My MOSFET amplifier designed for music

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The - 3db point is at around 120 Khz for the power amp alone, and around 100 khz for the amp as a whole. This picture shows that point where the output is - 3db down. At this point there is obvious phase shift of course.
I have one confession to make now :) The amp is to the circuit details posted of course and on carefully designed PCB,s, however there is one difference, C2 the 150 pf cap at the input is NOT fitted. The amp is 100% stable but it seemed "prudent" to include it if anyone was going to have a go perhaps on veroboard or similar ( Space, why did I just think of you :D :D ).
 

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And as the sun was shining (Light is everything with a 29.99 camera :) here is another shot of the internals, preamp along the side with FET switching done as near the inputs as possible. The board at the bottom left is a remote decoder, made from discrete logic ( pic programming is something I must get into ).
Each amp module has it's own offset protection on the PCB to the right of each "can". Note the orange earth bonding wire along the front top edge of the case.
And that's about it really.
 

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Hi Kle,
The tranny is a 300 va feeding a single bridge.
The main caps are 4700/63 volt high ripple types. There is further "local" decoupling (Around a 1000 mfd total per rail per amp) on the PCB's to the left of each can and finally 220 mfd actually on board next to the MOSFET's. To the left of the bridge and caps -- you can't see it in the picture-- is a series regulator (pre reg) that give +/-25 volts. This feeds the preamp which has local shunt regulation for all the active stages.
The case is earthed and the orange wire is an earth bonding wire to really make sure both sides of the case are at the same potential rather than relying just on cabinet screws etc.
The heatsinks !! The heatsinking capacity is actually better than it might look. The cans were from two Sony Betamax videos (SLC9) and were perfect for making amp modules in. I designed the PCB's to be an exact fit. The MOSFET's are clamped internally using the original "chopper transistor" hardware. There is a small integral heatsink at the rear, but this is helped by the fact that the "Aluminium can" is both thick and sandwiched between the heatsink and the internal plate the transistors are on. So it's all "one" big heatsink really, nice ventilation holes in it and the top plate of the case has slits in just the right place. Add then the fact it's all bolted to a metal case as well and it's all pretty good. The amp runs cool (almost cold) even after several hours, and even after say 1 hour of really serious :) listening it's only warm at the back, and cools back down within minutes.

No comments on the oscilloscope square wave testing anyone :)
 

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Hello Zeonrider,
I'm puzzled :) You have asked this before so I feel I am not understanding your question properly. Please can you explain. This is the plan of the listening room, same as I posted before :)
 

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update of amp.

Hi mooly,

I didn't blown off ha...ha....when i was making 60v*2 =120v Dx amp, it didn't blown me off too but i got shocked few times so its nothing with compare DX power supply. This amp is very cold running..one things is very good that it won't blown any components easily. I even did wrong with it but didn't eat any transistors at all. I was listing this amp this few days about two hrs each day to find any wrong. Now it is on my another table. i have made another channel. Trying to make heat sink. i will be making heat sink for my all amps. You have seen that heat sink is not good at all.

I will be making circular heat sink for few amps. I just posted this on to another thread. Small one will be 10inch size for mooly amp two channels, since its working nice, I don't want to change anything’s on this circuit. 12 inch 2 pcs will be for DX turbo(future amp) and for my class A - Aleph-3 will be 12inch 4 pcs.
Aleph-3 alrady finished and listing too, Nice and clean sound.

All will be made soon as long as I can get full data. Also need to think the box design will be made for this. Two amps already booked by my friends. I never profit money from here only they are paying my costing.

They enjoyed the sound quality. I don’t have oscilloscope and honestly I don’t even know how to use it. I use my sharp ear to listen, how clean the sound. God gave me good listing ear...ha….actually I am playing violin and piano.


The amp vocal is not very sonic its nice but still lack of sonic feels like rough, high freq is nice with a bit distortion (broken and missing signal). I think its won’t be solve due to crossover distortion as all the AB amp suffering. Anyway you all can make without any dough, it will works 100%. As I am so stupid on electronics, I can make why you can’t?


Thank you
michael
 
Re: update of amp.

space2000 said:
1. Aleph-3 already finished and listing too, Nice and clean sound ...

2. They enjoyed the sound quality ...

3. The amp vocal is not very sonic its nice but still lack of sonic feels like rough, high freq is nice with a bit distortion (broken and missing signal) ...
Hi space2000

Do you prefer the Aleph-3 to Mooly's amp?

Does point 2 refer to the Aleph-3 or to Mooly's amp?

Point 3 must refer to Mooly's amp, so are you saying that Mooly's amp does not have an accurate midrange?

thanks
:)
 
Hi,
The driver emitter being directly coupled to the output, thereby 100% feedback used, the stage now is a voltage follower with low output impedance, opening the door for an even more musical sound without GNF. The input stage could have a Renardson-like topology, which is considerably more linear than Mooly`s.
 

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Lumba Ogir said:
Hi,
The driver emitter being directly coupled to the output, thereby 100% feedback used, the stage now is a voltage follower with low output impedance, opening the door for an even more musical sound without GNF. The input stage could have a Renardson-like topology, which is considerably more linear than Mooly`s.
Hi Lumba Ogir

Are you able to alter Mooly's schematic to show us what you mean. Especially for me because I am not very good at this.

thanks
:)
 
Re: Re: update of amp.

KLe said:

Hi space2000

Do you prefer the Aleph-3 to Mooly's amp?

Does point 2 refer to the Aleph-3 or to Mooly's amp?

Point 3 must refer to Mooly's amp, so are you saying that Mooly's amp does not have an accurate midrange?

thanks
:)


hi,

two amps are totally dfrrnt then each other. there construction to every things. mooly amp is class AB and aleph is class A. there is few things are prn and crn.

molly amp has deep bass like class AB usually have it. high tone is nice with moderate perfection as it is AB. mid not really very sonic but nice to listen. its running very cold...no problem to deal with heat. over all is nice as it is AB amp. easy to make no need worry about over heating. very stable. i made in one day and its works. i never spoiled one pc components on mooly amp.

Aleph-3 class A amp (not easy to build). it has 100% fine high and sonic in mid tone but low bass a bit wek. bad is only for 30w have to use huge power supply and the heat sink. worst problem is the heat. most of the works have to do on heat sink.That is really really bad. i already spoiled 21 IRF9610 mosfets on it, until now i don't know what cause it was but i had finally managed it. i found very sensitive on soldering iron. overall nice clean sound but there are many things to consider.

have to match IRF9610 and IRF240. i took 12 pcs from 27 mosfets for matching purpose. i spend $$ lots for making class-A. anyway i suces at last. (this part will cost u some money).


all this are base on my own exp. choice is yours now. you can make aleph or mooly. i have done both....easy to make is mooly, hard to make is aleph-3.


best regards
michael
 
hi mooly,

For signal source is DVD player and my speaker is twin 8inch type woofer with mid and twtr. it is tower type speaker box. huge bass can be produce from its. even my windows can shake including heavy TV. i never use sub amp. i think i don't need sub. but For class A amp may be will require sub.

anyway have you seen the heatsink?

thank you.
michael