Although I know RIAA's above comment is in jest, just to be clear for future readers... If you don't follow the 1/10th ratio rule, you will not get a flat amplification of the preamp signal with frequency aberrations in the bass response.
Also, it may be possible to modify the amplifier to address this issue (depending on amplifier design). My first watt f4s (simple class A without feedback) have a 47.5k input impedance, but can be modified to have a higher I.I. simply by changing out the resistor on the input. I was informed that I could use anything up to 250k without changing the operation/sound of the amp. Doing so enabled me to use much smaller output caps on my Don Sachs 6sn7 preamp, and allowed me to afford some top end duelund's that greatly improved the sound. No idea if this is possible on the bakoon... but hopefully useful information regardless. |
Thanks Al. I should have paid more attention in school :) Somebody gave me that formula and told me the REF 10 and Bakoon would be fine. Thanks for stopping me from blowing up my gear!! LOL |
Chris ( @cal3713 ) thanks for quoting my post from another thread in this one, where it is also relevant as you indicated. @riaa_award_collectors_on_facebook, keep in mind that the majority of tube-based components having line-level outputs employ coupling capacitors at their outputs, which often cause their output impedance at deep bass frequencies to rise to **much** higher levels than the specified output impedance (which is usually based on a mid-range frequency such as 1 kHz). So in those cases the 10x ratio should be applied to the 20 Hz output impedance, if it is known. (If the component has been reviewed by Stereophile JA’s measurements will indicate that number). If the 20 Hz output impedance is not known, and there is reason to believe that the tube-based component employs an output coupling capacitor as most of them do, I suggest applying a ratio of 50x to 75x to the specified output impedance. Some here have even suggested 100x. Also, the minimum recommended load impedance ARC almost invariably recommends for their line stages and preamps is 20K, including for the Ref 10, even though its specified output impedance is 600 ohms balanced and 300 ohms single-ended. And for a few of their designs I’ve seen recommendations of "60K recommended, 20K minimum." And just to cite one further example, the Herron phono stage which I use has a specified output impedance of 400 ohms, but its manual recommends a minimum load impedance of 50K "for optimum performance." Although Keith Herron has indicated that 20K would usually be acceptable, in most systems. Perusing JA’s past measurements of tube-based line-level components will reveal numerous other such examples. Regards, -- Al |
You wouldn’t want your preamp output impedance to be more than 1/10 (preferably 1/20th) of the amplifier’s input impedance. Al’s correctly points out that some tube preamps have output impedances that can exceed that level (particularly at certain frequencies). Good warning from Al. Not an issue with nearly all solid state preamps. To be clear divide the amp input impedance by the preamp output impedance. Charles |
Not sure that's going to effect too many people. Multiply by 10 to get your number. REF 10 by Audio Research comes in about 60% of the Input Limit. The Luxman C900 comes in at 10%. I'd love to see a list of how many amps would go over that 10K figure....maybe some Boutique stuff. |
Since many people in here are considering the bakoon 13r, I thought I'd quote a post from @almarg on the input impedance:
"Re the Bakoon 13R, be aware that the input impedance of its RCA input is only 10K, which will not be a good match for many and perhaps most tube-based components.
I believe the other input choice provided by the 13R, a "Satri Link," would only be usable if driven by a Bakoon component providing that kind of output.
Regards,
-- Al"
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Bob, you will probably need longer spikes if the carpet is thick, in order that one maintains the gap as intended. Or arrange for them to stand on something solid.
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@stephendunn There are certainly posters out there who's ears I trust that use and enjoy digital correction.
Unfortunately my only experience was *not* good. I had a Lyngdorf tdai-3400 for some time and turning on room perfect kind of made me sick to my stomach... the music sounded "blended" for lack of a better term. Definitely less natural than without. I had the amp for about 6 months, so I knew it well and had obviously done RP setup many, many times. Just couldn't get it to sound right with my Coincident PREs. Every time I turned off any form of digital processing it got better actually, but never quite right.
Very curious to hear about your experience and add another data point. |
Thanks for all the replies. I had a strong feeling that most would recommend the 8". I had my heart set on the 10" but room changes dictate looking at the smaller option. Will also look at the 10" small monitor. Btw flooring is suspended with carpeting.
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I know that John from Refined Audio has said he slightly prefers the 8" over the 10".
Another avenue to consider is using the 10" with room correction software. I have 10" Nenuphars in a relatively small room 13 x 15 x 10 and think they work great, but have noticed that some mid to lower bass notes get muddled (I have no acoustic treatments other shelves of records). I am going to borrow a Dspeaker anti-mode x4 to see if it corrects this. Won't happen till late July, but I'll report back. |
11' x 12' = 132 sq ft = 12.3 sq meters
At the Cube Audio website we find these recommendations:
Nenuphar Basis -- 25-100 sq m
Nenuphar 10" -- 20-40 sq m
Nenuphar Monitor 10" -- 12-25 sq m <====
Nenuphar Mini Basis 8" -- 20-60 sq m
Nenuphar Mini 8" -- 12-25 sq m <====
Nenuphar Mini Monitor 8" -- 12-20 sq m <====
Magus 8" -- 15-30 sq m
Bliss C 8" -- 15-30 sq m
Robert |
Bob, 8 inch is my recommendation as well. What’s your floor finish? |
I have the Nenuphar 10" in a 15’ x 13’ room. Drivers 60" from the front wall and 7’ apart center to center. Listening position 7’ triangle so also in a near field configuration. I’ve tried them in every position I could think of and always come back to this. Toe-in is important. I started with them straight on then toed them in in tiny increments looking for a balance of sound stage and center image.
I’ve noted that in the last year or so Peter B. from AV Showrooms and others have placed them on the front wall and prefer that position in those rooms. It doesn’t work at all in my room. The sound stage collapses in depth, imaging disappears. The bass isn’t all that much if any better. These speakers have magical properties that will manifest for you if you find the right formula for them in your space. If the rest of your system and placement are right they will create sonic places, architectures, landscapes...places for you to go. When Srajan said they are a benign psychotropic drug, maybe he was having a similar experience. |
Dave,
Thanks for your opinion. My guess is also the F8's would be a better match in that room. Any one else with experience in a small room? |
@bobheinatz Bob, I would personally choose the Nenuphar Mini (F8 Neo driver) speakers for that sized room (11 x 12).
Keep in mind, I have my Nenuphars (10s) pulled way out into the room and listen to them in a somewhat nearfield position. My room is 19 by 26.
Perhaps those who have their Nenuphars placed much closer to the front wall will provide their recommendations? |
Hi everyone,
I had planned on purchasing the Cube Nenuphar 10 this fall for my 14 x 18 room but my system is now being relocated to a 11 × 12 room. Is this room to small the the Nenuphar 10's? Should I being looking at the Nenuphar 8's instead?
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Thks guys.
I was sure these specs will fit well the cubes.
to be continued.......,, |
<<help decoding these specs and opinion on compatibility with the cubes...
Output Impedance <0.8 ohm
Damping factor >10>>
Yup, DF = 8 ohm/0.8 ohm = 10
Here are some other amps for comparison:
Mola Mola (Class D) = 0.003 ohm, so DF = 2666 <== avoid
Bryston 4B (Class AB) = 0.016 ohm, DF = 500 <== avoid
Aesthetic Atlas (zero feedback hybrid) = 0.25 ohm, DF = 32
FirstWatt SIT-3 = 0.26 ohm, DF = 31
FirstWatt SIT-1 = 0.27 ohm, DF = 30
LTA Z10 (ZOTL) = 1.2 ohms, DF = 6.7
Audio Nirvana 300B SET = 2.7 ohm, DF = 3
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Hello,
Looking at the level of the stated distortion and accompanying output impedance and damping factor of >10 (Does this mean But <20?) is consistent with a zero NFB (Or very low level of NFB). So based on these measurements they suggest that (on paper) this amplifier should be a pretty decent match with the Nenuphar. Only an educated guess as other aspects of the amplifier aren’t known. Speaker impedance =8 ohm ÷ output impedance of roughly 0.8=10 which is the DF (At least for 8 ohms).
Charles |
i cant interpret these specs to know how this integrated will be a good match to nenuphars. knowing that low damping factor is prefered for the nenuphars.... any help decoding these specs and opinion on compatibilty with the cubes. HD & N< 0.15 % @ 5W output, < 1 % @ 40W output < 5 % @ 52W outputInput Impedance>15 kohmsOutput Impedance<0.8 ohms (damping factor >10 reference to 8ohms load @ zero global feedback)
Thks |
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Thanks for the heads up David. The 1 cubic foot sealed box DIY version will be my next audio journey and it's good to see the thread staying alive. Really looking forward to the building experience. Curious if I'll be able to pull off a high gloss black piano paint job. |
FYI - There are two Nenuphar active listings here on the 'Gon. Both in the Black finish. One New, the other a showroom demo. |
Hi cal, However you made a valid point. Negative feedback (NFB) level manipulation does affect these amplifier parameters. 1 Gain output decreases as NFB is increased.. 2 Output impedance decreases as NFB increases. 3 Damping Factor increases as NFB increases. Output impedance and Damping Factor have an inverse relationship. Charles' |
I just ran into the damping factor thread and see the above comment was completely unnecessary. Sorry Robert. |
@rwpollock Not an answer to your question, and it's been stated earlier in the thread, but just keep in mind that adjustable damping factor and adjustable levels of negative feedback are (always?) synonyms. Might be useful for expanding your amp search if you've been looking for amps with adjustable df... |
Speaking of different solid state amplifiers, I was doing some reading on damping factors and came across a link to two Gold Note amplifiers out of Italy, the IS-1000 (integrated) and the PA-1175 (power amp). Both models have a DF option which can be changed on the fly. The high setting has a DF of 250 while the low setting is at 25.
Has anybody listened to one of the Gold Note amps?
- Robert |
I would agree that although DF is a factor that needs consideration there are additional variables involved that also influence amplifier and Nenuphar compatibility. People are expressing happiness with the Bakoon 13R driving the Nenuphar so something is obviously going right to make this possible. Charles |
I can’t comment on the Bakoon 41 with the Nenuphar’s, I only have experienced the Bakoon 13R with the Cubes and like Srajan have found the combination to be very compatible, so there has to be other factors at play here other than DF. I believe Srajan’s preference was the 13R over the 41 but he may not have had the Cubes at that time? The 13R has the latest JET Satri circuit which makes for a very fast response, full bodied and open sound as verified by customer feedback here in the UK.
If anyone in the USA is interested in the Bakoon products, please contact Bakoon directly through their website. |
Robert,
Yes,
Now I wonder exactly which Bakoon amplifier jtgofish was referring to in his response to Duke on the damping factor thread. It sure seems as though there is variance amongst the Bakoon amplifier models.
There’s the possibility that a number of them could sound excellent with the Nenuphar despite differences in the level of DF. Again one would suspect the higher output impedance Bakoon amplifiers (Lower DF) to be (In theory) the preferred choice.
Charles |
Bakoon writes:
"The patent-pending JET Bias circuit has brought the SATRI circuit to a whole new level in terms of electrical performance and sound quality. Our Circuit is now reborn and renamed as the JET SATRI circuit, an ultrafast, wide bandwidth, full discrete design with zero negative feedback. It is also our first circuit that doesn't even use output emitter resistors, resulting in lower output impedance than ever before, with direct, ultra fast response to the loudspeakers."
So the 13R has "lower output impedance than ever before" which means higher damping than before. It makes one wonder what their older (and $3K more expensive) 41 amplifier would sound like with the Nenuphars.
- Robert |
Nice to hear positive comments about the Bakoon from others. Thanks for posting David. |
Hi David,
Thanks for providing the 2 posts. Duke hit the nail directly on the head. When I switched from a very good push pull 100 watt tube amplifier to an 8 watt SET nearly 11 years ago this was my experience. Just as Duke describes, more musical nuance and inner detail revealed. Increased sense of performer presence. Simply more realism and definitely increased emotional connection/engagement with listening to music. Bottom line, more pure and natural sound quality.
I can now understand how the Bakoon amplifier generates similar results to a good SET amplifier (Or in Duke’s case an Atma-Sphere amplifier). Zero NFB and a higher output impedance certainly suggests that the damping factor (DF) would be relatively low. This would make it quite compatible with the Nenuphar. Makes sense to me.
Charles |
For those using Bakoon amps, here is member @jtgofish 's response to Duke's above copied post: All that is what I hear with Bakoon amplifiers.Which are class A/B but which are reputed to be zero negative feedback/high output impedance/ current drive/probably low damping factor amplifiers.In simple terms they simply sound incredibly clear and pure.Which I have really only heard elsewhere from expensive SET amps like the Kondo Ongaku. JT, thank you. |
Cycling back from the 'Damping Factor' thread. Duke's ( @audiokinesis ) answers and findings are likely relevant to what member owners of the Nenuphar are reporting on. Copied here: First a bit of background: I design speakers with fairly high and unusually smooth impedance curves so that they have very similar response with both amplifier types across most of the spectrum, and then include user-adjustable bass tuning to adapt to the effects of amplifier damping factor into the bass region impedance peaks. So frequency response differences are minimal, and generally relegated to the region south of 100 Hz, where there can be a "free lunch" to the tune of an extra 1/4 to 1/3 octave extension with a low-damping-factor amp.
The following is my opinion; I can’t "prove" any of this. Consider these to be generalizations; I’m not a writer of audio prose; and [disclaimer] I'm an Atma-Sphere dealer:
With low-damping-factor tube amps, I hear more of a sense of ease and liveliness and immersion. I’m hearing more stuff going on, it’s like the voices and instruments have more texture. Music is more engaging at lower sound pressure levels, which I think is related to the low-level details not needing as much SPL in order to be audible. At high sound pressure levels the difference is arguably even more noticeable, as there is an absence of the edginess which often starts to set in as the SPL goes up. I’m hearing more of a difference in soundscape and ambience from one recording to the next, with more of a sense of being "transported into" the recording, especially when it’s a really good one. There is a powerful emotional experience (some might call it spiritual) which some music can convey, but it calls for intensity and density and freedom from distractions. The least expensive amplification I have found which can do this is low-damping-factor tubes... specifically, the Atma-Sphere S-30 and M-60 [dealer disclaimer reminder]. |
Stephen (and other posters here who are interested in this), I've posted your question about damping factor and scale / image size in the "Damping Factor - Interesting Article" thread.
I'll cycle back, with a copy/paste, if the 'topic' is addressed and/or answered there. |
I googled the Yamaha AS 3200 and according to Yamaha, THD 0.07% Damping Factor (DF) is 250 at 1K HZ and 8 ohms Those numbers suggest a generous amount of negative feedback NFB is utilized. On paper not a particularly good match for the Nenuphar but listening is the final arbiter. Charles |
I wonder if the new Yamaha a-s3200 would be the best match for these speakers ?.. .. |
Steve, Cube Audio's Grezegorz made it clear to Srajan Ebaen that the voice coil excursion and the phenoic spider of the Nenuphar are very well controlled by the magnetic field provided by the very powerful neodymium magnets (81 total). He also mentioned the importance of the driver’s carefully determined geometry and level of cone/whizzer stiffness employed. Grzegorz clearly intended for the Nenuphar to pair in excellent fashion with low DF amplifiers.
It seems this speaker will also sound quite good with amps of higher (to a point) DF but will most probably display their ultimate performance with the targeted low DF amplifiers. Your listening impressions do seem to bear that out. Charles |
I would like to add my two cents to the discussion about amp compatibility, specifically regarding damping factor, with the Nenuphars. To recap: I've had extended auditions with three amps: the LTA Ultralinear, The First Watt SIT-3 and the First Watt SIT-1. I settled on the SIT-1 for its overall superiority--not just one thing it did better than the rest. However, one area in which the SIT-1 excelled that I believe might be related to damping factor is scale. As mrubey and others have commented, the Nenuphars are capable of creating the scale of much larger speakers. But not only does the SIT-1 bring a noticeably increased sense of largeness through a sound stage that opens more in every direction, but it increases immediacy and involvement when playing at low volumes. I found this to be even more important than increasing the largeness of scale since I'm an early riser and play at relatively low volumes for several hours before others wake. Does this have something to do with damping factor? I don't know, but Charles and some of the other more technically astute posters might. Although all the amps I've mentioned have relatively low damping factors, the SIT-1's factor is 2 which is the lowest by a significant margin. |
I have met a few local audiophiles through classified ads, and I did sell a pair of Triangle floorstanders to a neighbor. He drives them with his Sony receiver and is quite happy. He felt no need to upgrade anything else. |
I live just outside San Antonio Texas.
I actually have a new friend in Victoria who wants to come up.
He has friend in Houston that has a Kondo Kagura based system.
I hope to experience that someday.
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So, in which state do you live? |
Good morning david_ten,
A party of one. The audiophile disease is a lonely pursuit. I have exactly three audio buddies in real life. The closest is about an hour and a half away. I try to turn people on to this stuff but few get it. It’s not that they don’t hear, it’s more that they don’t give themselves time to come under the spell properly. Also, people don’t know or have forgotten how to listen as the primary experience. And then there are those who are incredulous about the expense. "You mean you could have bought a boat instead of a stereo?" Some get it and want to get away from it as fast as they can so it doesn’t infect them becoming the expensive itch that must be scratched.
My wife used to hate it but is learning to appreciate it. Until just recently when she looked at it all she could see was dollar signs.
Dave Slagle and or Jeffery Jackson have a blog called HiFi heroin.
True enough. |
I'm a bit late to the party @mrubey I think not. Sounds like you've been partying for the better part of a year now. Wonderful to hear!!! |
Hi guys,
Im a bit late to the party here but being a Nenuphar owner I thought I should contribute my nothing but positive experience with these magical speakers. I’ve had them for about a year. They were Refined Audio’s 2019 AXPONA demos. My last speakers were RETHM Trisha’s so I was already soaked in the single driver widebander koolaide. At first I was powering them with an Audion 2A3 which has a preamp section and was more than enough power for digital sources. It didn’t quite make it happen with the lower signal of my phono stage. I tried a few line stages, I couldn’t find the synergy I was looking for. By luck I was able to buy one of the last SIT 3s available. I also sold/replaced the rest of my kit and arrived at where I am now which for me is grail level. The Nenuphars powered by the First Watt SIT3, The Truth buffered no gain linestage, Sutherland 20/20 phonostage, VPI Classic 2 SE, Ortofon 2M White SE mono cartridge currently mounted while waiting for new Soundsmith Paua stereo cart. I had been listening to a Grado Reference 2. The Nenuphar and SIT 3 could not work better for the music I listen to which is 80% acoustic. The other 20% is Steely Dan, Allmans, some old fusion, nothing too grungy. This system loves Steely Dan. Right now though for analog I am stuck in mono until my new cartridge comes. I was just listening to the 45rpm mono pressing of Billie Holiday Body and Soul. It was so present and so beautiful I was utterly in awe of her and her band. Srajan said these speakers are a benign psychotropic drug if you are receptive enough to get it. I find that when I am able to be that relaxed into it, and with the right recording, there is a deep sonic architecture occurring. An album that demonstrates this in way that I could hardly believe is the MoFi One Step of Yes, Fragile. I don’t listen to much prog anymore in my advanced years but it was huge part of my youth and I had to have this album. What the sound of this record coming through these speakers does in my minds eye is astonishing. I gained a whole new respect for Eddie Offord.
I have heard a few true cost no object systems. I truly think the only thing any of them has over my system is the ability to produce scale.
The actual scale of a symphony or ZZ Top live. None of them had the kind of intimacy I felt with Lady Day a little while ago and that’s what I was shooting for when I chose my components. I want Gillian Welch or Joan Baez or Janos Starker to be present. I don’t care if I feel a kick drum in my chest.
The Cube Nenuphar give me everything I could want. The only upgrade I wound ever make from here is the turntable and I don’t really feel a need for that.
FYI: I’ve noted that Peter B and others are placing them close to the front wall. That does not work in this room at all. My optimum location is 60" from front wall to drivers. 7’ apart driver to driver. Listening position in 7’ triangle with that. Toe in just a few degrees, found by by ear to optimize center image/soundstage relationship.
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There has to be other factors.
As Srajan has said ( 6 Moons Bakoon 13R review) “ Of all the speakers I would saloon around on the Bakoon, Nenuphar was the hostess with the mostest”.
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The Nenuphar driver was very specifically designed to mate well with high output impedance amplifiers. It utilizes a "powerful" magnet to control the driver. Srajan Ebaen certainly confirmed this with his review where he used multiple amplifiers. the higher the output impedance (lower damping factor) the better the sound.
It is quite interesting how some listeners/owners of the speaker are reporting very good sound with amplifiers that don’t meet the desired criteria. It really seems that a high DF amplifier would deaden the sound of the Nenuphar as the driver would be markedly ’over damped’. I realize you have to trust what you hear but this seems very counter intuitive. I wonder what additional factors are involved here. Charles |
Any thoughts on the output impedance question? IIRC, the 13R prides itself on low output impedance which should translate in a high damping factor
Robert |
Bakoon 13R is my preference with the Cubes. I’m using it with the Bakoon DAC21 which is out of production but I’m looking forward to a new dac from Bakoon in the imminent future. Physically the new dac will match the 13R. I’m expecting it not to cost more than the amp.
I’m over joyed with the sound I’m getting with the Cube/Bakoon pairing and I have had great comments from customers. The Bakoon very small, which proves bigger is not always better. I’m finding increasingly people want a simple and uncluttered system. |
