Rhumba Extreme 1.2 is on the way

[JSQT]

Thanks in part to the endorsements in this forum, I now have a modified Rhumba Extreme 1.2 on order! Andy says they will be able to upgrade one of the remaining 1.2 extremes to 1.3 specs with no real loss in performance between the modified 1.2 and the new 1.3 (a couple of lights and switches on the 1.3 apparently).

Looking forward to see if it will replace the 509X as the preamp of choice for the MQ-88SE!

I have high hopes.

[joeinid]

Congratulations! It'll be a wonderful preamp.

[Shadowfax]

Awesome! I can't wait to hear the outcome, and see some pics.

[JSQT]

The Rhumba Extreme 1.2 arrived yesterday and I was able to spend about 3 hours with it last night.

First impressions are very good - I admit, I thought I'd be a little more blown away right out of the box but it could be that I'm used to HOW GOOD the preamp in the L-509X is that the strengths of the BL are not as immediately evident.

One clear strength the BL has over the 509X pre - the soundstage is quite a bit wider and more expansive. Layering is much more detailed. The "black" background and the space around the notes is improved with the BL.

Where it can't stack up against the Luxman is in terms of bass control, attack and authority. Kick drums seem softer on the BL... Vocals are natural and lifelike but there are times where it almost seems the singer backs off the mic or something, rather than being consistently forward like with the Luxman. The Luxman also has a sweeter top end, notes seem to be a bit more natural and dynamic on pianos and strings.

This is a little surprising to me, as the "rhythm" and bass command seem to have been big talking points from BL and the reviews I have read online. I am wondering if it's just a matter of having to burn in the caps or something - or could it be the NS Mullards that come stock with this preamp. Considering buying another pair of Ciftes or Amperex tubes, but I want to give the preamp time to fully bloom and break in.

Finally, it occurred to me that I'm not making most use of Bob's patented power technology, because I do not have a direct wall outlet to plug the preamp into. I have no available wall outlets left - only going into my power strip. I know this is not ideal but I wonder how big of an effect it could have on the sound I am hearing. Unfortunately where my gear is placed, I have no other access to power without running an extension cord which would also not be ideal (nor I assume allow the BL to fully benefit from the wall AC).

Very interested in hearing from any other owners on my initial impressions!

[UltraFast69]

On my DAC it was recommended to use the OEM power cable and to plug directly in the wall.

I tried changing cables and went back to the OEM, the I plugged it into my Distribution and the soundstage collapsed, back into the wall and it literally snapped back.

So if the maker recommends direct into a wall, I would find a way to do this. An option is to jump off your first distribution to a second and rearrange what is plugged in so power hungry is on primary and secondary for sources and such.

Curious what you find out.


Sent from my iPhone using Tapatalk Pro

[JSQT]

I do think if I have the preamp at the far left side of my console I can stretch the PC over to another outlet which is close to my speaker. It won't be ideal in the looks dept; I'll have a very visible black PC suspended between the console and the outlet. Currently my AVM 60 is plugged into that outlet so I'll get that moved into the power distribution behind the console. At least that will show me what the difference is between the two options. It kills me that I have my entire home AV system against a 16' wall, which has a single outlet in the middle of the wall.

[Mechnutt]

Give it time to burn in. Caps and tubes will change over the next 50 hours or more. Especially the capacitors over a longer period of time. Teflon caps take about 500 hours to break in.

[Shadowfax]

Wasn't this a Demo Unit that was already used and broken in, or was it a brand new unit? I guess it says a whole lot for Luxman.

[JSQT]

Andy at Backert says this unit is just about burned in as it needs to be - I don't believe this was a demo unit, but it was modified after I placed my order with the 1.3 upgrades. I am guessing they ran it in on the bench over the past 10 days.

I have done a few things that are seeing improvements.

Placement: I had this unit on the glass top of my BDI Corridor cabinet (and yes, the terracone feet scratched my glass, yuck). BL recommends not to place on a glass surface so now it is on a vented shelf in the vented Corridor cabinet.

AC: I had it plugged into a distro strip and it was recommended to plug directly into the wall.

Input: Plugged directly into the REC OUT per Andy's advice since I only have 1 source component (Qutest). This added some additional snap to transients.

All of this has shown improvements in the Rhumba Extreme's performance. It is still a close call between the pre section in the 509X and the BLRE though. Each of them have some big strengths - the BLRE has a deeper, "blacker," wider soundstage with better layering and separation. The 509X still has better control over the bass and transients. It seems to have a "higher end" presentation where the BLRE has a more "musical" presentation.

It's going to be a tough call... I am optimistic that tube rolling with the BLRE could close the gap even further.

[Mechnutt]

Some tube rolling may fix some of those issues. Do you know if it has teflon caps? They take 500 hours of burn in. When I replaced the worn out Jensen PIO caps in my BAT, it took 150 hours to get back to sounding great like it did. I thought I ruined the preamp at first. Then one day around 150 hours turned it on and the first few notes played and I started smiling because it was like someone flipped a switch and changed the sound.

[Jack]

Agreed, impatience and snap judgements are not your friend in this hobby and can cost you a lot of money.

[JSQT]

Some tube rolling may fix some of those issues. Do you know if it has teflon caps? They take 500 hours of burn in. When I replaced the worn out Jensen PIO caps in my BAT, it took 150 hours to get back to sounding great like it did. I thought I ruined the preamp at first. Then one day around 150 hours turned it on and the first few notes played and I started smiling because it was like someone flipped a switch and changed the sound.

Yes, they are teflon V-Caps. Andy did say they ran it in on the bench while doing the mods/upgrades and I shouldn't expect a whole lot more improvement, but it's good to know that your experience has yielded even better results with further burn in.

[JSQT]

After a full day of tweaking and experimenting I can say I am very happy with the Rhumba Extreme!

To recap & follow up on what was done after initial setup, where bass appeared to be restrained...

I am now plugging the Qutest directly into the REC OUT, which bypasses Inputs 1-4, since the Qutest is my only source. It did help with cleaning up a bit of the softness and restoring some snap and detail to the sound.

After initial setup on the glass top of the BDI Corridor I learned that glass tops were not recommended for placement. The BLRE went on a wooden shelf in the cabinet and the bass did focus a bit more and overall sound was cleaner and smoother. HOWEVER, because I have my Orbi satellite and Hue Bridge close to that shelf, I noticed some motorboating (digital cycling noise) in the background. So I stole my wife's cutting board and using IsoAcoustic Oreas I replaced the BLRE on the top of the cabinet. This did result in a massive improvement in the overall sound.

I also eliminated the high level speaker wire connection from the MQ-88uSE to the eSub and went directly from the OUT 2 of the preamp into the sub. This restored a great deal of balance to the bottom end. I also did some further experimenting with the crossover and phase settings of the eSub, moving the crossover from 70 down to 60. Resulted in a much better blend with the La Scala IIs and eliminated some directionality I hadn't noticed before.

All of these tweaks got me to the point where I no longer felt the need to swap the L509X back in to compare - currently I have solid, well-controlled bass with presence and heft, better transients and cleaner background. This combined with the strengths of the BLRE over the 509X I already mentioned (massive soundstage with pinpoint placement accuracy, well-defined space around the notes, more musical unspooling of the music/greater liquidity) have me in a happy place where I am pretty confident I'll be able to let the 509X go to a new home, and explore further gains through tube rolling with the Rhumba Extreme.

Fit and finish of the Rhumba Extreme is top-notch. It's not an exceptionally heavy unit, but it is a solid, attractive, exquisitely machined piece. The toggles are satisfying to flip around and the remote is a heavy piece of jewelry - the best remote I've ever owned from any component. I'm really glad I was able to restore placement on the top of the cabinet with the wood cutting board because this is not a component you want to hide away in a cabinet.

The final piece of the puzzle was the delivery of a new Hugo M Scaler late in the afternoon. Although not related to the Rhumba Extreme, the gains are jaw-dropping when feeding the Qutest dual BNC inputs at full resolution. Suddenly all boundaries between the listener and the music disappear. It's like a portal has opened to the soundstage; it's almost unreal how much of an improvement it makes. It does, on some recordings - particularly with male vocals - add a bit of thinness to the sound I've experienced when upsampling from Roon in the past. But I chalk that up to the limitations of the Qutest more than anything else, and I can definitely see a DAVE upgrade in the next year.

A note about the M Scaler and Rhumba Extreme - I should clarify that I'm not intending to project the gains of the M Scaler to the Rhumba Extreme. When putting the M Scaler in bypass mode, listening to the non-upscaled audio through the system is still remarkably transparent, engaging, and dynamic.

All-in-all this is very close to end-game for me. In fact if it wasn't for the tiniest bit of thinness in male vocals when upscaling to the Qutest, I'd probably not even think about further upgrading to the DAVE, but knowing me, I'll always be nagged that there's "one last step" to achieve. I'm excited about doing some tube rolling with the Rhumba Extreme, but now we're talking the last 1% of gains in this system. At the budget level of most of these components (around $5K each between pre, amp, digital front end, etc) I cannot see experimenting with $3000 power cables or the like. Maybe down the road I end up swapping out the La Scala IIs for Volti Aluras, but for me this is definitely a good place to hit the pause button on the gear sickness and start enjoying music for a while!

[mep]

Some tube rolling may fix some of those issues. Do you know if it has teflon caps? They take 500 hours of burn in. When I replaced the worn out Jensen PIO caps in my BAT, it took 150 hours to get back to sounding great like it did. I thought I ruined the preamp at first. Then one day around 150 hours turned it on and the first few notes played and I started smiling because it was like someone flipped a switch and changed the sound.

Curious as to how you knew your Jensen PIO caps were worn out. What was the failure mechanism?

[Mechnutt]

Curious as to how you knew your Jensen PIO caps were worn out. What was the failure mechanism?

I had a popping sound when turning on or off the BAT coming through the speakers (I can't remember which one). Also, changing any input caused a loud pop. I called BAT and spoke with Vicktor Khomenko himself about the issue. He stated that it was due to cap failure in the 6 pack of caps and that they should all be replaced. Apparently, when my VK51se was built, the caps had a high failure rate over time and that my issue was one they regularly saw. He offered to replace the caps for labor only which was $900. I bought the caps direct from Jensen and had my EE friend do it for free. All 12 needed to be to be replaced. Never had a pop since.
.

[mep]

I had a popping sound when turning on or off the BAT coming through the speakers (I can't remember which one). Also, changing any input caused a loud pop. I called BAT and spoke with Vicktor Khomenko himself about the issue. He stated that it was due to cap failure in the 6 pack of caps and that they should all be replaced. Apparently, when my VK51se was built, the caps had a high failure rate over time and that my issue was one they regularly saw. He offered to replace the caps for labor only which was $900. I bought the caps direct from Jensen and had my EE friend do it for free. All 12 needed to be to be replaced. Never had a pop since.
.

Thanks for your response. You usually worry about power supply electrolytic caps going bad over time and not film caps.

[puroagave]

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