Cool, using PC power supply scrap for driver HS ..True DIY..
This is the main reason for my visits to DIYaudio .. to see
people improvise and use the bounty of garbage to
create better "mousetraps".
One can have a killer amp with garbage.., check out
this monster tranny for Quasi amps....
45-0-45/ 600VA and 18-0-18 at 150VA(perfect for rear channel
chipamp) for 0$..
And 2 nice flatscreens to run the "cheetah" (4 -1uf 50v caps
in SMPS) 2$ = 400$ free flatscreens..What a good day at
the dumpster!!
PS.. I see everyone uses toroids for quasi amps ,is there any
drawbacks to use a standard squareblock transformer . Also
If I run a lm3886 gainclone off the smaller secondary, would that
affect the performance of the main amps.??
thanks in advance..OS
This is the main reason for my visits to DIYaudio .. to see
people improvise and use the bounty of garbage to
create better "mousetraps".
One can have a killer amp with garbage.., check out
this monster tranny for Quasi amps....
An externally hosted image should be here but it was not working when we last tested it.
45-0-45/ 600VA and 18-0-18 at 150VA(perfect for rear channel
chipamp) for 0$..
And 2 nice flatscreens to run the "cheetah" (4 -1uf 50v caps
in SMPS) 2$ = 400$ free flatscreens..What a good day at
the dumpster!!
An externally hosted image should be here but it was not working when we last tested it.
PS.. I see everyone uses toroids for quasi amps ,is there any
drawbacks to use a standard squareblock transformer . Also
If I run a lm3886 gainclone off the smaller secondary, would that
affect the performance of the main amps.??
thanks in advance..OS
I have posted about E-type (square) vs. Toroid transfomers
a number of times through my years here at www.diyaudio.com
But if you do not read my posts, why should I bother to repeat my self. Again & again.
To every new comer here in forum, like ostripper
I have nothing against using, re-using E-type trafos.
As a matter of fact, I bough some big 100 VA from surplus sale some 10 years ago.
And they work really well.
I also happen to know there are a great number of members here, doing the same as me.
I have even re-winded secondary of one of those.
To get the custom Voltage I need.
For use with one N-Channel Class A amplifier.
Here is my image of this diy E-type transformer work of mine.
Lineup transformer re-winding factory
a number of times through my years here at www.diyaudio.com
But if you do not read my posts, why should I bother to repeat my self. Again & again.
To every new comer here in forum, like ostripper
I have nothing against using, re-using E-type trafos.
As a matter of fact, I bough some big 100 VA from surplus sale some 10 years ago.
And they work really well.
I also happen to know there are a great number of members here, doing the same as me.
I have even re-winded secondary of one of those.
To get the custom Voltage I need.
For use with one N-Channel Class A amplifier.
Here is my image of this diy E-type transformer work of mine.
Lineup transformer re-winding factory
Attachments
There are 1 million posts plus here, lineup
I am not god to read them all.
Neat to rewind, never found the time, there is to much junk to
choose from here!! Amps are new to me , as you see I do
everything .. screens,TV, PC ,software,etc.
But I like DIY spirit,to rewind,remanufacture, reverse engineer.
It is fun and rewarding to produce better stuff from nothing!!
As you see I,m just "getting it together" new screens ,pico
PC scope(real cheap), Many good amp parts to make 5
amps which I will post soon...
I am not god to read them all.
Neat to rewind, never found the time, there is to much junk to
choose from here!! Amps are new to me , as you see I do
everything .. screens,TV, PC ,software,etc.
But I like DIY spirit,to rewind,remanufacture, reverse engineer.
It is fun and rewarding to produce better stuff from nothing!!
As you see I,m just "getting it together" new screens ,pico
PC scope(real cheap), Many good amp parts to make 5
amps which I will post soon...
hi quasi
i powered my
everything checked all was ok
first i checked with 40-0-40 3 amp transformer auxilarry rail tied to
positive rail but i cold not set my biasing the voltage does not go over 4.5 volts across positive rail resistor (100 ohm ] . then i switched actrk600 with 70-0-70 auxilary 85 volt dc again the same thing .once i blew my 100 ohm resistor .checked everything all ok iam using 33pf instead of 39pf does that make any difference.mosfet source resistors are 0.5 ohm
http://i35.tinypic.com/30icdqp.jpg
http://i35.tinypic.com/k0lfmo.jpg
http://i34.tinypic.com/szk3us.jpg
i powered my
everything checked all was ok
first i checked with 40-0-40 3 amp transformer auxilarry rail tied to
positive rail but i cold not set my biasing the voltage does not go over 4.5 volts across positive rail resistor (100 ohm ] . then i switched actrk600 with 70-0-70 auxilary 85 volt dc again the same thing .once i blew my 100 ohm resistor .checked everything all ok iam using 33pf instead of 39pf does that make any difference.mosfet source resistors are 0.5 ohm
http://i35.tinypic.com/30icdqp.jpg
http://i35.tinypic.com/k0lfmo.jpg
http://i34.tinypic.com/szk3us.jpg
ostripper said:There are 1 million posts plus here, lineup
I am not god to read them all.
Neat to rewind, never found the time, there is to much junk to
choose from here!! Amps are new to me , as you see I do
everything .. screens,TV, PC ,software,etc.
But I like DIY spirit,to rewind,remanufacture, reverse engineer.
It is fun and rewarding to produce better stuff from nothing!!
As you see I,m just "getting it together" new screens ,pico
PC scope(real cheap), Many good amp parts to make 5
amps which I will post soon...
No, I really did not think you should go read my 3000 posts, to find a couple about E-type Transformer.But is quite easy to find those posts, wehere I inform about SQUARE Old trafos:
- 1. http://www.diyaudio.com/forums/search.php
- 2. Author = lineup
- 3. Find all posts including this word: e-type
Rewind transformers secondary:
- hard work!
- difficult to take apart, rewind & put together again
- without some trafo winding machine is it really h
llravslanka said:
You say 33pF instead of 39pF.
If you mean those small feedback / compensation caps.
This is not the way .....
More SAFE to use 47 pF or even 68, 100 pF.
Higher value = stabilty, a bit slower amplifie
Lower value = in-stability, a bit faster amplifier
Be careful NOT go down in value from what Quasi recommendation
.. because this comes CLOSER to In-Stability
and maybe Some S-M-O-K-E
I’m working on this NMOS500W a couple of days ago and still searching for some of the components. If someone have doubt please give some advice. Only change I made C7 cap replaced with 100/25v.
http://i34.tinypic.com/2ex1o4l.jpg
http://i36.tinypic.com/149zfd1.jpg
http://i33.tinypic.com/153nvd3.jpg
http://i33.tinypic.com/34825jc.jpg
Bushulo
http://i34.tinypic.com/2ex1o4l.jpg
http://i36.tinypic.com/149zfd1.jpg
http://i33.tinypic.com/153nvd3.jpg
http://i33.tinypic.com/34825jc.jpg
Bushulo
In the schematic shows C7 = 100 uF
If you mean Voltage rating of C7 .. it is not very critical.
There will only be some 0.1 Volt across that cap, normally.
At start up, there may be a bit higher voltage.
For some milliseconds (0.001 sec) only.
But the chance this cap would be destroyed, is minimal.
Even if using 100uF/10Volt cap.
( I can see quasi recommends 100uF/63V .. this is only for 100% safety.)
One trick, to be able to use for example one good bipolar capacitor rated Very Low Voltage,
would be to put two 1N4148 across this cap.
One diode in each direction. (Antiparalleled).
This would limit Voltage across cap C7 to ~0.7 Volt max, at any time.
We see this trick some times used in Power Amplifiers.
This way we can use very good capacitor
with as low Voltage rating as 5 Volt DC.
If you mean Voltage rating of C7 .. it is not very critical.
There will only be some 0.1 Volt across that cap, normally.
At start up, there may be a bit higher voltage.
For some milliseconds (0.001 sec) only.
But the chance this cap would be destroyed, is minimal.
Even if using 100uF/10Volt cap.
( I can see quasi recommends 100uF/63V .. this is only for 100% safety.)
One trick, to be able to use for example one good bipolar capacitor rated Very Low Voltage,
would be to put two 1N4148 across this cap.
One diode in each direction. (Antiparalleled).
This would limit Voltage across cap C7 to ~0.7 Volt max, at any time.
We see this trick some times used in Power Amplifiers.
This way we can use very good capacitor
with as low Voltage rating as 5 Volt DC.
rvalanka,
The holes on the pcb for fixing the screws for the power transistors are small. Small in the sense that the head of the screw should pass through this pcb hole. If u fix the transistor along with the pcb to the heatsink, the transistor will make poor contact to the heatsink as its position will be restricted by the leads. Also, if u tighten these scews over the pcb, it will definitely break.
Gajanan Phadte
The holes on the pcb for fixing the screws for the power transistors are small. Small in the sense that the head of the screw should pass through this pcb hole. If u fix the transistor along with the pcb to the heatsink, the transistor will make poor contact to the heatsink as its position will be restricted by the leads. Also, if u tighten these scews over the pcb, it will definitely break.
Gajanan Phadte
Wasim wrote
Now that u have constructed the Nmos350, and u want to use it, it will be better if u make a separate sub woofer from scratch. This is because your existing powered sub woofer cannot be connected to it.
Even if u disconnect the internal amp of your existing sub woofer, the driver most probably does not have the 350Watt power handling capability(this is an assumption and will be 99% correct).
Remember, I do not recommend to tear open the sub woofer as it will loose its construction integrity.
If u want to know the reasons to the first para, visit http://sound.westhost.com/
Gajanan Phadte
Now that u have constructed the Nmos350, and u want to use it, it will be better if u make a separate sub woofer from scratch. This is because your existing powered sub woofer cannot be connected to it.
Even if u disconnect the internal amp of your existing sub woofer, the driver most probably does not have the 350Watt power handling capability(this is an assumption and will be 99% correct).
Remember, I do not recommend to tear open the sub woofer as it will loose its construction integrity.
If u want to know the reasons to the first para, visit http://sound.westhost.com/
Gajanan Phadte
gmphadte said:Wasim wrote
Now that u have constructed the Nmos350, and u want to use it, it will be better if u make a separate sub woofer from scratch. This is because your existing powered sub woofer cannot be connected to it.
Why? and if I construct a sub-woofer from scratch how could i connect that with Nmos.
Even if u disconnect the internal amp of your existing sub woofer, the driver most probably does not have the 350Watt power handling capability(this is an assumption and will be 99% correct).
My sub woofer is 500Wrms 4ohm.
Remember, I do not recommend to tear open the sub woofer as it will loose its construction integrity.
If u want to know the reasons to the first para, visit http://sound.westhost.com/
Gajanan Phadte
Wasim said:
Wasimbhai
You will have to disconnect the internal amplifier from the driver first. See if you can remove the driver and access the amplifier, do not attempt to dismantle the enclosure. Once you have access inside, disconnect the amplifier from the input terminals and from the driver. Once this is done, you can connect the NMOS output to the driver. Always remember, do not connect the output of one power amplifier to the input of another one, there's bound to be a lot of fireworks!!!
Hari