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Post by copperx on Mar 8, 2023 21:36:29 GMT -6
I just had this idea while reading about DOAs in the EQP5 thread.
The JLM is reportedly a great opto compressor, but it doesn't have the midrange push that the LA3A has. I was wondering, has anyone tried using Hairball's Raindog DOA, the one that sounds like the frontend of an LA3A, in a JLM LA500?
Maybe that could get the JLM closer to the LA3A character? Hmm ...
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Post by Blackdawg on Mar 8, 2023 22:40:45 GMT -6
I just had this idea while reading about OPAs in the EQP5 thread. The JLM is reportedly a great opto compressor, but it doesn't have the midrange push that the LA3A has. I was wondering, has anyone tried using Hairball's Raindog DOA, the one that sounds like the frontend of an LA3A, in a JLM LA500? Maybe that could get the JLM closer to the LA3A character? Hmm ... I have the Raindog DOAs. But no JLM LA500s to try it.. |
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Post by copperx on Mar 8, 2023 22:51:50 GMT -6
I just had this idea while reading about OPAs in the EQP5 thread. The JLM is reportedly a great opto compressor, but it doesn't have the midrange push that the LA3A has. I was wondering, has anyone tried using Hairball's Raindog DOA, the one that sounds like the frontend of an LA3A, in a JLM LA500? Maybe that could get the JLM closer to the LA3A character? Hmm ... I have the Raindog DOAs. But no JLM LA500s to try it..  The DIYRE's OLA5 also uses an opamp. I guess it could also work in that one, if it's pin-compatible. |
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Post by Blackdawg on Mar 9, 2023 1:28:07 GMT -6
I have the Raindog DOAs. But no JLM LA500s to try it.. The DIYRE's OLA5 also uses an opamp. I guess it could also work in that one, if it's pin-compatible. it is indeed compatible. I do have the OLA5. Though it's DOA is on the output side. I think the LA500 is on the input? So would be a bit different. |
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Post by copperx on Mar 9, 2023 8:43:42 GMT -6
The DIYRE's OLA5 also uses an opamp. I guess it could also work in that one, if it's pin-compatible. it is indeed compatible. I do have the OLA5. Though it's DOA is on the output side. I think the LA500 is on the input? So would be a bit different. I see. Might work better on the JLM. I'm tempted to build a LA500 one just to try this out. |
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Post by Blackdawg on Mar 9, 2023 10:36:32 GMT -6
it is indeed compatible. I do have the OLA5. Though it's DOA is on the output side. I think the LA500 is on the input? So would be a bit different. I see. Might work better on the JLM. I'm tempted to build a LA500 one just to try this out. Im in the middle of moving. But can dig one of my OLA5s out to do this. I'd planned on a big op amp shoot out but just got on the back burner. |
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Post by copperx on Mar 9, 2023 11:25:13 GMT -6
I see. Might work better on the JLM. I'm tempted to build a LA500 one just to try this out. Im in the middle of moving. But can dig one of my OLA5s out to do this. I'd planned on a big op amp shoot out but just got on the back burner. That would be fantastic!! I have an Audioscape V3A and I could run a source file to compare tones! |
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Post by copperx on Mar 31, 2023 0:21:57 GMT -6
Im in the middle of moving. But can dig one of my OLA5s out to do this. I'd planned on a big op amp shoot out but just got on the back burner. Hi! Did you ever get around doing this? Or the opamp shootout that you had planned? |
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Post by Blackdawg on Mar 31, 2023 0:35:17 GMT -6
Im in the middle of moving. But can dig one of my OLA5s out to do this. I'd planned on a big op amp shoot out but just got on the back burner. Hi! Did you ever get around doing this? Or the opamp shootout that you had planned? I didn't. But I did get most my gear unpacked. So should be able to do this soon. I started the op amp shoot out. Need to finish it. |
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Post by copperx on Mar 31, 2023 0:37:48 GMT -6
Hi! Did you ever get around doing this? Or the opamp shootout that you had planned? I didn't. But I did get most my gear unpacked. So should be able to do this soon. I started the op amp shoot out. Need to finish it. Awesome! 👍👍 |
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Post by Blackdawg on Apr 24, 2023 9:38:55 GMT -6
I didn't. But I did get most my gear unpacked. So should be able to do this soon. I started the op amp shoot out. Need to finish it. Awesome! 👍👍 You got a bass track you'd like to hear run through? Or you want me to grab something from like Telefunken or Cambridge?(aka free track anyone can download) |
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Post by copperx on Apr 24, 2023 11:56:41 GMT -6
You got a bass track you'd like to hear run through? Or you want me to grab something from like Telefunken or Cambridge?(aka free track anyone can download) Any track will do! If you have a guitar one that would be great too. |
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Post by audiospecific on Dec 16, 2023 20:04:26 GMT -6
I just had this idea while reading about DOAs in the EQP5 thread. The JLM is reportedly a great opto compressor, but it doesn't have the midrange push that the LA3A has. I was wondering, has anyone tried using Hairball's Raindog DOA, the one that sounds like the frontend of an LA3A, in a JLM LA500? Maybe that could get the JLM closer to the LA3A character? Hmm ...
Well where they went wrong was their parts selection.
Rupert Neve always said, "its not the design as much as the parts chosen as in their construction to make a circuit sound wonderful".
More forward midrange... OK, That shouldn't be too hard. That should be just a few resistor and cap changes for that.
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Post by audiospecific on Dec 16, 2023 22:37:11 GMT -6
Its that pretty red
But I wouldn't use those junk 33 ohm & 10K resistors that is part of your 'sterile' sound.
and solder one of these across each 470 uf cap:
There is some mojo for you. with some more air and mid oomph
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Post by anders on Dec 18, 2023 16:32:48 GMT -6
[…]But I wouldn't use those junk 33 ohm & 10K resistors that is part of your 'sterile' sound.[…]There is some mojo for you. with some more air and mid oomph I'm trying to learn (and am also the happy owner of a dual JLM opto). Could you please explain like I'm five why using wire wound resistors plus the polystyrene across those caps have this effect? |
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Post by audiospecific on Dec 18, 2023 19:47:43 GMT -6
[…]But I wouldn't use those junk 33 ohm & 10K resistors that is part of your 'sterile' sound.[…]There is some mojo for you. with some more air and mid oomph I'm trying to learn (and am also the happy owner of a dual JLM opto). Could you please explain like I'm five why using wire wound resistors plus the polystyrene across those caps have this effect?
They are not just wirewound resistors. These are Anton-perry type.
The ideal resistor would only offer resistance in DC, but pass all AC current, Insertion loss is a product of signal resistance in AC. The 10K resistors are silver alloy Anton-perry type, the 33 are regular copper alloy. The only reason why i chose a different 33 ohm is price because the silver ones will not make a difference between each other , but the MRA5 (silver anton-perry) would probably fit better because they are about the size of a standard 1/4 resistor.
Since you are having issues with midband, removing insertion loss would be my first thing to do.
non-polarized caps have the worst insertion loss of electrolytics, as internally they are two polarized caps with the negative leads tied together. Bypassing them with a polystyrene, that has one of the lowest insertion loss will lower the overall insertion loss of the capacitor.
Also now looking at their schematic. The last one I would make an MRA5 resistor would be r26 (4.7K). Also I would pick up low ESR caps for the input (c1&c2) mou.sr/3ErXJHP These are sold under the brand names 'Mills' and 'Vishay/Mills' depending on the supplier.
I really don't know how Jim (the original designer of all these La comps) would feel about these clones and their substandard parts. I know how he would build them though.
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