Since ages, I wanted to design a good active 3-way system, with ALL parts on a single board. Just connect transformer, three drivers and the input signal and GO
Now, it's finished. I didn't want to go the chips-amp way, so I used three discrete power amps. Combined with Linkwitz-Riley 12dB/octave filters and a thermal protection.
To be exactly, this is all on that single board:
A: one power supply consisting of 2X 10,000µF/40V electrolytics (charged to 2X 37 Volts) to power the two power amps for mid and high,
B: one power supply consisting of 2X 10,000µF/63V electrolytics (charged to 2X 60V) to power the bass-amp,
C: two discrete power amps, using fast transistors throughout the design, 2SA1303 / 2SC3284 as output devices,
D: one discrete power amplifier using fast and rugged components throughout, 2X 2SA2151A / 2X 2SC6011A as output devices,
E: a 3-way active crossover, Linkwitz / Riley, second order, using the latest opamps by National Semiconductor
F: parallel stabilization for the opamps
G: thermal shutdown using a relay in the input
This all got crammed on a PCB measuring just 100 X 184mm. This PCB is mounted flat on a heatsink measuring 150 X 200mm.
First measurements using an Audio Precision system one showed perfect behavior of the filters and amplifiers. Level of the mid and high amps can easily be adjusted by turning a pot on the PCB. Idle-current of all amps can be adjusted using 12-turn pots. That's easy!
A transformer of 2X 25V and 2X 15V is needed for this, power around 300 Watts minimum.
First impression: with just 2X 25V transformer on ALL amplifiers (put a bridge in the connector instead of the 15V windings) sound was extremely powerful, accurate and LOUD, LOUD!! Did I already mention it was LOUD?! Even bass-consuming music like Gigi D'agostino came out like someone was hammering my head every time
Now it is a success, I'll just HAVE to have me some of those double sided PCBs made in a more professional quality than the one I made myself for the prototype!!
I plan to combine it with three pairs of loudspeakers:
1. the Visaton VIB extra II that I made years ago, with a Dynaudio D76-AF in it,
2. a new project using a vintage 12" Philips woofer, and a 2" dome midrange by Philips, combined with a DT-300 tweeter by Monacor,
3. another new project using a Seas alu-woofer, midrange TBA, and some kind of Ribbon tweeter.
And HERE the question to you all comes: does anybody have good experiences with a cetain make and type of ribbon tweeter? I'm new to these, but I heard some in Adam loudspeakers... and all I thought was <WWHHOOOWW!!!>
Thanks in advance,
Timmo.
Now, it's finished. I didn't want to go the chips-amp way, so I used three discrete power amps. Combined with Linkwitz-Riley 12dB/octave filters and a thermal protection.
To be exactly, this is all on that single board:
A: one power supply consisting of 2X 10,000µF/40V electrolytics (charged to 2X 37 Volts) to power the two power amps for mid and high,
B: one power supply consisting of 2X 10,000µF/63V electrolytics (charged to 2X 60V) to power the bass-amp,
C: two discrete power amps, using fast transistors throughout the design, 2SA1303 / 2SC3284 as output devices,
D: one discrete power amplifier using fast and rugged components throughout, 2X 2SA2151A / 2X 2SC6011A as output devices,
E: a 3-way active crossover, Linkwitz / Riley, second order, using the latest opamps by National Semiconductor
F: parallel stabilization for the opamps
G: thermal shutdown using a relay in the input
This all got crammed on a PCB measuring just 100 X 184mm. This PCB is mounted flat on a heatsink measuring 150 X 200mm.
First measurements using an Audio Precision system one showed perfect behavior of the filters and amplifiers. Level of the mid and high amps can easily be adjusted by turning a pot on the PCB. Idle-current of all amps can be adjusted using 12-turn pots. That's easy!
A transformer of 2X 25V and 2X 15V is needed for this, power around 300 Watts minimum.
First impression: with just 2X 25V transformer on ALL amplifiers (put a bridge in the connector instead of the 15V windings) sound was extremely powerful, accurate and LOUD, LOUD!! Did I already mention it was LOUD?! Even bass-consuming music like Gigi D'agostino came out like someone was hammering my head every time
Now it is a success, I'll just HAVE to have me some of those double sided PCBs made in a more professional quality than the one I made myself for the prototype!!
I plan to combine it with three pairs of loudspeakers:
1. the Visaton VIB extra II that I made years ago, with a Dynaudio D76-AF in it,
2. a new project using a vintage 12" Philips woofer, and a 2" dome midrange by Philips, combined with a DT-300 tweeter by Monacor,
3. another new project using a Seas alu-woofer, midrange TBA, and some kind of Ribbon tweeter.
And HERE the question to you all comes: does anybody have good experiences with a cetain make and type of ribbon tweeter? I'm new to these, but I heard some in Adam loudspeakers... and all I thought was <WWHHOOOWW!!!>
Thanks in advance,
Timmo.
I calculated all for a mains voltage of 240 Volts, even then the voltages on all electrolytics remain UNDER their rated values...
Normally, we have 230 Volts and in Europe, this is fairly stable. I never, ever measured 240 Volts here.
In addition, I used QUALITY capacitors, no Chinese rubbish for me
I once tried how much a Philips 10,000µF/100V capacitor could handle: I had to go OVER 110 Volts just to have a current flow of 1mA... so there is some room over the specs. Of course, I never recommend this, but a 40V rated Philips capacitor will not die when it has 41V on it for a day or so.
But, you certainly have a point in regions where mains voltages do vary wildly...
Thanks for the hint,
Timmo.
Normally, we have 230 Volts and in Europe, this is fairly stable. I never, ever measured 240 Volts here.
In addition, I used QUALITY capacitors, no Chinese rubbish for me
I once tried how much a Philips 10,000µF/100V capacitor could handle: I had to go OVER 110 Volts just to have a current flow of 1mA... so there is some room over the specs. Of course, I never recommend this, but a 40V rated Philips capacitor will not die when it has 41V on it for a day or so.
But, you certainly have a point in regions where mains voltages do vary wildly...
Thanks for the hint,
Timmo.
Now it is a success, I'll just HAVE to have me some of those double sided PCBs made in a more professional quality than the one I made myself for the prototype!!
beetje laat, bijna 2 jaar verder, maar ben wel benieuwd of je hier nog verder mee gekomen bent ?
oops, sorry, english it is
bit late, almost two years later, but was wondering if you made any progress ?
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