UcD like topology amp.

[wimdehaan]

2 weeks ago I finished my PCB and did change the input opamp to a 8 DIL version instead of SMD. I did practise my SMD soldering using a microscope and a Weller SMD station, it looks pretty good after some practising, even using my normal solder station I am now able to solder SMDs.

Will the V3 version PCB layout and circuit be published here? So shoud dI wait before buying the components for the original Cakeamp class d amplifier?

[annton]

Originally posted by wimdehaan
For those who are interested. I do have 40 new never used still in packiging IRFI4212H-117P mosfets. You can reply this message on this forum and i will answer. Will shipped from Holland and price is 80 euros, exlcuding shipping. I will only send as registrate mail. Wim
I have to many projects and just can't finish them all, my time is limited at the tiem and coming time.

You still got some spare IRFI4212?

[annton]

One more stupid question. Is the half core listed on farnell ungapped?

[Bender.ru]

Hi, annton!

i use ungapped EPCOS RM8, RM10 cores, material N87. Gapped it by myself.


Hi, wimdehaan!

v3 just prototype, i didn't test & measure it, may be later post some docs, but not soon :-).

[wireland]

Originally posted by annton


You still got some spare IRFI4212?

I have the same question.
(Not that I dont have my own sch/PCB plans, but the price is quite good for 1 eur per FET indeed.)

And one another.

What if I use a FET with Qrr of 2000+ nC? (like IRFP series)
Do I need to bypass the body diode?
Will I need a separate gate driver like IR2110? In any case, would it do any good?
Maybe any of them?

Any artefacts?

Or will the chip cope with driving the FET into closure?

Yeah, sorry, I know that I should RTFM, but I am quite new to integrated stuff in this area.

Anyway, there are some obvious stupidness in this thread (maybe intentional).
Like ordering a separate airgap with the cores, or using 2 cores for double airgap

Excuse me, I am not a "builder" more than a planner, and I am quite mediocre in some aspects.

crusher

[Bee]

Hi Bender

Did you gap the RM10 core by fitting a 1mm spacer? Or did you gap just the centre pole? If so - how?

[Eva]

Note that gapping all legs of the core results in a big stray field. Ideally only the center leg should be gapped, although this has its own disadvantages like more magnet wire heating, but it's not as harmful as the stray fields.

[Ouroboros]

Don't forget that when you buy gapped RM cores, that only one core half has the shorter centre leg. The other half has the centre leg level with the outer ones.
For the prototypes of a bridged 400W amplifer design I am doing for my employer, I used ungapped N87 ferrite RM cores bought from Farnell, and used bits cut off an old credit card to gap them. As Eva says, this does give some external magnetic field (which has the main effect of making the steel clips holding the core halves together 'sing' along with the audio signal), but it allows the use of the easier-to-obtain ungapped cores.

[Bender.ru]

Hi Bee

I gap only center leg. Eva told about reason to do it that way .

here is some pics of my technic (post #1), it allow to form any gap i need with tolerance +/- 0.01mm:
http://www.vegalab.ru/forum/showthread.php?t=12973

[Bee]

Would these larger stray fields cause any interaction between two modules?

Bender, I'm impressed! I don't speak Russian, but I understand Google Translator a little, so I see what you are doing. But if you are only holding the tray in your hand, how do you get the diamond burr to take an even amount off from all over the leg surface?

Anyone else tried gapping an RM core?