Eeh, get a bigger solder iron ?
Even if you pre-heat the binding posts, i doubt 30W is going to cut it.
Me use 100W solder transformers for bulky works like that, come with the Pro work-station from old days Philips lab.
(2 of the biggy solder transformers, built-in variac, isolation transformer, a few dozen AC power sockets, mains fuses, the works)
Here => http://www.diyaudio.com/forums/pass-labs/103130-pumpkin-preamp-perfect-f4-6.html#post1259450
Grey things on the left behind the Lavazza coffee tin
Look, me is Mr Ne-ne-ne-ne Nineteen
Even if you pre-heat the binding posts, i doubt 30W is going to cut it.
Me use 100W solder transformers for bulky works like that, come with the Pro work-station from old days Philips lab.
(2 of the biggy solder transformers, built-in variac, isolation transformer, a few dozen AC power sockets, mains fuses, the works)
Here => http://www.diyaudio.com/forums/pass-labs/103130-pumpkin-preamp-perfect-f4-6.html#post1259450
Grey things on the left behind the Lavazza coffee tin
Look, me is Mr Ne-ne-ne-ne Nineteen
Last edited:
I'm not familiar with your PCBs, although I've built another version of the F5.
Where is your LED located? Is it on the PSU, or one/both of the amp PCBs, or on the amp front/rear panel (pilot light)?
If you are CERTAIN you have clean + and - rail voltages, how about disconnecting the one channel giving you problems (disconnect the rail voltages) and confirm the other channel is working OK. That will help you troubleshoot.
Ken
Where is your LED located? Is it on the PSU, or one/both of the amp PCBs, or on the amp front/rear panel (pilot light)?
If you are CERTAIN you have clean + and - rail voltages, how about disconnecting the one channel giving you problems (disconnect the rail voltages) and confirm the other channel is working OK. That will help you troubleshoot.
Ken
WHAT?
http://www.firstwatt.com/pdf/prod_f5_man.pdf
But for XP, a current prouduct?
you'll need to start here Pass Laboratories or here nelson@passlabs.com
http://www.firstwatt.com/pdf/prod_f5_man.pdf
But for XP, a current prouduct?
you'll need to start here Pass Laboratories or here nelson@passlabs.com
oh man... I'm getting desperateOther channel similar behavior. The LED on the cvillers bords lights up and
fades out after 2-3 seconds. When turn on now the amp again, the LED gets not started although 24V measured over the LED. So obviously it is broken as well. Ok maybe I choose the wrong LED but this has nothing to do with the amp itself, wright? There is no short!
As I believe that I'm not a complete idiot I guess there must be something wrong in general. Could it be that with the pcb's from cviller V.1.1 is something wrong (printing). Or have I used the wrong BOM although I bought the Tech-DIY Kit? It should be ok, isn't it?
How can I easily check if the FET's are ok? I mean without desolder them.
Cheers,
Mallard
Please verify - your amp is fully constructed and electrically complete, ready to be switched on? If so,
Check the V+ 0 V- on the PSU.
Confirm that the amp boards are connected properly and check the voltages on the amp boards. (This was one of my mistakes)
Do you have 3 multimeters? Can you borrow any? Bias is much easier to set if you have 3.
Check the V+ 0 V- on the PSU.
Confirm that the amp boards are connected properly and check the voltages on the amp boards. (This was one of my mistakes)
Do you have 3 multimeters? Can you borrow any? Bias is much easier to set if you have 3.
I agree completely.
However, it is much easier to see the relationships between bias and offset when you have 3 meters. This is especially true at low bias settings when you are trying to determine which pot is pulling offset and which is adjusting current.
Having just 2 meters makes the process slower and less intuitive.
Small steps in the wright direction.
I have one channel now biasable, so it seems to work ok.
I still have the light bulb in and when I set the bias towards 0.5V the PSU voltage goes down to ~5V. (and the light bulb turns on again).
What is the typical PSU supply voltage when bias is set correctly and the bulb is not in anymore?
Since there is still one channel left not biasable I have to compere them step by step to check whats the reason. What I can say is I have max DC offset of 10mV
and voltages over source resistors remein zero. doesn't matter how long I turn on the pots.
Cheers,
Mallard
I have one channel now biasable, so it seems to work ok.
I still have the light bulb in and when I set the bias towards 0.5V the PSU voltage goes down to ~5V. (and the light bulb turns on again).
What is the typical PSU supply voltage when bias is set correctly and the bulb is not in anymore?
Since there is still one channel left not biasable I have to compere them step by step to check whats the reason. What I can say is I have max DC offset of 10mV
and voltages over source resistors remein zero.
doesn't matter how long I turn on the pots.Cheers,
Mallard
Ok I do my tests now without the light bulb. No smoke, no firework, no fuse plop... so far so good.
One channel works fine!
The other one is still the same as this morning. I double checked all connections and parts on the pcb twice. Compared it to the working pcb, it's 100%
similar soldered and the values of all the resistors are the same, so couldn't find any short or damage.
Looking at the schematic: what could be a logical reason for the output DC voltage does not to change (10mV fix) at all and the voltage
over R11 and R12 remains Zero? For any reason there is no Uds on both
Mosfets. A reason for this could be a damaged Mosfet, but both at the same time without spectacular effects?
I'm still open for constructive help
Cheers,
Mallard
One channel works fine!
The other one is still the same as this morning. I double checked all connections and parts on the pcb twice. Compared it to the working pcb, it's 100%
similar soldered and the values of all the resistors are the same, so couldn't find any short or damage.
Looking at the schematic: what could be a logical reason for the output DC voltage does not to change (10mV fix) at all and the voltage
over R11 and R12 remains Zero? For any reason there is no Uds on both
Mosfets. A reason for this could be a damaged Mosfet, but both at the same time without spectacular effects?
I'm still open for constructive help
Cheers,
Mallard