[time-nuts] Re: 5065A - A15 (PSU)

[Magnus Danielson]

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 <comsec at 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 at 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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