Hi djk,
In practice peak is slightly < 6dB so need to use 3.3K as R5 for a bit more (if wanted). I produced a similar finished product in 1992, but it didn't have discrete 80dB regs (only LT317/37) and no ground planed PCB as it has now.
Hi Bob,
LPF? I have/had Theils original work and Small's and Keele's. And EV original design. I have used this in 3 way active x'overs to boost compact vented subs, to control cone excursion and prevent unloading. Worked well at disco installations with 6 x 15" pumping the floor.
Cheers,
Greg
In practice peak is slightly < 6dB so need to use 3.3K as R5 for a bit more (if wanted). I produced a similar finished product in 1992, but it didn't have discrete 80dB regs (only LT317/37) and no ground planed PCB as it has now.
Hi Bob,
LPF? I have/had Theils original work and Small's and Keele's. And EV original design. I have used this in 3 way active x'overs to boost compact vented subs, to control cone excursion and prevent unloading. Worked well at disco installations with 6 x 15" pumping the floor.
Cheers,
Greg
Oops - I meant to say High pass filter.
My subs are a pair of JBL 2245H in the alignment published in Audio back in '83 or so - 8.5 ft^3 tuned to 24 Hz, with a Q=2 high pass at 24 Hz. I agree, better regulation and opamps do sound better than the original BX63's TL074 and wall wart.
Recently I have been playing with varying the Q, but seem to gravitate towards 2 for music. Movies can be more fun with a bit higher Q when the neighbors are out.
My subs are a pair of JBL 2245H in the alignment published in Audio back in '83 or so - 8.5 ft^3 tuned to 24 Hz, with a Q=2 high pass at 24 Hz. I agree, better regulation and opamps do sound better than the original BX63's TL074 and wall wart.
Recently I have been playing with varying the Q, but seem to gravitate towards 2 for music. Movies can be more fun with a bit higher Q when the neighbors are out.
Here's the performance -
Frequency Response +6 dB at 20 to 50Hz adjustable, then flat to > 3MHz
Low Rolloff -15 dB /octave below boost frequency to - 40 dB at 0.1 of boost frequency.
Distortion < 0.005% 20Hz - 20KHz at 1Vrms output
Gain 0 dB , resettable up to + 8 dB by resistor deletion (see text).
Hum and Noise < - 100 dBA (weighted) but depends on enclosure, wiring and external earthing.
Crosstalk below FFT noise floor up to 1KHz , -80 dB at 10KHz.
The unit can be adapted to many purposes -
Used with a 10K volume control as a buffer into a power amp to eliminate input filter interaction.
Used to provide up to 8 dB gain for low signal sources
Used as a 12 dB/octave active filter/buffer for the high pass L and R outputs when using a stereo system with a DIY sub.
Cheers,
Greg
Frequency Response +6 dB at 20 to 50Hz adjustable, then flat to > 3MHz
Low Rolloff -15 dB /octave below boost frequency to - 40 dB at 0.1 of boost frequency.
Distortion < 0.005% 20Hz - 20KHz at 1Vrms output
Gain 0 dB , resettable up to + 8 dB by resistor deletion (see text).
Hum and Noise < - 100 dBA (weighted) but depends on enclosure, wiring and external earthing.
Crosstalk below FFT noise floor up to 1KHz , -80 dB at 10KHz.
The unit can be adapted to many purposes -
Used with a 10K volume control as a buffer into a power amp to eliminate input filter interaction.
Used to provide up to 8 dB gain for low signal sources
Used as a 12 dB/octave active filter/buffer for the high pass L and R outputs when using a stereo system with a DIY sub.
Cheers,
Greg
Hi amplifierguru...wanted to make this circuit...explain to me,will it make those low frequencies audible..example...m using a sub eq made by my friend(don't know which schematic he used),it has some deep bass but where you want to really here the deep notes,its like its phasin them out...e.g.theres this audio track by young jeezy,put on ft kanye west....(hope you don't mind if i use tracks to explain)..my sub is not able to produce the last final bass note....it kinda phases that beat out....was wondering if your circuit could boost that bass so that it can be audible....
That looks suspiciously close to a simple highpass with a high Q like it is used for some sixth/forth order alignments.
The advantage is reduced excursion below cutoff, especially compared to the Linkwitz transform. The disadvantage is degraded temporal behaviour.
As always: You can't have everything !
Regards
Charles
Edit: Sorry, didn't look at post #5 !
The advantage is reduced excursion below cutoff, especially compared to the Linkwitz transform. The disadvantage is degraded temporal behaviour.
As always: You can't have everything !
Regards
Charles
Edit: Sorry, didn't look at post #5 !
Bass Expander
Hello
I purchased an Altronics K5561 Bass extender. this is the same unit as described in Electronics Australia and I believe was also sold by Jaycar at one stage.
I made some modifications to the feed back and cut off resistors using 2 mechanically linked linear pots. I could tune the bass booster and optimise it for my speakers ,Old Jensen bass reflex
running 12" phillips speakers as the main driver 35 years old.
Amp is MF XT 100 but the bass response was muddy, The bass expander improved the bass but Im still not happy with it, I think it will be best to invest in better speakers.
I checked the distortion and phase lag on scope it was very large.
Im away until December but I will post the values and scope screen pictures when I return
Hello
I purchased an Altronics K5561 Bass extender. this is the same unit as described in Electronics Australia and I believe was also sold by Jaycar at one stage.
I made some modifications to the feed back and cut off resistors using 2 mechanically linked linear pots. I could tune the bass booster and optimise it for my speakers ,Old Jensen bass reflex
running 12" phillips speakers as the main driver 35 years old.
Amp is MF XT 100 but the bass response was muddy, The bass expander improved the bass but Im still not happy with it, I think it will be best to invest in better speakers.
I checked the distortion and phase lag on scope it was very large.
Im away until December but I will post the values and scope screen pictures when I return
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