Paul,
Mine isn't loud, but I can hear it and it annoys me. As I do not have
much other things causing noise, one becomes aware of that constant
tone. Then again, the frequency is high enough that it is relatively
easy to locate it in the room. Thing is, the ear is about most sensitive
to tones and noise at about 3 kHz, so it's not strange to become "aware"
of it. Me having a background in audio can be part of it, who knows.
Cheers,
Magnus
Den 2021-12-03 kl. 16:11, skrev paul swed:
Ulf pretty funny. I knew someone had developed a replacement integrator for
the 5065a. It was indeed you in 2017. Small world.
With respect to the inverter I will need to listen to my unit. I do not
recall anything very loud. But loud is different for every person. Like the
idea of eliminating the -20 inverter but that really means changing A3 and
A7 significantly. I had not realized that the DC bias to the photocell
actually comes from the input opamps output on A7. Something to learn every
day.
Regards
Paul
WB8TSL
On Thu, Dec 2, 2021 at 7:11 PM Shawn <com...@xmtservices.net> wrote:
Let me second Paul's question.
I too am interested in the purchase of 2 of these boards and am happy
to contribute funds in the advancement of this project.
Shawn
On Thu, 2021-12-02 at 15:09 -0500, paul swed wrote:
Ulf I would have replied off list. Are you intending to sell blank
PCBs?I was recently thinking about the same thing as I watched the
cfld move abit.I know there is also a earlier thread on this subject
3-5 years ago.RegardsPaulWB8TSL
On Thu, Dec 2, 2021 at 11:15 AM Ulf Kylenfall via time-nuts <
time-nuts@lists.febo.com> wrote:
Since the A15 regulator board is mentioned...
I recently decided to try to improve the Voltage Regulator board
A15inorder to use a better voltage reference than CR5 (9V) and
alsosee if Icould reduce the drift and noise of the Magnetic Field
winding.After some experimenting, I am reasonable satisfied.
The board has been completely redesigned.
The drift and noise of the +20V is reduced. Thermal driftcompared
to theoriginal design from the MagFieldcircuitry is also reduced
significally.
Modern thru-hole components are used facilitating manual assembly.A
total of 10 PCB's have been ordered (Double side, solder
masksilkscreen, plated holes etc.) but I did not opt for over-
nightdelivery, so itwill be another couple of weeks for them to
arrive.I will assemble a board for myself and, unless covid makes
itimpossible,take the 5065A to my former employer and evaluatethe
performance usingstandards available.If it performs well, the
design will be placed into "public domain".Best RegardsUlf
KylenfallSM6GXV
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