I managed to purchase a deleted 3 way stereo active crossover kit, old stock. Can you cross over experts comment on it? Also does it look easy to mod it to a 2 way stereo?
http://www.siliconchip.com.au/cms/A_30278/article.html
But it uses the very old fet input quad opamp the TL074
Is there and new you beaut fet input quad on the market that will sub for this, maybe Analog Devices or Burr Brown?
Cheers George
http://www.siliconchip.com.au/cms/A_30278/article.html
But it uses the very old fet input quad opamp the TL074
Is there and new you beaut fet input quad on the market that will sub for this, maybe Analog Devices or Burr Brown?
Cheers George
After looking a bit closer I think to make it a 2way instead of a 3 way all I have to do is move the source leg of VR3 (VR6) to pin 14 of IC3d and just use the bass and treble rca's and forget about the mid range one, can anyone double check my thoughts?
Then all I need is a decent subsitutes for the tired old TL074's.
Cheers George
Then all I need is a decent subsitutes for the tired old TL074's.
Cheers George
Attachments
Take a look at the OPA4134 as a substitute chip - I think the pinout is the same, but verify for yourself.
For two way use, you have it right, unless you want to EQ your woofer or provice a rumble filter. Then just use the Mid out as your low.
Check out sound.westhost.com for a Linkwitz Reilly crossover calculator. I assume that you will want to change the frequencies.
When using a straight L-R crossover, use drivers that are fairly flat for an octave either side of the crossover point. Don't use drivers with big breakup mode peaks unless you are crossing them out a couple octaves below the beginning of the breakup or you are likely to hear the breakup (AKA distortion).
Enjoy.
For two way use, you have it right, unless you want to EQ your woofer or provice a rumble filter. Then just use the Mid out as your low.
Check out sound.westhost.com for a Linkwitz Reilly crossover calculator. I assume that you will want to change the frequencies.
When using a straight L-R crossover, use drivers that are fairly flat for an octave either side of the crossover point. Don't use drivers with big breakup mode peaks unless you are crossing them out a couple octaves below the beginning of the breakup or you are likely to hear the breakup (AKA distortion).
Enjoy.
Thanks Bob I'll look into that opamp.
If I just use the high and the low pass as they are, the high pass goes through 2 opamps but the low pass will have to go through 4 opamps, in my post previous to your's I think it a better way for the low pass, as it too will then only go through 2 opamps like the high pass.
Cheers George
If I just use the high and the low pass as they are, the high pass goes through 2 opamps but the low pass will have to go through 4 opamps, in my post previous to your's I think it a better way for the low pass, as it too will then only go through 2 opamps like the high pass.
Cheers George
Hi,
Its a simple 4th order linkwitz/riley crossover.
Completely ignores most of the issues relating to speaker design.
Take a good look around this site to understand active crossovers :
http://www.linkwitzlab.com/index.html
/sreten.
Its a simple 4th order linkwitz/riley crossover.
Completely ignores most of the issues relating to speaker design.
Take a good look around this site to understand active crossovers :
http://www.linkwitzlab.com/index.html
/sreten.
sreten said:Hi,
Its a simple 4th order linkwitz/riley crossover.
Completely ignores most of the issues relating to speaker design.
Yeah but the kit cost me $15aus, and it's worth a try, all it has to do is give a 24db slope at my chosen point of 300hz without humping up or sagging at the cross over, i don't want it to do anything fancy just give me a clean crossover, and more important not get in the way too much, i still like the minimalist approach, dislike too many ic's between source and speakers
And Bob just looked at the OPA4134 it looks the goods but it looks as though it's only available now in SMD, unless i can find old stock somewhere in DIL.
Cheers George
Got fooled by the data sheet saying it was available in DIP14. How about using it with This ? Quickly exceeds the cost of the crossover, though. You might just give it a listen with the TL074s and see if you want to be bothered changing out the opamps. I've heard good things about the OPA2227, so would assume that the 4227 should be nice, too.
As long as your woofers don't have breakup modes <700 Hz. or so and your mids are flat to 150 Hz. you should get acceptable (if not optimal) results. For that price, it is worth a shot! You could build notch filters if required on prototype boards.
For upgrades, consider the bypass caps at the chips and electrolytics in the power supply. You may want to upgrade the power supply if your first listen shows promise.
As long as your woofers don't have breakup modes <700 Hz. or so and your mids are flat to 150 Hz. you should get acceptable (if not optimal) results. For that price, it is worth a shot! You could build notch filters if required on prototype boards.
For upgrades, consider the bypass caps at the chips and electrolytics in the power supply. You may want to upgrade the power supply if your first listen shows promise.
sreten said:
Hi,
Its very simple to convert to to a two way at 300Hz.
You need to connect the output of IC1a to the output point of 1C3d.
(i.e. to the inputs of IC3c and IC5d - removing other connections)
Yeah Streten that way looks even easier, just use the input IC (IC1a) to drive the midrange out and bass out sections, same as what I had in mind except, you were wprking from the front and I came from the rear, I'll see on the board which is going to look the cleanest way of mutilation surgery.
All the OPamps that have been mentioned are hard to get here in Aus or worth a fortune like $23 each for the OPA4227 from Farnell, what a ripoff. And I need 6 fo them that's $138!!!!!!!!
Cheers George
It did'nt have TLO74's in the kit it has Motorola LF347's and it's all built working like a charm.
I made the input 100k with no filtering or coupling cap it gives perfect 200k sqare waves no ringing and is flat out to 600k.
Modded 2 way works perfect, xover at 239hz go down flat to 3hz probaly dc, and has zero dc offset on all 4 channels, what more could I want for $15.
Tomorrow I'll hook it up to the ML monoliths to see how it sounds.
Does anyone know if the Motorola LF347 is good bad better than the TLO74?
Cheers George
I made the input 100k with no filtering or coupling cap it gives perfect 200k sqare waves no ringing and is flat out to 600k.
Modded 2 way works perfect, xover at 239hz go down flat to 3hz probaly dc, and has zero dc offset on all 4 channels, what more could I want for $15.
Tomorrow I'll hook it up to the ML monoliths to see how it sounds.
Does anyone know if the Motorola LF347 is good bad better than the TLO74?
Cheers George
Hi George,
have a good look at your PSU. You are likely to gain more here than anywhere else.
Can I suggest you expeiment with the input filter on the buffer (IC1a) The low pass is set very low ( 10k*220p=72kHz) try 2k0 or 4k7 to let a bit more treble through (220pF=NP0 ceramic or good plastic stacked film).
The high pass filter is also a bit tight (47k*1u=3.4Hz) try 2u2F or higher. It says NP implying electrolytic, don't, use a good plastic film.
have a good look at your PSU. You are likely to gain more here than anywhere else.
Can I suggest you expeiment with the input filter on the buffer (IC1a) The low pass is set very low ( 10k*220p=72kHz) try 2k0 or 4k7 to let a bit more treble through (220pF=NP0 ceramic or good plastic stacked film).
The high pass filter is also a bit tight (47k*1u=3.4Hz) try 2u2F or higher. It says NP implying electrolytic, don't, use a good plastic film.
The NS LF347s I've heard don't sound as good as the TI TL074s, despite similar specs.
Leave the input resistor at 10K when using either of these opamps. They will go through phase reversal and could blow up in certain circumstances without this resistor, been there, done that.
Hang a 1 Meg resistor on the wiper of the pot to ground. If the pot goes noisey you will latch to the rail otherwise.
Leave the input resistor at 10K when using either of these opamps. They will go through phase reversal and could blow up in certain circumstances without this resistor, been there, done that.
Hang a 1 Meg resistor on the wiper of the pot to ground. If the pot goes noisey you will latch to the rail otherwise.
hey guy!have you ever heard about "samples"??free samples of DIP opa4227 from texas instruments!!direc to your home!!and...for the smd adaptatort i use www.futurlec.com: 70cent for an adaptator...a right price!!
AndrewT said:
Thanks Andrew but in the post before yours, I have already taken all filtering and coupling off, as for the supply there is a lot more than is on the Silico Chip artical, I measured the noise and hum and at the Teks most sensive .2mv per div I got .06mv of noise and .08 of hum! with the input shorted, and it's not in a case yet!!
And yes djk, I was wondering about the series 10k on the input, you recon put it back for safety, ok
Cheers George
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.