I do not want to spoil this power amp thread, ...so just in brief: The crossover is a LR 4th order type. Maybe Toni is willing to give you more details. I work on a combination of this crossover with a Jan Didden 8-channel RF-remote volume control. Will show more pics when the unit is finished.
Cheers, Martin
Cheers, Martin
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As the bias is very low - about 45mA per device - about 50W power dissipation per channel - a total of ~ 200 - 250W for the 4 channel "beast" we do not need a big power plant ...Now that is going to be very heavy and you need a neat and tight packed internal layout. Quite a task..!
By the way, have you purchased a power plant lately?
BR, Toni
OT:
It's a variable frequency Linkwitz-Riley state variable 4th order filter.
As the schematic is copyrighted material (from the book "The design of active crossovers" from Douglas Self) I am not able to show you the used schematics.
This schematic is similar to the used one: http://www.rane.com/pdf/linriley.pdf
I have added a 16 step selector for finetuning the crossover frequency.
BR, Toni
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Mains control
attached schematics for controlling mains.
Note: needs a special firmware for the used microcontroller!
BR, Toni
attached schematics for controlling mains.
Note: needs a special firmware for the used microcontroller!
- inrush current timing
- re-powering delay
- auto power on even if push buttons are used
- 3 independent temperature sensors to avoid amplifier overheating
- 4 channel DC speaker control
- muting signal to either control soft muting (e.g. lm3886/lme49830) or external speaker relais pcb
- external power on (e.g. 12V opto coupled signal from preamplifier)
- MCU serial port with TTL level RS232
BR, Toni
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power supply for one channel ...
attached power supply schematics and gerber files.
Feel free to use for non commercial DIY projects.
WARNING: this circuit provides very high DC voltages and is therefore very dangerous and can be lethal. I am not responsible for any costs, damage and/or injury using these schematics. Do not use this schematics if you do not have the necessary experience and knowledge.
BR, Toni
attached power supply schematics and gerber files.
Feel free to use for non commercial DIY projects.
WARNING: this circuit provides very high DC voltages and is therefore very dangerous and can be lethal. I am not responsible for any costs, damage and/or injury using these schematics. Do not use this schematics if you do not have the necessary experience and knowledge.
BR, Toni
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You can insert low ohmic resistors(0.1 to 0.22 ohm) between C11 - C13 and C12 - C14 and get much lower ripple.
Thanks - this is done by pcb layout already. The output ripple is extremely low.
BR, Toni
Dear keantoken,
all not special marked resistors are standard low inductive metal film 1% / 0,6W.
Maybe using expensive special resistors you will get some better Noise and/or THD values closer to the simulated one.
BR, Toni
Interesting. Apparently some precision resistors don't do so well:
Bruno Putzeys r4 random rants, raves and ramblings
Bruno Putzeys r4 random rants, raves and ramblings
Yes I know this article. But don't panic. If we have a THD analyzer and some standard parts for comparison we can easily check the quality.
BR, Toni
Just4Fun - 2stageEF with symmetrical input/VAS
... maybe worth a try with real devices ...
BR, Toni
... maybe worth a try with real devices ...
- about 4 ppm THD20K@200W@8R
- output stage with MJL3281/MJL1302 instead of TTC5200/TTA1943 (2SC5200/2SA1943)
BR, Toni
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Hi Toni
I think you have looked at Bob Cordell's p139
Personally, I like the complementary IPS because it lowers noise for my super-efficient horns.
You removed resistors to the rails for the Current Mirror helpers because simulation showed minimal effect?
Best wishes
David
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Dear David,
this thread would not exist without the excellent books of Bob Cordell and Douglas Self.
Think I have mixed up Bob Cordell APA p139 figure 7.10 and Douglas Selfs's APAD6 p226 figure 8.21.
The resistor is indeed missing. Maybe I thought it is useless. Must check again ...
BTW: the current amplifier - sa2013 - is deadly silent. My Friends and I have tested it also with very sensitive horn speakers - no noise.
Scan-Speak beryllium - no noise.
BR, Toni
this thread would not exist without the excellent books of Bob Cordell and Douglas Self.
Think I have mixed up Bob Cordell APA p139 figure 7.10 and Douglas Selfs's APAD6 p226 figure 8.21.
The resistor is indeed missing. Maybe I thought it is useless. Must check again ...
BTW: the current amplifier - sa2013 - is deadly silent. My Friends and I have tested it also with very sensitive horn speakers - no noise.
Scan-Speak beryllium - no noise.
BR, Toni
On adding the resistors as shown on p139 THD20k@200W@8R worsens from 0.000384%
to 0.000793%.
This is a good reason to remove them...