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    Remote control for preamp from china

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    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Remote control for preamp from china

    Post by peterh on Sun Aug 03, 2014 7:48 am

    I have started to build a cathode follover and remote volume / power control.

    http://www.ebay.com/itm/111333858449?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

    It needs 5-12V DC
    It has output for controlling 1 of 4 channels and also an "power on" signal
    all controlled from the remote.


    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Remote control for preamp from china

    Post by peterh on Tue Sep 30, 2014 2:12 pm

    First power on and test of main channel ( i have two channels, the other is to buffer tape
    output). Surprisingly it worked at once and gave ( subjectivly ) a good impression. I'll keep
    it connected a few days.

    Remaining is an arduino that will control power to preamp(s) and power amp. The last one
    will be protected by a delay to prevent power cycling and to make shure that in the
    event of power failure it won't restart. This will also give me power on/off by remote control, a
    new feature for dynaco-class amps !

    Remaining is also some metal work to mount all rca-connectors. When finished i'll publish
    some photos and details if interest exists.




    Bally

    Posts : 25
    Join date : 2010-05-18

    Remote Control

    Post by Bally on Tue Sep 30, 2014 11:14 pm

    absolutely peterh, please post pictures and details of your project. I am anxious to see your integration of the arduino in the preamp. Possibly remote/relay driven?

    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Remote control for preamp from china

    Post by peterh on Wed Oct 01, 2014 4:14 pm

    A first glimps : http://n.manet.nu/fm1/fm1.html


    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Remote control for preamp from china

    Post by peterh on Thu Oct 02, 2014 4:20 pm

    arduino programmed, now it's time to mount the digital stuff.
    I'll use relays for interfacing to outside ( the are only usd2 a piece anyway). I also have
    got a couple of small SSR , one will be used in the fm1 to control tubepower.

    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Remote control for preamp from china

    Post by peterh on Fri Oct 03, 2014 1:50 pm

    A setback occurred. The internal +5V regulator does not cope with the load of a dual relay module.
    I will mount another DC regulator that will supply +5V to the relays. Not really a problem as
    i get them on ebay for less then 3 dollars.
    Another setback was that a (double)relay module did not operate the relays, there is as usual
    no documentation, but i could not get it to function. Change of module fixed the problem.
    ( DOA from ebay), that's the price one pays for the low prices.
    Also made a program change for a "status led" to be visible from outside, black when powered on,
    blinking during power on delay and lit when both relays active.

    Stay tuned :-)

    Bally

    Posts : 25
    Join date : 2010-05-18

    Remote Control

    Post by Bally on Fri Oct 03, 2014 10:44 pm

    Thank you for the posts. I have been following the project with interest.
    For some reason I thought that instead of using the arduino with shield, you would program the chip and build your board around it.
    But this way works fine too!
    By the was hook up pins for the relays are VCC to +5: Gnd of course to Ground: Int1 and Int2 are to the assigned pins of the arduino/ shield.
    Hope it helps with getting the relay to work.









    Oops ......re-read the post and saw you had solved the problem.....


    Last edited by Bally on Fri Oct 03, 2014 10:50 pm; edited 1 time in total (Reason for editing : additional info)

    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Remote control for preamp from china

    Post by peterh on Sat Oct 04, 2014 5:05 pm

    Bach in ON ! All electrical parts are installed and working, some chassies parts remains.

    Also remaining is adaptation of my PAS-3 to get it remote-startable.



    peterh

    Posts : 642
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Remote control for preamp from china

    Post by peterh on Sat Nov 01, 2014 5:20 pm

    I-ve done some adjustments to the "power sequencer" ( as you might remember i have an arduino
    microprocessor to delay the power-on for the poweramp).
    After reading dave gillespies article about "power tube flashing and the reasons"
    ( http://www.tronola.com/html/maximize_tube_life.html ) i have fine-tuned my power control:

    - at startsignal(1) it will delay 3s before powering up preamp. This prevents preamp powersurge if
    power fluctuates.
    - after startsignal it will power on poweramp after 25s.
    The above delays are unconditional, under no conditions will amps be "power cycled " faster
    then this. If power is dropped the startcycle will be repeated from beginning.

    When startsignal is removed the poweramp is shut down. After 3s will the
    preamp be turned off. This will give poweramp time to unload it's caps and thus be
    safe even if the preamp will surge it's output at power off.

    If powerdown cycle is aborted and a new startsignal is detected, a normal startcycle is done.

    (1) "startsignal" or better named power control signal is a DC > 3V Draws very
    little current, could be battery operated.

    The arduino itself has it's own PSU, and will at not turn on amps until a complete startcycle is done.

    Why ? Just for the fun of it. And, maybe, save some tubes.

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    Re: Remote control for preamp from china

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