[anubisgrau]

welcome to the club.... i wrote here about a superiority of more sophisticated trannies geometry long time ago... the first TVC i've heard that seriously demolished plain vanilla promi was a local DIY double-C core TVC.... still the best i've ever heard - wild energy and amazingly real timber

[audiodoc]

My interest lies in 1:2 windings because I'm using a Audio Consulting 1:2 output for my cd player with excellent results.Why not a preamp tvc with the same?I've read the higher ratios don't sound as good.I want to examine this option before I splurge on the C-core tvc and have Nick upgrade it very soon with 1:2 option.

Mike

[tanchiro58]

F100 told me the new TVC Signature (monoblocs too) has so-called Big Fat Mama C-cores which is double wounded of the Reference TVC but not sure if they have 1:2 ratio.

[PromitheusAudio]

Nick:Is it possible to make the C-cores tvc's with a 1:2 output for those needing more gain and maintain excellent sound quality?

Mike

Mike
there is 2 options for you.
The c-core tvc would be able to do a 1:2 output. Of course this has to be specially wound for this
the better option is to use another transformer to step it up and then feed it to the TVC. this way, i could separate the two functions and keep the tvc doing whats best and the step up to do what is best

contact me off line if you would like to find out more

[PromitheusAudio]

welcome to the club.... i wrote here about a superiority of more sophisticated trannies geometry long time ago... the first TVC i've heard that seriously demolished plain vanilla promi was a local DIY double-C core TVC.... still the best i've ever heard - wild energy and amazingly real timber

Actually it was your findings, that led us to persue this core topology. However core topology is just one part of the transformer design.
The next would be the winding geometry, core thickness.
For instance we made a 125W SET OPT using EI core with a split bobbin cross-winding which does 12Hz to 42Khz -3dB. THe EI core uses 0.35mm m6 steel. Proving the EI core format can be made to sound good using good winding topology. Note the OPT weights 8kg bare.
So the most important is the winding style. Using thinner core thickness and core topogy would definetly build on the good winding format

So in short, Anubisgrau findings were the start off for our c-core series
cheers
Nicholas

[Speedy381]

Having been very happy with my Apollo for the past year, I am excited about the prospect of the C-cores. I will report when fitted.
Nicholas, can you pm me?

Ian

[fr338]

I am a new user of ref C-core TVC. I have no experience with TVC in the past. It took more than 200 hours of break-in before I feel the ref C-core TVC has come to a stability. Being a new user of TVC, I must say the result is very positive. The TVC is not simply a volume control. It gives  a more spacious sound and removed the granular texture of digital source. It reduce the bass quantity a bit though. I am interested to know if other TVC models have similar effect. Besides, the ref C-core TVC is very microphonic. I can hear the knob turning sound being picked up and replayed on the speaker (  not switching noise , but the wood knob clicking sound). The TVC pair also pick up hum and noises from around. I have grounded the ground post of the TVCs to the chassis of my tube amp ( an iron-steel chassis), but hum and its harmonics is still quit audible. I guess my AC lines must be quite noisy.

[cityjim]

fr338 ,

 do you have ALL your equipment powered from the same outlet or power strip ?

 Or do you have some amps one on outlet and say a sub on another ?

 All of your equipment needs to be on the same outlet/power strip . If you have a sub for example plugged into another outlet/circuit , you will get hum .

 Also you do not connect your TVC to another piece of gear . If you need to Earth ground your TVC to rid the hum , you need to take a minimum 10ga. wire from your TVC to the Earth ground prong at the wall socket directly . Give your TVC a clean path to Earth ground . By connecting your TVC to another piece of gear , you create ground loops that cause hum .

 Here is a quick test . Take a wire long enough to reach your TVC and the Earth prong on your outlet . Connect the TVC ground to the outlet Earth prong and see if your hum goes away . If so you have a ground loop .

 Also you need to check the A/C polarity of all your gear . Making sure you don't have say 120 volts going down the neutral leg of your amp or cd/dvd player let say for example . All your power cords need 3 prong plugs . A lot of low end dvd players have 2 prong power cords . You can still polarize it by opening the top cover and ensuring the hot or 120 volt leg reaches the proper terminal .

 Most common 3 prong plugs are connected like so . The longest prong of the bunch in the center of the plug is the Earth ground . Look at the plug with the Earth prong lower than the other two . Like you are ready to plug it into the wall . The prong on the left or the wide prong is the neutral . The smaller or right side prong is the hot or load prong . Polarized plugs are fat on the left and slim on the right prongs . Grounding is a science .

 Oh for the microphonics , I would stuff the inside of your TVC with 2 inch open celled foam . The kind that easily smashes down with your fingers . Some usages are mattress pads or maybe an upholstery shop can help you . Simple yellow foam is all . Don't worry about the exotic Black Hole 5 or the like . Stuff it like so . Just line the inner workings and try not to compress the foam on itself . Use scissors to cut around the transformers and other parts that need clearance . Pack it like a bag of ice on a 6-pack of beer . You will notice blacker backgrounds and a more at ease sound . This is a must for tube preamps also . Let me know if this helps .

regards
cityjim

[fr338]

cityjim,

Thanks a lot for your helpful information. I must try them out. I am not sure if all my gears are from the same power bus, since there are two outlets on the wall, and I used one outlet to a power filter feeding CD and DAC, while another outlet feed a PS Audio Ultimate Outlet ( so probably a balanced transformer) for my SE amp. So are the signal ground isolated due to the use of Ultimate Outlet ?

[cityjim]

fr338 ,

 you found your problem right there . 2 outlets on the wall . Those can create a daisy chain grounding effect . One of the outlets might and normally will measure differently to Earth ground . Cheap very old outlets been used thousands of times over a home owners usage . I see ground loop city at your house my friend . One of your outlets might not even have a ground connection .

 Best is to install a dedicated 20 amp breaker at your electrical service panel . Don't sweat it because these parts are relatively cheap . You might need an electrician to wire it up . 10ga. Romex wire and at minimum 10 foot deep copper ground rod . Go to a hardware store and get a hospital grade outlet . Use a minimum 6ga. pure copper ground conductor to wire in your ground rod to the service panel . Best to CAD weld or braze the ground rod connection . Use a 5/8ths inch diameter or larger ground rod . No clamps either on the ground rod . So what your equipment is looking for is a "clean - solid - direct" path to Earth ground . Buy a 5 outlet power strip and plug into your new "audio only" outlet . Plug your audio system into this ONLY . I would open this power strip and silver solder any friction fit connections . Get rid of the on and off switching capability per outlet . Wire the thing in direct . Again you might have to buy polarized power cords . Keep this in mind . There are numerous ways to improve your Earth ground .

 So to answer your question you have a ground loop . I see your yellow icon smacking his head . Don't sweat it . You were looking for power and spotted the other outlet . Even if you don't "hear" a hum in your system , adding a dedicated 20 amp line and good Earth ground will lower the noise floor on your audio only power line . Which your amps and so on are connected to . You just lowered the noise floor of your entire audio system .

 Depending on your house wiring , those 2 outlets might be on different breakers . You'd definitely have a ground loop there . You'd have differences in potential to Earth ground across the outlets .

 I would remove the so called ultimate outlet and the other power filter . Run all your equipment direct . These devices are sonic band-aids . They attempt to correct improper wiring/grounding that most homes have . They also increase the impedance on your power line . Something you do not want . Also these items add measurable noise to your power line . Again , not at my house ......  Let me know how this turns out for you . Be careful doing this .

cityjim

[fr338]

cityjim,

Thanks again. Seems lots of work is needed on the wiring, and I don't know if it can be done on my place since the power lines are hidden behind the wall. 

But I will at least use one outlet for all and put damping into the Ref C-core.

Will update how it goes.

[cityjim]

fr338 ,

 well at least get you a 5 outlet power strip and connect all your gear to one outlet . This "should" fix your hum . If not I can tell you how with what you are working with . If you have an attic you are golden . Pretty easy to fish a wall and run some Romex . Changing out the outlet is cake . Installing the new breaker is pure comedy . Your electrical service is obviously live . Shouldn't take an electrician a few hours to install you a dedicated outlet . Probably $200 or so just guessing . Now if you live in an apartment you are screwed . If so maybe you could bribe the maintenance man with a couple pizzas and some cold beer . Do an under the table cash arrangement .

 On the microphonics and the transformer issue , I was changing some tubes in my tube preamp one day . I left the top cover off just swapping tubes around with the system on . I noticed a lot of glare and the sound was WAY off . I was like WTF . These tubes can't be that bad . Later I resorted to the original config with the top cover on . Now I went a few days with crap sound , no top cover on . Puzzled at the time smear microphonic mess that was going on with my sound . I had my system playing and decided to install the top cover . The second I placed the cover down the good sound came back . I was like wow . I know all tubes are microphonic but that bad ??? That is when I got the idea to load the interior of my tube preamp with foam . Like I told you I loosly packed it like pouring a bag of ice over a six pack of beer in a cooler . 95% of the interior is foam now .

 Now the sound is way more relaxed and the backgrounds are pitch black . Clearly able to hear all instruments more isolated like they should be . Now the played sound is not being fed back into the tubes like before . So when you hear guys taking the top cover off and claiming it sounds better ..... not at my house . Oh and I'm aware that you are having a transformer issue with microphonics . Just that tubes act the same way so I shared this with you . Hope it helps . Can't see why it won't . If you take your fingernail and tap your transformers , and you hear it through your speakers , you have a microphonic issue . Sound is going into your transformers and being amplified and played back . Foam to the rescue . The foam will absorb most of the sound . Go to the land fill and get a couch seat cushion . Use the foam from it .

 Can you take some pictures of that C-core monster ? I am thinking about buying one .


cityjim

[fr338]

cityjim,

I live in apartment so I probably will try single power strip as the first step.

I have some wool that was left after my last speaker build. Can I use wool to stuff the inside of the chassis ?

No problem I will take some pics and upload here during weekend.

[cityjim]

fr338 ,

 I don't see why the wool would cause any issues . Give it a shot . It might be messy upon removal is all .


cityjim

[fr338]

In the weekend I managed to :

1. Use one power strip for CD transport, DAC and power amplifier ;
2. Put in wool to fill the cavity of the wood chassis.

Here is my findings :

1. Changing to one power strip and ground the ground tip of Ref C-core to the Earth of the power strip does not improve the hum and its harmonics. However I double the wire thickness connecting to the chassis of the power amp( I was using a telfon multi-stranded silver plated wire and  now I use two twisted together) has some improvement. Now I can hardly hear the harmonics of the hum at my listening place. I can still hear the noise if I am from the speaker by 5cm but this is no more a big concern to me.

2. Filling the cavity with wool -- I tested with the input of Ref C-core opened and the microphonic effect is still very prominent. But since this is the best I can do, I closed the cover, reconnected to the DAC and do listening test again. I found the bass to be more solid ( previously the bass seems to be lighter comparing to without Ref C-core). The texture is also more realistic and the silky nature retains there. Oh now I love the Ref C-core even more.

I am thinking adding a sand base for a next step tweak.

I attached two pictures showing before and after adding wool.

[NewBuyer]

AFAIK, these are the very first internal pics of the new C-core TVC. Very interesting.

About solving the possible ground loop / hum issue: Are the input and output ground lines tied together internally, in that TVC?

[fr338]

NewBuyer,

Yes, the in and out gounds are tied together. I did a measure with DVM and they are shorted.

[Early B.]

In the weekend I managed to :

1. Use one power strip for CD transport, DAC and power amplifier ;
2. Put in wool to fill the cavity of the wood chassis.

Here is my findings :

2. Filling the cavity with wool -- I tested with the input of Ref C-core opened and the microphonic effect is still very prominent. But since this is the best I can do, I closed the cover, reconnected to the DAC and do listening test again. I found the bass to be more solid ( previously the bass seems to be lighter comparing to without Ref C-core). The texture is also more realistic and the silky nature retains there. Oh now I love the Ref C-core even more.

I'm not clear on what you mean here. Are you saying that the wool made the bass more solid, and improved the texture of the music?

Has anyone else tried this wool tweak on their TVC? If so, what were your results?

Thanks.

 

[Gpj]

Re wool in the tvc:  Baaaaaah  :oops:couldn't help myself. Sorry

[munosmario]

"That is when I got the idea to load the interior of my tube preamp with foam . Like I told you I loosly packed it like pouring a bag of ice over a six pack of beer in a cooler . 95% of the interior is foam now ."

cityjim, since it works it seems like a good idea specially for transformers; but in an enclosed tube preamp, how about heat dissipation and lessening tube life because excessive temperature. Anti-microphonic devices for tubes are made out of highly heat conducting metal shields, or screens that let the heat through, or elastometer bands/rings/or teflon clamps that only cover a small section of the tube, so that heat generated by the tubes can radiate away.

munosmario