[shafu]

So I have these two amps and I'm trying to decide which way to go. Note, this is with the HD600 and Cardas cable - the RKV has Telefuken Tubes, MPX3 has three Sylvania VT-231s. Pros and cons that I've experienced:

RKV Pros:
Awesome midrange - I can really hear vocals come up and really present themselves well. It's such a lush warm sound with the vocals. It can almost be called seductive.

Soundstage - while not as wide as the MPX3, still has nice depth and seems more natural and realistic.

Looks - Okay, my wife isn't a huge fan of the MPX3, but thinks the RKV looks very classy. I really like the old school German look and feel of the amp. It's the type that the average person looks at and is impressed. And is not too too surprised at the price tag (unless you tell them it's specifically for headphones).

RKV Cons:
Details and impact - So a lush tube amp isn't supposed to be that detailed, but it should at least have a little bit of crispness. The impact of the lows aren't there compared to the MPX3. I guess this is what people call "speed" of the amp?

Volume Pot - As nice as the amp looks, the volume pot is a bit sticky. Minor point as I'm not that picky, but it's enough that it is noticeable versus the MPX3.

Noise floor - I've switched outlets and it's noticeably quiet, but the MPX3 is almost dead quiet in comparison.


MPX3 Pros:
Sensitivity to everything around it - as soon as I change a cable, tube, anything, the sound shows right through. It's a tube roller/cable roller's dream amp.

Impact/Detail - It is pretty fast. If I didn't know any better, it would be a nicely rounded solid state amp. I feel as though the sound is neutral across the spectrum. While the RKV is much more forward in the midrange (most noticeable in vocals again), I can clearly hear all of the note separations with the MPX3

MPX3 Cons:
Looks: So I have to admit, the old chassis is not the classiest looking amp. It has a nice rugged, customized feel to it, but the RKV wins hands down in this category.

Soundstage – The MPX3 is wider, but also seems like it has less depth. Meaning, I feel like I hear the sound to the extreme left and right, but not really blended in the middle as well as the RKV.

Conclusion:
I’m torn. I like both amps, but I should really end up selling one or the other. And I like each amp for different reasons. The RKV also has the capability of driving the K1000 which is a big plus, but I also wonder if I would end up missing the MPX3 which has a “one of a kind” sort of feeling towards it.

Any recommendations?

 

[Rob N]

MPX3 pros.-You can have various upgrades to the MPX3 which are not available on the RKV.

 

[Hirsch]

If you try a different driver tube, using the Sylvania VT-231's as outputs, the Singlepower amps can take on a different character. It might be worth trying a staggered plate Ken-Rad VT-231 as the driver, or a round plate Tung Sol (the Tung Sol is considerably more expensive if you find them). The Tung Sol in particular can add even more detail, while either can firm up the low end and mids even more.

 

[Thump]

The RKV is the only quality amp I've had any serious experience with so I can't make a meaningful comparison. But my volume control knob is silky smooth, one of the best I've every used on any equipment. Maybe something is wrong with yours?

On the looks issue, upon seeing my RKV my wife's first comment was "so how much did that thing cost anyway?" So good looks can sometimes backfire.

 

[shafu]

My volume pot is not too bad with the RKV, but not nearly as smooth or with the nice heavy motion with the alps pot...

It sounds like more votes for the MPX3. Funny that the RKV used to be THE amp to get not too long ago. Now everyone loves the MPX3 (for good reason mind you).

Any other thoughts?

 

[tone]

Quote:

Originally posted by shafu It sounds like more votes for the MPX3. Funny that the RKV used to be THE amp to get not too long ago. Now everyone loves the MPX3 (for good reason mind you).

I've been waiting for awhile for someone to compare the mpx3 to the rkv. Thanks for posting your thoughts shafu! its nice hearing from someone that has owned both amps.

I used to have a rkv and i loved the immense soundstage,bass and midrange. After i pay some bills i would love to eventually pick up another amp and the mpx3 is one of the leading contenders right now (tube and $800 or less).

 

[NeilPeart]

I love my MPX3, but if you have any plans to go with the K1000 then I recommend the RKV any day. The RKV/K1000 combo is one of those synergous couplings that sound better than they have any right to. That combo is easily one of the top rigs of all time. The RKV also sounds great with the HD600, but I prefer an HD600/MPX3 system over an HD600/RKV. In a perfect world you could just get both of 'em!

 

[bobjew]

I would vote of course for the MPX3 with a Zu cable for the Senns. In my system the cable had a nice synergy with the Tung Sols as the lead (gain) tube. The mids and hf took on a nice shimmery quality with lots of air. If you use a Ken Rad or two for either of the other tubes you can also expect big, dynamic Bass as well as the beautiful mids and highs from the TS. The VT-231's are also nice as well with a TS.

 

[NeilPeart]

I gotta back bobjew on the Ken-Rad tubes. I wasn't dissing the MPX3 in the least; I love my MPX3/Zu Mobius/Senn HD580 (especially with the Ken-Rads).

However, if a K1000 is in the cards then the RKV is one of its soul-mates (and it sounds damn good with the HD600 too)!

 

[shafu]

I have the K1000 paired with the RKV and it really is beautiful. The only problem is, it's less practical to listen to (leaks both ways) so I find myself listening more and more to the HD600s. What I need to do is listen to the K1000 and really let it soak in.