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Zotl10 a 10 watt speaker or headphone amplifier using the EL84 tubes. . .

Discussion in 'Headphone Amps (full-size)' started by jamato8, Oct 10, 2015.
  1. jamato8 Contributor
    Well for any of the power hungry headphones out there or someone desiring both a nice tube amp for the easier to drive speakers Urban Audio has come out with the David Berning Zotl 10. Pretty exciting to me because I have some nice Klipsch speakers but also have the HE-6 headphones and I love tubes, especially the E84's and this amp uses those and some other special tubes. 
    I bet this would even work well with my Newform Research 645's. 
    After hearing and owning the micro Zotl, I can only imagine what the Zotl 10 will sound like. On that note, :^), I should find out in about a week and a half.
    The amp will put out a little more than 10 watts into 4 ohms, 10 watts into 8 ohms and about 3 watts into a 50 ohm load. The 1st 2 or 3 watts is class A.  
    Info from the website:


    1. Designed by David Berning - one of the world’s premier amplifier designers
    2. Hand-wound coils & impedance converters
    3. 10 watts per channel with little or no hum
    4. Transformer-less design eliminates intermodulation distortion inherent in all transformer designs
    5. Impedance converters simulate correct theoretical output transformer turns ratio
    6. Low impedance output easily matches a wide range of speakers and cannot be damaged with no load
    7. No adjustments – tubes are auto-biased
    8. Automatic protection circuitry
    9. High voltage turn on delay to maximize tube life
    10. 10 - 20 years tube life depending on use
    11. Push-pull, Class AB output stage
    12. No heavy power or audio transformers
    13. Universal voltage power supply (autosensing 100-240VAC 50/60Hz)
    14. Has one input through Alps volume control for direct connection to high output sources
    15. Second set of inputs bypass volume control for direct input


    1. TUNG-SOL Russian vacuum tubes
    2. Locking headphone jack w/ silver contacts
    3. Silver-coated Teflon copper insulated wiring
    4. Alps volume control
    5. Hand-wound coils & impedance converters
    6. Gold connectors throughout signal path
    7. 5-way gold binding posts  
    8. High quality metal film resistors  
  2. Compassionator
    Hmm, interesting. 
    10 watts seems a bit much for a headphone amp and not enough for speakers less than 92db.  More like a tweeter/mid amp or to drive a true high efficiency speaker with solid bass like a Klipschorn or Hartsfield.
    Also, $2400 seems overpriced for something not built by Berning himself.  Better check those solder joints for cold/resistance.  10-20 year tube life is a bold claim.  A buddy of mine had the original ZH270 and it blew a few tubes.  He first took it to the local tube guy and he took one look at it and could not make heads nor tails out of the circuit design.  He sent it back to Berning and he fixed it fast as he built the amp and knew exactly what went wrong.  That could have been be a big problem if Berning was not around to fix it.
    If you've got a HE6 or Abyss, First Watt seems to be a safer bet (as per testimonials) and a better value as Nelson Pass builds each one himself.  Or even a better value if you can build one yourself as some of those designs are available.
    Having said the above, it might be worth the risk as the Berning amps sound really good if not a bit lean sounding. 
  3. jamato8 Contributor

    From talking to Mark, who builds the amps, what is done is to David Berning's specifications. Also there is a protection circuit in these. To me, more wattage is not an issue, even with sensitive phones as it is distortion from under powering speakers or phones that can cause real problems, though less so with tube equipment as they generally soft clip vs what a solid state amp does with hard clipping. I have Newform Research 645's that can run fine from 10 watts. 
    Having the micro Zotl and having done a lot of soldering over the years, many years, the solder work and joints on the micro Zotl is fine. No signs of any poor workmanship or hint of cold soldering. 
    The HE-6 will be great to try with this amp. They are also coming out with a D. Berning 40 watt. 
  4. mourip
    Hi Jamato8.
    Any update on the ZOTL10?
    I have Mark from Urban Hifi coming by tomorrow to demo the ZOTL2 and ZOTL10 in my system which uses Omega Alnico speakers which they intend to carry in their new store here in DC.
    LTA makes the ZOTL products here in DC so it is easy to meet up with them.
    Also looking forward to seeing their new store in Takoma Park Maryland(DC).
  5. jamato8 Contributor

    No updates. Looking forward to your impressions. 
  6. mourip
    Mark from Urban Hifi which is the new Washington DC storefront for Linear Tube Audio(LTA) came by this morning to demo the David Berning designed LTA ZOTL2 and ZOTL10 in my speaker based system. I was pretty amazed.
    We first replaced my current amp with the ZOTL10. I have a First Watt SIT2 which lists for $5K. I bought it used but it still cost more than the MZ10 does new. The MZ10 bested it in nearly every way. It is exceedingly transparent and quiet. The soundstage is deep with excellent layering and localization. Human voice is the best I have heard. Excellent tonality. 
    Next we replaced my tricked out 301A DHT tubed preamp with the MZ2 and the upgrade LPS. Everything was better with an even darker background and more realistic presentation.
    It takes a bit to get used to the sound. At first you think something is missing or was removed. It was. Everything that was not the music was gone. What was left was just great tonally satisfying music. Some folks have mentioned that the sound is "lean" or "dry". I would say that it was just more truthful or accurate. I do imagine that on poorly recorded or multi-miked material it could be pretty unflattering.
    Sorry to say that I did not plug in my phones for a listen as I was really looking for a speaker amp, at least to start. After hearing the MZ2 I might go for the whole package.
    This gear performs way above it's price.
  7. mourip
    This thread is a bit dead but since it is for a speaker amp and this is HF that makes sense :)

    I thought that I would let folks know that the Z10 now has an option for a linear power supply that brings it up to another level. I live near LTA and have been previewing/evaluating their new supply for several months. It makes an already great amp a lot more dynamic and contributes to a bigger soundstage. It handles large orchestral and choral pieces handily allowing much better instrument localization.

    I returned the prototype today and also received back my Z10 for which I purchased the upgrade.

    FYI. I am using CEI 7062(12AT7), Telefunken 12AU7) and Amperex Miniwatt EL84 tubes.
    Last edited: Sep 9, 2017
  8. willsw
    We have also not given up on the ZOTL10 as a headphone amplifier, and are hard at work on the integrated version of the amp that will feature headphone outputs, optional electrostatic headphone outputs, as well as speaker outputs. Time, though, is a slow thing.

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