no problems merlin , you can't bias it with the light bulb in series . thats just for starting up so that if you have a problem you don't let out too much smoke 🙂
turn off your amp , disconnect the lightbulb , RETURN !!!!your pots to ZERO !!! before connecting your amp direct to mains .
if you don't have zenmod's guide to biasing up go find it before proceeding . i believe he posted it in 6L6's original build thread .
and i repeat RETURN YOUR POTS TO ZERO !!!!
cheers Woody
turn off your amp , disconnect the lightbulb , RETURN !!!!your pots to ZERO !!! before connecting your amp direct to mains .
if you don't have zenmod's guide to biasing up go find it before proceeding . i believe he posted it in 6L6's original build thread .
and i repeat RETURN YOUR POTS TO ZERO !!!!
cheers Woody
lmaoooooo , no i think jim had a mod do a lot of editing . kind of a shame . there was a lot of good stuff there .
gotta get dinner on , but bbs .
Ok, I reviewed the first page of this thread. I'll have to print out a hard copy for reference.
Anyways, what does mosfet Iq refer to? Isn't that the voltage across R11 or R12?
DC offset it the voltage at the speaker outputs.
And max voltage is voltage between v+ & v-.
That right?
Anyways, what does mosfet Iq refer to? Isn't that the voltage across R11 or R12?
DC offset it the voltage at the speaker outputs.
And max voltage is voltage between v+ & v-.
That right?
oh cool , just realized 6L6 saved that in diff format . was more interesting in the original zm post though 😛
Iq refers to current "I" I=v/r . in this case the known is r .47 ohms so voltage is what you're monitoring over r11 &12 to arrive at that current .
and yes dc offset is the voltage at the speaker outputs .
not sure what max voltage you're reffering to .
Iq refers to current "I" I=v/r . in this case the known is r .47 ohms so voltage is what you're monitoring over r11 &12 to arrive at that current .
and yes dc offset is the voltage at the speaker outputs .
not sure what max voltage you're reffering to .
From Zen Mods biasing procedure:
"place one voltmeter across PSU caps ( best between + and - of PSU) to observe max voltage of PSU"
My ASSUMPTION is that one is curious to see how stiff the PS is.
"place one voltmeter across PSU caps ( best between + and - of PSU) to observe max voltage of PSU"
My ASSUMPTION is that one is curious to see how stiff the PS is.
yup , sorry , making pizza dough . and thanx andersonic re: Iq = quiescent current (idle current) learning every day here 🙂
According to the mod to whom I spoke with, there was a software malfunction, which (for an unknown reason) cloned the thread, and they (the mods) couldn't delete one without modifying the other... So they locked it up and reported the problem to one of the admins, who has probably forgot about it or has in buried in a to-do list.
Hopefully it will get fixed. 🙂
It's kind of hard to get to P1 & P2 once the mosfets and board have been mounted (to reset the pots to 0 ohms).
Isn't setting R11 and/or R12 to 0v DC a good alternative?
Isn't setting R11 and/or R12 to 0v DC a good alternative?
Only if you want to create smoke.
You need to adjust P1 and P2 down to zero ohms before firing it up!
Ok, I'll dismount the whole board and mosfets.
There are no test point on the front of the board to check the values of the pots?
There are no test point on the front of the board to check the values of the pots?
Turn the trimpots fully counter clockwise until they click. They should be at 0.
Unless you can't put a screwdriver on the pots while installed, there is no reason to dismount the board.
If you do need to take out the board to measure/verify the pot's position, take a pen or thin sharpie and mark the direction you need to turn the pot to make it go down.
Unless you can't put a screwdriver on the pots while installed, there is no reason to dismount the board.
If you do need to take out the board to measure/verify the pot's position, take a pen or thin sharpie and mark the direction you need to turn the pot to make it go down.
I understood it as if the pots could not be reached. If that is the case, I would suggest to make them reachable.
I can reach the pots and turn them no problem. I'll just have to keep turning them counter clock-wise until I hear a click.
Do they keep click when they reach the limit of the pot?
Do they keep click when they reach the limit of the pot?
Yes, the pots will click click click at the bottom or top of their range, as the adjustment doohickey clutches.
Plug in your light bulb tester in and fire it up. If the bulb glows for just a teeny bit (as the caps charge) and then get dim, you most likely have the pot adjusted down to zero.
Remove the light bulb tester and turn it on. Hook up your meters and start the bias procedure.
Plug in your light bulb tester in and fire it up. If the bulb glows for just a teeny bit (as the caps charge) and then get dim, you most likely have the pot adjusted down to zero.
Remove the light bulb tester and turn it on. Hook up your meters and start the bias procedure.
hey, 6L6
happy to say your other thread is OK again
http://www.diyaudio.com/forums/pass-labs/182723-how-build-f5-87.html#post2573711
happy to say your other thread is OK again
http://www.diyaudio.com/forums/pass-labs/182723-how-build-f5-87.html#post2573711
I'm new to this forum and have to say that I am completely fascinated.
I'm seriously considering taking the plunge on building the F5 and have a couple questions:
1. I remember reading Nelson has a large stock of cases for First Watt. Is he willing to sell the cases to DIYers on a one off basis?
2. Has anyone done a F5 in a multi-channel system? I.e. 5 channels of F5 amplification in one case with one power supply? This would definitely interest me.
Thanks in advance for your help! -Gordon.
I'm seriously considering taking the plunge on building the F5 and have a couple questions:
1. I remember reading Nelson has a large stock of cases for First Watt. Is he willing to sell the cases to DIYers on a one off basis?
2. Has anyone done a F5 in a multi-channel system? I.e. 5 channels of F5 amplification in one case with one power supply? This would definitely interest me.
Thanks in advance for your help! -Gordon.