Op Amps and their effect on sound quality in DSPs?

[jtrosky]

On a Dodge Challenger forum that I am a member of, there is a member that is saying how replacing the Op Amp in the Rockford Fosgate DSR-1 provides a "significant improvement" in sound quality. He is also saying that the same Op Amps that are used in the DSR-1 are also used in the Helix devices - and again, are of poor quality. For example:

"By making a simple change of analog chain op-amps from the very poor performing MC33078's (marked by MYU and actually same one used in Helix) to Burr-Brown OPA-1642's a significant improvement can be made to the DSR-1."

He also mentions that the DACs used in the Helix devices are of poor quality - basically saying that the DAC's used in the RF DSR-1 are better performing (than both the JL TWK and Helix devices). For example:

"As far as the DSR1 goes, the Cirrus DSP's DAC (24bit/96kHz) is better performing than the JL TwK's DAC (24bit/48kHz) for example, and does 32bit/196kHz input processing. The HELIX gives you analog output opamps less than half the slew rate and settle time you need for proper 24bit operation and the AKM DAC's are 32bit. (settle time in the ms range when you need ns range) The AKM discrete DAC's suffers from lower dynamic range and more THD+N than the Cirrus' on-die DAC. If I'm going to have to address shortcomings in the device I choose, I'd rather choose the one that actually has better performance. So in reality, yes, less is more."

He loves the "less is more" line. :-) Although, he also says that his $50 Polk speakers play cleanly to 27hz - and that by using 1st order passive crossovers, he doesn't have to worry about time alignment between his door and dash speakers - and that the PAC AmpPro is a poor device - and that an 8" sub in the rear-deck will perform better than a dedicated subwoofer in the trunk, etc, etc, etc. MANY people have tried the 8" sub in the Challenger rear-deck and it just doesn't work well in real life. :-)

Link to actual thread is here, if interested (only about 2 pages long):

https://www.challengertalk.com/threa...package.678268


Having used both the DSR-1 and an AmpPro/Helix combo myself, I can definitely say that the AmpPro/Helix combo is a MUCH better all around solution. Even besides the sound quality improvements, the software for the Helix alone is *LIGHT YEARS* better and *so* much more powerful and flexible than the DSR-1 "mobile-only" app interface (which is one of the biggest "cons" of the DSR-1, IMO).

Anyway, I was curious what some of the more experienced people here thought about some of these statements he's made. I find it hard to believe that the Rockford DSR-1 has better-performing components than a Helix (or even the JL TWK devices) - but what I'm really curious about is if replacing the op amps in something like a DSP would actually provide any significant improvement in sound quality like he's claiming. I have my doubts, but I don't know the technical details well enough to truly know...

[JCsAudio]

I compared the DSR-1 directly to my TwK88 by setting the tune in the DSR1 the same as my TwK88 and swapping it in. Let’s just say I sold the DSR-1 and still have the TwK88. Even the Dayton 408 is much better in my opinion and I own that one too. If you go to DIYMA and search OP-Amp swap for amplifiers and find those that did it, you should eventually conclude after hours of reading that it does not make any difference worth the trouble. I forget his exact name but something like Bnae38 that has done a lot of work with this. He repairs amplifiers. Of all the things that make a big difference in sound qaulity, amplifiers of a certain qaulity level (not hard to reach over $250) and the associated electronics are not on the short list.

[nadams5755]

There’s all kinds of supporting circuitry around the adcs, dacs, and opamps that get overlooked. These have a massive impact on the sound quality of the overall circuit. Chip designers usually have reference circuits. Equipment manufacturers may drift from this reference design for various reasons: change the sound, change the price point, or availability of components are three reasons. You may even have a bad batch of electronics which were manufactured with the wrong components negatively impacting sound.

swapping opamps without considering the supporting circuitry could be catastrophic or just sound bad. Some opamps will work fine in the same circuit.

[SkizeR]

Based off of the "other" things he has said, I can tell you that he's not someone to trust lol. That said, most models of helix processors use different parts from one another. I know on the older generation models, swapping op amps was common. But the newer stuff sounds even better out of the gate

Sent from my SM-G975U using Tapatalk

[jtrosky]

Ok, thank you all. So basically, from what I've researched and what has been said here, it sounds like op amp replacement in DSP's and/or amplifiers is something that used to be more common and *possibly* worthwhile "back in the day", but with modern equipment, it rarely results in any significant improvement (and can actually result in a significant *decrease* in performance if an appropriate replacement isn't used).

Does that about sum it up? I mean I found it hard to believe that Audiotec Fischer, for example, would skimp on something so inexpensive if it was actually a worthwhile "upgrade". I mean why would they use a $1 op amp in a $700 DSP if a $3 op amp made a significant improvement (those prices are made up, but you get the point) - from what I gather, op amps are generally pretty inexpensive components in the scheme of things.

I'm *positive* that the user on that other forum won't be able to provide any actual data to back up his claims (measurements, etc) - but I think I'll ask anyway - just to see what his response is. :-) If he *truly* believes that a DSR-1 with an "upgraded" op amp is a better solution than a Helix or a JL Twk, then he is obviously only *truly* concerned with one thing - and that is spending less $$$$.

[nadams5755]

Reach out to the Amp Doctor in the UK about what you gain/change with an upgraded helix pro mk2.

[Jdunk54nl]

I would bet that changing some of the components in the dsr1 would make it better and may even get better than a base model older gen Helix and maybe better than a twk (I think the twk and the dsr1 use the same analog devices board though but I could definitely be wrong about this too).

But what will not be better any time soon is the connection issues with the dsr1. I've had some good laughs about some connection stories on the dsr1 and the 360.3. You don't have to worry about those with the jl or helix. To me, I don't care if it sonically sounds better if I can't connect to the dsp to make changes.

[cueball981]

Just the fact that he says the AmpPro is a crappy product makes me suspect. I run one in my RAM 1500 with absolutely no problems.

[Sam Spade]

Op amp upgrades are more common in home audio. I have seen/heard of it in CD players, preamps, headphone amps. However, the aim is usually to get rid of IC op amps and replace them with solid state.

About 10 years ago I upgraded my Marantz CD80 with a Burson low jitter digital clock and op amps plus new caps and a double crown TDA1541A S2 DAC chip. It made a significant difference but given we changed everything at once I can't tell how much of it was the op amps. It is a 30yo CD player but competes well with modern players like my Cambridge Audio 840C.

I now have a Burson Conductor 3X reference preamp/headphone amp/DAC. Burson build to support opamp changes, much like different tubes in tube gear. https://www.bursonaudio.com/products/conductor-3x/

Burson's op amps: https://www.bursonaudio.com/products...ound-opamp-v6/

I also have a Sparko headphone amp coming. Sparko make the best op amp around according to some reviewers. https://www.youtube.com/watch?v=rLbmXjQo8bE

Sparko upgrade gear here including op amps: https://sparkoslabs.com/shop/

It follows that there could be significant differences between IC op amps. But my experience is all about getting rid of IC op amps and putting solid state in.

I have been contemplating seeing if I could put solid state op amps into my Helix Ultra. I don't know what kind of op amps it uses though.

Cheers
Sam

[dobslob]

I can say that there is a lot to the OP amp discussion that gets totally blown out of proportion. Back when I was with Elettromedia we modified some bitOnes with sockets to make swapping OP amps very easy. Having tested several different OP amps in basic headphone amplifiers we were aware of the differences they could make. A single set in a DSP running full range still exhibited the same characteristics, but by the time we were running through multiple channels with crossovers the effect seemed to be lost and the upgraded units couldn't be differentiated from the stock bitOne by anyone. Not that it is the best reference, but that was my experience.