referencing pin 1 on my XLR input. XLR pin 2 shows 0V and pin 3 shows .5V. Any thoughts on what might be causing this? Bad cap?

I’ve triple checked for any accidental solder bridges and reflowed everything a couple times now just to be safe. Pre seems to work fine with mics that don’t require phantom.

Whoops

Re: Access-312 Build Thread
« Reply #584 on: September 02, 2019, 10:55:37 PM »
I’m having some trouble with my phantom power. Everything is grounded according to the diagram drawn out in the earlier replies

Hi,
what diagram are you following for the grounding?

I posted some grounding layouts that are more efficient than what's been said in the early posts of this thread

3nity

Re: Access-312 Build Thread
« Reply #585 on: September 11, 2019, 07:55:16 PM »
Whoops thanks for your kind support on this project.
Im bussy working and you always give good advice!
I appreciate it!
Life is a path, death the destination.

Whoops

Re: Access-312 Build Thread
« Reply #586 on: September 12, 2019, 06:28:56 PM »
Whoops thanks for your kind support on this project.
Im bussy working and you always give good advice!
I appreciate it!

I try to help and give the advice I can, but I feel that in the last years in this forum new users don't even read the project pages.
I think some forum Etiquette is being lost, it was definitely not like this in the past.

Most of the questions being constantly asked by a new user in this thread were already answered a few times before.

With the nice layout you have made and your pcb, your documents, plus reading this thread for some other ideas and info it becomes really easy to do an API type mic pre project, but people seem to  don't want to put any effort.

3nity

Re: Access-312 Build Thread
« Reply #587 on: September 15, 2019, 09:39:02 PM »
True.
The thing people look nowadays is the result not the learning... Thats what was cool when i came here learning and share..
Life is a path, death the destination.

Whoops

Re: Access-312 Build Thread
« Reply #588 on: September 16, 2019, 09:13:59 AM »
True.
The thing people look nowadays is the result not the learning... Thats what was cool when i came here learning and share..

Yes, totally agree, that has been lost since this forum became like a superkarket

There should be some rules and guidelines for new members, since the registration of new members boomed, so that the nice Etiquette this forum had would not be lost.

Re: Access-312 Build Thread
« Reply #589 on: September 23, 2019, 12:56:09 AM »
Well I think this thread is awesome and definitely appreciate everyone's help and advice here, props to Whoops and 3nity. I've read this thread many times now,
Looking for answers but sometimes the answer isnt totally obvious and one just has to ask  :) 


3nity

Re: Access-312 Build Thread
« Reply #590 on: September 28, 2019, 09:00:43 AM »
Talkieparade
Its normal dont worry.
The non obvious stuff its part of the fun it makes you learn and discover.. It can be very long i know but you have to be willing to read and search.

If not just ask.. We dont mind sharing.
Life is a path, death the destination.


 

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