Rudi's Dual Mono Balanced Amp - RPX100 - how much better than markl amp could it be?

The RPX-100 is brand new, I don't think anyone has one yet. It's intended for the guy with both re-wired balanced and regular headphones. It's an all-in one, no-compromise solution with separate mono sections, 2 for balanced headphones, 2 for standard headphones. I suspect it weighs a ton.

If you use only standard headphones like me, the RPX-33 probably makes more sense as you aren't paying for all the extra balanced topology and functionality.

OTOH, if you think someday you might go balanced or might want to experiment with some balanced headphones, here's a top-quality amp that leaves the door open and will let you play around without sacrificing sound quality.

"Only" 11kg according to Rudistor's website.

Based on this description:

"The RPX-100 comes after a log hours of work at the RudiStor R&D labs, it use only discrete components, and since RPX-100 use four independent high-current power amplifiers based on bipolar transistors, it is a pure quad mono amplifier. The amplification units work, two per channel on positive and negative phase of the sound signal. A real no compromise solution."

It sounds like a single-ended solution to any balanced headphone desire. Both is my highlighting.

This echos the resonse I got from Rudy when I asked this question. Both the RPX-100 and RPX-33 use all discrete components and are both exceptional sounding. For single ended applications, the RPX-33 provides equal performance. And perform, it does; I just love mine.

Rudi does offer a good upgrade policy, so my thoughts of going balanced are not completely off the table; nor is the dream of the RP010-B.... 8~)

Have you folks tried using the RPX-33 with an IEM? I have a set of UE-10 pros and am interested in a high-end amp.

Oh? What's the upgrade policy? I'm told my RP010 mark 1 can't be turned into a mark 2. Is it a trade in policy? Well I'm not the original owner so I dunno how much it applies. Still would like to know the policy though.

You betcha. I use Sensaphonics 2X-S out of the "Low" hp out and it's dead quiet; sounds absolutely brilliant. What's cool is that I can plug in big cans and IEMs at the same time and not have to adjust the volume too much as I switch and swap. I also use Yuin PK1s to great success.


Sorry, I meant trade-in; though it is limited to amps of a higher value, hence the use of the term upgrade; and it is limited in time span.

Rudy is simply a class act all the way around and a welcome addition to the set of truly talented amp builders to which we have access.

Rudi's RP 7.1 was very nice. Althought I prefer my DHA3000 over the RP7.1 for my L3000, and R10, but the RP 7.1 with the HD-650 w/ Zu was one very muscial.

This is about the only negative thing I can say about the RPX-33.
Although its noise floor doesn't amplify, it still possesses a floor. A floor that IMO; even through its low gain, is a bit too high. But the biggest issue I still have, despite all my efforts; is a buzzing in the right channel.
An expected defect overruled by none other then Rudi himself as a result of external interference. To be honest though, I do not agree. What I do now agree with though is "the RPX-33 is not made for IEMs."

The amp is either way to susceptible, or too much of a risk for a dedicted IEM application.
IMO a much better solution is the GS-1. It has a lower floor, and a great PSU that produces no noise. It’s also more of an efficient straight through; a signature IEM’s adore.
The Rudi’s a power gobbling beast that lacks the articulation needed for supersensitive transducers, and you'd be losing out on what makes the RPX-33 so special: the abundance of flawless technical abilities. We all know IEM's are not that technical.


BTW
markl don't you have your RPX-100 yet? We're not getting a review after all?

I'm not a technical person, so my ability to properly explain is somewhat limited. But my understanding is that Rudi's high-end amps (such as the RPX-33 and the RP010, and the RPX-100) all use *no feedback* in their design, and are pure delicious, unadulterated Class-A. This a purist approach which is one of the chief reasons they sound so friggin' great; transparent, clear, full, and precise. That pure Class-A goodness gives them that tubey yummy-ness. But going that route isn't always without some consequences for some people.

IEMs are hyper-sensitive by design, this is the reason (for example) Ray Samuels designed a separate amp specifically for them. Using feedback can lower the noise floor to a level that won't have consequences for an IEM, but is not necessarily the purist approach. So there are some design trade-offs to make an amp 100% compatible with all IEMs.

I can't report on any IEMs with the RPX-33 or the RP010, as I don't have any. I can say that with "normal" headphones, noise floor is not an issue. My RP010 (like all Rudi's high-end designs) has two jacks, one high-gain, and one low-gain. I have already reported that out of the High gain jack, with my very sensitive Sony R10s, there is a *teeny tiny* level of hiss audible from the amp, but it's at such a low level, analog tape hiss from most CDs is at a much higher level and this sound gets lost anyway once actual music is playing. (This low-level noise was not audible out of the High jack of the RPX-33; but that's just a sign of how much more transparent the RP010 is). I doubt highly this noise would be audible out of any other headphone than the R10, certainly not any Sennheiser. If that bothers you, you always have the Low-gain jack out of which there is absolutely ZERO noise.

Bottom line is that the RPX-33 and the RP010 (and I presume the RPX-100) are designed for "normal" headphones. They are designed to give you the RAW, PURE signal-- you are staring directly into the very heart of the amp, not being held back at a polite distance.

So, I can't say Rudi's better designs are "incompatible" with IEMs, we already have one report that says otherwise.

My Dad has a pair of better quality IEMs; I'll ask to borrow them and will report back.

All said and done,

The RPX-33 is a god to full sized, but not so much for IEM's.

OK, so here I am listening to my RP010 with Ultimate Ears Super.Fi 5Pro.

There is ZERO noise out of the Low jack. There is an audible low-level noise out of the High jack, slightly higher than I get with the R10.

Hmmm, I have to differ on the IEM with RPX-33 story. Perhaps it's the other gear in the chain that is making your gear more susceptible to hearing amp noise with IEMs. By that, I mean better gear overall that is simply more resolving. I do not hear any sort of buzz in either channel at any tolerable volume level.

ETA - my hearing is not the best, however... Daily occurrence: "What's that, Dear, turn it what? . . Oh." . . .

When I got home this evening, I warmed up the gear and grabed my IEMs. Wanting to get to a higher volume pot level, I chose the coldest and what I think is a clean recording, Steely Dan Aja; the Mobile Fidelity Sound Lab gold master yada yada yada version. Sounded free from noise; best I could tell. I also grabbed my girlfriends E500s to give them a whirl with the RPX-33; same thing, pure music and monster controlled bass. No discernable amp noise even at high listening levels.

This is not to write that the RPX-33 is perfect for IEMs; I also own the T-Hawk (for portable that is), and don't doubt the GS-1's prowess with IEMs (curiosity is now peaked; tell us more please!

Hi drp, I'm not reporting on the RPX-33, only the RP1010. Like I said, my experience shows the RPX-33 is less susceptible to hum/noise than the RP010 which is more sensitive (that's part of what you get with the higher price tag). I'm not surprised you hear no noise out of the RPX-33 with various IEMs...