LA-4 Help Thread!
- Thread starter Luny Tune
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Luny Tune
Well-known member
I don't know where a 11148 transformer is used normally or how it's wired there. If it's used where we substitute it for a Lundahl LL5402, OEP A262A2E, Cinemag CMOQ-2S et.c. in our clones then I'm sure it'll fit the LA-4 as well. But check a schematic where it's used to find out how it's supposed to be wired.
Luny Tune
Well-known member
I know you're looking for a 2U panel, but let me give you my 1U too. If for nothing else but inspiration...helterbelter said:
http://dl.dropbox.com/u/1683654/LA-4_2U_Unfinished_w-CloneLogo.fpd
http://dl.dropbox.com/u/1683654/LA-4_1U.fpd
Luny Tune
Well-known member
http://waltzingbear.com/Schematics/Urei/LA_3A.htm
There you have the LA-3 schematic.
There you have the LA-3 schematic.
Luny Tune
Well-known member
No, you can easily put an input transformer in there if it's just for getting the sound of it. I've tried a LL1540 in it. Works just fine to put it between the input XLR and Input on the PCB.
The "problem" is that now you have two things that is meant to do the same job in there. The input transformer and the input stage on the PCB. They're both meant to de-balance the signal again. It's not a problem when you put in the tranny for it's sound but the opration kinda renders part of the input stage redundant. See? I think a more interesting idea would be to replace the whole input section in the circuit, or or at least the de-balancing circuit, with an input transformer and I believe it can be done. I did try to at first with the Lundahl tranny but I got no sound through it so I must have fumbled somewhere along the line. I've tested so much with that particular comp so I've decided to leave that one alone from now on not to ruin it completely. I may pick up the proto type again for experimenting with it.
Anyways, look at specs and schematics and give it a shot. The worst thing that can happen is that you don't get the sound you're looking for and then you'll have to live with it as is, but to my ears that's not half bad either. ;D
I love the LA-4 as it is and I removed the input transformer again. It sounds really good with it in there but somehow I don't find it necessary. It kinda gets a bit of the 1176 sound to it and one thing I love about the LA-4 compared to the 1176 is it's more in-your-face mids. It has a lovely presence to it in my opinion and once the optos sound as they should it doesn't need any fattening up either. I'm recording my girlfriend's second album right now and play my guitar with just a G9 and an LA-4 straight on to disk. I love it. No eq, extra comp or anything afterwards either... Yummie!
The "problem" is that now you have two things that is meant to do the same job in there. The input transformer and the input stage on the PCB. They're both meant to de-balance the signal again. It's not a problem when you put in the tranny for it's sound but the opration kinda renders part of the input stage redundant. See? I think a more interesting idea would be to replace the whole input section in the circuit, or or at least the de-balancing circuit, with an input transformer and I believe it can be done. I did try to at first with the Lundahl tranny but I got no sound through it so I must have fumbled somewhere along the line. I've tested so much with that particular comp so I've decided to leave that one alone from now on not to ruin it completely. I may pick up the proto type again for experimenting with it.
Anyways, look at specs and schematics and give it a shot. The worst thing that can happen is that you don't get the sound you're looking for and then you'll have to live with it as is, but to my ears that's not half bad either. ;D
I love the LA-4 as it is and I removed the input transformer again. It sounds really good with it in there but somehow I don't find it necessary. It kinda gets a bit of the 1176 sound to it and one thing I love about the LA-4 compared to the 1176 is it's more in-your-face mids. It has a lovely presence to it in my opinion and once the optos sound as they should it doesn't need any fattening up either. I'm recording my girlfriend's second album right now and play my guitar with just a G9 and an LA-4 straight on to disk. I love it. No eq, extra comp or anything afterwards either... Yummie!
Rybow
Well-known member
I just wanted to confirm something. I finally got my MC33079 IC's from Digikey. They were back ordered for 2 months. Also got some gray hill rotary switches for channel 2. Sexy! Anyways, back to the point. Luny suggests putting the MC33079 in the side chain. After some investigation, I am under the impression that the side chain IC is #3, but it could also be #1. Not quite sure what a side chain handles as I am used to itb side chain.
I am also having a hard time tracking down the LED's for the diy opto. Its the 150mcd rating that seems to be difficult to get. The current LED's I have loaded are 2V 20 mA 35 degree 2700mcd. The 2700mcd is obviously way too high. I am wondering if that is the cause of my ratio issue because the LED gets too bright too fast causing the LDR to really smash the crap outta everything. I emailed a local parts store, but they had no clue what I was talking about. Would it be a red diffused LED type?
I ran a bass track through my LA 4 to see if it would make a difference to the track. I have had some issues with this track trying to get it to sit nicely. My LA 4 grunged it up, tightened it, and really made it fit into the mix! Love this thing on bass and vocals so far. Even in its "not quite working right yet" form.
I am also having a hard time tracking down the LED's for the diy opto. Its the 150mcd rating that seems to be difficult to get. The current LED's I have loaded are 2V 20 mA 35 degree 2700mcd. The 2700mcd is obviously way too high. I am wondering if that is the cause of my ratio issue because the LED gets too bright too fast causing the LDR to really smash the crap outta everything. I emailed a local parts store, but they had no clue what I was talking about. Would it be a red diffused LED type?
I ran a bass track through my LA 4 to see if it would make a difference to the track. I have had some issues with this track trying to get it to sit nicely. My LA 4 grunged it up, tightened it, and really made it fit into the mix! Love this thing on bass and vocals so far. Even in its "not quite working right yet" form.
Luny Tune
Well-known member
I'm happy to hear you like it, and your experience there is just like mine. ;D
Please note that I'm still in a learning process and take my notes only as an indication of "where I am" right now. I may suddenly discover that the all important thing is something entirely different than I thought yesterday.
First off; Yes, the sidechain IC is #3. Note how it suddenly seems to work...sort of...with "less effort". Sounds a bit like there's more "hole through" when it's compressing. Difficult to describe, and please do reort back with your experience with it.
And then; Yes, I do believe that 2700 mcd is too bright....but I certainly suggest that you try it out anyway. I could be wrong!!
I suspect that how bright the LED is do have influence on where on the LDR's curve we're working. Maybe you can check it out with the ones you got there? In return, and if they don't give you the attack and release we're looking for, I'll send you some of my LEDs that I have found work perfectly well.
I'll shoot a bit of video of the meter in one of my units so you have an indication of the movement you should get from an adjusted version. Remember you must go through the whole adjustment procedure everytime you change a LED, a trimmer, an LDR or anything that has an impact on how it works!
By the way, here's the link to the LED's I'm using so far. They're 10mm and thereby twice as big as the LEDs in the original, but they work as intended with the NSL 6910 LDR. The shop is in Denmark but they do ship to anywhere in the world although it may not be that clear to you when you browse the site:
http://www.el-supply.dk/?Gid=210&VNr=45A.2D
And here's their note on ordering from outside Denmark:
http://www.el-supply.dk/?Sid=5
(Scroll to the bottom of the page!)
Please note that I'm still in a learning process and take my notes only as an indication of "where I am" right now. I may suddenly discover that the all important thing is something entirely different than I thought yesterday.
First off; Yes, the sidechain IC is #3. Note how it suddenly seems to work...sort of...with "less effort". Sounds a bit like there's more "hole through" when it's compressing. Difficult to describe, and please do reort back with your experience with it.
And then; Yes, I do believe that 2700 mcd is too bright....but I certainly suggest that you try it out anyway. I could be wrong!!
I suspect that how bright the LED is do have influence on where on the LDR's curve we're working. Maybe you can check it out with the ones you got there? In return, and if they don't give you the attack and release we're looking for, I'll send you some of my LEDs that I have found work perfectly well.
I'll shoot a bit of video of the meter in one of my units so you have an indication of the movement you should get from an adjusted version. Remember you must go through the whole adjustment procedure everytime you change a LED, a trimmer, an LDR or anything that has an impact on how it works!
By the way, here's the link to the LED's I'm using so far. They're 10mm and thereby twice as big as the LEDs in the original, but they work as intended with the NSL 6910 LDR. The shop is in Denmark but they do ship to anywhere in the world although it may not be that clear to you when you browse the site:
http://www.el-supply.dk/?Gid=210&VNr=45A.2D
And here's their note on ordering from outside Denmark:
http://www.el-supply.dk/?Sid=5
(Scroll to the bottom of the page!)
Rybow
Well-known member
Thanks for the help Luny! Much appreciated!
The 2700 mcd LED's are the ones I have in right now. I just picked up some smaller ones that have a wider viewing angle to try out. Hopefully get those in tonight and test them out. Thanks for the link as well. I'll see how the new ones I got work out and report back with that, as well as the MC 33079 in IC #3.
I am still learning as well, and have never used an LA 4 before, so all the info you give on different parts is awesome! I am having a lot of fun experimenting with different configurations. Thanks again!
The 2700 mcd LED's are the ones I have in right now. I just picked up some smaller ones that have a wider viewing angle to try out. Hopefully get those in tonight and test them out. Thanks for the link as well. I'll see how the new ones I got work out and report back with that, as well as the MC 33079 in IC #3.
I am still learning as well, and have never used an LA 4 before, so all the info you give on different parts is awesome! I am having a lot of fun experimenting with different configurations. Thanks again!
ArnauTS
Well-known member
After a long read it's time to start to buy the pcb and components
Thanks for the great project ;D
Thanks for the great project ;D
Matthew Jacobs
Well-known member
ArnauTS said:
You won't regret it
My favorite Comp thus far....
Gonna build 2 more...
J
helterbelter
Well-known member
Hi Maestro,ilfungo said:
I used your design, but I adjusted it to a 1HE after all. I discovered that I didn't have enough space in my racks for a 2U ! I have to check the last few things, then I'll post it here too.
Luny Tune said:
Haha, I haven't been here much lately !
I haven't seen your post until now. Thanks for sharing !
Your clonelogo'ed 2u looks fantastic, (it is pretty expensive though...). And while looking at your 1HE, I see that I mustn't forget to add the linkswitch and the holes for the overload leds....
I'm currently working on 5 different frontpanels that I need to order. But the finances probably allow me to order just 2 for now, haha. The LA4 will be the first to order, that's for sure. ;D
ArnauTS
Well-known member
Great newsMatthew Jacobs said:ArnauTS said:
You won't regret it
My favorite Comp thus far....
Gonna build 2 more...
J
i want a dual one but i'm sure i will use it after my 1176 revision J, cant wait to start soldering this, hope i get all the money soon ;D
Luny Tune
Well-known member
You're most welcome, ArnauTS. ;DMatthew Jacobs said:You won't regret itArnauTS said:
My favorite Comp thus far....
Gonna build 2 more...
I'm absolutely agree with, Matthew. It's the kind of comp you can easily use more than one or two of if you mix OTB or "just" in a hybrid setup like I do where I use only hardware for eq and dynamics processing.
Luny Tune
Well-known member
I don't think so. Considering the tolerance on those things, I think you're fine, BUT I'm not absolutely sure what that particular RC thingy does right there in the circuit... Maybe someone who knows can pitch in here? I think it's a simple filter, a low pass filter, but I'm not sure...
pedroplanet
Well-known member
I've just finished(the electronic part of) my unit using NSL32's and it sonds good,
but distorts too much when compressing more than -10db at any ratio...
the ratio trim is fully cw and no luck... its too agressive...
waiting for the Vactec VTL5C4/2 and Clairex CLM 6000 for testing
@Luny:
Do you think I'd need to Change R13 (the 82KΩ just above jumper 2 on the pcb) to a 16KΩ resistor using any of the the optos above?
but distorts too much when compressing more than -10db at any ratio...
the ratio trim is fully cw and no luck... its too agressive...
waiting for the Vactec VTL5C4/2 and Clairex CLM 6000 for testing
@Luny:
Do you think I'd need to Change R13 (the 82KΩ just above jumper 2 on the pcb) to a 16KΩ resistor using any of the the optos above?
Luny Tune
Well-known member
Yes. As mentioned in the notes in the .pdf file, if you're using the NSL-32 (and probably other optos as well) you need to do one of two things:
Luny Tune
Well-known member
@pedroplanet
Don't disqualify any optos before you've been able to complete the adjustment procedure all the way through. If you can't adjust the ratio trimmer as intended it WILL distort more than it's supposed to.
@Everybody
I found this webshop that has the Silonex LDRs and where you can shop even if you don't have your own business. They cost a little bit more than in other shops but not a lot. It's in Germany but they ship anywhere:
http://www.metrius.de/index.php?language=en
I got real tired of Allied Elec. because they say they can't calculate shipping costs before the order has been processed and is ready to be sent... And the reply to my asking for a price was:
"We cannot estimate freight because the shipping costs are not calculated until the package is boxed up and scanned to go out on the truck. I can't even get the parts picked until the ticket prints out at which point the parts are already paid for. We do over 9000 order a day and stock over 155,000 parts, so we have to follow a process.
Your best bet is to log onto the website of what ever freight carrier you chose and estimate from our location to your zipcode."
Checking with UPS and others left me with shipping costs around $100-150 and RS Components and Farnell ships with the same companies for 1/10 of that, stocking 430,000 and 450,000 parts respectively, I might add...
Metrius also ships at a reasonable price...of course...at present time stocking 370,497 parts. I can see how it most be really difficult for Allied Elec. to tell you how much you'll have to pay until they've actually withdrawn the money from your account... :
Don't disqualify any optos before you've been able to complete the adjustment procedure all the way through. If you can't adjust the ratio trimmer as intended it WILL distort more than it's supposed to.
@Everybody
I found this webshop that has the Silonex LDRs and where you can shop even if you don't have your own business. They cost a little bit more than in other shops but not a lot. It's in Germany but they ship anywhere:
http://www.metrius.de/index.php?language=en
I got real tired of Allied Elec. because they say they can't calculate shipping costs before the order has been processed and is ready to be sent... And the reply to my asking for a price was:
"We cannot estimate freight because the shipping costs are not calculated until the package is boxed up and scanned to go out on the truck. I can't even get the parts picked until the ticket prints out at which point the parts are already paid for. We do over 9000 order a day and stock over 155,000 parts, so we have to follow a process.
Your best bet is to log onto the website of what ever freight carrier you chose and estimate from our location to your zipcode."
Checking with UPS and others left me with shipping costs around $100-150 and RS Components and Farnell ships with the same companies for 1/10 of that, stocking 430,000 and 450,000 parts respectively, I might add...
Metrius also ships at a reasonable price...of course...at present time stocking 370,497 parts. I can see how it most be really difficult for Allied Elec. to tell you how much you'll have to pay until they've actually withdrawn the money from your account... :
