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    Auto-Bias board on Roy's website?

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    cci1492

    Posts : 241
    Join date : 2016-05-09
    Age : 58
    Location : Bergen County NJ

    Re: Auto-Bias board on Roy's website?

    Post by cci1492 on Wed Jan 09, 2019 2:01 pm

    Will the amps eventually ship with 2 sets of instructions, one with the other without?
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    tubes4hifi
    Admin

    Posts : 1501
    Join date : 2008-11-30

    Re: Auto-Bias board on Roy's website?

    Post by tubes4hifi on Wed Jan 09, 2019 3:31 pm

    Bob is selling all amplifier kits, and Roy (that's me) is selling all auto-bias upgrades, so the instructions are separate,
    but keep this in mind if you haven't bought either one yet . . .
    the four bias pots are NOT installed if you are going to use the auto-bias board.
    If you are using PIO caps, they must be insulated and not stick up more than 3/4" off the driver board (K40s are usually too fat, use K42 caps instead)
    C17 & C18 should be less than 3/4" tall (Bob still has some older taller ones, new ones are supplied with ST70 & ST120 auto-bias boards)

    jsl1234

    Posts : 39
    Join date : 2017-08-28

    Re: Auto-Bias board on Roy's website?

    Post by jsl1234 on Fri Jan 11, 2019 2:16 pm

    Hi, does anyone have a photo/example showing they moved the bias lights on the AB board to show through the driver board cover?

    I’m thinking the lights would be neat if inserted in the hole that used to provide access to the bias adjustment pots?

    Otherwise how do you know if the lights are on/working without unbuttoning the the amp?

    Thanks
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    tubes4hifi
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    Re: Auto-Bias board on Roy's website?

    Post by tubes4hifi on Fri Jan 11, 2019 2:42 pm

    I'll be making a change to the driver board to allow that, but it will be at least a couple of months before I need to order more driver boards
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    pavlikkkk

    Posts : 24
    Join date : 2018-03-02
    Age : 71
    Location : Czech Republic

    Re: Auto-Bias board on Roy's website?

    Post by pavlikkkk on Fri Jan 11, 2019 3:43 pm

    jsl1234 wrote:Hi, does anyone have a photo/example showing they moved the bias lights on the AB board to show through the driver board cover?

    I’m thinking the lights would be neat if inserted in the hole that used to provide access to the bias adjustment pots?

    Otherwise how do you know if the lights are on/working without unbuttoning the the amp?

    Thanks
    is that it?

    jsl1234

    Posts : 39
    Join date : 2017-08-28

    Re: Auto-Bias board on Roy's website?

    Post by jsl1234 on Fri Jan 11, 2019 4:08 pm

    I assume this shows where the wires need to originate. What I was asking is has anyone actually done the mod and mounted the lights (or alternative) on the optional driver board cover that sits atop the drive PCB (and inserted the wires through the driver board routed through where the pot adjustment holes are since the bias adjustment pots are removed as part of the AB install as I understand it. I was thinking the wires to the lights could go straight up through each pot hole or at least the pot hole (no pun intended) would provide some space for the led to be mounted about the driver PCB board.
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    Bennyhaha812

    Posts : 16
    Join date : 2016-12-06
    Age : 44
    Location : Western MA.

    Re: Auto-Bias board on Roy's website?

    Post by Bennyhaha812 on Fri Jan 11, 2019 5:26 pm

    For sake of saving me from flipping over my amp and putting the multimeter on it, what is the voltage and amperage of the led? I may consider buying some 3mm led units of proper value and helping jsl1234 out with the modifications jumping the power from the AB board at the locations noted by Pavlikkkk. Aside from a variety of other mods this was something he was interested in and since I like to play, why not??? Roy, can you send me a AB board for a st-70/120 and PayPal invoice me please? Thanks.

    New2Tubez

    Posts : 31
    Join date : 2018-03-20
    Location : NY

    Re: Auto-Bias board on Roy's website?

    Post by New2Tubez on Fri Jan 11, 2019 5:47 pm

    I got but haven't installed the AB or modded the VTA board but got these for the purpose you mention:

    https://www.mouser.com/ProductDetail/Lumex/SSL-LX3044UEGC?qs=%2fha2pyFadui7ivFq1vSLB8k3ryryuuMNMdYGeVxffnZ209HnnWzxFQ%3d%3d

    Pavel said they would be fine. I didn't want anything bright and these only address relocating the 4 blue LEDs and not the red one. I haven't done the board yet but most likely will before Roy has new ones. The newly posted proper instructions will be very helpful!  Thanks Pavel and Roy for these.

    jsl1234

    Posts : 39
    Join date : 2017-08-28

    Re: Auto-Bias board on Roy's website?

    Post by jsl1234 on Fri Jan 11, 2019 6:07 pm

    Just curious, are they available in blue over green? My thinking was the blue compliments the soft glow of red from the tubes, but that may be taking things a bit too far on my part, don't know.

    New2Tubez

    Posts : 31
    Join date : 2018-03-20
    Location : NY

    Re: Auto-Bias board on Roy's website?

    Post by New2Tubez on Fri Jan 11, 2019 6:13 pm

    jsl1234 wrote:Just curious, are they available in blue over green? My thinking was the blue compliments the soft glow of red from the tubes, but that may be taking things a bit too far on my part, don't know.

    I'm not sure but they had a few colors. I just wanted mine to blend in so I wouldn't see LEDs on the board. No you're not taking it too far. I spent a few hours looking.
    Hopefully your tubes are glowing orange, BTW :)

    If you look way back on this thread, there might be mention of power requirements, etc but IIRC, Pavel said almost anything would work. Probably best to find the color you like and run the rest by him.

    jsl1234

    Posts : 39
    Join date : 2017-08-28

    Re: Auto-Bias board on Roy's website?

    Post by jsl1234 on Fri Jan 11, 2019 6:16 pm

    " ....your tubes are glowing orange, BTW"...indeed they are right now, and have been most of the day Smile

    Great amp with a great supportive community.

    Thanks
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    pavlikkkk

    Posts : 24
    Join date : 2018-03-02
    Age : 71
    Location : Czech Republic

    Re: Auto-Bias board on Roy's website?

    Post by pavlikkkk on Fri Jan 11, 2019 7:03 pm

    New2Tubez wrote:I got but haven't installed the AB or modded the VTA board but got these for the purpose you mention:

    https://www.mouser.com/ProductDetail/Lumex/SSL-LX3044UEGC?qs=%2fha2pyFadui7ivFq1vSLB8k3ryryuuMNMdYGeVxffnZ209HnnWzxFQ%3d%3d

    Pavel said they would be fine. I didn't want anything bright and these only address relocating the 4 blue LEDs and not the red one. I haven't done the board yet but most likely will before Roy has new ones. The newly posted proper instructions will be very helpful!  Thanks Pavel and Roy for these.

    you can use these LEDs. Will not they shine too much (1100mcd)?
    Pavel

    New2Tubez

    Posts : 31
    Join date : 2018-03-20
    Location : NY

    Re: Auto-Bias board on Roy's website?

    Post by New2Tubez on Sat Jan 12, 2019 12:31 am

    pavlikkkk wrote:
    New2Tubez wrote:I got but haven't installed the AB or modded the VTA board but got these for the purpose you mention:

    https://www.mouser.com/ProductDetail/Lumex/SSL-LX3044UEGC?qs=%2fha2pyFadui7ivFq1vSLB8k3ryryuuMNMdYGeVxffnZ209HnnWzxFQ%3d%3d

    Pavel said they would be fine. I didn't want anything bright and these only address relocating the 4 blue LEDs and not the red one. I haven't done the board yet but most likely will before Roy has new ones. The newly posted proper instructions will be very helpful!  Thanks Pavel and Roy for these.

    you can use these LEDs. Will not they shine too much (1100mcd)?
    Pavel

    I'll have another look. I spent a long time searching for these, thought they were a good choice and ordered them. I looked through all of our PM's but couldn't find a reference to the ones I got. Maybe those were deleted..?
    I definitely don't want them to be bright. I just barely want to know they're on. Is there an mcd range to look for that would do this?

    Thanks
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    pavlikkkk

    Posts : 24
    Join date : 2018-03-02
    Age : 71
    Location : Czech Republic

    Re: Auto-Bias board on Roy's website?

    Post by pavlikkkk on Sat Jan 12, 2019 6:47 am

    New2Tubez wrote:
    pavlikkkk wrote:
    New2Tubez wrote:I got but haven't installed the AB or modded the VTA board but got these for the purpose you mention:

    https://www.mouser.com/ProductDetail/Lumex/SSL-LX3044UEGC?qs=%2fha2pyFadui7ivFq1vSLB8k3ryryuuMNMdYGeVxffnZ209HnnWzxFQ%3d%3d

    Pavel said they would be fine. I didn't want anything bright and these only address relocating the 4 blue LEDs and not the red one. I haven't done the board yet but most likely will before Roy has new ones. The newly posted proper instructions will be very helpful!  Thanks Pavel and Roy for these.

    you can use these LEDs. Will not they shine too much (1100mcd)?
    Pavel

    I'll have another look. I spent a long time searching for these, thought they were a good choice and ordered them. I looked through all of our PM's but couldn't find a reference to the ones I got. Maybe those were deleted..?
    I definitely don't want them to be bright. I just barely want to know they're on. Is there an mcd range to look for that would do this?

    Thanks
    for example:
    https://www.tme.eu/en/details/l-934mbdk/tht-leds-3mm/kingbright-electronic/
    avatar
    Kramer

    Posts : 43
    Join date : 2018-02-11
    Age : 31
    Location : Chicago

    Re: Auto-Bias board on Roy's website?

    Post by Kramer on Sat Jan 12, 2019 1:37 pm

    After reading the new installation instructions provided by Pavel, thank you very much for taking the time to put that together, I see that the removal of R37 and R38 is no longer listed. Is this step not necessary to properly install and use the AB-Q board?
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    erhard-audio

    Posts : 92
    Join date : 2017-04-07
    Age : 60
    Location : Tucson, AZ

    Re: Auto-Bias board on Roy's website?

    Post by erhard-audio on Sat Jan 12, 2019 2:05 pm

    Kramer wrote:After reading the new installation instructions provided by Pavel, thank you very much for taking the time to put that together, I see that the removal of R37 and R38 is no longer listed. Is this step not necessary to properly install and use the AB-Q board?

    by removing the original bias trimmers, R37 & R38 are effectively taken out of the circuit, so no longer have a function and can be left on the pcb, that is how I see it. This can perhaps be confirmed by Roy.
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    Kramer

    Posts : 43
    Join date : 2018-02-11
    Age : 31
    Location : Chicago

    Re: Auto-Bias board on Roy's website?

    Post by Kramer on Sat Jan 12, 2019 3:17 pm

    erhard-audio wrote:
    Kramer wrote:After reading the new installation instructions provided by Pavel, thank you very much for taking the time to put that together, I see that the removal of R37 and R38 is no longer listed. Is this step not necessary to properly install and use the AB-Q board?

    by removing the original bias trimmers, R37 & R38 are effectively taken out of the circuit, so no longer have a function and can be left on the pcb, that is how I see it. This can perhaps be confirmed by Roy.

    That makes perfect sense, thank you for the clarification.

    New2Tubez

    Posts : 31
    Join date : 2018-03-20
    Location : NY

    Re: Auto-Bias board on Roy's website?

    Post by New2Tubez on Sat Jan 12, 2019 4:08 pm

    pavlikkkk wrote:
    New2Tubez wrote:
    pavlikkkk wrote:
    New2Tubez wrote:I got but haven't installed the AB or modded the VTA board but got these for the purpose you mention:

    https://www.mouser.com/ProductDetail/Lumex/SSL-LX3044UEGC?qs=%2fha2pyFadui7ivFq1vSLB8k3ryryuuMNMdYGeVxffnZ209HnnWzxFQ%3d%3d

    Pavel said they would be fine. I didn't want anything bright and these only address relocating the 4 blue LEDs and not the red one. I haven't done the board yet but most likely will before Roy has new ones. The newly posted proper instructions will be very helpful!  Thanks Pavel and Roy for these.

    you can use these LEDs. Will not they shine too much (1100mcd)?
    Pavel

    I'll have another look. I spent a long time searching for these, thought they were a good choice and ordered them. I looked through all of our PM's but couldn't find a reference to the ones I got. Maybe those were deleted..?
    I definitely don't want them to be bright. I just barely want to know they're on. Is there an mcd range to look for that would do this?

    Thanks
    for example:
    https://www.tme.eu/en/details/l-934mbdk/tht-leds-3mm/kingbright-electronic/

    Thank you Pavel,
    Looks like I was way off w/ 1100mcd. Replacements ordered in 50mcd. Stay tuned...

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    Re: Auto-Bias board on Roy's website?

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