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Author Topic: Sontec MEP-250 Op-amp mod?  (Read 4741 times)

aleatoric

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Sontec MEP-250 Op-amp mod?
« on: January 05, 2012, 03:01:00 pm »

So I am finally getting around to modding my Sontec MEP-250EX to reduce the gain range from +/- 12dB to +/- 6dB.  I am having a tech do it as there seems to be a number of revisions over the years to the band card design and all the instructions I have read and looked at (thanks again to those on here who helped) did not apply to my specific unit.  I also admittedly don't have much soldering experience outside of cables and just feel a bit more comfortable paying someone else to do it. 

Anyway, when inquiring about the mod with a tech I was asked if I wanted "the lower distortion op-amps as well".  After asking for clarification I was told "On the EQ modules resides either a TL072 or NE5532 monolithic op-amp.  Top of the line for 1980.  Thirty years have made some improvements". 

The op-amp mod itself is rather cheap, especially if I get it done at the same time I have the gain range reduced.  What I am wondering though is if it is something I want to do?  I am currently very happy with the sound of my MEP-250EX and am wondering if these older op-amps actually are part of the "Sontec sound" if you will and going for lower distortion is a step in the wrong direction. 

Does anyone have experience with "upgrading" the monolithic op-amp's on a Sontec MEP series?  Any thoughts or advice is appreciated. 

Thanks. 
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SafeandSoundMastering

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Re: Sontec MEP-250 Op-amp mod?
« Reply #1 on: January 06, 2012, 11:05:22 am »

Hiya if you want to retain the sound it has leave it "as is".

I do not have direct experience with that unit but I know in all op amp experiments I have ever
done the sound is changed for better or worse, it very much depends on the circuit and the opamps interaction with surrounding components.

Maybe someone can suggest if it is a subjective improvement or not.

cheers
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Barry Gardner
SafeandSound Mastering UK based online mastering studio.

aleatoric

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Re: Sontec MEP-250 Op-amp mod?
« Reply #2 on: January 06, 2012, 01:35:51 pm »

As of now I'm leaning towards not getting the op-amp mod done as I'm very happy with the sound of my MEP250EX in its current state. 

By the way the tech I have been corresponding with is Dan Zellman in NYC.  I know he has worked on a number of Sontec's and performed the "gain range mod" to quite a few MEP250's.  The way the op-amp mod was brought up to me it seems as though he has performed it before for some units.  My hope in making this thread was to find someone who has gone through with this mod and hear their impressions. 


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Ben F

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Re: Sontec MEP-250 Op-amp mod?
« Reply #3 on: January 09, 2012, 05:33:32 am »

From the photos that I have seen, I don't think the new Sontec MEP-250 use the good old NE5532 on the filter boards. I'm pretty certain the new ones are discrete. Either way, it's really just a feedback circuit so not a large effect on the sound. Nothing wrong with NE5532s in the right circuit.
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aleatoric

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Re: Sontec MEP-250 Op-amp mod?
« Reply #4 on: January 09, 2012, 02:22:22 pm »

Thank you for the info Ben. 
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bblackwood

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Re: Sontec MEP-250 Op-amp mod?
« Reply #5 on: January 11, 2012, 02:11:18 pm »

I wouldn't mess with it.
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Brad Blackwood
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aleatoric

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Re: Sontec MEP-250 Op-amp mod?
« Reply #6 on: January 11, 2012, 05:29:41 pm »

I wouldn't mess with it.

Cool.  My thoughts as well. 

I'll just be going with the gain range mod.  Now to try to find an appropriate time to send it off...
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TotalSonic

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Re: Sontec MEP-250 Op-amp mod?
« Reply #7 on: January 18, 2012, 01:20:37 am »

Does Dan Zellman know better than some the other posters on this thread?  imho the answer is yes.  Those National Semiconductor LM series opamps work out nicely.   

Best regards,
Steve Berson
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