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Post by minivan on May 24, 2008 5:50:08 GMT
calling the help from diy expert such as sandyk and leo,etc.. some1 just lend me a burson discrete single opamp to play with on the opamp output of my zhaolu d3. according to the burson webpage www.bursonaudio.com/Burson_Discrete_Opamp_101.htmu need to ground the burson op-amp. but i dont know which pin to ground on the opamp , a search on the net tell me it's pin 3 , +in in this diagram, mine is single opamp: so is this the pin to be ground onto the rca ground? need to have some confirmation from the experts before i go ahead thanks in advance
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Deleted
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Post by Deleted on May 24, 2008 6:22:08 GMT
minivan I have never used the Burson opamp, but I imagine that they are referring to the lead shown in the photo on their website. As it is a replacement for an opamp,I imagine that it would need to be connected as a normal opamp, with gain setting resistors etc. It can't be used as a straight buffer with a single input pin. Have a look at the attached link for further information. SandyK www.mhennessy2.f9.co.uk/articles/op-amps.htm
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Post by minivan on May 24, 2008 7:13:31 GMT
hi sandyk , yeah, it's a replacement for the opamp, all the pins of the burson opamp will go into the socket where the opamp goto , except one wire u need to grounded. my problem is dont know which pin to go to ground , emailed burson but get no reply from them
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Deleted
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Post by Deleted on May 24, 2008 7:56:36 GMT
minivan NONE of the normal 8 pins. Have a look at the photos on their website from the link you posted. There appears to be a flying lead, possibly connected to the copper case ? SandyK
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leo
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Post by leo on May 24, 2008 10:42:18 GMT
Simply run the wire to a ground point on the pcb, the point where the phono input sockets are grounded to the pcb is fine
Make sure you have at least +/15v supplying the Burson, also the supply needs to be good quality, local regulation is best
Let us know how you get on
So does the Zhaolu D3 use a pair of single op-amps or just 1 x dual ? I don't know the output stage of this unit
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Post by minivan on May 24, 2008 10:59:12 GMT
hi leo i know the wire is going to the ground of the pcb, but i dont know where the other end of the ground wire going to, which point on the burson opamp should i connect the other end of this ground wire to? the zhaolu use a pair of single op-amps, right now i have a pair of burson single-opamp to replace them
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leo
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Post by leo on May 24, 2008 11:52:10 GMT
So the ground wire that should be attached to the Burson module isn't there? if this is the case you are going to have to post me a pic of both of those discrete op-amps pcb side, reason being is that they are usually mirrored, you must connect the correct part, its a bit hard to explain and a pic would be much easier Its the 1st or last pin that needs grounding (soldered row of pins on the Burson pcb), which one depends on the module, sometimes you may have 2 the same or 1 thats mirrored if you understand what I mean
BTW you gave me an idea Minivan, I've just tried a dual Burson in the Elcheapo dac which I believe uses the same dac chip as your Zhaolu I've raised its supply to +/-15v, I won't comment on the sound just yet ;D
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leo
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Post by leo on May 24, 2008 12:04:48 GMT
BTW the ground pin does NOT connect to any of the op-amp socket or its 8 pins
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Post by minivan on May 24, 2008 13:33:24 GMT
sorry i dont have very good camera 1st pic shown 2 wire from the burson opamp connected to the opamp socket 2nd pic has 3 wires from the burson opamp connected to the opamp socket. on the 3rd pic, if we label the pin number top down, left to down, then we have 2 wire connected from burson opamp to pin 2 and pin3 on the left rail of the socket and 3 wires connected from burson opamp to pin 6 , 8, 9 on the right rail of the socket i plugged the burson opamp straight into the socket of my zhaolu , i can hear sound but the volume is very very low. so i assume i would also need to supply +/-15v to it later on after i get this ground wire sort out.
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leo
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Post by leo on May 24, 2008 14:38:03 GMT
Look very closely at the bottom pics, also look closely at the different track layout for each of those modules, do you see they are mirrored ? you need to solder a wire to those pads I marked on the actual pcb and then to ground Look closely at your modules, does it look like something was soldered onto the end pad but has broken off the other side where the white copper shield is? also the pad that the wire solders onto should NOT be connected to the horizontal pad next to it, (see theres a row of 6 pads at the bottom If you don't ground the modules they are left floating If you have any doubts let me know, its easy to damage these things
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leo
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Post by leo on May 24, 2008 14:40:59 GMT
If you connect any of the op-amp sockets to ground you are basically going to be shorting it out which is what you don't want, the discrete modules need a separate ground, these are not the same as op-amps so they have to add an extra lead from the pcb for the ground
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pagan
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Post by pagan on May 25, 2008 1:25:30 GMT
Why won't Burson help you?
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Post by minivan on May 25, 2008 3:23:48 GMT
thanks guys for the help,will give it a try , glad i asked here before i try,i actually have the ground wire soldered onto the pin 3, in+ already lol. lucky i did not go ahead to try it out.
yeah , i email burson and they reply saying solder the ground wire to the rca ground , which i already know, but then they dont response anymore after i asked where to solder on the burson opamp module. the things does not come with any instruction and their webpage did not state where to solder on the module, which i thought it's very strange.
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Deleted
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Post by Deleted on May 25, 2008 3:34:29 GMT
minivan I presume that Burson already have the earth wire attached as in the photos on their website. Perhaps your friend disconnected the earth wires before giving them to you to try ? SandyK
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Post by minivan on May 25, 2008 9:44:35 GMT
thanks leo for the pic, it work. sandyk : u r right , the previous owner remove the wire b4 i received it. as always, whenever i have problem , u 2 always come to the rescue . thanks heaps now there's another problem , i cant get sound coming out from the left hand side, now i have to find out if there's any loose connection.
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leo
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Post by leo on May 25, 2008 11:11:18 GMT
No probs. The one thats faulty, are you sure that it was not connected the wrong way around at any time? if it was it'll certainly be damaged.
Check the hard wiring going from the Burson module to the socket its soldered to, make sure theres no shorts,breaks etc
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Post by minivan on Sept 2, 2008 4:56:08 GMT
i finally have the burson opamp installed in my zhaolu, burson replaced the faulty ones free of charge, very good customer service. currently i am running the burson straight out of the opamp socket of my dac. since the dac in the zhaolu is v out. is it possible to run the signal straight out from the dac to the burson and provide ur own psu to the burson opam ? would this make a improvement?
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rickcr42
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Post by rickcr42 on Sept 20, 2008 23:03:27 GMT
sounds about right but one thing-you ideally want this to be a low impedance connection so wire size may end up a critical "make or break" situation.If for some reason you get hum or buzz after the install increase the guage of the drain wire and if that does not help move the connection to the junction of the LAST power supply filter cap "common".A high impedance ground is just looking for trouble.
BTW-As has been already mentioned a typical op-amp has no true ground node but rather is a "floating" circuit so it is the actual signal,both input and output,that is referenced to ground (or it would have no point of reference telling the circuit what to do with the signal)
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