ms dual op amp conversion...here we go folks

bogart · Post by **bogart** » Mon Aug 31, 2009 1:16 pm

Ok...so here's the plan...I am going to convert an ms amp to dual op amps and got the adaptors today....got the wrong ic though...so I've got to order the right ones....but It is well on the way to being a reality....pics of the adaptors that just came....should be pretty bad ass

GX3 · Post by **GX3** » Mon Aug 31, 2009 1:44 pm

Ok some one tell me ......why one would do this???? I will have a work bench soon in the new house and i need to start figuring some of this stuff out

Post by **fuzzysnuggleduck** » Mon Aug 31, 2009 2:00 pm

I'm also interested in what dual op amps provides that a single op amp doesn't. My understanding is most op amps have a single output. Are the dual op-amps going to be wired in series or parallel?

I don't know shit, enlighten me!

bogart · Post by **bogart** » Mon Aug 31, 2009 2:02 pm

Just to do it if you want the honest to god truth. It splits the load on a 2 channel op amp and then each chip runs each side...so the amp will have 6 balanced op amps rather then sharing any common's on the board. Greater efficiency and less room for signal noise is my understanding of it...Eric showed me this and I figured I would give it a whirl.

It utilizes much smaller components so the clearance on the bigger ms amps won't be an issue under the ground rail for the opamps there...u5-6-7 if I recall correctly without dragging an op amp out....

I just want to do it to do something different and it is great practice for smd rework...the chips that drop on the adaptor are not whole through....

bogart · Post by **bogart** » Mon Aug 31, 2009 2:06 pm

ms op amps are 2 channel devices...but share a common ground...I am not 100% about this guys...I am learning just like ya'll but I've looked at the schematics on ms op amps and I see how it works...I just can't copy the info on this tutorial over in this area.....it describes how it works.....

Post by **fuzzysnuggleduck** » Mon Aug 31, 2009 2:12 pm

Well, keep up posted dude. It's always fun reading about someone's adventures with the soldering iron

Misfire · Post by **Misfire** » Mon Aug 31, 2009 5:42 pm

We are going to use my MS275 as the test bed..... oh God don't leave me with a pretty heat sink!!!! I trust Bogart.

Post by **Eric D** » Mon Aug 31, 2009 5:52 pm

Ok, I think you guys are getting the wrong impression here.

Common op-amps like those used in MS amps are two channel. They have 8 pins. One is the negative, one the positive. Each channel has three pins, inverting input, non-inverting input, and an output.

The ONLY reason to do this dual op-amp deal is because better quality op-amps are not sold in dual channel packages. They are only sold as a single channel. This is for good reason. If you are spending $20 on an op-amp, and it is for some critical testing device (99% of the time not audio related), $20 is less than $40 if you only need a single channel.

Putting a pair of single channel op-amps on these adapter boards still gives you the negative issues of a typical dual channel op-amp, both share the same negative and positive power supply connections. Yes they are isolated from each other, which may help noise or crosstalk, but they are so physically close on these adapter boards I doubt there would be an improvement in those specs.

bogart · Post by **bogart** » Mon Aug 31, 2009 6:20 pm

Eric...I got the wrong ic's with these...I am looking and am unsure of the correct size as they are about half the size...

I will send you three of these if you want em..

I ordered the adaptors you had sent me the link to p/n 020302 from Brown Dog....I didn't look at the feet spacing at all and am unsure of the pin on the board....

what do you think...any idea's with out seeing it....

I've got some other stuff here for you too...pm me your addy mate and I'll send you this stuff

bogart · Post by **bogart** » Mon Aug 31, 2009 6:32 pm

Ok...so the dual adaptor allows two s08 single channel op amps to be used in place of the single dip 8 pin....

the kits that are pre made use either opa627ua burr brown or opa827ai burr brown chips...so what would be the analog devices contemporary component be...I am looking and may find it....but if someone else locates the appropriate ic....do let me know as I need to order them....

Post by **Eric D** » Tue Sep 01, 2009 6:38 am

Do a Google search for "best op amp for audio" and start researching. You need to find one which meets your tastes, not just one that costs a lot. Once you find the best single channel unit in your price range, order the S08 versions of them from digikey or where ever else you can get em.

chaplin · Post by **chaplin** » Tue Sep 01, 2009 7:39 am

With adapter Brown Dog... good op amp is: Analog Devices AD8066 but with vdc max +/- 13v

bogart · Post by **bogart** » Tue Sep 01, 2009 8:10 am

I am looking into the pin voltages on the chips....once I find that info I will know....all the s08 chips I am looking at have different values so I need to see which has the correct values and I'll post it when I find everything

jbondox · Post by **jbondox** » Tue Sep 01, 2009 10:04 am

What about changing it to the ZPA series inputs with a line driver? which would be real cool if you could build an AINET interface to the line driver for some serious noise rejection... if you were using Alpine

freshkryp69 · Post by **freshkryp69** » Tue Sep 01, 2009 4:11 pm

Ive heard the bb604's are a great op-amp ....anyone else got any #'s of op-amps to try???

freshkryp69 · Post by **freshkryp69** » Fri Sep 18, 2009 3:18 pm

what we need to try and do is build a super clean separate power supply for the op-amps with adjustable voltage output,and while were at it we need to try and use some of those (Burson Audio) discrete op-amps..they are supposed to be the best money can buy,each and every component that they use is burned in and checked for tolerance. apparently they accept no compromises when they make there discrete op-amps.. checkout there website and read what they have to say about the op-amps that most of us use..the only thing that I can see that might be an issue is the size of these badboys...

so would the Doc or someone else be up to the task of building an power supply??? mabey even a separate box mounted outside of the amp?? Ill put up my 2250 and my 2125 as test amps...

late