Auto-Bias board on Roy's website?

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.

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.

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

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

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?

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.

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/

tubes4hifi wrote:yeah, wow, those LEDs would have been blindingly bright, and they also cost 5x as much as anything you'd need.
Sorting thru Mouser offerings by price and then by brightness, I think I'll order some of these
HLMP-KB45-A0000   30mcd and ten for $6.40.   I'm used to buying red and green LEDs for under a dime each.

pavlikkkk wrote:

Here are the new detailed AB-Q assembly instructions ST70-ST120 and AB-Q MK125:
AB-Q M125

AB-Q ST70-ST120

ranges wrote:

pavlikkkk wrote:

Here are the new detailed AB-Q assembly instructions ST70-ST120 and AB-Q MK125:
AB-Q M125

AB-Q ST70-ST120

Hello
Is the link for the M125 broke
I can not seem to open it
Thanks

pavlikkkk wrote:

ranges wrote:

pavlikkkk wrote:

Here are the new detailed AB-Q assembly instructions ST70-ST120 and AB-Q MK125:
AB-Q M125

AB-Q ST70-ST120

Hello
Is the link for the M125 broke
I can not seem to open it
Thanks

Thanks

I'm sorry. It's alright
Pavel

pavlikkkk wrote:

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?

tubes4hifi wrote:the lastest instructions from Pavel still seem to be wrong, V1 OUT is actually V1 GRD (grid), same for V2 OUT, V3 OUT, V4 OUT.
Also, the steps 11-14 are wrong!!   The output tube grids actually connect to the VTA driver board, same as before, not directly to the AB board!
Should be  
11. Re-connect the Rg1 wire from the VTA driver board  to pin 6 in the V1 socket
12. Re-connect the Rg2 wire from the VTA driver board to pin 6 in the V2 socket
13. Re-connect the Rg3 wire from the VTA driver board  to pin 6 in the V3 socket
14. Re-connect the Rg4 wire from the VTA driver board  to pin 6 in the V4 socket

updated/corrected instructions for the ST70-ST120 auto-bias are here on my website
www.tubes4hifi.com/ST70-AB.pdf

the instructions for the M125 were correct unless someone else can find an error that I don't see

tubes4hifi wrote: it's a ONE TIME ADJUSTMENT !!   Set it and forget it for the next 20 years!!
jfine  - yes, still possible to monitor if you want, but now the 10 ohm cathode resistors are on the auto-bias board instead of on the output tube sockets.
           But really, no need to monitor, since they will ALWAYS be EXACTLY correct, except during warm-up, when they ramp up the current slowly,
           protecting those tubes!