I tried a lot of combinations with the 6-24AXO and had never the feeling of lacking or low bass
or that there could be something wrong in the highs.
It was always an excellent performance far above all expectations!
I have driven the AXOs with Waynes Line Stage, ACP+,B1 NUTUBE-pre, BA-3-pre, Aleph P1.7,
Primare-pre.
The AXOs have driven a few amps like F5T-Monoblocks, BA-3, BA-1-Monoblocks, M2X, 50W-SE-Schade-Monoblocks and a few other brands.
The only problem was in some combinations - 50Hz - hum. I think caused by many devices in the chain
and grounding reasons.
But this 6-24 AXO is excellent! Your work is to adjust it properly, that it can shine in your chain...
Cheers
Dirk
or that there could be something wrong in the highs.
It was always an excellent performance far above all expectations!
I have driven the AXOs with Waynes Line Stage, ACP+,B1 NUTUBE-pre, BA-3-pre, Aleph P1.7,
Primare-pre.
The AXOs have driven a few amps like F5T-Monoblocks, BA-3, BA-1-Monoblocks, M2X, 50W-SE-Schade-Monoblocks and a few other brands.
The only problem was in some combinations - 50Hz - hum. I think caused by many devices in the chain
and grounding reasons.
But this 6-24 AXO is excellent! Your work is to adjust it properly, that it can shine in your chain...
Cheers
Dirk
I think it can be even better if the cheap 50K pots are replaced by fixed resistors. The potentiometer sockets can be a good thing after all, making a switch to fixed resistors easier.
The 10uF output cap can be a little smaller, especially on the tweeter, no?
I just completed building and calibrating my build of the DIY biamp 6-24 crossover, using some of the tips and pointers provided here to separate signals out my DAC to feed the low pass to a pair of Class D amps driving 15" woofers, and the high pass to a Phase Linear 700B driving the mid ranges and tweeters on a build of Troels Gravesen's The Loudspeaker-3. Given the characteristics of this speaker design, I chose 10 and 4.7 nF caps and find an equal voltage crossing right around 740 Hz using the trimmer pot settings recommended with the PASSXO calculator.
In particular, I used the Vishay/Spectrol linear 50K pots suggested by Dirk in post #754, setting them to desired values prior to install, as well as the Preci-Dip 10 pos IC sockets to hold the Wima caps suggested by Nelson Pass in post #230.
The assembly was straightforward, thanks to the guide by 6L7, and the many quality posts here from the community. Thanks in particular to Dirk for his inspiring and illustrative posts, and, of course, to Mr. Pass for his design and making the kit available to us.
Calibration was also fairly straightforward using a Sigilent scope and REW software to generate tones and frequency sweeps. The response curves across each of the 2 sets of 2 outputs laid very nicely on top each other, requiring only the (slight) adjustment of 3 of the 4 output volume trimmer pots to match lowest output. I don't know if this is the be-all end-all of a sound calibration approach but ...
With only a few hours of burn in and a couple of hours of listening to a variety of music, I AM VERY HAPPY WITH THIS CROSSOVER!!!. My Phase Linear amp is working a lot less harder at volume, and the overall sound quality is, if anything, improved at all listening levels. Wow. Me so happy.
In particular, I used the Vishay/Spectrol linear 50K pots suggested by Dirk in post #754, setting them to desired values prior to install, as well as the Preci-Dip 10 pos IC sockets to hold the Wima caps suggested by Nelson Pass in post #230.
The assembly was straightforward, thanks to the guide by 6L7, and the many quality posts here from the community. Thanks in particular to Dirk for his inspiring and illustrative posts, and, of course, to Mr. Pass for his design and making the kit available to us.
Calibration was also fairly straightforward using a Sigilent scope and REW software to generate tones and frequency sweeps. The response curves across each of the 2 sets of 2 outputs laid very nicely on top each other, requiring only the (slight) adjustment of 3 of the 4 output volume trimmer pots to match lowest output. I don't know if this is the be-all end-all of a sound calibration approach but ...
With only a few hours of burn in and a couple of hours of listening to a variety of music, I AM VERY HAPPY WITH THIS CROSSOVER!!!. My Phase Linear amp is working a lot less harder at volume, and the overall sound quality is, if anything, improved at all listening levels. Wow. Me so happy.
Did you consider phase when measuring in Rew?I just completed building and calibrating my build of the DIY biamp 6-24 crossover, using some of the tips and pointers provided here to separate signals out my DAC to feed the low pass to a pair of Class D amps driving 15" woofers, and the high pass to a Phase Linear 700B driving the mid ranges and tweeters on a build of Troels Gravesen's The Loudspeaker-3. Given the characteristics of this speaker design, I chose 10 and 4.7 nF caps and find an equal voltage crossing right around 740 Hz using the trimmer pot settings recommended with the PASSXO calculator.
In particular, I used the Vishay/Spectrol linear 50K pots suggested by Dirk in post #754, setting them to desired values prior to install, as well as the Preci-Dip 10 pos IC sockets to hold the Wima caps suggested by Nelson Pass in post #230.
The assembly was straightforward, thanks to the guide by 6L7, and the many quality posts here from the community. Thanks in particular to Dirk for his inspiring and illustrative posts, and, of course, to Mr. Pass for his design and making the kit available to us.
Calibration was also fairly straightforward using a Sigilent scope and REW software to generate tones and frequency sweeps. The response curves across each of the 2 sets of 2 outputs laid very nicely on top each other, requiring only the (slight) adjustment of 3 of the 4 output volume trimmer pots to match lowest output. I don't know if this is the be-all end-all of a sound calibration approach but ...
With only a few hours of burn in and a couple of hours of listening to a variety of music, I AM VERY HAPPY WITH THIS CROSSOVER!!!. My Phase Linear amp is working a lot less harder at volume, and the overall sound quality is, if anything, improved at all listening levels. Wow. Me so happy.
I haven't gotten that far yet, but plan to do so asap. I expect some differences owing to the passive crossovers separating the mid-range and tweeters on the high-pass outputs being driven by the PL 700B. Looking at the XO outputs on the scope, I see a bit of waveform phase difference on the high-pass output ... but its probably not more than a few degrees ... like ~25-30 us @ 5000 Hz. The low pass outputs lie exactly on top of each other (at least as far as I can discern).
That is great. Hopefully Troels thought about phase when he designed the speaker and you won’t have to worry about it for the midrange driver and tweeter. Not much the 6-24 can do about it, unless you cascade another 6-24. I will attempt stacking a bunch of horns, and I am just asking for trouble. I made it possible to move the horns to find a good position.
Looks like @audionut has the answer. I started back through the whole thread again and found this -https://www.diyaudio.com/community/threads/diy-biamp-6-24-crossover.357657/post-6343241
If my understanding is correct, we could conceivably use a 0.1uf Cap on the input (as per Nelson Pass' schematic) as the impedance on the input section is very high.
If my understanding is correct, we could conceivably use a 0.1uf Cap on the input (as per Nelson Pass' schematic) as the impedance on the input section is very high.
Hello Delineation,
test it, listen to it. Easy procedure. You could add two short wires to the pcb (where the cap is normally soldered in) and then you can easily swap caps to the wires. If you made your decision which value is best for you - solder the cap into the pcb. As long as you have a cap as DC-offset - protection at the in- and output,
nothing bad will happen. If you use a bipolar cap- take care for correct polarity.
Cheers
Dirk
test it, listen to it. Easy procedure. You could add two short wires to the pcb (where the cap is normally soldered in) and then you can easily swap caps to the wires. If you made your decision which value is best for you - solder the cap into the pcb. As long as you have a cap as DC-offset - protection at the in- and output,
nothing bad will happen. If you use a bipolar cap- take care for correct polarity.
Cheers
Dirk
Are film caps and Bi-polr caps equally as good as DC-offset?Hello Delineation,
…As long as you have a cap as DC-offset - protection at the in- and output,
nothing bad will happen. If you use a bipolar cap- take care for correct polarity.
Cheers
Dirk
Wait, film caps are bi-polar. But so are some electrolytic capacitors, including the Nichicon Muse 10uF in this design. I have been so confused about this.
Wiki:
Electrolytic capacitors are polarized components due to their asymmetrical construction and must be operated with a higher voltage (ie, more positive) on the anode than on the cathode at all times. For this reason the polarity is marked on the device housing. Applying a reverse polarity voltage, or a voltage exceeding the maximum rated working voltage of as little as 1 or 1.5 volts, can destroy the dielectric and thus the capacitor. The failure of electrolytic capacitors can be hazardous, resulting in an explosion or fire. Bipolar electrolytic capacitors which may be operated with either polarity are also made, using special constructions with two anodes connected in series. A bipolar electrolytic capacitor can also be made by connecting two normal electrolytic capacitors in series, anode to anode or cathode to cathode.
Wiki:
Electrolytic capacitors are polarized components due to their asymmetrical construction and must be operated with a higher voltage (ie, more positive) on the anode than on the cathode at all times. For this reason the polarity is marked on the device housing. Applying a reverse polarity voltage, or a voltage exceeding the maximum rated working voltage of as little as 1 or 1.5 volts, can destroy the dielectric and thus the capacitor. The failure of electrolytic capacitors can be hazardous, resulting in an explosion or fire. Bipolar electrolytic capacitors which may be operated with either polarity are also made, using special constructions with two anodes connected in series. A bipolar electrolytic capacitor can also be made by connecting two normal electrolytic capacitors in series, anode to anode or cathode to cathode.
Last edited:
If you put a capacitor in series with the music-signal it will allow the AC-signal (music - signal) to pass through the capacitor and it will block a DC-offset-voltage at the amps output. If there would be a large DC-offset at the output of your 6-24AXO, then this would go into your poweramp and could destroy it or this would move your cone of the driver / loudspeaker out - perhaps far out. Ever tried to put a 1.5 V battery to a bassdriver?
What is the cone doing? It moves out from its 'mid-position' - whether away from the magnet or to the magnet, depending on polarity.
This is the main function of those caps - protection from DC-offset
And you can use filmcaps or bipolar caps. Which sound better to your ears - you have to find out yourself.
I slightly prefer filmcaps. But I was surprised how good the Nichicon MUSE ES (bipolars) sound (those in the green 'jacket').
Enough for today
Cheers
Dirk
What is the cone doing? It moves out from its 'mid-position' - whether away from the magnet or to the magnet, depending on polarity.
This is the main function of those caps - protection from DC-offset
And you can use filmcaps or bipolar caps. Which sound better to your ears - you have to find out yourself.
I slightly prefer filmcaps. But I was surprised how good the Nichicon MUSE ES (bipolars) sound (those in the green 'jacket').
Enough for today
Cheers
Dirk
Back on post #245 it was asked about raising the input impedance to work better with a tube preamp. I'm in the same boat, having a preamp with 0.47 uf output caps. As I understand it, this would create a significant low frequency roll off when paired with a 12k nominal input impedance produced by the 50k pots in the XO. In order to use the XO with a low roll off, I'd need to have a high nominal impedance (if I understand it correctly). So the question is, would anything bad happen if I swapped out the 50k pots with something really high, say 500k pots, to get a larger nominal input impedance? I see pots that high from various vendors. Or would it be better to just throw some resistors in as a voltage divider in that situation? Assuming I know the voltages to set for the resistors.
Thanks for the replies in advance. I'd rather spend a few bucks on resistors that reinvest money in expensive output caps.
Thanks for the replies in advance. I'd rather spend a few bucks on resistors that reinvest money in expensive output caps.
Does anyone else see large voltage transients on the outputs when powering the device on or off? I am seeing large + voltage jump on outputs (several volts) upon startup that settles down to 0 volts after several seconds and a ~2-3 V negative drop that returns to 0 volts upon power off. It looks like the voltage spike on startup is causing my amplifier to blow line fuses.
I put this together as part of a revised power supply filter for the diy Sony Vfet and similar amps
to go in the diyAudio store and I have a nice pile of them ready to ship.
This circuit delays power to a relay (or relays in the case of the crossover) which connects the
audio output either to the active circuit (on state) or to ground (off state) by the Q2, R8, C7
portion of the circuit so as to avoid turn-on thump. It also will immediately turn off the output
when the voltage falls below a value set by P1.
P1 is adjusted to where this happens just below the normal operating voltage. The relay(s) have
a flyback diode, and are chosen for the supply voltage. You can parallel or series more than one
relay. The transistors are generic. In this schematic the intended supply 36 volts, but for 24 volts
you would simply reduce R7 to something like 18K.
Works like glue....
The full supply filter board will be posted more generally later.
to go in the diyAudio store and I have a nice pile of them ready to ship.
This circuit delays power to a relay (or relays in the case of the crossover) which connects the
audio output either to the active circuit (on state) or to ground (off state) by the Q2, R8, C7
portion of the circuit so as to avoid turn-on thump. It also will immediately turn off the output
when the voltage falls below a value set by P1.
P1 is adjusted to where this happens just below the normal operating voltage. The relay(s) have
a flyback diode, and are chosen for the supply voltage. You can parallel or series more than one
relay. The transistors are generic. In this schematic the intended supply 36 volts, but for 24 volts
you would simply reduce R7 to something like 18K.
Works like glue....
The full supply filter board will be posted more generally later.
With V+ = 36 volts and V- = 0 volts and NPN (Q2) VBE = 0.7, I calculate that Q2 turns on, and the relay pulls-in, (and the muting stops, and the amp begins to drive the speaker load), about 2.9 seconds after power is applied.
math:
Vthevenin = (2.2 / 29.7) * 36 = 2.67 volts
Rthevenin = 2.2K // 27.5K = 2.04K ohms
Tau = Rthevenin * C7 = 2.04E+3 * 4.7E-3 = 9.6 seconds
V_NPN_base(t) = Vthev * (1 - exp( -1.0 * t / Tau ) )
0.7 = 2.67 * (1 - exp( -1.0 * t / 9.6 ) ) ... solve for t, the time at which V_NPN_base equals 0.7V
t = 2.9 sec
math:
Vthevenin = (2.2 / 29.7) * 36 = 2.67 volts
Rthevenin = 2.2K // 27.5K = 2.04K ohms
Tau = Rthevenin * C7 = 2.04E+3 * 4.7E-3 = 9.6 seconds
V_NPN_base(t) = Vthev * (1 - exp( -1.0 * t / Tau ) )
0.7 = 2.67 * (1 - exp( -1.0 * t / 9.6 ) ) ... solve for t, the time at which V_NPN_base equals 0.7V
t = 2.9 sec