all this time i am a member of this forum ( yet ammatuer and inexpirienced in design ) i noticed all this wonderfull people of the forum working with terms like THD , idle current, transistor foldback, W rms, voltage, swing , mosfets, BJTs and many many others ...... nice glossary for all the audio people ....
i wish to add a new term ..... its called OD/SC
WHICH MEANS
OUTPUT DEVICES PER SCHEMATIC .......!!!!!This will give you the number of burned transistors that you need to make one schematic to work and this you have to calculate toghether with individual expirience and/or wrong or bad evaluated schematic !!!!!!
just now i ve been a victim of my own inexpirience and made nistakes on a very nice design that cost me many many nice mosfets..... but ...i am learning ......
Given the opertunity i would like to thank so much Dr Bora Jagodic
for sharing with me one very nice design ..... that produces amounts of power toghether with vey warm and clear sound .....
thank you bora so much !!!!!!
I often find an inverse relationship of air to cost - as my mouth is drawn tighter under higher pressure.
of course, I have a break-over point - at which the smoke begins to emit from the ears, and loud noises (not unlike the sound of nouns, verbs and adjectives) are emitted - at this point the millilitres per cost is exponential over time.
of course, I have a break-over point - at which the smoke begins to emit from the ears, and loud noises (not unlike the sound of nouns, verbs and adjectives) are emitted - at this point the millilitres per cost is exponential over time.
Ah yes. Nothing like charred fibreglass and flames to prove you've a mistake, or design error. Been there, done that.
One particular problem child was a 100/w amp I had redesigned the o/p stage with bipolars rather than fets. It sounded very clean, but had an instability problem, which would take out the emitter resistors in the driver stage, without warning, in one or the other channel. Fortunately, the rest was so robust, it wasn't destroying 8 x $28 transistors.
The most embarrassing moment this occurred was during a party, playing "smoke on the water". But twenty minutes later, we were back on the air again, to the amazement of a few.
Cheers,
Geoff.
One particular problem child was a 100/w amp I had redesigned the o/p stage with bipolars rather than fets. It sounded very clean, but had an instability problem, which would take out the emitter resistors in the driver stage, without warning, in one or the other channel. Fortunately, the rest was so robust, it wasn't destroying 8 x $28 transistors.
The most embarrassing moment this occurred was during a party, playing "smoke on the water". But twenty minutes later, we were back on the air again, to the amazement of a few.
Cheers,
Geoff.
one of the worst sounds you can hear is MMMMMMTP!!!!!!!!! (a short burst of 60hz followed by a loud click and pop) that's usually an expensive sound...... i once worked on a harmon kardon that would go "ticticticpffp" after it was repaired...... the oscope revealed the ticking as a 10khz oscillation in the amp that occurred in short repetitive bursts until the output transistors shorted.
Hahahah! Well people DO pay lots of money for machines that produce smoke... Though like my unique measuring technique for measuring cone excursion, too bad using semi conductors to produce smoke can be done only once....
Strange, because people don't mind fire crackers to explode only once. Though they sometimes pay lots of money for fireworks...
Strange, because people don't mind fire crackers to explode only once. Though they sometimes pay lots of money for fireworks...
Pulse-R. Where have you been? The 10" shifter in the open cell battery trick was performed by a TA at the Kew Tel exchange about 1970.
The TA simply rolled up his sleeve, retrieved the shifter, then washed the shifter and his hand in the wash basin. He thought he was lucky. The shifter could have landed on the buss-bars, resulting in a mass conversion of H and O to H2O.
V-bro. Us Ausies may be slow to develop. We were young men when we used to put electrolitic caps across 52v, reverse polarity. Better than a fire cracker, with nasty gasses.
We had a lot of fun as trainees, and got paid for it. Bonus.
Geoff.
The TA simply rolled up his sleeve, retrieved the shifter, then washed the shifter and his hand in the wash basin. He thought he was lucky. The shifter could have landed on the buss-bars, resulting in a mass conversion of H and O to H2O.
V-bro. Us Ausies may be slow to develop. We were young men when we used to put electrolitic caps across 52v, reverse polarity. Better than a fire cracker, with nasty gasses.
We had a lot of fun as trainees, and got paid for it. Bonus.
Geoff.
Another most spectacular meltdown I experienced as a kid was when my father used to put my R/C controlled car on the charger overnight. It was equipped with a NiCad pack and -fully charged- they go up in smoke very quickly when short circuited. My father just stuffed some charge leads in the banana sockets of the charger and I pulled them out in the morning careless and unknowing of the dangers. It went 'cleck....cleckprrprrrpfffggggggsssssssssshhhhhhhhhhhprrrrttpprrrrrttppppprrrrtssssshhhhdffffffffffffffffffffffffff........ffffff......fffff............ff......... for three minutes and eventually it appeared only one cell was damaged, it worked fine after replacement..
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