op amp rolling

This is the actual setup. Figured out how to upload the pic. I've used an RTA to balance the subwoofer levels to the speakers using the sub out on the back of the amp then dialed it in with Dirac live in the node icon. 

Your Klipsch RPM 600II  are a very forward sounding, lively speaker. I would choose an op-amp that warms things up a bit, and maybe an R2R DAC to help make things more listenable.....Better yet would be to sell the Fosi amps and upgrade to a beautiful sounding, lush tube amp if you want keep those speakers. 

My apologies for being off topic , I have a modded Akitika G-102 paired with a Rogue RP-1. The combo of a tube pre and the ability to roll gives me a considerable latitude in regards to tone. I’ve powered Klipsch Heresys and Zu Omens with great results. I wonder how a tube DAC might fit your need. I’ve not played with your speakers but I see a lot of crossover mods done. Happy Listening, Mike B. 

The speakers are forward/bright. I’ve heard them. Great initial audition, bad hard on long term listening sessions.
 

I’d keep the Fiosi as is for now and upgrade the speakers.

second system! sorry-typo on original post!

I will say that the system is quite a departure from my main system which uses electric static speakers and Macintosh gear, but I don’t want to reinvent the wheel. I’m just having fun with this all digital system in a simplistic set up.That being said, I don’t wanna be reinventing the wheel here. I’m quite happy for right now to work with what I’ve got. I actually like the way the system sounds for what it is. I just wanted to tame down the forward brightness of the clips in the class D apps with maybe some mellow or sounding op apps. if anybody out there has done it I’d love to hear about it. I'm getting into streaming and probably will inegrate it into my main system but for now I'm enjoying the simplicity of this system and checking out new music. I like tinkering with equipment so I thought it would be fun to mod the amps.

I did the same thing for a bedroom system for the same reasons.  Got a pair of Fosi ZA3s and rolled the op amps with Burson V7 Vivids (yes, op amps cost more than the unit).  There's a lot of talk on removing ALL of the op amps and just inserting the XLR and channel amps, since you won't use anything else (second channel, RCA), so you only need two op amps if you run them as mono and use only one input. I tried with stock, with Vivid, with extraneous op amps removed.  All three slightly nuanced and removing extras DID make a difference.  Call it an "inexpensive" system, but the centerpiece is a Topping Centaurus R2R and it is worth every penny. Added a Schiit Saga pre, WiiM Ultra, etc. Super fun to build this.

I also have the Fosi monos and have upgraded the op amps to the SparkoS brand. For balanced, you’ll need two op amps per mono and not three. Three if you’re also swapping out the op amp for the RCA input.

I don’t recall the improvements I heard as I did the swap many months ago, but to my recollection there was more detail in the music. I was pleasantly surprised with the improvements the SparkoS made to an already good sounding pair of monos. 

I also upgraded the power blocks but that improvement, if there was any at all, was rather small and I might have just imagined it. But the SparkoS was clearly audible.

audiodwebe

Are you running the mono's or the za3?

bigeks357

Did the vivids reign in and take some of the edge off? Do you think it was significant enough to justify it? Looks like about 500.00 for the six. Won't bother with the sub outs. Doubt there would be any appreciable gains there.

audiodwebe

Removing RCA op amps makes a difference and the amps still function for XLR?

I used to have a pair of FOSI V3 Monos where I settled on the MUSES02 op-amps after trying the Sparkos. They were reasonably priced (relatively) and sounded the best to me.

Thanks! I'll do some research on the Muse.

Using the Node icon for all the frontend duties eArc for video stuff and a cheap Sony Blu Ray player just in case. Pretty bare bones but that was the point. 2500. Total investment! The result is still surprisingly good! Just thought swapping out the op amps might take some of the digitallyness off the amps lol. Not a word- I know!

https://forum.audiogon.com/users/johnnybwood
 

There are five op amps inside the fosi ZA3 - one for each channel (2), one for the sub out, and one for each input (RCA and XLR). If you are decided on your output and running them as monoblocs, you only need two new op amps and can pull the extraneous ones. That means you only need to purchase four op amps, or two pairs. Put one in the XLR or RCA slot, and one in the right (mono) channel out. I thought the sound became more alive, expanded the dynamic range. It puts the high end in your face a bit, but not bright. They are aptly named vivid. For $160 or so per pair, it was worth the punt and totally worth it for the project and education on Class D.  Is it worth the sound? For me, totally. 

Thanks! I've been looking at the vivids. I'm running one dual mono for each speaker with XLR splitters and biwire to maximize the output. Tried them mono non-biwired not nearly as defined and lost there punch so I feel splitting is worth. That will mean three pairs of op amps. Iv3 heard theonos are brighter than the za3's so don't think I will go that way. 

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

so you're saying swapping didn't yield any benefit on the balanced input stage, only RCA? Just amplification stage? I was looking at the vivids so I take a shot at those. The za3's have enough height inside the case for those. I didn't the v3's would have room. Shouty is an apt description of those speakers. It's quite a departure from the sound of my electrostats but I like mixing up listening experiences. Hearing things in a different way.

@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

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!

Hey, johnnybwood.

Sorry for the late response.

I hav the V3 Monos. With them, you only need to swap out the opamps in the RCA circuit if you're using RCA. Like others, I paid more for the opamps than I did for the amps. 

But like I said before, the improvements were easily noticeable.

@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.