Decware Taboo MK IV Review

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by DoctorZ, Apr 18, 2022.

  1. DoctorZ

    DoctorZ Friend

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    Marv's Take: https://www.superbestaudiofriends.o...decware-taboo-mk-iv-review.12214/#post-384131

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    Hi, I'm a random dude who lives in Corpus and I happen to know Marv. Marv knows that I am an audiophile so he drops by the office stuff so I can check it out. Most recently, Marv dropped off a ZMF Atrium headphone and Decware Taboo amp. I really liked the Atrium and stole it from Marv. When I got a chance to try out the Decware Taboo, I thought this combination with the ZMF was super. I asked Marv if I could take the amp home and borrow it. I've never loved any pieces of gear that much that I asked to borrow them. He replied that I could borrow it for an extended period of time only if I wrote a review, so here it is. For context, I listen to speakers at home. My speakers are the Tekton Lore non-floorstanding model. I have a Bifrost for a DAC and an Emotiva integrated amp. I listen to both speakers and headphones.

    I am going to keep my comments brief because I don't normally write reviews. I tried the Taboo as a speaker amp with the Lores. The immediate thing that I noticed was big the soundstage that expanded outside the boundaries of the speakers. This was noticeable on Yosi Horikawa's music where he went to a forest and recorded sounds all around. The downside was that I could not get enough volume from the Taboo. I like to listen very loud. I think the Lores are 94db efficient. I cannot say if the Taboo didn't have enough power or gain or if Tekton fudged the specs on the Lores.

    With the ZMF Atrium headphone, the Taboo has been the best headphone amplifier I've so far. Marv said he would bring in better stuff. I'm sure better stuff exists, but for me, this is the best yet. I'm familiar with entry and mid level gear from companies like Emotiva, so this for me this is the best I've heard for now. Other tube amps I've heard sounded veiled, less detailed, very warm. The Taboo is slightly warm compared to solid-state amps but not overly so. The bass is one of the highlights. There is a lot of slam. I know the ZMF Atrium hits hard, but this amp takes it to another level. There is lots of detail and textures. The mids are lush. Sound is tubey, not too much. Closer to solid state than the Freya+ that sounded more tubey. The high end was smooth with no grain. There is a lot of drive and rhythm to the music that the Taboo conveys. Bottom line is that I just liked the sound and love listening to it.
     
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  2. Merrick

    Merrick A lidless ear

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    Thanks for the review! If I'm reading the Taboo listing correctly, it does 2W into 8 ohm speakers. If you like the sound of the amp and want more speaker power, you could try mono block Zen Triodes or a single Zen Triode Integrated. Decware is quality stuff!
     
  3. k4rstar

    k4rstar Britney fan club president

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    Hi random dude from Corpus, thanks for sharing
    I think it's probably a bit of both. When you say listen very loud I assume you mean a max SPL of 100-103dB. If your speakers were truly 94dB/w/m sensitive you would want amplifier power between 5-10 watts RMS. The decware will clip before reaching those levels.
     
  4. purr1n

    purr1n Burned out

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    I could be wrong, but the tweeter on the Lore Mini looks to be a Peerless based on its size, screw holes, plate, and characteristic coating over the dome. This tweeter is pretty ubiquitous. It's smooth sounding, but does take a bit of power to get going. The real sensitivity of this tweeter is about 91-92db for 2.8V at 1m. The 95db [email protected] is likely fudged. Or if not fudged, it's not 94-95db sensitivity according to my point of view.

    BTW, I happen to be looking at this Peerless tweeter right now in front of me. I've used it in other designs. I would never consider this for a high-efficiency design to be used for flea powered SET amps. The Lore Mini's need a bit more, say 10-20W, and with more gain than what most SET amps can do.

    speaker.jpg

    The Taboo in all likelihood doesn't have that high of a gain as with most two-stage SET amps. This isn't the fault of the Taboo. @DoctorZ: can you bring the amp back so I can test on bonifide 94-95db sensitivity speakers, and also so I can take some measurements. However, before you do so, let me let you borrow some modded LCD-X. I would be curious to get your opinion on how the Taboo drives planars.
     
  5. purr1n

    purr1n Burned out

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    To add some more context, there is better, but at significant higher cost. It comes down to exotic transformers and output tubes (nothing beats the classic DHTs like the 45, 2A3, 300B, or rarer variants - pick your poison - that OOP PX25 or whatever). I'd say that the Taboo is about on par with the DNA Starlett, but these two amp have different sounds and use cases. I bet the Taboo can power the more efficient 8" Lowthers and Voxactivs in a BLH without issue.

    The Taboo has a rich robust tone without any sense of weaksauce. The Woo WA6 SE is half the price, but tonally I don't think it's anywhere as smooth, and the WA6 at times can sound just a tiny bit weaksauce (overall distortion) with harder to drive headphones. The WA6 is also most certainly a bad match for planars. The DNA is a headphone only amp. Compared to the best stuff out there, the Taboo lacks ultimate microdetail, microdynamics, and layering. I feel the Starlett, which is a little bit more money is better at the micro stuff. However, the Starlett is also a bit more "wet" or bloomy sounding per DNA's house sound. What the Taboo does is have a strong rhythmic drive, actually quite similar to the Amps and Sound tube amps.

    For the price, we are getting something that is absolutely worth it. You guys know that I don't give 4.5/5 or 5/5 stars in gear reviews. And that if I say that it's worth it, actually more than worth it for the price, then that does mean something very important - considering that I only compare to good sounding gear and use those as benchmarks.

    @DoctorZ: Did you try the Lucid mode dial?
     
    Last edited: Apr 20, 2022
  6. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    We should probably just ask him to measure how loud he listens. My wife would consider anything over 90db to be really loud and I think personally that once you get over 95db it's pretty loud and once you get to 108db that's the point where it's physically uncomfortable.

    As far as power requirements it will be a huge difference. He might need 8W or he might need 20W.
     
  7. Wobbletits

    Wobbletits Acquaintance

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    I legitimately think tekton just copied the datasheet sensitivity of the 8" (eminence beta8?) or 10"(eminence 10" something) driver in the lore mini / lore as their sensitivity specification.
     
  8. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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  9. purr1n

    purr1n Burned out

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    I'm thinking it could be running the 4-ohm version: BC25TG35-04 which does have higher voltage sensitivity (but not power efficiency).
     
  10. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    Probably, that's going to still be about 3.5db off. I wish manufacturers could be honest about this, but 80% probably don't even have access to the half space chambers to measure.
     
  11. Pancakes

    Pancakes Friend

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    The crossover components will also reduce sensitivity. In general (but not always), tweeters being more sensitive than mids & woofers will have a resistor in series.

    The general consensus is that while being relatively efficient, Tekton's ratings are optimistic.
     
  12. Melvillian

    Melvillian Friend

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    Thanks for the review. Sounds to me like you're about to go down the tube amp rabbit hole.
     
  13. DoctorZ

    DoctorZ Friend

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    I used the Lucid mode. The manual says it is crossfeed. I set the dial at the midway point or right under it. Crossfield is too much after that setting.

    I like @purr1n;s idea with the Tyr and Koss electrostatic headphones. He dropped by today with more toys for me. Will let the man himself talk about it.
     
  14. purr1n

    purr1n Burned out

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    @k4rstar called it. Part of it is the amp (lacks gain) and the other part was the Lore's overstated sensitivity. Here we plugged in the Taboo directly into 94-95db sensitivity speakers. It gets to moderate volume with the pots cranked all the way up. By moderate, I mean not loud, not loud enough, because these speakers beg to be played loud. The sound was good only at lower volumes. At moderate volumes, it seemed to struggle. The Taboo had no problems with getting headphones loud though.

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  15. Paul Scandal

    Paul Scandal Rando

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    Tweeter has little to do with sensitivity. Woofer has far more sound energy.
     
  16. Aklegal

    Aklegal Almost "Made"

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    I haven't read a description of the "lucid" control. How does it affect the sound?
     
  17. purr1n

    purr1n Burned out

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    It's basically a crossfeed. Ties the floating secondaries of the OPTs together with a resistor. There are no extra stages and other crap that usually results in slightly lower sound quality. It's actually a super clever idea. There's a switch for turning it on and there's a pot to dial in the amount. A small dose sounds good. I like about one-third turned up. Over the halfway mark on the knob and we end up with a wall-o-sound.

    In the specific case of the Lore Mini, we could expect the custom Eminence woofer to be more sensitive than the Vifa / Peerless tweeter. However, this is besides the point. Most traditional speaker designs today will have tweeters far more sensitive (in their intended operating regions) than woofers, especially if baffle-step correction is taken into account. Baffle step correction is often used in tower speakers designed to be placed a few feet from the walls.

    Tweeter sensitivity has everything to do with the overall sensitivity of a speaker. This is what we are talking about here. If the tweeter cannot reproduce the range it is supposed to, say 2000-20kHz with the same SPL as the woofer with the same voltage, then the overall sensitivity of the speaker will be limited. Also vice-versa. As I said, most of the time with today's speakers, it's the woofer that usually can't keep up with the tweeter.
     
    Last edited: Apr 25, 2022
  18. purr1n

    purr1n Burned out

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    I wanted to do a follow up on the Decware Taboo at home with the Frugelhorns I just built. In short, I have to say that I am impressed! I lined the Taboo up with the EC 45 Custom and the Fisher KX-200 and I have to admit that I didn't miss much from the much more expensive EC. Note that both the EC and Decware are SET amps. The FIsher is a classic fixed bias push-pull. So it wasn't surprising that the Decware Taboo's presentation sounded more similar to that the EC: more seductive, beguiling, refined, delicate, capturing all those microdynamics. Had I not done any comparisons to anything else, I would have been happy here. It's only when directly compared to the EC where I would start to nitpick: noting that the Decware is a bit slower and softer in transients, especially on the transient edges, and that the soundstage isn't as deep or expansive, but closer, more intimate. The Taboo is bloomier and wetter than the EC, but isn't particualarly a bloomy. (The EC amp is not bloomy in the overall scheme of tube amps). Still, none of this was distracting, as in distractingly bad because the comparison isn't fair. We are comparing a rather affordable SET amp with the Decware brand name and reputation to an amp which is not commercially available custom built to my specifications

    Personally I think the Decware Taboo a good point to stop if one wanted a SET amp without going into credit card debt (don't do this because it will ruin your future and skew your sensibilities making you blame "evil" banks instead of yourself). This assuming one has true (as opposedly to falsely advertised) 94-95db senstivity speakers. (The FE168NS are rated lower efficiency by Fostex, but I think Fostex was being conservative, and the back loaded horn certainly helps).

    PXL_20220529_145351971.jpg

    I was able to get moderate volume levels with the volume knobs at the 12 o'clock position using a DAC with 4Vrms balanced output and a hot-rodded Mani 2 (higher gain). Still, I don't think the Taboo is an amp that you want to crank the volume. The gain is rather low and the transients get softer as the volume is cranked. The Fisher KX-200 stays there for a reason. The Fischer PP has more heft, more authority, but lacks the finesse and tends to smooth things over a bit (not a bad thing with digital sources).

    In a nutshell:
    1. Affordable SET amp for headphones and speakers with expected (per the higher standards here) performance for the price. Especially impressive with high-effiiciency speakers (where the manufacturer did not fudge the numbers).
    2. It's SET: single ended triode. This is the holy grail of sound if one can live with its limitations.
    3. Can drive low impedance loads because it's transformer coupled. Not capacitor coupled OTL which all sound veiled to varying extent. This is a huge plus!
    4. Just a touch of bloom and wetness, between EC and DNA. Not anywhere like the Feliks OTLs (with most output tubes) which made @Hands want to throw them out the window.
    5. Voiced on the warm side but not excessively so. Smooth highs.
    6. Two volume controls instead of one seems a bit clumsy.
    7. Outputs are differential only. Need to reterminate headphones to 4-pin XLR.
    8. Gain is on the low side. May need a hot source / efficient transducers. Notoriously inefficiency planars like the HE-6 are a no-go. However today's lower-impedance high-senstivity planars are good. Same goes with traditional dynamic headphones.
    9. Low power. Sound gets soft when cranked up with speakers. Headphones are fine.
    10. Likely could have obtained better sonic performance with tube rolling, but I did not attempt to do any whatsoever. Sounds good with provided tubes and I cannot stress how important this is. Amps that require good or speshal tubes aren't good amps, they are money sinks.
    11. Bias meters are cool.
    12. USA made, if that matters to you.
    I'll put the Taboo on the APx555 in a bit. The Taboo was equipped with the following tubes. Measurements may and will likely be slightly different with different tubes.

    6P15P output tubes
    6Н1П / 6N1P input tube
    5U3C rectifier
     
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    Last edited: Jun 5, 2022
  19. purr1n

    purr1n Burned out

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    Decware Taboo MK-IV
    0dBu into 333-ohm dummy load (high Z dynamic headphone @100db SPL, e.g.Sennheiser) via 4-pin headphone out
    upload_2022-6-5_12-21-53.png
    AC mains a bit high from a measurement perspective, but considered how insensitive our ears in the lows, no one is going to hear -60db down. This seems corroborated with Zach and my experience using the ZMF Atriums. Distortion is rather with low second harmonic at -84dbFS and third at -89dbFS. 4th and 5th harmonics muted with a bit of grass the rest of the way. THD+N is 0.1% which is reasonable and expected for this design, THD without the N (more reflective of the actual sonics, removing the hum which our ears can't really heard) is probably more like 0.02%.

    THD-N no weight
    upload_2022-6-5_12-39-43.png

    THD-N A-weighted (to account for perceived loudness in human ear)
    upload_2022-6-5_12-38-21.png

    THD-N 400Hz HP (assuming we are acclimated to hum which is ubiquitous in our homes - more than you would think)
    upload_2022-6-5_12-40-40.png

    Decware Taboo MK-IV
    0dBu into 8-ohm dummy load (high efficiency speaker) speaker posts
    upload_2022-6-5_12-24-41.png
    The amp has a harder time driving 8-ohm loads. Second harmonic -50dbFS and third at -70dbFS. Note AC mains is lower with this load down to about -70dbFS. No one is gonna hear this, especially in couch a few feet from the speakers. THD is a bit higher at 0.26%

    upload_2022-6-5_12-43-2.png

    This likely accounts for the amp's softer sound.
     
    Last edited: Jun 5, 2022
  20. purr1n

    purr1n Burned out

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    Here is idea of a high-efficiency low impedance planar (entry level HiFiMan, Audeze LCD-X)

    Decware Taboo MK-IV
    -10dBu into 8-ohm dummy load (high efficiency low impedance planar) via speaker posts
    upload_2022-6-5_12-48-21.png

    Highish AC mains but almost -60db down will not be audible. Second and third harmonics with second dominant and no higher harmonics. This harmonic distortion pattern will sound good. Dominate third harmonic sounds bad in the mids and highs. Second harmonic by itself sounds kind of muddy. The combination of the second and third with the second just above the third sounds good.

    Decware Taboo MK-IV
    THD sweep (THD vs voltage)
    RED = 333-ohm load' BLUE = 8-ohm load speaker posts
    upload_2022-6-5_13-6-16.png

    This confirms my observations. The Taboo will have an easier time with efficient low-Z orthos. Speakers when cranked up will start to sound soft. The Decware makes just under a watt for 8-ohm loads. The ZMF Atrium (and Sennheiser HD6xx) sounded great.

    Decware Taboo MK-IV
    Voltage Gain
    CH1 = 8-ohm load, CH2 = 333-ohm load
    upload_2022-6-5_13-10-0.png

    As I mentioned, the Taboo has very low gain. Without efficient transducers or a hot source, there may not be enough room on the volume knob. +3.5db can work with most headphones.
     
    Last edited: Jun 5, 2022

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