25W Class A amp with Lateral MOSFETs

Sorry, I don't do reviews any more. My marketing department has been fired... :clown:
:) Its not about review or compare both the amps .. just interested to understand about MP3 sounding good here
.. as most of my source material is in MP3 stuffs .. could you please tell about MP3 being sound nice ..

being a newbie sometimes it's difficult to relate with the adjectives used to describe the sound for example some say sounding warm , (warm relate with heat but not very clear to relate it with sound )
 
:) Its not about review or compare both the amps .. just interested to understand about MP3 sounding good here
.. as most of my source material is in MP3 stuffs .. could you please tell about MP3 being sound nice ..

being a newbie sometimes it's difficult to relate with the adjectives used to describe the sound for example some say sounding warm , (warm relate with heat but not very clear to relate it with sound )


This question deserves its own thread.


Lossy CODER/DECODERs (CODECs) all have a "sound". How each person experiences that sound will likely be different.


I suggest that you record some live sound that is familiar to you (a voice of someone you know well) as an uncompressed WAV file and then compress that file with your CODEC of interest.


Play the uncompressed and compressed files in succession to hear the "sound" of that CODEC.


The earliest CODEC was LPC (Linear Predictive Coding) and that is the "sound" of the Cylon Warriors of the 1980s TV show "Batlestar Gallactica". Very monotone and metallic.


To me, the newer-than-LPC CODECs can sometimes sound like the voice being reproduced in inside of a flushing toilet. These CODECs are what is used in cell phones to make the data stream as compact as possible.


MP3 is just another CODEC. A variant of MP3 is used in the USA for over-the-air FM HD radio.
 
All Lateral MOSFETs of that power/size behave and sound almost the same.

I prefer TO-3P/TO264/TO247 over TO-3 (one hole against four).

Me too. I may have to look long and hard to get the flat-packs. It's just that I have a large number of TO3's from the same batch, and when I saw your excellent circuit diagram, I thought to put all those to good use.

Thanks for all your effort and for sharing, that's very nice of you.

Regards,
Nick
 
What pre for this amp?

Hi,
I've just built this amp and it's just amazing! I have used the Exicon Lateral Mosfets ECX10N20 and ECX10P20 for the outputs, everything else were respected from the schematic. Many thanks for sharing your projects with us!
I've seen many schematics of yours in other threads for the First Watt F4 or F5 Preamplifier and I want to ask you kindly what Pre (designed by you, of course) do you recommend for this amp? Could you share with us a schematic? I'm sure many others will be interested.
Thanks for the answer and kindness!
Regards,
Horia.
 
Hi Phil,
please tell how much gain do you need ?
The amp already has 20 dB (10 V/V). For 6 dB more, just change R2 to 470R and you'll have 26 dB (20 V/V) which should be enough for most sources and just the 10k-25k pot at the input will suffice - amp's input impedance is high enough.
 
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Hi,
I've just built this amp and it's just amazing! I have used the Exicon Lateral Mosfets ECX10N20 and ECX10P20 for the outputs, everything else were respected from the schematic. Many thanks for sharing your projects with us!
I've seen many schematics of yours in other threads for the First Watt F4 or F5 Preamplifier and I want to ask you kindly what Pre (designed by you, of course) do you recommend for this amp? Could you share with us a schematic? I'm sure many others will be interested.
Thanks for the answer and kindness!
Regards,
Horia.

Hi Phil, what changes need to be made when using those Exicon mosfet? Thanks.

~Kecap
 
Hi Phil, what changes need to be made when using those Exicon mosfet? Thanks.

~Kecap

Phil has already informed that everything else is as per schematic.
Exicons are more or less equivalent to renesas parts albeit with 200V rating compared to the 160V for renesas parts.
Replacement for 2SK1058/2SJ162 which are not available any longer.

regards
Prasi
 
Phil has already informed that everything else is as per schematic.
Exicons are more or less equivalent to renesas parts albeit with 200V rating compared to the 160V for renesas parts.
Replacement for 2SK1058/2SJ162 which are not available any longer.

regards
Prasi

Thanks, Prasi, for answering before me! I've just put the Exicons on the boards without any other changes and sound great!
The only change I did was to replace the R2-1K with 475R because I wanted more gain and didn't want a Pre before the Amp. That's all.

Regards,
Phil
 
I highly reccomend this amplifier.....I am using just under 400mA as Iq and sound is superb!

After more than 5 years of living with this wonderfull amplifier, I have tried to make a small change in the circuit...

The idea was to change the feedback into two seperate loops, one DC and one AC, but keeping the gain as standard...

C10/C17 was exchanged with R2, so R2 now is connected to ground. R2 is changed from 1k to 470R (halfed).
Then a AC-second loop is made with a 10k resistor from output terminal to junction between C10/C17 and R2.

My simulations of the change, shows better bandwith and higher PSRR, but I don't know how reliable this is....but including the output capacitor in the loop makes the sound change to my liking...

:)
 
Hi Skorpio,
I tested your 2-loops idea and it brings some improvement indeed :up:
I also changed the input device into N-JFET which made some other changes necessary and the whole thing now looks like this (and sounds somewhat better) :)


Please don't ask me about parts substitutes, power increase or to compare it with other amps/designs....
 

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