TPA3255 - all about DIY, Discussion, Design etc

[DarkOne]

DarkOne, if audio band captured correctly, S/N is too bad -60-70db(A) like 10-12bit. Probably the problem is low-resolution ADC you used.

Its only poor old USB scope, I have no audio measurement rig.

 

[29285]

Not sure if its useful, here is FFT with inputs shorted to ground.

I do not think this is very useful, because FFT-level depends on the bandwidth of FFT bins. A useful number was an A-weighted level measurement which can be obtained with a soundcard and a software like ARTA.

The plot attached shows TPA325x output noise on the left channel, on the right channel the noise of the soundcard as a reference.

 

[DarkOne]

I do not think this is very useful, because FFT-level depends on the bandwidth of FFT bins. A useful number was an A-weighted level measurement which can be obtained with a soundcard and a software like ARTA.

The plot attached shows TPA325x output noise on the left channel, on the right channel the noise of the soundcard as a reference.

I dig out my old sound card ESI Juli@ from a bin and as soon as I find TRS cables that are long enough I will hopefully measure something

 

[JMF11]

Hi,


Sourcing of inductors: is there a reasonable source for Codaca CSCF2014-6R8M ? They don't appear in classic components sellers, nor in Aliexpress :-(


I saw that in 2017 the minimum batches were 200 pieces directly from the manufacturer.


Has a better option been identified yet ?


I understand that the alternative is to buy Wurth inductors directly from them.


Best regards,


JMF

 

[IVX]

JMF11, they have Sagami's clones as well, why you don't like something like CPD1715F?

 

[earsofgold]

TPA3255 board is back in stock at 3e Audio ebay.

TPA3255 2x260W 2Ch Class D Audio Amplifier | eBay

I bought one, only 3 left now! They have a mono one as well.

 

[doctormord]

Hi,
Sourcing of inductors: is there a reasonable source for Codaca CSCF2014-6R8M ? They don't appear in classic components sellers, nor in Aliexpress :-(
Has a better option been identified yet ?


JMF

Ferrocore from TME:
HCI2114-7R0

HCI2114-7R0 FERROCORE - Inductor: wire | TME - Electronic components


Bourns PQ2614BHA-6R8K:
PQ2614BHA-6R8K Bourns | Mouser Deutschland


Be aware, these are a bit bigger in dimension, comparable to Coilcraft SER2915/18 series.

 

[doctormord]

A cheap test candidate might be the Sumida CDEP147NP-6R1MC-95 or
CDEP147NP-7R7MC-95



Digikey:
308-1608-1-ND
308-1609-6-ND

 

[irs20957]

Сheap RM8+ cooper wire)))
HandMade)))

 

[IVX]

I didn't ask Miden but Senija once offered me Sagami style coils with the aside gap. It could reduce idle power dissipation(fewer eddy currents). The drawback is the gap has to be 1.5-2 times bigger, hence there is noticeable less room for a copper.

 

[JMF11]

Thanks Doctormord for the advices about the inductors. This is very helpful.


IVX, it seems unfortunatly not reallistic to source those nice Codaca indusctors here.


JMF

 

[IVX]

JMF11, I don't know Codaca but Miden and Senija can supply a small bunch of coils. At least Miden asked me just 30RMB(12RMB delivery included) for 3pcs samples with customized inductance. Senija makes for me samples for free(but actually slooow)

 

[doctormord]

...it seems unfortunatly not reallistic to source those nice Codaca indusctors here.

Right, you'll need a minimum order qty of about 200pcs per value but depends on modell. They do offer sample shipping. I once had CSCF2014-6R8M sampled at $1.60 each + $32 shipping and handling.


Is Miden a manufacturer or reseller? As they list Coilcraft and Sagami but state "Brand: Miden" it is not clear if they sell knock-offs, genuine brand or own "rebrands".

 

[irs20957]

handmade inductors

handmade inductors

 

[doctormord]

Any data available?

Isat for 10/30%, L vs f, L vs Temp, L vs I, Idc vs Temp-rise, Coreloss, DCR

 

[irs20957]

Calculations are made in "Ferrite Magnetics Desing Tool"

 

[irs20957]

Next version PCB i may be using unductor Sagami

 

[IVX]

irs20957, you can try to use EP type standard core, which is pretty similar to sagamy shape. BTW, today I measured MIDEN HPFS1719A, the result is noisy but anyway L=-20% current is less than could be

 

[doctormord]

Calculations are made in "Ferrite Magnetics Desing Tool"

Proper Y-Axis scaling would be nice because linearity is just a matter of scaling.

 

[irs20957]

See this))