Building f-5 cviller layout questions? - diyAudio
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Old 23rd May 2011, 08:16 PM   #1
semi932 is offline semi932  United States
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Default Building f-5 cviller layout questions?

I've populated two boards from the diy store with a kit bought elsewhere.

I know the parts are installed correctly except for maybe the pots for setting bias.

Is there a certain polarity for these?

Also I didn't install any thing in the led area as it's not necessary in my app.
Should this make any difference? Doesn't look like it to me.

I'm getting a dead short when plugging in one board with the dim bulb tester.
I know the power supply is ok as I tested it with a good 3886 board and everything is as it should be.

Can't find any mistakes on board and I have gone over it many times and all is correct.

Frustrating as I'm ready to hear some good sounds.

Any insight?
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Old 23rd May 2011, 08:23 PM   #2
Marra is offline Marra  United Kingdom
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Regarding the trimmers you need to measure the resistance across R3 & R4; assuming they are the same as my cviller pcb's. Clockwise or anti depends on how you've installed them. Lots of info on all the other F5 threads.
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Old 23rd May 2011, 08:47 PM   #3
anilva is offline anilva  India
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Quote:
Originally Posted by semi932 View Post
I've populated two boards from the diy store with a kit bought elsewhere.

I know the parts are installed correctly except for maybe the pots for setting bias.

Is there a certain polarity for these?

Also I didn't install any thing in the led area as it's not necessary in my app.
Should this make any difference? Doesn't look like it to me.I'm getting a dead short when plugging in one board with the dim bulb tester.
I know the power supply is ok as I tested it with a good 3886 board and everything is as it should be.

Can't find any mistakes on board and I have gone over it many times and all is correct.

Frustrating as I'm ready to hear some good sounds.

Any insight?
It is quite easy to get the pots right. Measure the pots across it's legs and the ohmmeter should read 0 (across one free leg and the other two which are shorted by the pcb), irrespective of how you have mounted them. Bulb will light up, if the pots are set higher...
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Old 23rd May 2011, 08:47 PM   #4
alazira is offline alazira  United States
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Quote:
Originally Posted by semi932 View Post
I've populated two boards from the diy store with a kit bought elsewhere.

I know the parts are installed correctly except for maybe the pots for setting bias.

Is there a certain polarity for these?

Also I didn't install any thing in the led area as it's not necessary in my app.
Should this make any difference? Doesn't look like it to me.

I'm getting a dead short when plugging in one board with the dim bulb tester.
I know the power supply is ok as I tested it with a good 3886 board and everything is as it should be.

Can't find any mistakes on board and I have gone over it many times and all is correct.

Frustrating as I'm ready to hear some good sounds.

Any insight?
The LED's aren't needed. It will help if you post a picture.
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Old 24th May 2011, 01:11 AM   #5
semi932 is offline semi932  United States
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Quote:
Originally Posted by anilva View Post

It is quite easy to get the pots right. Measure the pots across it's legs and the ohmmeter should read 0 (across one free leg and the other two which are shorted by the pcb), irrespective of how you have mounted them. Bulb will light up, if the pots are set higher...

So if the bias is too high it will keep the bulb bright?

I'll recheck all and check this point.
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Old 24th May 2011, 01:22 AM   #6
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see marra's post for how to check your pots
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Old 24th May 2011, 01:45 AM   #7
qusp is offline qusp  Australia
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yep, there are actual physical indications of the direction, albeit under the board
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Old 24th May 2011, 04:54 PM   #8
semi932 is offline semi932  United States
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Thanks for the help all.

Just the bias was causing my dbt to stay lit.

It's playing now at a low bias but it does sound great.

I've got a few more things to do with it before being complete but happy for now.
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Old 24th May 2011, 05:25 PM   #9
Marra is offline Marra  United Kingdom
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Quote:
Originally Posted by semi932 View Post
Thanks for the help all.

Just the bias was causing my dbt to stay lit.

It's playing now at a low bias but it does sound great.

I've got a few more things to do with it before being complete but happy for now.
Congrats. Pics.

Sounds even better after a couple of weeks use.
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