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Author Topic: Bi-amping/ Tri-amping  (Read 6403 times)

exztinct01

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Re: Bi-amping/ Tri-amping
« Reply #15 on: May 12, 2016, 10:37:12 PM »
After some reading and thinking, I decided that a newbie like me should really start with building amps for a single driver speaker like guitar, then full range, then the biamped and triamped systems. Will take years though  :P
Have to study more.

Anyway, I never really liked the idea of a passive crossover because of inductors. I just don't want to work with them. I don't know why.
~ Stephen

Enzo

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Re: Bi-amping/ Tri-amping
« Reply #16 on: May 12, 2016, 11:41:10 PM »
Well, get over that, because transformers are inductors too.

exztinct01

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Re: Bi-amping/ Tri-amping
« Reply #17 on: May 13, 2016, 03:50:40 AM »
Well, get over that, because transformers are inductors too.
:dbtu:
~ Stephen

Vitrolin

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Re: Bi-amping/ Tri-amping
« Reply #18 on: May 13, 2016, 01:49:50 PM »
Well, get over that, because transformers are inductors too.

And so are speakers...

exztinct01

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Re: Bi-amping/ Tri-amping
« Reply #19 on: May 14, 2016, 01:57:22 AM »
More questions:
1. Can I use non-complementary power transistors? (e.g. MJ15003 and TIP36C, or 2N3055 and TIP36C, one is TO-3 paired with a TO-247?)
2. Can I use non-complementary output driver transistors? (e.g. Edit: MJE15032 and BD140)

My sources just don't have the complements.
« Last Edit: May 14, 2016, 10:14:32 AM by exztinct01 »
~ Stephen

phatt

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Re: Bi-amping/ Tri-amping
« Reply #20 on: May 14, 2016, 09:09:50 AM »
No,,, but you can build a power amplifier with 2 MJ15003. :dbtu:
My old Laney uses both NPN power devices in push pull,,, as do many other guitar amps and hifi amps.

Just like my Laney,,,a lot of guitar amps use very basic power Amp circuitry running from 35Volt~ 40Volt rails which can output  30~40 Watts easy and that can be more than enough for small to medium venues.

There is no great tonal difference between complimentary paired outputs and sziklai paired output,,, just different configuration.

Google; Sziklai pairs for more info,

Adding a pic of my Laney schematic ,,this is about as basic as you can get and it's been flogged for many hours/Years.
Yes it will not win a technical award for best design but it can keep up with a very loud drummer.
And it never overheats even though it only has a basic heat sink. :o

BTW have you read Teemu's book?  it is a free download on this site,,,, it will help a lot :dbtu:
Phil.

exztinct01

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Re: Bi-amping/ Tri-amping
« Reply #21 on: May 14, 2016, 10:36:41 AM »
should i read it first, before sloan's and self's? I've just downloaded copies of those two books but I don't have time to read for these past few days as my dad just died and burial's tomorrow. Maybe I'll start reading those books the day after tomorrow.
« Last Edit: May 14, 2016, 11:39:34 AM by exztinct01 »
~ Stephen

g1

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Re: Bi-amping/ Tri-amping
« Reply #22 on: May 14, 2016, 11:48:13 AM »
There is no great tonal difference between complimentary paired outputs and sziklai paired output,,, just different configuration.

Google; Sziklai pairs for more info,
Do you mean quasi-complimentary rather than sziklai pairs?  Google says siklai is making a darlington out of an NPN and a PNP.

extinct01:  Very sorry to hear about your father.  Stay well.

Enzo

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Re: Bi-amping/ Tri-amping
« Reply #23 on: May 14, 2016, 05:52:23 PM »
When you are reading books to gain an overall understanding of a complex topic like electronics, you should read into all of them a little ways.  Every author has his own way of expressing himself, and of communicating the material.  Some will connect with you better than others.  Some authors tend to be very proper, formal, and traditional, but when I write, I like to be informal to try to take some of the edge off the fear the student has.  Every approach has its place, but students that like my way might not do as well in a formal setting, just as some students who do well in a formal class don't do as well when they talk to me.  So find the book that seems to make sense to you the best.  As you grow in this field, you can always go back later and reread the other books, chances are once you learn a little, the books that didn;t work so well before will be a lot more clear.

exztinct01

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Re: Bi-amping/ Tri-amping
« Reply #24 on: May 17, 2016, 08:59:20 AM »
There is no great tonal difference between complimentary paired outputs and sziklai paired output,,, just different configuration.

Google; Sziklai pairs for more info,
Do you mean quasi-complimentary rather than sziklai pairs?  Google says siklai is making a darlington out of an NPN and a PNP.

extinct01:  Very sorry to hear about your father.  Stay well.

Yeah, I googled sziklai and read that it uses npn and pnp pairs. The one using two npn's is quasi complimentary. Although I haven't read positive reviews for it, read it was used only because pnp's are so expensive in those early days.
~ Stephen

Enzo

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Re: Bi-amping/ Tri-amping
« Reply #25 on: May 17, 2016, 01:28:24 PM »
Don't worry about what hifi guys say about it.  They will obsess over some tiny detail.

Peavey used quasi-complementary output stages for years in many popular, good sounding amps.  The design may have come from an era when PNP transistors were less reliable, more expensive, but that doesn;t mean it is not a valid engineering approach.  Nothing at all wrong with quasi.

exztinct01

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~ Stephen

J M Fahey

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Re: Bi-amping/ Tri-amping
« Reply #27 on: May 23, 2016, 03:23:14 AM »
Very much doubt so.
Thosem are not designers but forum fans who typically cut and paste from different amps whithout actually *designing*  anything (as in their calculators are not used) and amps are treacherous: they *look*  good because they have ben robbed from real designs, but the combined parts may not match at all.

Just cut the head of a perfectly sane pig and junk it, then glue in its place a chicken head, just cut from a perfectly healthy chicken, do you think the pigchen yhoujust *designed* will live?

Proof of "no clue" is that they simulate circuits (never actuallly build tghem, by the way) and post ridiculous numbers such as "0.62065% distortion" ....... REALLY???? No kidding!!!!!!

Unless very very experienced, an Engineer degree does not hurt at all and even so I know *many* EEs who can not, don't fancy an untrained person can design an ampbetter than a commercial designer.

Throwing some numbers at a simulator and  getting others in exchange does not make a designer, at all.

Go for some commercial kit or clone some commercial well made amp and you'll be miles ahead, or worst case, use the datasheet/handbook example.

By the way, that's what Leo and Jim did themselves ...I don't think they didn't succeed !!!!!

exztinct01

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Re: Bi-amping/ Tri-amping
« Reply #28 on: May 23, 2016, 03:47:19 AM »
Go for some commercial kit or clone some commercial well made amp and you'll be miles ahead, or worst case, use the datasheet/handbook example.

By the way, that's what Leo and Jim did themselves ...I don't think they didn't succeed !!!!!

I love that idea of cloning well made commercial amps  :dbtu:
Guess not being an EE is not much of a disadvantage after all  :)
Learning while building, awesome.

Anyway, I was told by a new friend (I just found him in a forum and discovered he lives a few hours drive away from me) that he'd help me build a P3A. He has the tools and skill to build the chassis, and that's what I lack now. But to minimize the cost, I thought , what if I just use an available toroidal transformer I have now. Problem is the toroid's secondary is 42-0-42 and rated at 300 watts. It also has other secondaries, 17-0-17 and 0-12. Is there any mod that I can do to the P3A to be able to use that traffo, like maybe adding more pairs of output trannies? I don't mind you scolding me if such ideas are stupid  :loco
~ Stephen

J M Fahey

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Re: Bi-amping/ Tri-amping
« Reply #29 on: May 23, 2016, 10:25:02 AM »
Sorry but 42+42VAC amounts to +/- 59V, for an about 250W amp , way too much for P35 .

But a discarded home Hi Fi amp such as an old Pioneer/Sansui/Akai typicaly 40W/ch might donate a suitable transformer, same with a dead 60/100W guitar/bass/keyboards/PA amp.

 

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