[F-100]

Thanks Nick & Anubisgrau for clarifying my question. 

[rollo]

Nicholas,

      Glad to see you back in action. I should be receiving the two box dual mono ref. unit today according to DHL. I am anxious to compare this to the single box dual mono ref. TVC with silver wiring. We will see if the Neotech 7N copper wiring for the two box version makes a difference . I believe it will but time will tell.
       As mentioned earliar, I will initiate a tour of the single box Ref. dual mono TVC.
       All I ask is that you pay shipping to next party and write a review of your findings with the TVC. When ready to go I will post a tour thread in Audio Central. The first 5 are in. If we get more interest we will keep it going.
       As we all know the TVC is a break through in passive preamps. No matter what manufacture TVCs are a leap forward from the resistor based models. What makes the Promitheus a clear winner is the PRICE to PERFORMANCE ratio.
       
   rollo
       
,

VC.

[Russell Dawkins]

I guess the whole consideration of conductor carrying a signal being in close proximity to a sheet metal surface has gone by the wayside. Enamelled wire would be the most serious case, as it is able to be so close, due to the thin insulation. A comparison of two units, identical except for the bottom plate, would be instructive.

[rollo]

I guess the whole consideration of conductor carrying a signal being in close proximity to a sheet metal surface has gone by the wayside. Enamelled wire would be the most serious case, as it is able to be so close, due to the thin insulation. A comparison of two units, identical except for the bottom plate, would be instructive.

 

    Russell,
                The bottom and top plates are Stainless steel. The later units have the wires undled in a way to insure no contact with the S/S plates. Earliar versions may require some Dynamat or equivalent material to get the most out of it. The trannies are screwed directly to the bottom plate. Removing for comparison would be difficult. I would suggest removing the top plate and compare.

rollo

[Russell Dawkins]

    Russell,
                The bottom and top plates are Stainless steel. The later units have the wires undled in a way to insure no contact with the S/S plates. Earliar versions may require some Dynamat or equivalent material to get the most out of it. The trannies are screwed directly to the bottom plate. Removing for comparison would be difficult. I would suggest removing the top plate and compare.

rollo

I thought the metal bottom plate was an option and that wood was standard. By the way, I am talking about proximity, not contact.

[rollo]

Well guys,

    Its here. The dual box dual mono with Neotech 7N wiring. Your going to want this. Right out of the box you could tell. I will listen a bit tonight and then let it cook for 365HRs. It is just so natural sounding. I am amazed.
     The ebony cones are beautiful and well made. The ebony knobs are better than the origanal as far as grain and color is concerned.
       My only complaint is that the bubble wrap used for shipping leaves an imprint which is tough to remove. Maybe a piece of paper or cardboard could be used in between.
      Nicholas has out done himself with this effort. By the way the grounding post eliminated the very slight hum I had. Let me stress slight.

   I'm so glad ,I'm glad, I'm glad, I'm glad .[Cream]

 rollo

[gooberdude]

Congrats Rollo!      If and when you pop the top, please post pics of the new internal wiring.

over the last few weeks i've had my TVC opened up 2x, doing the few tweaks previously listed.

One of those times i put on latex gloves and carefully pulled the groups of wires (not indiv wires) so they weren't touching other wires or the chassis or the trannies.   i think this resulted in better sound, but its hard to tell the effects.

there's no doubt in my mind, that for my tvc, the sound is a bit smoother with the lid off.  its really splitting hairs though!!  not a huge change by any means w/lid on or off.

If the trannies have no isolating material in between them and the metal bottoms, i'd address this 1st.    keeping the tranny vibes from entering the metal bottom plate (thus keeping that plate from vibrating) might be  important sonically.


looks like there's a nice TVC for sale in the Trading Post here...

[rollo]

    Russell,
                The bottom and top plates are Stainless steel. The later units have the wires undled in a way to insure no contact with the S/S plates. Earliar versions may require some Dynamat or equivalent material to get the most out of it. The trannies are screwed directly to the bottom plate. Removing for comparison would be difficult. I would suggest removing the top plate and compare.

rollo

I thought the metal bottom plate was an option and that wood was standard. By the way, I am talking about proximity, not contact.

   

    Russ,
             Yes Russ my mistake using the word earliar. You are correct the proximity can interfere with the singal. That is why I recommended removing the top. Nicholas thought the additional weight would help in shipping damage, however the concept is flawed IMO.  I feel the original wood plates were a more effective design. The return of the wood is feasible if the TVC can be protected better for shipping.
              Would like to see a piece of varnished Spruce or Maple instead.
rollo

[gooberdude]

i think the wooden bottom is best too, i'd like to see a thicker bottom plate on mine though.

the wood bottom is highly beneficial if using Mapleshades pointed top Ultimate Triplepoint footers too.  according to their site, sharp points into wood is best.   

[tanchiro58]

i've finally had a chance to hear promitheus in a normal (not-ref) version from nov 2006, 4 RCA inputs and 2 RCA outputs, against another fully DIY TVC, with a single input and dual mono volume selectors (9 steps only).

sorry to say but promitheus was clearly beaten, hands down.

still i found it amazing device for 340$ only.

however i found its tonal balance not to my taste, at least in comparison with another device. it sounded thin and dry, with not so much weight in bass and overal fluid in sound compared to the DIY TVC. but the main issue was an emotional involvement: promitheus sounded a bit "mechanical" or "confused", while the DIY TVC had tremendous ability to put together all the sound details into emotional associations - from singers swings around a microphone, to players moves around their instruments.

our small panel, consisted of 4 experienced audiophiles more keen on analogue/valve school of thinking, had no doubts about the winner and the difference was not too small. i hope that later versions of promitheus are better - there was an obvious room for a substantial improvement.

the main design difference between 2 TVCs is a core geometry. promitheus has EI cores while our DIY TVC has plain iron, double-C cores. also the DIY TVC has 6db gain.

nick, have you ever tried making a TVC with a different core geometry?

the pics of the DIY TVC are here:

anubisgrau
Thanks for the nice productive comments

I played with few core materials, and often found the bigger the better in terms of weight. In your pic's i see the double c core are way bigger than the current tvc size. I did some study and found the bigger core material often you get that effect you metnion whether it is c-core or EI core. Often the C-core is often very much more expansive to make due to the core being always more expansive to make. Also i noted down in my study the less wires you have, less taps it is easier to make the trans better as thicker wire can be used. Again it comes down to size, yes the body is often more, simple deductive reason bigger core weighter sound.

Perhaps i should make the tvc in bigger size cores. Note that the audio consultating also uses EI core. 

Hi Nicholas,

I have experienced with two different trannies EI and Double C-core in my active tube preamp and tube amp. You are right about the labor costs and the size of the trannies. Double C-core has very sweet, clean, less noise and faster than EI core but the cost is way high like Electraprint selling over USD$1000.00 for a pair of output trannies. Besides I will have a chance to compare between Double C-core and R-core, which is more expensive but it will bring you to another higher level of music (like Audio Note Japan, Wavac...) 

Regards,
Tan

[tanchiro58]

i think the wooden bottom is best too, i'd like to see a thicker bottom plate on mine though.

the wood bottom is highly beneficial if using Mapleshades pointed top Ultimate Triplepoint footers too.  according to their site, sharp points into wood is best.   

I have good results with DH cones, Shun-Mook discs with my TVC wood bottom, which I like the sound more than a stainless steel bottom. But I will try to insert copper sheet between the two trannies and a wood bottom since copper is a good candidate to prevent vibration from the trannies. Does anyone have any experiences of this?

Tan

[gooberdude]

Another poster mentioned the Black Hole pads.   i'd bet these might work the best, since the material is designed to isolate trannies.   a hard metal might not be the best, tough to absorb vibes...

there's an online seller of this stuff, its about $20 for a sheet.   Michael Percy might also sell it.  google search.

[GHM]

Here's a pic sent too me by a Promitheus user in Atlanta, GA. He decided to change the color a bit. Looks very nice!

[anubisgrau]

GHM, what does it stand on?

[launche]

looks like a spray painted concrete paver to me.

[anubisgrau]

  Its here. The dual box dual mono with Neotech 7N wiring. Your going to want this. Right out of the box you could tell. I will listen a bit tonight and then let it cook for 365HRs. It is just so natural sounding. I am amazed.
     The ebony cones are beautiful and well made. The ebony knobs are better than the origanal as far as grain and color is concerned.
       My only complaint is that the bubble wrap used for shipping leaves an imprint which is tough to remove. Maybe a piece of paper or cardboard could be used in between.
      Nicholas has out done himself with this effort. By the way the grounding post eliminated the very slight hum I had. Let me stress slight.

rollo
i don't get one thing: has nicholas changed a wire he is using for winding? i remember you complaining about the sound of silver, but the TVC i was listening a few days ago had a copper wire - a silver wire was only to be seen behind the connectors on the back. this one is from oct/nov 06.
were some earlier models wound with silver or i completely messed something up?
cheers g

[Paul_Bui]

Even though it doesn't do imaging as wide...

I lied.  Another listen today on a different track, while my eyes closed, proved that I was wrong.  Depending on recordings, the TVC can be utterly detailed and imaging well beyond the speakers.

Have a good weekend everyone!

[daz_bike]

Hi Rollo,

That's great news about your double box TVC arriving.  I have been following this thread for a while now and as a result I ordered a TVC from Nicholas which is also a double box design.  Maybe the second one to be made after yours?  Inspired by yourself of course!  I have nicknamed it the Promitheus "Rollo design TVC".  Mine is going to be using double run silver rather than copper.  Horses for courses.

I will naturally be very interested to hear about your experiences with the double box TVC. 

Just one thing, could you please advise the width and depth of each box.  I am deciding on which shelf real estate I put these in.  Having double boxes will give plenty of options in terms of placement.

Cheers

[rollo]

  Its here. The dual box dual mono with Neotech 7N wiring. Your going to want this. Right out of the box you could tell. I will listen a bit tonight and then let it cook for 365HRs. It is just so natural sounding. I am amazed.
     The ebony cones are beautiful and well made. The ebony knobs are better than the origanal as far as grain and color is concerned.
       My only complaint is that the bubble wrap used for shipping leaves an imprint which is tough to remove. Maybe a piece of paper or cardboard could be used in between.
      Nicholas has out done himself with this effort. By the way the grounding post eliminated the very slight hum I had. Let me stress slight.

rollo
i don't get one thing: has nicholas changed a wire he is using for winding? i remember you complaining about the sound of silver, but the TVC i was listening a few days ago had a copper wire - a silver wire was only to be seen behind the connectors on the back. this one is from oct/nov 06.
were some earlier models wound with silver or i completely messed something up?
cheers g

   

   No, the trannie wire is still copper. The wires I ordered are Neotech 7N copper for the input and output connections only. The TVC comes standard with silver hookup wire. For an additional cost [email Nocholas] you can order with the copper. The silver buss connections to the positive leg of the RCAs were eliminated at my request. Now there is a direct connection from the trannie to each output[2] with the Neotech wire.
   A ground wire is connected to the trannie and then to a ground post at the rear of the unit. This was done at my request as well. This has made the TVC dead I mean dead quiet. In its early hours [8] I believe hearing more info from a darker background. Now there is absolutely no hum coming out of the speakers. There was a slight hum before that I mentioned. However I did not ground unit itself before as I thought, in my haste to hook it up I didn't.
   The only tweaks I will do now is remove the bottom plate and replace with 3/8" TH. ebony. Put blackhole pad on the three exposed sides of trannie. Remove top and place a wooden cigar box filled with sand which just fits and rests on screw block. I was lucky enough to find two with a perfect fit. Be advised that Dynamat or Blackhole Pad applied to the S/S plates works very well with some weight on top and looks better too. The box filled with sand is probably overkill but I am an audiofool I mean phile.
      Kidding aside it sounds soooooooooo good.

 rollo 





   

[rollo]

daz_bike,

               The box measures 7 1/4"x 10 3/4". The thing that struck me immediately was the bass. With only 8 HRs or so on the TVC the bass is more powerfull, goes lower and has more weight. The entire presentation has more weight with a fuller sound.
             I listened with the ground connected and disconnected. When connected the presentation was more authoritative with again better bass. Disconnected was very good but not the same in the gestalt department.
              The sound is more organic with the copper wiring. There is still plenty of detail which is presented in a more natural way. The depth of the soundstage is more evident . The backup singers on Leonard Cohen were clearly behind him and in there own space. Amazing.
               If you guys recall in my original review after 365 HRs I felt the TVC was a tad thin. Not now. Its just right. The newfound authority is addictive.
              What is so puzzling to me is the TVC has only 8 HRs of play and sounds very good at this juncture. This is opposite of my previous findings. The tonality is spot on. Actually got goose bumps last night. That hasn't happened since I last listened to vinyl.
            For the first time EVER I can honestly say, that I did feel a need to listen to vinyl. What more can I say. Yes the TVC still needs to open up at the extremes. The bass as deep and authoritative as it is needs to tighten up a bit. The top end lacks the ultimate in decay and bloom but that will change with extended use.
           Now to me imaging and staging create the illusion of the real thing. Now the TVC presents a bigger more 3D image than it ever did. There is more space between the instruments and the depth is more evident in the recording when present.
           Out of the box this TVC  outperforms its predecessor by a long shot. It sounds as if it has been broken in for a while. When I put the first unit in [single box silver wired dual mono] the top and overall sound was thin and over detailed. over time it basically went away. To date the original unit has changed and still sounds great. In comparison the new unit just has the weight and authority of the real deal. Female voice will give you goosebumps.
            It is too soon for an overall review as time will tell more. However the new unit is ahead at the first listen stage, and by allot.
            As I mentioned earliar the ground made a big difference in bass and weight, so install a ground wire from the screw [inside box, just remove nut] holding down the trannie [both] to a ground post [drill a hole in rear of box] and connect to external ground. Do this you will not be disappointed. I believe this should be standard in all future units.
           I believe that the TVC in this configuration is now better than the S&B we compared the first unit too. My active pre is crying now as it well should as it may have finally lost its home. Well for CD anyway, the phono section can be used independently by bypassing the linestage.
         Well, enough for now.

  rollo