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Post by swurveman on Feb 4, 2017 8:32:14 GMT -6
My 4 channels preamp has one channel that has is not reproducing any low end. So, I contacted the manufacturer who suggested I remove the opamp from the bad channel with one from one of the good channels and see if that solves the problem.
Having never removed/exchanged an opamp I'm wondering if there's any tool that is best for doing this and any "best practice" advise from the many wise RGO member's.
Thanks to anybody with advise !
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Post by Johnkenn on Feb 4, 2017 8:58:08 GMT -6
It's like a 2520 style OA with the pins?
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Post by Martin John Butler on Feb 4, 2017 9:00:34 GMT -6
I changed an opamp in my Warm Audio preamp. It supposedly pulls out easily, and then you pop the new opamp right in. The thing was, it was really tricky to get the new one seated. It took me 10--15 minutes before all the little prongs lined up. That may not happen in your case, but be prepared to be patient, and it'll work eventually.
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Post by swurveman on Feb 4, 2017 9:05:29 GMT -6
It's like a 2520 style OA with the pins? Yes. Sorry if this is basic stuff. I just am always cautious when doing something the first time.
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Post by swurveman on Feb 4, 2017 9:06:02 GMT -6
I changed an opamp in my Warm Audio preamp. It supposedly pulls out easily, and then you pop the new opamp right in. The thing was, it was really tricky to get the new one seated. It took me 10--15 minutes before all the little prongs lined up. That may not happen in your case, but be prepared to be patient, and it'll work eventually. Did you just use your fingers?
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Post by Martin John Butler on Feb 4, 2017 9:13:28 GMT -6
Yes. It wasn't too difficult, just wiggle a little. Of course, you're unit may be different than mine, but I'm sure a gentle touch with small pliers wouldn't do any harm either. It's good you asked first, but it's no big deal, once you take a look, it'll be obvious what to do. Do be careful though, you don't want to accidentally crush something else.
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Post by swurveman on Feb 4, 2017 9:18:04 GMT -6
Yes. It wasn't too difficult, just wiggle a little. Of course, you're unit may be different than mine, but I'm sure a gentle touch with small pliers wouldn't do any harm either. It's good you asked first, but it's no big deal, once you take a look, it'll be obvious what to do. Do be careful though, you don't want to accidentally crush something else. Thanks!
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Post by maq3396 on Feb 4, 2017 9:39:21 GMT -6
The trick is to apply even pressure around the opamp board (not the components on it!) So that it comes up evenly.
The pins may be a bit stiff the first time you remove it but these loosen up quickly.
Nice information on opamp installation and construction can be found on Jeff Steiger's page at CAPI.
Jeff also sells another of opamps either in kit form or assembled.
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Post by Johnkenn on Feb 4, 2017 9:54:27 GMT -6
Yeah, just rock it out slowly. Of course, it won't pass sound without it.
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Post by indiehouse on Feb 4, 2017 9:55:08 GMT -6
My 4 channels preamp has one channel that has is not reproducing any low end. So, I contacted the manufacturer who suggested I remove the opamp from the bad channel with one from one of the good channels and see if that solves the problem. Having never removed/exchanged an opamp I'm wondering if there's any tool that is best for doing this and any "best practice" advise from the many wise RGO member's. Thanks to anybody with advise ! Hammer and an electric saw. Works every time.
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ericn
Temp
Balance Engineer
Posts: 15,009
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Post by ericn on Feb 4, 2017 10:13:37 GMT -6
My 4 channels preamp has one channel that has is not reproducing any low end. So, I contacted the manufacturer who suggested I remove the opamp from the bad channel with one from one of the good channels and see if that solves the problem. Having never removed/exchanged an opamp I'm wondering if there's any tool that is best for doing this and any "best practice" advise from the many wise RGO member's. Thanks to anybody with advise ! Hammer and an electric saw. Works every time. Nah Bosch SDS demolition hammer, at least that's what I told my wife to justify keeping the small one in the apt!😎
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Post by Bender on Feb 4, 2017 11:51:40 GMT -6
Be gentle, those holes are tight,fresh,& inexperienced now.... but before long you'll be able to pop those babies in & out like throwing a pickle down a hallway.
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Post by svart on Feb 4, 2017 12:33:09 GMT -6
Lack of low end is usually a sign of a cap in the signal path going bad.
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Post by NoFilterChuck on Feb 4, 2017 13:28:14 GMT -6
no one said it, but wait a bit after you power down the unit so there isn't any stray voltage in the circuit that could shock you.
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Post by Ward on Feb 4, 2017 13:29:21 GMT -6
My 4 channels preamp has one channel that has is not reproducing any low end. So, I contacted the manufacturer who suggested I remove the opamp from the bad channel with one from one of the good channels and see if that solves the problem. Having never removed/exchanged an opamp I'm wondering if there's any tool that is best for doing this and any "best practice" advise from the many wise RGO member's. Thanks to anybody with advise ! Hammer and an electric saw. Works every time. Don't forget the slot screwdriver and 1/2" chisel!
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Post by bowie on Feb 4, 2017 13:47:37 GMT -6
I don't know if anyone mentioned, but there's socketed and soldered. If it' socketed, I slip a tiny flat-head screwdriver under one end to get it started. When seating the new one, use the same screwdriver to help the pins on one side find their way in while I anchor/start the opamp on the other side of the socket. Never had a problem using that method.
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Post by wiz on Feb 4, 2017 14:54:47 GMT -6
I don't know if anyone mentioned, but there's socketed and soldered. If it' socketed, I slip a tiny flat-head screwdriver under one end to get it started. When seating the new one, use the same screwdriver to help the pins on one side find their way in while I anchor/start the opamp on the other side of the socket. Never had a problem using that method. From your description you are referring to IC based op amps... these are 2520 style.... cheers Wiz
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Post by johneppstein on Feb 4, 2017 15:38:27 GMT -6
I don't know if anyone mentioned, but there's socketed and soldered. If it' socketed, I slip a tiny flat-head screwdriver under one end to get it started. When seating the new one, use the same screwdriver to help the pins on one side find their way in while I anchor/start the opamp on the other side of the socket. Never had a problem using that method. Erm, they're talking about API style discrete opamp modules, not chips...
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Post by swurveman on Feb 4, 2017 16:50:24 GMT -6
Thanks guys for your advice!
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Post by bowie on Feb 4, 2017 17:17:54 GMT -6
I don't know if anyone mentioned, but there's socketed and soldered. If it' socketed, I slip a tiny flat-head screwdriver under one end to get it started. When seating the new one, use the same screwdriver to help the pins on one side find their way in while I anchor/start the opamp on the other side of the socket. Never had a problem using that method. From your description you are referring to IC based op amps... these are 2520 style.... cheers Wiz I don't know if anyone mentioned, but there's socketed and soldered. If it' socketed, I slip a tiny flat-head screwdriver under one end to get it started. When seating the new one, use the same screwdriver to help the pins on one side find their way in while I anchor/start the opamp on the other side of the socket. Never had a problem using that method. Erm, they're talking about API style discrete opamp modules, not chips... Sure thing. I only looked at the original post with no mention to which piece of gear it was. Thx for the clarification.
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Post by kcatthedog on Feb 4, 2017 20:41:17 GMT -6
You might like this
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Post by aamicrophones on Feb 4, 2017 22:29:09 GMT -6
You might like this Hello, if they are the 2520 style then carefully pry up on side then the other. You want the 2520 to come out evenly and slowly so the pins do not bend and are not stressed. Is there no low end at all? Reduction of low end is often caused by a failing capacitor. Especially, if electrolytics are used as coupling capacitors after the output of the 2520 OP amp. The 2520 is a dc coupled discrete OP amp and there's usually a 400ufd capacitor that couples the output of the OP Amp into the output transformer. If there is DC on the output of the 2520 then there is a problem with the 2520 otherwise its probably the output coupling capacitor failing. On the bench I look at the output of the 2520 before the coupling capacitor with an oscilloscope while sending a sine wave through the channel. I sweep the oscillator through the low end and if I measure DC at the output or the low end is rolling out then its a faulty 2520. I have the schematic and pin-outs for the 2520 around somewhere. Cheers, Dave Thomas aamicrophones.com
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Post by swurveman on Feb 5, 2017 7:46:05 GMT -6
Lack of low end is usually a sign of a cap in the signal path going bad. I told the service tech that I had low end dropout and he still wanted me to change the opamp. We'll see. I'll do it tomorrow. Just out of curiosity, is changing a cap just as simple?
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ericn
Temp
Balance Engineer
Posts: 15,009
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Post by ericn on Feb 5, 2017 11:50:32 GMT -6
Lack of low end is usually a sign of a cap in the signal path going bad. I told the service tech that I had low end dropout and he still wanted me to change the opamp. We'll see. I'll do it tomorrow. Just out of curiosity, is changing a cap just as simple? That would involve desoldering and desoldering so to most know, and if it's SMD a very big NO ! He's probably having you swap the OPAMP because it is simple enough to not involve a Round trip of shipping!
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Post by svart on Feb 6, 2017 8:24:41 GMT -6
Lack of low end is usually a sign of a cap in the signal path going bad. I told the service tech that I had low end dropout and he still wanted me to change the opamp. We'll see. I'll do it tomorrow. Just out of curiosity, is changing a cap just as simple? 100% that you'd need to unsolder and solder it.. Do you see any puffy electrolytic caps? They'd likely look like they're bulging or have crusty stuff on the top or underneath, or even possibly look like liquid is leaking out of them.
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