2stageEF high performance class AB power amp / 200W8R / 400W4R

[astx]

...
Tomorrow I will fire up the amp's PSUs for the first time and then couple them up on the bench.

Congratulations! Nice test setup! Your heat spreader designed for MODU case series "Pesante Dissipante" looks very good!

BR, Toni

 

[astx]

housekeeping circuits - new hardware version 4

... more SMD parts ...
... prototype board ready for programming...

Have fun, Toni

 

[thimios]

... more SMD parts ...
... prototype board ready for programming...

Have fun, Toni

Nice and compact design!

 

[ArDean]

can u help me to add ne5532 to ltspice model please.
thank you

 

[astx]

can u help me to add ne5532 to ltspice model please.
thank you

Your question is a bit out of topic ...

• Extract attached zip file.
• Copy "NE5532.asy" to your LTSpice symbol directory (e.g. c:\Program Files\LTC\LTspiceIV\lib\sym\Opamps)
• Start recent version of LTSpice and load the attached asc file "ne5532_opamp_sim.asc".
• Run simulation

How to add your own symbols/models: Adding a permanent component to LTspice - LTwiki-Wiki for LTspice

More libraries can be found at LTspiceIV-library Library Listing Expanded - LTwiki-Wiki for LTspice

BR, Toni

 

[astx]

Nice and compact design!

Thanks!

New "mains inrush control" pcb: I2C library ported to pic16f1829.

Prototype is working:

• able to detect and feed data to LCD display
• able to detect and read up to 8 additional LM75 temperature sensors
• WIP for MCP23008 and MCP23016 port expanders

BR, Toni

 

[ArDean]

out of topic i am really sorry, but thanks alot for the attachment zip file
you are so kind thanks again n success for u always

 

[SGK]

Very cool!

 

[mkc]

Hi Toni,

I have a "what-if" question regarding your MT2015-50W. I have seen you are running ~28VAC transformer and you have measured ~80W in 8 ohm. How much will I violate SOA I change the transformer to 33VAC?

Thanks,
Mogens

 

[astx]

Very cool!

Thanks!

Hi Toni,

I have a "what-if" question regarding your MT2015-50W. I have seen you are running ~28VAC transformer and you have measured ~80W in 8 ohm. How much will I violate SOA I change the transformer to 33VAC?

Thanks,
Mogens

Dear Mogens,

it should be SOA save to use this transformer. This would give a maximum of +/-52V DC supply (33*1,41 + 10%).
I will drive my SA2015 4 channel amp with +/-45V DC (~ max. 50VDC).

BR, Toni

 

[mkc]

Hi Toni,

Thanks. Also, in post #1422 there is a picture where the back of the mosfets can be seen. What is the meaning of what is written on the mosfets? mA at fixed Vgs? What is your experience with matching of Mosfets from the same tube?

Sorry for all the questions.

Thanks,
Mogens

 

[astx]

...
What is the meaning of what is written on the mosfets? mA at fixed Vgs? What is your experience with matching of Mosfets from the same tube?
...

Dear Mogens,

the numbers are the order in which they appeared out from the tubes...
As you can see, there are big distances between numbers so even from the same tube/lot you can expect big variations.
E.g. I have bought > 150 pieces each to get enough good matched devices out from. Here an example of one tube of IRFP240:

#       Vgs_low V       Vgs_high V
001     3.440   3.926
002     3.442   3.928
003     3.436   3.925
004     3.442   3.932
005     3.448   3.938
006     3.458   3.949
007     3.460   3.953
008     3.464   3.957
009     3.465   3.959
010     3.476   3.970
011     3.333   3.819
012     3.324   3.808
013     3.317   3.803
014     3.367   3.849
015     3.362   3.846
016     3.359   3.844
017     3.347   3.831
018     3.344   3.829
019     3.359   3.845
020     3.366   3.854
021     3.372   3.859
022     3.378   3.862
023     3.380   3.863
024     3.371   3.856
025     3.369   3.855

If we sort this data ...

#       Vgs_low V       Vgs_high V
013     3.317   3.803
012     3.324   3.808
011     3.333   3.819
018     3.344   3.829
017     3.347   3.831
016     3.359   3.844
019     3.359   3.845
015     3.362   3.846
014     3.367   3.849
020     3.366   3.854
025     3.369   3.855
024     3.371   3.856
021     3.372   3.859
022     3.378   3.862
023     3.380   3.863
003     3.436   3.925
001     3.440   3.926
002     3.442   3.928
004     3.442   3.932
005     3.448   3.938
006     3.458   3.949
007     3.460   3.953
008     3.464   3.957
009     3.465   3.959
010     3.476   3.970

... you can see there are not very much good matched triple candidates if you set your difference limit to e.g. max. 10mV.
P-Channel MOSFETs (IRFP9240) are even worse.
You may need to buy 2 to 4 times more IRFs as you need for your project.

BR, Toni

 

[mkc]

Hi Toni,

Thanks. I will buy 50 of each then, and see if that isn't enough to get good pairs for 4 of MT2015-50W. TME seems to have them at a reasonably price.

Cheers,
Mogens

 

[astx]

...
TME seems to have them at a reasonably price.
...

Fortunately IRFP240 and IRFP9240 are really cheap compared to classical audio power transistors. Hopefully they will be available for a long time ...

 

[mkc]

Hi Toni,

Do you know if the Vishay P-channel has the same transconductance anomaly as the IRF P-channel type? I think I read a comment by Bob Cordell that the Vishay type didn't have it. But, I have not seen any tests confirming this.

Mogens

 

[dadod]

Hi Toni,

Do you know if the Vishay P-channel has the same transconductance anomaly as the IRF P-channel type? I think I read a comment by Bob Cordell that the Vishay type didn't have it. But, I have not seen any tests confirming this.

Mogens

Use different source resistors value for P type, one example is here. http://www.diyaudio.com/forums/solid-state/243481-200w-mosfet-cfa-amp-92.html#post4580555
I bought IRFs from TME and they are quite good matched if from the same batch.

 

[mkc]

Hi Dadod,

Thanks. That's good to know. Also, as I wrote to Toni in a PM, TME appears professional and the 2 times I have bought from them everything has been fine and shipment fast.

Mogens

 

[astx]

SA2015 current sharing resistors

Don't see any benefit using asymmetric source (current sharing) resistors.
Keep in mind if you change source resistors you need to redesign or omit the current limiter.

BR, Toni

 

[astx]

I'm planning to provide a limited number of KCS (key component sets) for hard to get parts to build SA2014 or SA2015 or housekeeping. Is there a need for the housekeeping V4 to provide 230V and 115V?

BR, Toni

 

[SGK]

Me!

I will relocate to the US at some point in the next few years. Maybe quite soon.