Mod your Beresford 7520

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Originally Posted by HighFidelityGuy

Thanks.

Just out of interest, how come the 100nF cap wasn't included in the 7520's original design if it helps all the opamps? :)

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Hi HighFidelityGuy.


Welcome to AOS nice to see you getting stuck in. It would be really cool if you could pop into the Welcome section and say hi to everyone, and maybe you could tell us a little bit about yourself and the kit you use and what kind of music you like.

On AOS we love to see photos of the kit everyone is using, so if you can it would be great if you could pop some into the Gallery.

I am sure everyone can't wait to get to know you and enjoy your contributions.:)


Regards D S D L

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Originally Posted by Dalek Supreme D L

Hi HighFidelityGuy.


Welcome to AOS nice to see you getting stuck in. It would be really cool if you could pop into the Welcome section and say hi to everyone, and maybe you could tell us a little bit about yourself and the kit you use and what kind of music you like.

On AOS we love to see photos of the kit everyone is using, so if you can it would be great if you could pop some into the Gallery.

I am sure everyone can't wait to get to know you and enjoy your contributions.:)


Regards D S D L

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Hi, thanks for the warm welcome. I'll dig out my camera and see what I can do. :)

Thanks.

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Originally Posted by rhmjmango

Would it be possible to show a pic of this mod?

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OK, here goes:

http://farm4.static.flickr.com/3459/...1e61ee3e_m.jpg

Sorry about the photo quality.
Here is the mounted and modded chip installed in the DAC.

Ken

Quote:

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Originally Posted by sponge

OK, here goes:

http://farm4.static.flickr.com/3459/...1e61ee3e_m.jpg

Sorry about the photo quality.
Here is the mounted and modded chip installed in the DAC.

Ken

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:)Nice! Thanks. This makes the mod. more clear to me.
I am not that much into electronics so i was wondering what does this cap do technically? (apart of enhancing the sound quality)
By the way, did you do this mod on both op-amps?

Quote:

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Originally Posted by HighFidelityGuy

Just out of interest, how come the 100nF cap wasn't included in the 7520's original design if it helps all the opamps? :)

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There is. It's the one marked MLC10 in the picture posted by Ken:). But the specs recommend that the 100nF is as close as possible to pin 4 and 8. So that's what the '0.1mF mod' is all about;). You are adding a 100nF as close as possible to pins 4 and 8. The one on the main PCB is not close enough once you start adding an adapter PCB. The distance from say pin 4 on the surface mount IC and the appropriate leg on MLC10 is now several mm longer. And that extra track increase is suddenly an obstacle/nice short length of RF aerial. Putting an extra cap in circuit and closer to the chip even things out again.

STan

Thanks Stan,

Just about to order a THS4032 from RS and not certain about the 100nK decouling cap spec. Is there a specific one that I should go for.

Should I order anything else for the 7510 6/4 whilst I am at it and have the lid off? (easy mods only though as I am a beginner).

Regards

Chris

Quote:

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Originally Posted by rhmjmango

:)
I am not that much into electronics so i was wondering what does this cap do technically? (apart of enhancing the sound quality)
By the way, did you do this mod on both op-amps?

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At the basic level the cap(s) remove any unwanted noise, spikes etc from the power rails - And yes, the mod is done on both chips.

Quote:

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Originally Posted by chrism

not certain about the 100nK decouling cap spec. Is there a specific one that I should go for.

Chris

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The ones I used I had in my spares box - They were originally from Digi-Key part number 399-4328-ND. There are plenty others that would do the job though.

Ken

Quote:

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Originally Posted by chrism

Thanks Stan,

Just about to order a THS4032 from RS and not certain about the 100nK decouling cap spec. Is there a specific one that I should go for.

Should I order anything else for the 7510 6/4 whilst I am at it and have the lid off? (easy mods only though as I am a beginner).

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It's 100nF ceramic.

If you are a beginner I wouldn't try changing the opamp in the 7510. A few beginners have ran into troubles:(.

Talking about a 0.1uF ceramic cap. I do not know what to look for on the farnell website. Can anybody help me out? Thanks!