It didn't explode....... YET (aka niges amp)

[jkeny]

one thing i went to briefly investigate that hum we had the other day at times and i couldn't seem to repeat it, was the first time i heard hum with the amp

i think you mentioned something about chokes in regards toroids?

Didn't we have the hum when my trafos were in but weren't being used for isolation (input and output 0Vs were commoned)? It went away when we broke that ground loop I seem to recall, but you were doing the fixing so do please correct me if my memory has failed me. Or did it hum before the trafos were introduced?

Hum issues can be fixed up in various ways, common-mode chokes can help but I find the off-the-shelf ones nowhere near as good as winding them yourself. You might also find that the precise point of connecting the input 0Vs to the power supply is crucial.

From memory (not always the most reliable) didn't I mention some hum when we first arrived i.e. before any experimenting with Richard's trafos? I think it became more noticeable when trafo was inserted & was not doing any isolation but completely disappeared when input/output grounds were disconnected & isolated?

Your mention of "precise point of connecting the input 0Vs to the power supply is crucial" is something we were discussing a page back with the final pcb layout of Nige's amp viewtopic.php?p=80839#p80839

[nige2000]

did we have hum with the sd card player aswell as the pc?

is winding transformers difficult ?
id like to experiment more with them on the signal input to amp
they sure were impressive on the day

[jkeny]

did we have hum with the sd card player aswell as the pc?

No, don't believe we did. I think you may have tracked it down to the PC monitor?

is winding transformers difficult ?
id like to experiment more with them on the signal input to amp

Tedious, I believe especially if using a high number of turns & difficult if very fine wire is being used & the risk of breaking is high but I'm sure Richard can give his hands-on experience with them

they sure were impressive on the day

Yes, agreed

[nige2000]

did we have hum with the sd card player aswell as the pc?

No, don't believe we did. I think you may have tracked it down to the PC monitor?

gnd loop through monitor earth is a common one
i never checked it
anyone with an audio pc needs to check it even if it doesnt hum it often dulls the sound
often fixed by unearthing monitor

is winding transformers difficult ?
id like to experiment more with them on the signal input to amp

Tedious, I believe especially if using a high number of turns & difficult if very fine wire is being used & the risk of breaking is high but I'm sure Richard can give his hands-on experience with them

they sure were impressive on the day

Yes, agreed

tempted to take a crack at it
as the one we tried on the soekris didn't work that great nor sounded good, think we concluded it was the low output of the soekris?
could be a cool solution to funky grounds in hifi

btw john got those chips in the post
thnx

[nige2000]

more booboo's
a great way to kill lm3875 is reverse polarity with 20 cells of lifepo4


prototype ready for new chips

[nige2000]

oh yea fixed this few days ago
back on the road

[sima66]

oh yea fixed this few days ago
back on the road

No more "welding"?! :)

[nige2000]

oh yea fixed this few days ago
back on the road

No more "welding"?! :)

all joking aside ive used less powerful welders

[Sligolad]

Great to hear Nige's amp sounding so good yesterday at Tony's.
Its reputation as a giant slayer is increasing every time we hear it now.

Tony's Jadis was added to the list of amps blown into the wind by this monster performer yesterday, it was a shock to me how much better it was on the day.

Adding a preamp only ended up holding it back which surprised me, looking forward to seeing its release next year and I think all who signed up for the Group Buy realized yesterday just how good a deal this is going to be when we get one in our hands.

Amazing work Nige.

Thanks again Tony for a great day....would have loved to try the pizza but had to run eventually!
Hope that Lampizator is still sounding great and you found all the parts.

[jkeny]

Great to hear Nige's amp sounding so good yesterday at Tony's.
Its reputation as a giant slayer is increasing every time we hear it now.

Tony's Jadis was added to the list of amps blown into the wind by this monster performer yesterday, it was a shock to me how much better it was on the day.

Adding a preamp only ended up holding it back which surprised me, looking forward to seeing its release next year and I think all who signed up for the Group Buy realized yesterday just how good a deal this is going to be when we get one in our hands.

Amazing work Nige.

Thanks again Tony for a great day....would have loved to try the pizza but had to run eventually!
Hope that Lampizator is still sounding great and you found all the parts.

Yes, I concur - the difference between Nige's amp & the Jadis was spectacular in the Bob Marley tracks which really demonstrated the grip on bass & overall balance that Nige's amp demonstrated.

Again, thanks to Tony & appreciate the pizzas but couldn't participate - hope the family enjoyed their pizza diet for the next week?