DIY quality, custom design-patterns of audio amplifiers

[mac1257]

DIY quality, custom design-patterns of audio amplifiers.

All amplifiers are low-load resistance,for the use of multiple
speakers, and it is only normal technique.
Information is Compline, together with professional precision
application of power.
The information is varied and good for the school boards.

[Rainwulf]

Nearly impossible to read those heh..

[mac1257]

Amendment-general, he noticed two things to the amendment and
I've included one common scheme, to find these things.

[ostripper]

Not to be critical , but most amp designs on this forum are light years ahead of these designs.

OS

[mickeymoose]

Well, maybe 30 years. E

[CBS240]

At least.......not to mention the advances in semiconductor technology in the last couple decades. My next amp will be made using 'E-pad' matched mosfets from ALD and planer stripe DMOS devices as the output stage. Its a bit of an experiment and if it works, coupled with everything else in the circuit, should be quite extraordinary.

[ostripper]

Originally Posted by CBS240

At least.......not to mention the advances in semiconductor technology in the last couple decades. My next amp will be made using 'E-pad' matched mosfets from ALD and planer stripe DMOS devices as the output stage. Its a bit of an experiment and if it works, coupled with everything else in the circuit, should be quite extraordinary.

I really wasn't being critical to mac, I "port" the better ideas from 30 year old designs (mostly 20 YO Japanese designs), all the time. When you do this with modern semi's , you get "200%" !!! Twice the speed , half the size ... and that is just with through - hole components. I want to play with SMD , but most DIY'ers don't ... I just drilled several hundred holes and boy am I tired !

OS

[mac1257]

For some people, these are my old patterns. Interesting because
oldest audio transistors were the best, like people are healthier, but
what concerns people who have been somehow damage. There is
an old-new audio amplifiers are made from using a number of current
sources, which only gives you a cheap and a certain quality but not
the best and most are controlled power transistors, because
otherwise they can not as I gave.
This is my information is good and simple amplifiers and good for
e-schools and these amps are quite modern useless, because they
need the space cooling coils speakers, and this can not be denied.

[CBS240]

Originally Posted by ostripper

I really wasn't being critical to mac, I "port" the better ideas from 30 year old designs (mostly 20 YO Japanese designs), all the time. When you do this with modern semi's , you get "200%" !!! Twice the speed , half the size ... and that is just with through - hole components. I want to play with SMD , but most DIY'ers don't ... I just drilled several hundred holes and boy am I tired !

OS

The problem with the very small SMD parts is making the PCB tracks that are so fine. SOT-923 is pretty damn small. Also if you use a cad program with these tiny SMDs you want to make at least 2 layers, which can be difficult to create the plated holes or vias. A board house can create this for proto-types easily. The last one I made cost about $150 for 6 PCBs, not too bad. Production runs can get you ~30 PCBs for the same price.



One of the best improvements to power BJTs was the RET or ring emitter transistor, replacing the old epitaxial types used in audio before. Then came circuit ideas such as local error correction schemes, to correct the non-linearities of Darlington power transistors. Then came the invention of cheap available mosfets. When coupled with proper error correction these devices will outperform BJTs in just about every output stage application hands down, IMO. There have been major advances in small signal components too. Smaller companies such as Advanced Linear Devices or THAT Corp make specialized components. These didn't exist 30+ years ago. The new wave of SMD packages allow for smaller, tighter PCB design. It is true though that most DIYers don't like SMDs.

[CBS240]

The last one I made cost about $150 for 6 PCBs, not too bad. Production runs can get you ~30 PCBs for the same price.

I just got an e-mail quote from E-TekNet. For 4 PCBs, 2 layer at 21.89 each. Maximum board size 35 square inches for 2-layer board. Less than 10" in either X or Y direction. 0.062" thick board (FR4 material), 1 oz copper, minimum conductor width/ space >= 7 mil, , minimum annular ring >= 7 mil, minimum hole size >=12 mil (plated through). Non plated through holes are allowed. Board size>1"x1". Tin-lead HAL reflow and green LPI, white silkscreen for both top and bottom sides. For promotions, the boards should have no countersinks, no cutouts and no panels and V-scores. If your specifications are different, please go to PCB Quote Online for our 100% low price guaranteed quote.

Since the quality is very good (this is the company that made the last PCBs for me) for that price it is worth not having to drill 100+ holes per PCB. SMD pads are easy peasy to make this way.