Carlos illustrated before that they only need 1 square inch of plate for heatsinks each... I have tiny TO220 sinks on mine and I can't feel them heat up at all.
Just make sure the transistors are isolated from each other if they are going to share a sink... that one from a PC power supply?
Just make sure the transistors are isolated from each other if they are going to share a sink... that one from a PC power supply?
No problems...keep the big ones!
Will work cool this way...... less bias drift..... will help you to work stable.
Keep them in place.
regards,
Carlos
.........................................................................................................
Nordic
He is using the big one because have not tools to cut the metal.
Bigger is better than smaller..... your size is perfect Nordic.....but having bigger will not produce problems.
You output transistor, for example, are working warm...they will last for ever..... your grandson will be listening Dx amplifier.... as working cold, only electrolitic condensers will need replacement in 50 years more.
regards,
Carlos
Will work cool this way...... less bias drift..... will help you to work stable.
Keep them in place.
regards,
Carlos
.........................................................................................................
Nordic
He is using the big one because have not tools to cut the metal.
Bigger is better than smaller..... your size is perfect Nordic.....but having bigger will not produce problems.
You output transistor, for example, are working warm...they will last for ever..... your grandson will be listening Dx amplifier.... as working cold, only electrolitic condensers will need replacement in 50 years more.
regards,
Carlos
A very good idea to check bias and offset once more.
Zero is correct.... no oscilations.... perfect.
And after you finish...let the amplifier running into some resistive load.....do not need to be full power as you will have problems with the resistance heat....but force it to warm a little.
You can use a hair drier to heat it up too.
Then check you bias once more..... do not re-adjust.... as when turn cold it will return to the stand by point once more.
Will be a good experience to see the thermal drift.
Are you using VBE multiplier?
regards,
Carlos
Zero is correct.... no oscilations.... perfect.
And after you finish...let the amplifier running into some resistive load.....do not need to be full power as you will have problems with the resistance heat....but force it to warm a little.
You can use a hair drier to heat it up too.
Then check you bias once more..... do not re-adjust.... as when turn cold it will return to the stand by point once more.
Will be a good experience to see the thermal drift.
Are you using VBE multiplier?
regards,
Carlos
Reduce your bias to 600 milivolts over 10 ohms resistance
This way you will have it cool.
The temperature will be hard to feel touching.
Those drivers current are limited by the 180 ohms resistance that is installed "floating" between drivers emitters.
You can increase a little if you need.... till 270 ohms will work fine.
Increasing you will perceive more treble.... decreasing the effect will go to bass.
You will have around 4 to 4.5 watts of heat during stand by mode...without signal.... this heat will be perceived when the heatsink is too much small.
Tweaking this resistance you will need to readjust your amplifier.
regards,
Carlos
This way you will have it cool.
The temperature will be hard to feel touching.
Those drivers current are limited by the 180 ohms resistance that is installed "floating" between drivers emitters.
You can increase a little if you need.... till 270 ohms will work fine.
Increasing you will perceive more treble.... decreasing the effect will go to bass.
You will have around 4 to 4.5 watts of heat during stand by mode...without signal.... this heat will be perceived when the heatsink is too much small.
Tweaking this resistance you will need to readjust your amplifier.
regards,
Carlos
Yep, a tablesaw is indispensible for cuttting up heatsinks... Thanks Peter Daniels... nice thing I learned from you....
I have a metal scissor... my grandad used to build machines etc...
He for instance designed Rembrand's first machine that made filtered cigarettes...
nice tool... no way it could cut through that though...
I have a metal scissor... my grandad used to build machines etc...
He for instance designed Rembrand's first machine that made filtered cigarettes...
nice tool... no way it could cut through that though...
Be carefull Microp.... when we tweak amplifier we use to produce accidental
shorts.
Not to loose parts.... avoiding sadness and frustrations.... install fuses into your rails.... 5 amperes if you will use 4 ohms...and 2.5 to 3 amperes if you will use 8 ohms only.
Also install an output fuse.... 3 amperes will be fine using 8 ohms.
Solder a thin wire in parallel with the fuse... another small fuse over the glass fuse...this is to guarantee very low resistance..as some fuses create problems because of internal resistances.
No problems to the fuse work.... the very small wire soldered outside will melt too if you have overcharges.
regards,
Carlos
shorts.
Not to loose parts.... avoiding sadness and frustrations.... install fuses into your rails.... 5 amperes if you will use 4 ohms...and 2.5 to 3 amperes if you will use 8 ohms only.
Also install an output fuse.... 3 amperes will be fine using 8 ohms.
Solder a thin wire in parallel with the fuse... another small fuse over the glass fuse...this is to guarantee very low resistance..as some fuses create problems because of internal resistances.
No problems to the fuse work.... the very small wire soldered outside will melt too if you have overcharges.
regards,
Carlos
Cheap multimeters...
In home page... step... 16... Re-adjust your DC offset to a voltage lower than 3 millivolts.
The voltage there must be stable, not fluctuating.
As I am using cheap multimeters my output voltage is fluctating from 0,2 to 1mV.... is it right... the problem is in multimeter?
regards,
microp
In home page... step... 16... Re-adjust your DC offset to a voltage lower than 3 millivolts.
The voltage there must be stable, not fluctuating.
As I am using cheap multimeters my output voltage is fluctating from 0,2 to 1mV.... is it right... the problem is in multimeter?
regards,
microp
Yes....those 2 dollares multimeters use to produce overflow
But they do the job also...i also have two of those, two analog ones and one better one digital.
Your adjustment is perfect...this way you will have the amplifier cooler.
This "non fluctuating" will be removed from the home page soon.
regards,
Carlos
But they do the job also...i also have two of those, two analog ones and one better one digital.
Your adjustment is perfect...this way you will have the amplifier cooler.
This "non fluctuating" will be removed from the home page soon.
regards,
Carlos
Enjoy and send me pictures.
Directly to my mail box:
panzertoo@yahoo.com
Electronics, home, appliances, ventilators, floor, ceiling, wall paper, people around, people in the street, building, sky, street, automobile, television screen with a local program..radio sets, computer, family, daugther, wife, landscapes, dust, ant, mosquito, microbios, viruses...everything is interesting to me.
Remember...i am in South America...we do not use too much wood inside home..we do not use wood in the floor (ceramics we use...weather is hot here) we do not use wall paper, we have exterminated ants, not too much birds we have... the ones hawks have not eated..well..everything different here.
You are in the Old Soviet Block...your things..the old radio...all those things interesting to the Dx Corporation Chairman culture (me!..ahahaha)
Also, inform you family name.... you are one of those rare folks that are not shy... also Usernamex posted his head (not the face) you have a face..others do not have faces.... only me and you.
regards,
Carlos
Directly to my mail box:
panzertoo@yahoo.com
Electronics, home, appliances, ventilators, floor, ceiling, wall paper, people around, people in the street, building, sky, street, automobile, television screen with a local program..radio sets, computer, family, daugther, wife, landscapes, dust, ant, mosquito, microbios, viruses...everything is interesting to me.
Remember...i am in South America...we do not use too much wood inside home..we do not use wood in the floor (ceramics we use...weather is hot here) we do not use wall paper, we have exterminated ants, not too much birds we have... the ones hawks have not eated..well..everything different here.
You are in the Old Soviet Block...your things..the old radio...all those things interesting to the Dx Corporation Chairman culture (me!..ahahaha)
Also, inform you family name.... you are one of those rare folks that are not shy... also Usernamex posted his head (not the face) you have a face..others do not have faces.... only me and you.
regards,
Carlos
Hi microp,
When you watch the output voltage of an AF amplifer with a sensitive voltmeter, you will observe LF flutter noise about its nominal set potential.
Digital and analogue meters would probably give different readings of this, and so it would take a scope with long timebase period to capture it accurately.
This is inaudible and quite normal.
Cheers ........ Graham.
When you watch the output voltage of an AF amplifer with a sensitive voltmeter, you will observe LF flutter noise about its nominal set potential.
Digital and analogue meters would probably give different readings of this, and so it would take a scope with long timebase period to capture it accurately.
This is inaudible and quite normal.
Cheers ........ Graham.
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