PSN-L Email List Message

Subject: RE: Larry's three channel Amp board
From: "Dale Hardy" photon1@...........
Date: Mon, 17 May 2010 11:26:43 +1000


Hi Ted,
Are you referring to the 1 to 4 channel board ??? 
If so, instructions are on

http://www.seismicnet.com/serialamp.html

regards
Dale

-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Ted Channel
Sent: Monday, 17 May 2010 12:03 AM
To: psn-l@..............
Subject: Re: Larry's three channel Amp board

Folks,  Angel suggest I ask this on the psn list, at that's fine, I will.

To begin with I emailed my questions to Larry, twice, but got no reply, so 
he maybe on vacation or just not available.

I am working with two of Larry's three channel boards.  One I have and one 
at a college.    The one I have is working fine and has been for two years.
The college just started using theirs, and I do believe something is wrong.

I went to the college to check all the (settings) for the amp and the WinSDR

software.    Everything look normal and they are using all the same settings

I am using.   They are using identical Lehman and Vertical sensors, same 
city, same noise level.........Almost everything about our two stations are 
the same.   With one exception..............

On their WinSDR screen, they show the three traces coming in ch1,  ch2,  and

ch3, same as my three channel..........BUT   their "Y" axis is 600,   not 20

or 30 or 3 like mine, but 600.   They had it at 250, but made an adjustment 
to 600.........Yet the screens look correct, it is not black.............Why

is my question?

    I THINK the reason for this is,


............The board inside the box, has a Low gain and a
> High gain setting.   On Larry's one channel board it is a jumper pin.
> Install the gain is 200-2000,
> removed the gain is 950-9500................On Larry's three channel board
> there is a jumper pin also,  installed the gain is 145-1450.   With the
> jumper removed it is 650-6500.
> Each board also has a trim pot,  (10 turn potentiometer)?   This is also
> adjustable, but is shipped already turned to the minimal level.
>
> On one of the old one channel boards, I wanted try both high and low
> gains.   I opened the board and could see the jumper (Installed) so that
> would mean I was using the low gain of 200-2000 and the trim pot was at
> minimum so I was using 200 gain.   I was incorrect..........I could see 
> the
> jumper, so I thought that = installed.  But the jumper having two holes in
> the bottom, was only inserted onto one of the two pins, so this = not
> installed.  This means I was actually on high gain of 950-9500, with
> the trim pot to minimum=950 gain.

I have not opened my three channel board, and I have not opened theirs. 
Someone may have?
How does Larry ship board?   Jumper in or out?   Trim pot lowest point?

To make this more complex,  They failed to record the 5.1M off the coast of 
Oregon, and I recorded it perfectly on all three channels.
Could the (gain settings) account for this?

Thanks,
Ted





----- Original Message ----- 
From: "sismos" 
To: 
Sent: Sunday, May 16, 2010 7:32 AM
Subject: Re: Larry's three channel Amp board


> Hi Ted,
>
> Why take this topic off list.  We all own these boards and are
> interested in any related topics.
>
> Let's do it here, it's a big reason we are all on the list.
>
> My two cents.
>
> Angel
>
>
>
> On Sun, 2010-05-16 at 06:47 -0600, Ted Channel wrote:
>> Folks,  I have a series of questions concerning Larry's three channel
>> board.   psn-adc-eqamp.    If someone would email me direct please.
>>
>> Ted    tchannel@............
>
>
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