[Review] Malaysian Promitheus Dual Mono Reference TVC preamp

Discussion in 'Hi-Fi and General Audio' started by larkrise, Feb 23, 2007.

  1. larkrise

    larkrise Sheepdogs prefer red wine

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    Malaysian Promitheus Dual Mono Reference TVC preamp

    I'm not that good at hi-fi reviews, there's only so much vocabulary you can use to describe an aural experience! - so please take this as a brief report for those that may be interested, as promised, on the Reference version of the Promitheus transformer preamp. I ordered this reference version as i was so impressed by the standard. This is dual mono and balanced version, plus it has the special mahogany knobs! Out of the box it sounded superb, really nice, easy to listen to, good transients, fantastic detail just terrific - little more to say as I had no criticisms.

    I then rigged it up to a tuner 24/7 for a couple of weeks and this afternoon I put it back into the system. All of the above and more came through, in particular a great sound stage and detail and transients at lower listenng levels - something that is attractive to me as i some times listen very late at night. It is especially good at high end notes - bells, harpsichord just hang in the air and the bass is as good as I have heard anywhere with active preamps. This is something very special and at the price Nicholas is charging it is a giveaway. Highly - and I mean HIGHLY reccomended, if you want a tvc pay the extra for the reference. I have also used Promitheus's silver interconnects with this too - same wiring as the preamp and this has been an added factor to the quality set against some otheer quality silver XLR's I have.

    It's as good if not better than any expensive passive I've listened to. And before you ask I have no relatives in Kuala Lumpar!

    ;)
     
    larkrise, Feb 23, 2007
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  2. larkrise

    GHM

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    Nice little review. I have the same unit now. This being my third Promitheus. I found the dual mono to sound a bit fuller than the stereo version Reference TVC which I still own. Coming from the owner of the Music First...your praise means a lot.

    Good listening
     
    GHM, Feb 26, 2007
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  3. larkrise

    Tim F

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    Cheers larkrise...
    Price? and what were you comparing it with. Also what system was it on?

    Thanks, Tim
     
    Tim F, Feb 26, 2007
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  4. larkrise

    SteveC PrimaLuna is not cheese

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    Thanks for the review. I've been waiting to hear your thoughts on this one. Any thoughts from memory on how it compares with a Music First? I've no desire to upgrade at the moment myself, but it's interesting to hear :)
     
    SteveC, Feb 26, 2007
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  5. larkrise

    Mikeb

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    Hi Larkrise I bought your earlier Promitheus TVC preamp from you a little while ago and have been very happy with the results and would recommend it particularly considering the price. I have however found one problem with it when driving certain amps, in particular the Nelson Pass First Watt F3 power amp and the Pass Labs Adelph and the digital Teac AL700P. These amps have a low input sensitivity and when used with the Promiteus needs the volume control to be at maximum to get a resonable sound level, not ideal as it dosen't allow me to effectively control the level at all times as sometimes I would like it a little louder. I should mention that my speakers are highly efficient Tannoys of around 98bd efficiency so I don't know how it would work in a system where the speakers were of more normal sensitivity of around 88db. I note that some other TVC preamps have a setting of +6db output which I would appreciate and which would make it more universal. Does your new one have this feature, if not do you think the manufacturer could supply one?

    Regards Mike
     
    Mikeb, Feb 27, 2007
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  6. larkrise

    Uncle Ants In Recordeo Speramus

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    But doesn't this just suggest that this passive pre, like all passive pres isn't going to be suitable for use with power amps with low input sensitivity? I would have thought if you need to crank it all the way, 6db isn't going to make a whole lot of difference.
     
    Uncle Ants, Feb 27, 2007
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  7. larkrise

    mhuk easily distracted

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    Isn't the other side of the coin that the Promitheus is well suited to power amps with high input sensitivity? Isn't this true of all passive pre-amps?
     
    mhuk, Feb 27, 2007
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  8. larkrise

    SteveC PrimaLuna is not cheese

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    Mike, FWIW I use 87 dB sens speakers and I chose a magnetic pre with 6 dB gain for that reason. I rarely need to use it, but it's nice to have it there, and you definitely have a point.
     
    SteveC, Feb 27, 2007
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  9. larkrise

    Promitheusaudio

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    Mike
    I was looking your posting and see that you have insufficient gain.

    Actually the gain issue is not depending on speaker but it depends on 2 things
    1) power amp gain
    2) cdp or phono preamp output

    1) some power amp have high gain. At 0.7volts they have maximum power, however your amp is the opposite of this. I believe your amp has a sensitivity aroudn 1.5 to 2.0volts for max power. Some amps manufactures to get the lower noise value for their amps often have low input sensitivity to bring down the noise value.

    2) cdp or phono preamp output. Some cdp or dac have very high output like the AN DAC2.0 has a 4.0volt output which really supports passive preamp usage but limits you to passive preamp only as most active preamp will find it hard to match as there is too much gain

    We do not offer the 6db gain boost because i never like the sound of it. Also from your posting 6db is not enough too. WIth the 6db you are only 3 clicks away from maximum. Not much headroom either.

    What i can suggest is perhaps look into our new active tube preamp with transformer coupled output and separate tube power supply with chokes. The active preamp is design to be used with the tvc. THe active preamps used after the tvc. So the tvc is used to control the volume(getting the tvc benefits) and the active preamp is for the gain ( thus getting the active preamp benefits). Is a combo design made for the tvc users

    http://www.promitheusaudio.com/activepreamp.htm

    THis has a gain setting that can be made to the user's requiremenents. I am currently using the preamp with 14db of gain. Which would equate to 7 clicks on the tvc
    This option would set you back by USD500 though

    Hope this info helps
     
    Promitheusaudio, Feb 28, 2007
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  10. larkrise

    larkrise Sheepdogs prefer red wine

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    Hi all - sorry for delay in replying have been in Dublin on business and Prague end of week - what jet setting, I usually don't go anywhere! Nick has answered query re gain option - ie there is none. Comparison to Music First - well I no longer have one to A/B but the original Promitheus impressed sufficiently for me to sell on the Music First and bank the cash - this dual mono sounds very good indeed.

    Big test for me is I have now taken delivery of 4 matched NOS Mullards to try in my Eklipse Valve Pre - the Eklipse is really superb, one of hi-fi's little secrets has beaten pants off quite famous US valve pre at 4 times price, and it works with my Krell too. I am told that to try NOS Mullards in this is a must re sound upgrade. It's already neck and neck re active vs passive with hee two but shall give the valves a go later today and see what i think.

    Finally - re q's about my system - currently rather stable!! Sonus Faber Extrema speakers, Krell FPB300 power amp, Audio Synthesis Transcend CD Transport and Audio Synthesis Discrete DAC and undecided re Eklipe pre and Promitheus pre. Cables - nothing too exotic US stuff names escape me - haven't had coffee yet.
     
    larkrise, Feb 28, 2007
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  11. larkrise

    Lautrec

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    I'm very curious where are your thoughts at the moment re TVC vs Eklipse? Thnks
     
    Lautrec, Mar 4, 2007
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  12. larkrise

    larkrise Sheepdogs prefer red wine

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    Hi - good question for those following my saga of tube active versus transformer passive - yes I think I possibly do prefer the Eklipse, but to be perfectly honest it's simply a different sound rather than any differences in quality. There's body and warmth with the Eklipse - there is detail and more space with the prmitheus. the devil is that tvc's get better with use, so may be a while before I decide between the two, after all can't really use both can I? But- having said that i have a pair of speakers upstairs looking out of the window!

    Need to let Promitheus settle in and new valves settle in too - perhaps I should buy a little Bose side table thingie?
     
    larkrise, Mar 6, 2007
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  13. larkrise

    Lautrec

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    as promised on the larkrise's TVC sale thread, here are the pics of rather brilliant sounding TVC i had in my system for a couple of hours.

    absolutely killed anything i have ever tried before in my home including very expensive US preamps such as pass labs X2.5

    it's still a prototype - designer just rather wanted to test a principle of TVC according to some 50s instructions how to wind a transformer properly. he was so surprised with results that it's really dificult to imagine a room for serious improvement.

    it completely eliminates any need for either subwoofer or supertweeter for ATCs, including small ones such as 20s. bass performance is shockingly deep and fast and suddenly even an old (and criticized) VIFA tweeter on ATCs performes just perfect.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
    Lautrec, Mar 13, 2007
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  14. larkrise

    Tenson Moderator

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    Have you tried other TVCs in your system? The Stephens and Billington transformers in the Music First really are rather good.
     
    Tenson, Mar 13, 2007
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  15. larkrise

    Lautrec

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    no, this is the first TVC i have ever tried.

    can't imagine a better sounding pre, honestly.
     
    Lautrec, Mar 13, 2007
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  16. larkrise

    Tenson Moderator

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    Thats how I feel about the Music First, or more accurately the S&B transformers. Complete transparency IMO.
     
    Tenson, Mar 13, 2007
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  17. larkrise

    Lautrec

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    my biggest surprise with the TVC was not just a transparency. that's what i've somehow expected. however i didn't expect it to have such a full, rounded, enjoyable sound plus unlimited dynamics. i've heard some extremely transparent preamps that are crap, unlistenable (krell 250p). i've also heard a common objection that even the best TVCs suffer from dynamic congestions. this unit is not as such - it just has an amazing way of handling volume and dynamics. it goes louder but the sound never becomes unpleasant, just physically bigger and that's all.
    the TVC has such a tonal correctness that we were in a total disbelief this kind of natural reproduction is possible from a simple device like this.
    most likely it just shows how many active preamps are a piece of s***.
    in 2 hours i have a demo of an early version of promitheus TVC and i am very anxious about it. if it works as good as the one we've tried, the only active preamp i'll give a chance is EAR 864 just because i've already bought it (blind:))
     
    Lautrec, Mar 13, 2007
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  18. larkrise

    Lautrec

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    after our yesterday evening session with promitheus TVC (a plain version, not reference) against our DIY TVC (pictures on a previous page), we have all concluded that we have a gem in our hands with the homemade TVC.

    in comparison, promitheus sounded detailed but thin and dry, lacking fluidity and a full emotional involvement. there were moments when you could really see a singer swinging around a mike with the DIY TVC.

    no doubts promitheus is a great device for its price, not sure if my SS EC4.7 is any better as such (except for a RC).

    the difference between promitheus and our TVC is in transformer cores: promitheus uses EI cores that are inferior to double-C cores DIY TVC uses, also the later uses braided wire (not sure if this matter as much as a core geometry). i would expect a significant improvement if promitheus would have a better selector instead of rather cheap & plastic one. Our TVC is a single channel, dual mono volume control so these could be also points of gain.... and also 0db gain of promitheus could be a problem with quiet passages or simply quiet CDs. 6db of DIY TVC is enough for any situation.

    i am now very curious about other TVCs, especially those coming from a django manufacturer with amorphous cores.
     
    Lautrec, Mar 14, 2007
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  19. larkrise

    Tenson Moderator

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    Hi, Seriously try you ears on a Music First, or a Django with the S&B. I have tried both the Amorphous cores and the S&B and S&B is better. They have cores with around 50% Nickle, which is about as high/good as you can get.
     
    Tenson, Mar 14, 2007
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  20. larkrise

    mhuk easily distracted

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    diyparadise.com also sell TVC pre-amps (Maggie).
     
    mhuk, Mar 14, 2007
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