Lateral Mosfet amplifier circuit

passive420

Member
2013-06-11 3:39 pm
Browsing the web looking for interesting amp circuits specifically using lateral mosfets and found this one on electronics-diy.com here

I have attached the downloadable pdf schematic image below which shows the 50W version, however the web page itself shows the 100W version with two pairs of mosfets.

Would the forum mind giving the circuit a glance and any opinion as to whether it is a decent implementation. Importing the circuit into LT spice would certainly be a good learning project but hopefully someone can confirm it is a worthy amplifier.

I apologise if this circuit has been discussed, it has no official name as far as I can tell, so could not search for it.
 

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Hi passive420,

I've got a finished project - although there are some important differences - it's a similar overall arrangement and two pairs of Hitachi/Renesas Lateral FETs at the output:

TubSuMo hybrid with Lateral FET OPS

It can be built with jFETs at the input - LTP degeneration has to be increased in this case (R5, R10) - 2SK117 or 2SK170 will be good there. Although I like the tube at the input a lot. 12AU7 works well with the low anode voltage.

The one you're showing is a working circuit, but it requires some work for at least replacing some obsolete active devices and then re-checking the compensation, layout development, etc.

Could be an interesting project if you dare ;)

Cheers,
Valery
 

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kasey197

Member
2009-09-08 9:29 am
Browsing the web looking for interesting amp circuits specifically using lateral mosfets and found this one on electronics-diy.com here

I have attached the downloadable pdf schematic image below which shows the 50W version, however the web page itself shows the 100W version with two pairs of mosfets.

Would the forum mind giving the circuit a glance and any opinion as to whether it is a decent implementation. Importing the circuit into LT spice would certainly be a good learning project but hopefully someone can confirm it is a worthy amplifier.

I apologise if this circuit has been discussed, it has no official name as far as I can tell, so could not search for it.

Without commenting specifically on this schematic or on Valery's always excellent designs, I think its worth asking why so many parts ?

You can make a pretty excellent lateral amp with four active devices (zenquito or F5 variants) - so if you're going to start adding many more devices its worth asking what these additional parts will give you in return for the trouble.

Eg. Maybe we'll add devices for lower measured distortion at possibly lower idle dissipation ? Or perhaps you need a lot more power ?

If these objectives are not important to you, then simpler design is the right one.
 
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The first post is Suzy Jackson's reworking of a design by David Tillbrook. She used to have full details about it, and a preamp she designed, on her website. However I believe she took the contents down due to an unscrupulous Chinese ebayer having stolen her design + PCB, selling it for profit. Such a shame.
 
Well I'll be damned jaycee, a search for AEM6000 reveals a few threads here. Thought there would have been.

The Connex Suzy Jackson boards look very good indeed, I love SMD and would be tempted but buying ready made amp boards takes the fun out of it slightly. LazyCat's amps would be a good choice for ready made latfet amps.

Thanks all, most helpful. Hopefully some of Valery's boards will on their way.