op amp rolling

Hi @johnnybwood 

I have the Fosi V3 mono, but mine is being used to drive my home theater setup only. I started with this amp because it has good reviews and is inexpensive. after I purchased it, I read of OP-amp rolling, so I did jump in the bandwagon

Well, I can tell you, it does (OP-amp rolling) improve on the V3 sonics. IMHO, the opamp rolling improves about 20 to 30% based on what I hear. The opamps I use are the Sparkos SS3602 for the final drive and Burson Vivid v7 on the pre-drive stage. I like this combo rather than a full sparkos as the Vivid seems to add body to the instruments and the Sparkos is a dynamic op-amp

As again, YMMV as 20 to 30% (estimated) improvement may not be much BUT you can hear it. You also mentioned that you have the Klipsch RP600m2, which I have as my Horn reference speaker. I actually used the Klipsch to verify what I hear is true or just imaginative. Yup, OPamp rolling is like tube rolling, it does make a difference.

The V3 are in my home theater driving the L/R speakers, and they are B&W 707. I'm impressed that the V3 can drive this 84db sensitive speakers to loud enough levels and the clarity is amazing. 

You claim you have the Za3, which I am not familiar with. just be extra careful when you choose the Burson opamps. it has a tall heat sink, which can pose a problem on the Za3 case.

based on the comments above, I suggest you get a pair of sparkos and pair of Vivid v7. On a single amp, try a combination of the opamps and listen on your Klipsch what sound you like. note, sparkos are dynamic, Vivid V7 are detailed and has body and Rp600MII are detailed/shouty. another note, that opamp for the balance input and single ended, (it's the one closest at the back panel) does NOT have any effect (to me hearing) when I am using balanced input connection.

good luck

@johnnybwood 

yes, swapping the opamp close to the input side of the amp did not (I could not discern a tonal difference). If there was, I was not able to detect it. Note, I am using a balanced XLR. However, the opamps that were close to one another which was more in front of the amp, has most impact. So, in my particular configuration, I find that the Vivid v7 position was closed to the front, while the Sparko was towards the middle of the amp board. Swap it around and listen which best suits you

@johnnybwood  

if I’m to understand what I’ve been reading the op amp in the back is to convert the RCA input to a balanced signal so I believe it can be removed from the unit if using XLR. I've ordered two pairs of V7 classics to try on the Two amps running dual mono biwired. I'm hoping they will take some of the hard edge off the speakers and give a more analog feal from the system. Will be reporting back next week. Cheers!

Yes sir. that is what i also read. but I have not remove it, even if I am using XLR.

Vivid V7 will make the sound more full body, i think hardness will be less.

YMMV

Regards.