Hi Dan,
You've started building audio at a perfect time. The On Semi parts are about as good as they have ever been - ever. You have some great documented projects that will work with minimal trouble too! You'll do fine.
One note though. Building a circuit to sound "tube like" isn't always good. Transistors seldom sound like tubes. Given the cost, you could build one of each and decide then. You will not be wasting heat sinks or power supplies and will find out for yourself. Your parts can be recycled into your chosen design.
The finer points of building a really good amplifier can be implemented at the same time. Now you can match your transistors in the diff pair and current mirrors. Matching the output transistors can reduce your distortion by a factor of 10 before feedback. Neat eh? So now you can learn hands on.
Spend most of your time planning the project, this makes all the difference in the world.
Merry Christmas!!
-Chris
You've started building audio at a perfect time. The On Semi parts are about as good as they have ever been - ever. You have some great documented projects that will work with minimal trouble too! You'll do fine.
One note though. Building a circuit to sound "tube like" isn't always good. Transistors seldom sound like tubes. Given the cost, you could build one of each and decide then. You will not be wasting heat sinks or power supplies and will find out for yourself. Your parts can be recycled into your chosen design.
The finer points of building a really good amplifier can be implemented at the same time. Now you can match your transistors in the diff pair and current mirrors. Matching the output transistors can reduce your distortion by a factor of 10 before feedback. Neat eh? So now you can learn hands on.
Spend most of your time planning the project, this makes all the difference in the world.
Merry Christmas!!
-Chris
Now that I look , you will need 2 each of 100uf@63v and .1uf@100v for rails. I tailored this one for lower rails (40-45v)
it should be good for even lower rails (35v with R8-330R0
notice how Ma's in first plot go NEGATIVE (that is the strangeness
of bootstrapping.. The wattage at 45v is about 70W/8 -125W/4
you will also need a zoble network...same as lm3886..
BTW - here is what sort of "footprint" an amp like this has..
scroll down a little..board and wooden case..
http://www.diyaudio.com/forums/showthread.php?postid=1661337#post1661337
FA1 with junk trafo (45-0-45) and about 80$ parts,
Big caps are real expensive (45$)..
OS
it should be good for even lower rails (35v with R8-330R0
notice how Ma's in first plot go NEGATIVE (that is the strangeness
of bootstrapping.. The wattage at 45v is about 70W/8 -125W/4
you will also need a zoble network...same as lm3886..
BTW - here is what sort of "footprint" an amp like this has..
scroll down a little..board and wooden case..
http://www.diyaudio.com/forums/showthread.php?postid=1661337#post1661337
FA1 with junk trafo (45-0-45) and about 80$ parts,
Big caps are real expensive (45$)..
OS
anatech said:Hi Dan,
. . .
One note though. Building a circuit to sound "tube like" isn't always good. Transistors seldom sound like tubes. Given the cost, you could build one of each and decide then.
. . .
Spend most of your time planning the project, this makes all the difference in the world.
Merry Christmas!!
-Chris
Thank you!
And, its not about sounding tube-like. . .
Either the "parallel amplifier," with low gain, with an additional preamplification stage -OR- the "bootstrap cap amp," with normal gain and a great quality power circuit. . . will give me what I'm looking for.
If there is a question as to why, I'll have to defer to your guess being more accurate than if I were to attempt explaining. So, just guess.
ostripper said:Now that I look , you will need 2 each of 100uf@63v and .1uf@100v for rails. I tailored this one for lower rails (40-45v)
it should be good for even lower rails (35v with R8-330R0
notice how Ma's in first plot go NEGATIVE (that is the strangeness
of bootstrapping.. The wattage at 45v is about 70W/8 -125W/4
you will also need a zoble network...same as lm3886..
An externally hosted image should be here but it was not working when we last tested it.
BTW - here is what sort of "footprint" an amp like this has..
scroll down a little..board and wooden case..
http://www.diyaudio.com/forums/showthread.php?postid=1661337#post1661337
FA1 with junk trafo (45-0-45) and about 80$ parts,
Big caps are real expensive (45$)..
OS
Oh thank you.
I haven't been transformer shopping yet, but I'll do it now.
For reference a 60vct (30&30vac) is going to make a steady -42+42vdc on one of my power supplies or -48+48vdc on the other style. I'll be right back.
Okay, this:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=122-685
With 1 KPBC2504 (or 4 standard diodes) and 4 little caps makes 50vdc
Or this:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=122-680
With 4 MR756 (or MUR860) makes 48vdc
With 8 MR756 (or MUR860) makes 45vdc
With 2 KBPC2504 (or 8 standard diodes) and 8 little caps makes 40vdc
With 1 KBPC2504 (or 4 standard diodes) and 4 little caps makes 42vdc
EDIT: Single rectifier versions, with snubbed standard diodes, don't require expensive caps.
The one in italics is on-spec for a classic amp.
There is also a dual mono version possible.
So, what do you think?
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=122-685
With 1 KPBC2504 (or 4 standard diodes) and 4 little caps makes 50vdc
Or this:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=122-680
With 4 MR756 (or MUR860) makes 48vdc
With 8 MR756 (or MUR860) makes 45vdc
With 2 KBPC2504 (or 8 standard diodes) and 8 little caps makes 40vdc
With 1 KBPC2504 (or 4 standard diodes) and 4 little caps makes 42vdc
EDIT: Single rectifier versions, with snubbed standard diodes, don't require expensive caps.
The one in italics is on-spec for a classic amp.
There is also a dual mono version possible.
So, what do you think?
Way too expensive..
http://www.antekinc.com/AN-5435.pdf
And pricelist..http://www.antekinc.com/price1.html
AN 5435...$55.00 +10 UPS ha ha
500va is all you need for 2 amps , just buy 2- $3.00
25A bridge rectifiers at mouser + 8 $4.00 4700uf 80v
nichelons as well...
Since you are buying new, consider 45-0-45 or 50-0-50
AN -5445/50 ($57.00)for future headroom.
OS
BTW , above has 4 snubbers per module (heatsinked bridge) and
bleeder resistor/rail decoupling...1u/100v/ blue/red led
"idiot" lights..
http://www.antekinc.com/AN-5435.pdf
And pricelist..http://www.antekinc.com/price1.html
AN 5435...$55.00 +10 UPS ha ha
500va is all you need for 2 amps , just buy 2- $3.00
25A bridge rectifiers at mouser + 8 $4.00 4700uf 80v
nichelons as well...
Since you are buying new, consider 45-0-45 or 50-0-50
AN -5445/50 ($57.00)for future headroom.
OS
BTW , above has 4 snubbers per module (heatsinked bridge) and
bleeder resistor/rail decoupling...1u/100v/ blue/red led
"idiot" lights..
ostripper said:Way too expensive..
http://www.antekinc.com/AN-5435.pdf
And pricelist..http://www.antekinc.com/price1.html
AN 5435...$55.00 +10 UPS ha ha
500va is all you need for 2 amps , just buy 2- $3.00
25A bridge rectifiers at mouser + 8 $4.00 4700uf 80v
nichelons as well...
Since you are buying new, consider 45-0-45 or 50-0-50
AN -5445/50 ($57.00)for future headroom.
OS
BTW , above has 4 snubbers per module (heatsinked bridge) and
bleeder resistor/rail decoupling...1u/100v/ blue/red led
"idiot" lights..
Thank you!
May I use 51vdc rails along with 1 of NJW3281G (NPN) and 1 of NJW1302G (PNP) output transistors? This results in about $40 less price for me, due mostly to the decreased price of capacitors and the slightly decreased price of heatsinking. The 51vdc rails seems to be an advantageous range, also with barely any cost difference between dual mono (3a each) versus stereo (5a) options.
Resistors come in multi-packs anyways. There's no way to save by removing just one resistor... If you leave it though, no need for it to be 1k, 100 or even 10 might do. Try taking it out in simulation and see what the 20KHz THD does...
Hey Lineup.
I would love to get in on some discussion about amp designing, just to see what I know and to learn more...
But whenever I see them, the gurus have already beat me to them, and there's nothing left for me...
- keantoken
Hey Lineup.
I would love to get in on some discussion about amp designing, just to see what I know and to learn more...
But whenever I see them, the gurus have already beat me to them, and there's nothing left for me...
- keantoken
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