I'm sorry to hear that. I may have an extra PCB, but I don't know for sure yet. When do you need it?
Oh, I'm just trying to get all my ducks in a row for this project. I could probably wait a few weeks before I'll actually start ordering from Digikey and assembling anything. Thanks very much for the offer, let me know if you can work something out!
Hurray, I finally got around to stuffing one of the boards.
After lots of boardscratching and correcting mistakes I got it to work as calculated. Everything works within .5 dB of the transferfunction I designed for!
Now I can start building it in the chain and start listering.
After lots of boardscratching and correcting mistakes I got it to work as calculated. Everything works within .5 dB of the transferfunction I designed for!
Now I can start building it in the chain and start listering.
Judging by my email, there seems to be enough interest to justify another group buy of filter boards and possibly PSU boards. 😎
Who will step up to the plate and organize it? Somebody could place a signup on the WIKI to tell for sure. I don't have the time these days.
Actually, I love my new job, even if it takes a lot of time. 😀
Who will step up to the plate and organize it? Somebody could place a signup on the WIKI to tell for sure. I don't have the time these days.
Actually, I love my new job, even if it takes a lot of time. 😀till without received it 🙁
have you the tracking # or something to ask in my country customs abt it?
have you the tracking # or something to ask in my country customs abt it?
Sorry, Samsagaz, it seems that your shipment went to customs heaven (or the opposite direction).
I sent it via uninsured Airmail Letter Post per your request. There is no tracking on it. We can hope that due to the size of the package it got bumped down to "Airmail Parcel Post" which often takes 3 months.
I sent it via uninsured Airmail Letter Post per your request. There is no tracking on it. We can hope that due to the size of the package it got bumped down to "Airmail Parcel Post" which often takes 3 months.
Looking for (2) AFF PCBs
Anyone have two extra filter boards you're willing to part with?
I've decided to ditch the mediocre plate amp crossovers and build my own active stereo sub crossover. A couple of these look like the ticket, but I just found this and it's not looking like there will be another GB. 🙁
Also interested in a PSU 2.2 kit or board (may have a source found in the Trading Post section).
Thanks,
James
Anyone have two extra filter boards you're willing to part with?
I've decided to ditch the mediocre plate amp crossovers and build my own active stereo sub crossover. A couple of these look like the ticket, but I just found this and it's not looking like there will be another GB. 🙁
Also interested in a PSU 2.2 kit or board (may have a source found in the Trading Post section).
Thanks,
James
If there is going to have another group buy I'm interested to get a couple. If anyone have some to spare pls do let me know.
I have spare boards. But I also have a disproportionate number of OPAs as well. So I will sell boards happily with OPAs, and reluctantly (ie expensively) without.
eg boards $10 alone, or $7 with OPAs @ $2.50
email me if interested.
eg boards $10 alone, or $7 with OPAs @ $2.50
email me if interested.
You'll notice that Jerzy has been real helpfull telling us he's @ home.
I wonder if the PCBs have to re-cross the Atlantic?
I wonder if the PCBs have to re-cross the Atlantic?
Jimbo1968,
I can't send/recieve PM until I'm released from newb probation, so I'll try responding here......
I'd like two of these boards and perhaps a handful of the OPAs; that is if trans-Atlantic shipping doesn't cost too much.
You can e-mail me at james_sinclair AT juno DOT com
Thanks,
James
I can't send/recieve PM until I'm released from newb probation, so I'll try responding here......
I'd like two of these boards and perhaps a handful of the OPAs; that is if trans-Atlantic shipping doesn't cost too much.
You can e-mail me at james_sinclair AT juno DOT com
Thanks,
James
As I reported earlier: the filter behaves as predicted both electrically and acoustically (even though I eliminated all the buffers (!)).
One problem though: when implemented in a preamp-amp-speaker setup it starts oscillating at unpredictable moments mostly within a few minutes after start. Until that moment it sounds fine but listening to a oscillating (screaching) setup with the power amp fully blowing is not a pleasure.
I must admit I only used a test setup (the filter is bare, not build in a shielded case). I suspect that the filter (either input or output) is picking up signal from the speaker cables.
Anyone have experience with this problem?
Will casing help? I would rather experiment first before finishing the thing in a case.
Thanks
Dick.
One problem though: when implemented in a preamp-amp-speaker setup it starts oscillating at unpredictable moments mostly within a few minutes after start. Until that moment it sounds fine but listening to a oscillating (screaching) setup with the power amp fully blowing is not a pleasure.
I must admit I only used a test setup (the filter is bare, not build in a shielded case). I suspect that the filter (either input or output) is picking up signal from the speaker cables.
Anyone have experience with this problem?
Will casing help? I would rather experiment first before finishing the thing in a case.
Thanks
Dick.
dick van nierop said:
Do you use EQ sections or just the HP/LP filters?
If you use EQs with +gain you must also mount a capacitor acrosst the top resistor in the FB path... you problem could be missing this.
What opamps do you use?
\Jens
Hi Dick,
I don't think the lack of a shielding case is your problem.
Are the speaker cables near the crossover? Move them to miss the crossover.
Are there mains electrical cables UNDER the floor where your crossover is laid? Lift the crossover.
BTW,
your 19 Jan post had no attachment.
I don't think the lack of a shielding case is your problem.
Are the speaker cables near the crossover? Move them to miss the crossover.
Are there mains electrical cables UNDER the floor where your crossover is laid? Lift the crossover.
BTW,
your 19 Jan post had no attachment.
Thanks for you reply.
I don't use equalizers, just the LP and HP (without output buffers of IC9, so directly from IC8A (which I have rebuild to form a LP-filter) and IC5B.
My opamps are OPA2134.
I measured crosstalk and found that in the frequency range I can measure with my soundcard (up to 20 kHz) there should not be a problem.
With the speakerleads laying on top of the xover i measure a cross talk of -30 dB max. This can not cause the oscillation as it would require a crosstalk > 0 dB.
The measurement was done by disconnecting the xover from the poweramp and injecting the meaurementsignal directly into the poweramp. I then measured the output of the filter (see attachment).
Can it be that above 20 kHz there is a problem as the signal level seems to be rising rapidly?
So what next?
I don't use equalizers, just the LP and HP (without output buffers of IC9, so directly from IC8A (which I have rebuild to form a LP-filter) and IC5B.
My opamps are OPA2134.
I measured crosstalk and found that in the frequency range I can measure with my soundcard (up to 20 kHz) there should not be a problem.
With the speakerleads laying on top of the xover i measure a cross talk of -30 dB max. This can not cause the oscillation as it would require a crosstalk > 0 dB.
The measurement was done by disconnecting the xover from the poweramp and injecting the meaurementsignal directly into the poweramp. I then measured the output of the filter (see attachment).
Can it be that above 20 kHz there is a problem as the signal level seems to be rising rapidly?
So what next?
Attachments
RFI problem
I've been having problems with RFI on one channel - a band pass channel. ICs are LM6172 - single ended inputs. It's a 3ch 4 board setup with single RCA inputs.
I've tried various grounding schemes, different types of cable - shielded and unshielded, different lengths of cable and the only thing that will stop the white noise is touching pin 5 with something metallic.
I've changed the input buffer IC, caps and resistors.
I've tried a ground loop breaker.
Tried cutting pin 5 on the IC.
Touched up every solder joint.
Checked every solder pad.
Checked for any stray filaments of wire which have found their way onto the boards.
The RCAs aren't shorting against the chassis.
I've run out of things to try except for using ferrite beads on the cables 🙁
Additionally, if I touch pin 2 it picks up radio stations, sometimes several at once. Today it's bangra, yesterday was some kind of far eastern language talk show and the day before sounded like a commercial Spanish station. This is all well and good but I haven't really wanted to include any type of long distance radio receiver as part of the feature list.
😉 I've recorded todays broadcast on my PDA and will pop it up somewhere if anyone wants a listen although it's nothing to write home about. 🙂
It's so frustrating because it sounds just lovely when doing the pin 5 trick
I really don't want to have to balance a small screwdriver against the pin in order to listen music.
If anyone can suggest anything else to try, I'm all ears 🙂
If nothing can be done, I guess it's going to be a case of trying to get another board and starting from scratch.
I've been having problems with RFI on one channel - a band pass channel. ICs are LM6172 - single ended inputs. It's a 3ch 4 board setup with single RCA inputs.
I've tried various grounding schemes, different types of cable - shielded and unshielded, different lengths of cable and the only thing that will stop the white noise is touching pin 5 with something metallic.
I've changed the input buffer IC, caps and resistors.
I've tried a ground loop breaker.
Tried cutting pin 5 on the IC.
Touched up every solder joint.
Checked every solder pad.
Checked for any stray filaments of wire which have found their way onto the boards.
The RCAs aren't shorting against the chassis.
I've run out of things to try except for using ferrite beads on the cables 🙁
Additionally, if I touch pin 2 it picks up radio stations, sometimes several at once. Today it's bangra, yesterday was some kind of far eastern language talk show and the day before sounded like a commercial Spanish station. This is all well and good but I haven't really wanted to include any type of long distance radio receiver as part of the feature list.
😉 I've recorded todays broadcast on my PDA and will pop it up somewhere if anyone wants a listen although it's nothing to write home about. 🙂It's so frustrating because it sounds just lovely when doing the pin 5 trick
I really don't want to have to balance a small screwdriver against the pin in order to listen music.If anyone can suggest anything else to try, I'm all ears 🙂
If nothing can be done, I guess it's going to be a case of trying to get another board and starting from scratch.
- Status
- Not open for further replies.