The main problem you will run into with using those cabinets in a live non-home audio application is the mid and high frequencies. The waveguide looks to be quite exponential. They won't have much throw to them as they are designed to be near-field cabinets. A crowd absorbs high frequencies very effectively, so you'll end up losing much of it before the back of the room.
wg_ski said:
To be accurate, the models that i had sold was the VS-15, during 1995 if i remember well. And i did this to help an old friend which had got the agency of Cerwin Vega in Greece during this time.
Your remarks are by some way similar to mine regarding these loudspeakers. My tactics was to install them in 2 pairs in small clubs of 100 peoples as much, and to drive them (what a coincidence with what you said!
) with CS-800. I had enough ripped woofer's suspensions after 1 year of use! And no replacement cones! The only choice for repairing was the replace of the woofer... which was very expensive.Oh my! what a nightmare with the complaints of my customers!
Why you remember me these old bad moments
... bad wg_ski 
? Regs
Fotios
If I blow the woofers to kingdom come then ...
time to upgrade to a woofer that can handle more power....
If i dip my fingers into the car audio or the high end audio market i will be WAY more than these puppies can do.
Besides i heard from a lot of PPL that the CV has 2 or 3 versions of this 15" woofer and from what i heard they are using the weaker ones due to amplifier size needed to drive 2 of those monsters, which wont be a big problem for me
But at this point...
the way i have to build the amp(s) to drive the CLS215 has shifted.
for sure i want to bi-amp them due to better sonic performance and less stress on the speakers and crossovers.
i need to get those boards with the drivers going ASAP!!!
Fotios...
what wattage were the resistors you used on the output of your transistors ?
and unlike most of the people on this board i will pull the drivers on a separate board on the heat sink.
This allows me to put the driver board closer to the cap banks and keep wire lengths to a minimum.
time to upgrade to a woofer that can handle more power....
If i dip my fingers into the car audio or the high end audio market i will be WAY more than these puppies can do.
Besides i heard from a lot of PPL that the CV has 2 or 3 versions of this 15" woofer and from what i heard they are using the weaker ones due to amplifier size needed to drive 2 of those monsters, which wont be a big problem for me
But at this point...
the way i have to build the amp(s) to drive the CLS215 has shifted.
for sure i want to bi-amp them due to better sonic performance and less stress on the speakers and crossovers.
i need to get those boards with the drivers going ASAP!!!
Fotios...
what wattage were the resistors you used on the output of your transistors ?
and unlike most of the people on this board i will pull the drivers on a separate board on the heat sink.
This allows me to put the driver board closer to the cap banks and keep wire lengths to a minimum.
Attachments
I believe it's better to have the driver transistors near the output transistors than near the supply. Inductance in series with the output stage bases (which transforms into negative resistance seen from the emitters at HF) seems to be what causes problems with capacitive loads.
Having the whole output stage near the power supply is a pretty good idea though
megajocke said:
I believe it's better to have the driver transistors near the output transistors than near the supply. Inductance in series with the output stage bases (which transforms into negative resistance seen from the emitters at HF) seems to be what causes problems with capacitive loads.
Having the whole output stage near the power supply is a pretty good idea though
You do what you can - but such is the problem with scaling these amps up - they become their own stabilty problems and each implementation needs to be worked out individually. What used to work doesn't. And why you'll never get "audiophile" quality - it becomes more and more impossible to follow all of Self (and others') rules for proper layout when thing simply can't be connected at single points anymore. And you've got to back off on the amount of feedback (loop gain) because of those parasitics like distributed inductance in the base leads and bias lines. Distortion can be made reasonable, but you reach a point where it just won't go lower and doesn't need to be anyway.
megajocke said:
I believe it's better to have the driver transistors near the output transistors than near the supply. Inductance in series with the output stage bases (which transforms into negative resistance seen from the emitters at HF) seems to be what causes problems with capacitive loads.
Having the whole output stage near the power supply is a pretty good idea though
Sorry what i mean to say that the driver and output transistors will be on a separate board on the heat sink, allowing me to double up if i need to.
I will call this the output board.
the way i want to set it up is that if i would like to i can series 2 boards or more if i need more power
there will be provisions for power and signal input on both ends of the board.
wg_ski said:
So what your saying is drop the feedback circuit ...
OK
no biggie..
what software is there for simulating circuits in real time on the computer ??
also what software are you guys using to draw the schematics and setup the PCB's ??
MJL21193 said:
Oh yeah, you're ready...
ok ..
its been about 7 years since i dealt with this stuff.. i forgot most of this **** plus it was car audio.
besides...
last i was working on something it wasn't dealing with no where near the voltages and as many output devices.
Also been thinking about an auto biasing option through the NJL1302/3281 transistors...
Adrculda said:
I use as emiter resistors 0,33Ù/10W. Also, in Zobel four parallel/series connected resistors of 10Ù/5W each (like Peavey) because in high power output stages only one resistor of 5W in Zobel can be burned very easy, and has no audible effect so you can't perceive it... the only way for this it is when the output transistors starts to burned out...
As for the software that i use, it is a complette suite including except schematic, layout and fabrication manager also a spice simulator, an electromagnetic and a thermal analyzer. It is the EDWin XP of Visionics. Of course, there are better softwares like the Altium design center (previous Protel) and the top Orcad, but they are most complex from the enough complex EDWin that i am using.
This circuit presented by MJL21193, it seems very good and enough simple for such type works like your. Of course, MJL can offers to you ready the layouts of pcbs and the rest, because he is a very polite man. Thus, there is no reason to you draw and implement this circuit of ESP (as you said you are very hasty) consequently you don't have the need for a CAD-CAE software at this moment. Leave this option for later, now you must be looking to finish your work "ASAP".
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Fotios
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Fotios
MJL21193 said:No problem.
Here's one that actually works:
It's stable and maintains a steady idle current. To increase power, ramp up the voltage and add more outputs.
fotios said:
I use as emiter resistors 0,33Ù/10W. Also, in Zobel four parallel/series connected resistors of 10Ù/5W each (like Peavey) because in high power output stages only one resistor of 5W in Zobel can be burned very easy, and has no audible effect so you can't perceive it... the only way for this it is when the output transistors starts to burned out...
As for the software that i use, it is a complette suite including except schematic, layout and fabrication manager also a spice simulator, an electromagnetic and a thermal analyzer. It is the EDWin XP of Visionics. Of course, there are better softwares like the Altium design center (previous Protel) and the top Orcad, but they are most complex from the enough complex EDWin that i am using.
This circuit presented by MJL21193, it seems very good and enough simple for such type works like your. Of course, MJL can offers to you ready the layouts of pcbs and the rest, because he is a very polite man. Thus, there is no reason to you draw and implement this circuit of ESP (as you said you are very hasty) consequently you don't have the need for a CAD-CAE software at this moment. Leave this option for later, now you must be looking to finish your work "ASAP".
Regs
Fotios
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Fotios
Thanks all...
i had a busy 2 days here at home, but i have Orcad and Altium Design Center on their way... from a "Friend"
this way i can have the boards laid out the way i want them not how my PCB guy sees fit...
To be accurate, the only that i consider is missing from this circuit, it is a current mirror (not for the usual B.S. writen from members but for eliminating the DC offset in output, unless you must match the LTP transistors. A trim pot can balance the collector currents of LTP as well. Please MJL give instructions to Ardculda, this is your duty.
The second that is missing is a VI limitter for protecting output transistors from reactive loading. Also this, is very common and easy to implement.
These all are tasks regarding MJL and not me.
Don't worry Ardculda, MJL is a brave man ready to offer his service in everyone that needs it. It is a knight ready to kill the dragon with his amplifier spear.
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Fotios
The second that is missing is a VI limitter for protecting output transistors from reactive loading. Also this, is very common and easy to implement.
These all are tasks regarding MJL and not me.
Don't worry Ardculda, MJL is a brave man ready to offer his service in everyone that needs it. It is a knight ready to kill the dragon with his amplifier spear.
Regs
Fotios
fotios said:
You are a bit right...
looked for EDWin didnt have too much luck, but found OrCAD V16 and Altium Designer Suite V6.6 REALLY FAST !!
i have 2 versions of OrCAD one is the Full version and the other is the "Portable" version.
opened up the portable version and is a million times more advanced than that PCBExpres crap i was forced to work in
Love it though... waiting for the full version to finish downloading !
Doesnt seem like a problem since i want to add another pair of output transistors and at the same time we can implement those circuits.
well have to if i want to add that...
EDITED - spelling and poor grammar :S
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