Swaping those opamps around seems to me pretty harmless but if you only are swapping opamps and not examine the rest I'm pretty sure you will never be satisfied.safetyman said:Sorry guys, all this sounds like Greek to me.I am a noob and wouldn't have an idea where to begin. You guys think that I shouldn't just swap the OPA 2604 with the OPA 2132 or 2134? Originally, t came with an OPA 7??. I have forgotten the number, and the manufacturer suggested to switch to the OPA 2604. I did, it's nice but found the mid section rather glaring. Wanted to see if there were other chips that would make it sound better.
Safetyman, you must measure the voltage on the op-amp pins to check if the op-amp is working on single supply.
If you have continuity between pin 4 and ground, it's single supply.
In that case, PSU bypassing will be different, more simple.
But you need to give us clues, otherwise we don't know what we are talking about, it's just suggestions.
Open the amp, you have work to do.
If you have continuity between pin 4 and ground, it's single supply.
In that case, PSU bypassing will be different, more simple.
But you need to give us clues, otherwise we don't know what we are talking about, it's just suggestions.
Open the amp, you have work to do.
Chipmaster Carlos. Firstly, on the weekend I'll try to get a pic of the amp, and where the pair of opamps sit. Then I'll post up for my masters to guide me. This should be interesting. Is there anyway to implement a LM3886 into a car environment? Keeping my fingers crossed. My car system is not built for SPL but more for SQ. Suggestions, please.
Firstly, on the weekend I'll try to get a pic of the amp, and where the pair of opamps sit. Then I'll post up for my masters to guide me. This should be interesting. Is there anyway to implement a LM3886 into a car environment? Keeping my fingers crossed. My car system is not built for SPL but more for SQ. Suggestions, please.
OK, I don't know exactly how this looks but here goes. The first pic is that of the pre section with the chips. The second is of the PSU. Comments please.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Carlos, sorry have not got the time to do it. Gotta pull the amp out of the car and dismantle many many many screws b4 I can get to the chip. 
Once I get the chance I'll do it and let you know.
Can you be kind enough to explain what the difference will be between parallel and bridging a LM4780? What would be the situation where one would be more preferable than the other?
Thanks and a Happy & Fantastic 2006 to all.
Once I get the chance I'll do it and let you know.Can you be kind enough to explain what the difference will be between parallel and bridging a LM4780? What would be the situation where one would be more preferable than the other?
Thanks and a Happy & Fantastic 2006 to all.
I have a Chord SPA-1800 preamp that I'm starting to mod.
It has a single ended analog gain stage that's built around the OPA604. I'm going to replace these with either the OPA627 or AD843.
From there, the signal goes to balanced output transmitter which is based on the NE5532.
From there, each leg of the signal goes to a OPA604 before it gets outputed (4 OPA604's at the ouput, one each for left and right + and - signals). I haven't looked closely at this output stage, so I'm not sure if the last OPA604's are in the signal path or if they're some sort of correction servos. I'll probably replace these, as well, maybe with AD843's or OPA627.
My question is, is there a better alternative to the NE5532 for the balanced output transmitter? I've just started researching how this works, so I don't know how much of a factor the opamp is in this position versus an analog gain stage.
Thanks for your help.
KT
It has a single ended analog gain stage that's built around the OPA604. I'm going to replace these with either the OPA627 or AD843.
From there, the signal goes to balanced output transmitter which is based on the NE5532.
From there, each leg of the signal goes to a OPA604 before it gets outputed (4 OPA604's at the ouput, one each for left and right + and - signals). I haven't looked closely at this output stage, so I'm not sure if the last OPA604's are in the signal path or if they're some sort of correction servos. I'll probably replace these, as well, maybe with AD843's or OPA627.
My question is, is there a better alternative to the NE5532 for the balanced output transmitter? I've just started researching how this works, so I don't know how much of a factor the opamp is in this position versus an analog gain stage.
Thanks for your help.
KT
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