Promitheus TVC passive preamp anyone?

ashok · « **Reply #360 on:** 15 Nov 2006, 07:13 pm »

Hi Steve,

The equivalent circuit of a transformer I am used to in the analysis of power systems is shown here.

By "impedances representing the windings themselves", I mean the complex impedances r1 + jx1 and a^2*(r2 + jx2).

r1 and r2 are the winding resistances. x1 and x2 are derived quantities and depend on the self-inductance of the windings themselves, and the mutual inductance between the windings.

x1 = w * [L11 - a*L21]

where w = 2*pi*f, L11 is the self-inductance of the primary and L21 is the mutual inductance.

x2 = w*[L22 - L12/a]

with L22 the self-inductance of the secondary and L12 the mutual inductance = L21. "a" is the turns ratio of the transformer.

The magnetizing branch is the shunt Gc/Bm combination. Gc represents the I^2*R losses in the core. Bm = 1/(a*w*L21) (Susceptance).

So, with the secondary open-circuited, and neglecing Gc, the equivalent transformer impedance will be r1 + j*w*L11.

Neglecting the magnetizing branch completely leads to the equivalent circuit shown below:

with R1 = r1 + a^2*r2 and X1 = x1 + a^2*x2.

To get an idea of what R1 and X1 are in ohms, consider a 500kV - 345kV three-phase transformer, with an MVA rating of 300MVA. Such transformers typically have an X1 = 8% at the rated voltage and voltampere base.

Referred to the high-voltage side, X1 = 0.08* 500*500/300 = 66.67 ohms. The I^2*R losses are very small compared to the through-impedance, and sometimes R1 is neglected too from the transformer model.

The model you have shown for low frequency analysis is similar to the one I am using, except that the reactances x1 and x2 are not used.

One reference for the equivalent circuit I use is "Power System Analysis" by John Grainger and William Stevenson, Jr.

Ashok

fredgarvin · « **Reply #361 on:** 15 Nov 2006, 08:05 pm »

Gymane, have you had a chance to try the Promithius silver cable against the Bluejeans? I'm using Bluejeans myself and like them.

GHM · « **Reply #362 on:** 15 Nov 2006, 08:12 pm »

Quote from: fredgarvin on 15 Nov 2006, 08:05 pm

Gymane, have you had a chance to try the Promithius silver cable against the Bluejeans? I'm using Bluejeans myself and like them.

I sure haven't. I don't have the cables yet. They should be coming with the Energizer. If the Energizer ships out this week. I'll get a chance to compare the cables probably next week. I really like the BLJs and have no intentions of taking them out of the system.

Hopefully I'll be getting a second Promitheus unit. This will allow me the opportunity to loan one out to the AC members that ask me about trying it out in their systems without having to buy a unit out right.

gooberdude · « **Reply #363 on:** 15 Nov 2006, 09:09 pm »

i've had a silver IC from nick in for a few weeks now. keep in mind this is my 1st silver IC experience.

it does many things that my cables don't do in terms of airiness and an amazing quality to put sounds way outta the boundaries of my speakers - allowing the speaekrs to disappear. However, the lowest bass isn't there - not compared to the anti-IC's anyways. Also, there is a bit o' HF stuff going on that's fatiguing.

I really think this IC would shine if i sent it to get 'cooked' - i just doubt its gonna mellow out or sprout deep bass w/more normal use.

The silver IC is replacing a Heartland Cable w/Bullett plugs. Comparing the 2 is way too easy... The Heartland cable won't work right with the TVC...its dark, slow and sluggish nature really stands out when used after any source into the TVC. The 'speed' of this silver IC is impressive - I may order a 2nd set to go between my computer soundcard and some powered M-Audio monitors to replace a set of cheap/fat/slow monster cables.

Also, i've tried 2 difft unshielded ribbon IC's between pre & amp - both had serious HUMMMMM issues. Nick's IC is also unshielded, but made no noises when between the amp & TVC. to me this is a very good thing.

GD

fredgarvin · « **Reply #364 on:** 15 Nov 2006, 11:04 pm »

I've never used a silver IC either. My system is transparent and resolving so silver may be too zippy. Is your heartland cable the canare? If so, I'll bet the belden heartlands, the same that BLJ uses, would sound better. I never cared for the Canare starquad wire, myself. I have thought about trying Promithius or the Decware silver-litz, in Bees-wax!

darkmoebius · « **Reply #365 on:** 15 Nov 2006, 11:30 pm »

Quote from: fredgarvin on 15 Nov 2006, 11:04 pm

My system is transparent and resolving so silver may be too zippy.

Good silver cables(cryo'd and burned in) are actually supposed to be more relaxed and smooth than copper. All the detail, just without and edge or hardness often associated with it.

nodiak · « **Reply #366 on:** 16 Nov 2006, 03:49 pm »

Gymane,
which tvc are you getting? I am conidering the reference model 2.
Don

gooberdude · « **Reply #367 on:** 16 Nov 2006, 04:04 pm »

The heartland cable is the one listed on their site, uses Belden 89259 wire w/Eichmann Bullett plugs.
bought it a year or so ago when i needed a 2M cable for my cable tv box.

no idea why people like using this Belden wire in interconnects, the sound is slow and rounded
and dull - zero 3-D holography & it acts like molasses when used with the TVC. plus the shielding is thick & stiff - not easy to route around rack obstacles or to turn corners. if I were talking about cars instead of cables, the anti-IC's would be an Enzo Ferrari whereas the Heartland's are a Ford Taurus.

the silver IC from nick is gonna get cooked on Nordosts cable cooker soon, just found a local dealer.
based on the changes a few weeks of burn-in have caused, it might be the ticket. If the lowest bass registers bloom and the HF mellows, this will be one hell of a cable. there may not be a HF issue with these, it could be upper midrange or whatever....something is a bit fatiguing though still.

I like the Decware cabling too, interesting designs...bees-wax, so weird.
Some day soon i'm gonna drive down to peoria & visit them - best mtn biking in the Midwest at Jubilee State Park. their MG44 tower speakers look cool too.

GD

GHM · « **Reply #368 on:** 16 Nov 2006, 06:48 pm »

Quote from: nodiak on 16 Nov 2006, 03:49 pm

Gymane,
which tvc are you getting? I am considering the reference model 2.
Don

Hi Don..it will be the Reference SE version with three inputs and two outputs .

maxwalrath · « **Reply #369 on:** 16 Nov 2006, 06:54 pm »

Quote from: GHM on 15 Nov 2006, 08:12 pm

Hopefully I'll be getting a second Promitheus unit. This will allow me the opportunity to loan one out to the AC members that ask me about trying it out in their systems without having to buy a unit out right.

If you do get a second one, I'd love to give it a listen. I'm using a Patek now also, but I'm thinking of going back to an integrated for $$ reasons and to buy an LCD TV. I've been on the fence about trying one for a while.

GHM · « **Reply #370 on:** 16 Nov 2006, 07:00 pm »

Quote from: maxwalrath on 16 Nov 2006, 06:54 pm

Quote from: GHM on 15 Nov 2006, 08:12 pm
Hopefully I'll be getting a second Promitheus unit. This will allow me the opportunity to loan one out to the AC members that ask me about trying it out in their systems without having to buy a unit out right.

If you do get a second one, I'd love to give it a listen. I'm using a Patek now also, but I'm thinking of going back to an integrated for $$ reasons and to buy an LCD TV. I've been on the fence about trying one for a while.

No problem at all maxwalrath.

I have one other AC member that I've promised a listen so far. As soon as I get word of the other one shipping out. I'll send this one to him. After he listens for a week or so. I'll have him send it to you. Lonewolf has taught me a lot about sharing. That's what I love about this site. There's a wealth of nice peole here that do the same!

I've still got to get the current one back from my friend..he doesn't want to let it go!

lonewolfny42 · « **Reply #371 on:** 16 Nov 2006, 07:08 pm »

Quote from: GHM on 16 Nov 2006, 07:00 pm

Quote from: maxwalrath on 16 Nov 2006, 06:54 pm
Quote from: GHM on 15 Nov 2006, 08:12 pm
Hopefully I'll be getting a second Promitheus unit. This will allow me the opportunity to loan one out to the AC members that ask me about trying it out in their systems without having to buy a unit out right.

If you do get a second one, I'd love to give it a listen. I'm using a Patek now also, but I'm thinking of going back to an integrated for $$ reasons and to buy an LCD TV. I've been on the fence about trying one for a while.

No problem at all maxwalrath. I have one other AC member that I've promised a listen so far. As soon as I get word of the other one shipping out. I'll send this one to him. After he listens for a week or so. I'll have him send it to you. Lonewolf has taught me a lot about sharing. That's what I love about this site. There's a wealth of nice peole here that do the same! I've still got to get the current one back from my friend..he doesn't want to let it go!

Thank you Gymane.....

And your right..."There's a wealth of nice peole here that do the same!".....great !!!

Chris

GHM · « **Reply #372 on:** 16 Nov 2006, 07:45 pm »

Your welcome Chris!!

Hey if anyone wants one without waiting. There's one that just posted on Agon for $275. It is in New York state.http://cgi.audiogon.com/cgi-bin/cl.pl?preatran&1168880051

ebag4 · « **Reply #373 on:** 16 Nov 2006, 07:47 pm »

It's already sold. It must have sold the moment it came up because my offer couldn't have been too far behind.

GHM · « **Reply #374 on:** 16 Nov 2006, 07:51 pm »

Quote from: ebag4 on 16 Nov 2006, 07:47 pm

It's already sold. It must have sold the moment it came up because my offer couldn't have been too far behind.

HOLY CRAP that was extremely fast!! There was only 7 views when I found it. I tried to buy the last one posted before this one. It must have sold in 10 minutes of the posting.

gooberdude · « **Reply #375 on:** 16 Nov 2006, 07:52 pm »

GHM & ebag4, what do you think of the ads description of the TVC's 'non-sound'?

I've not heard another TVC, just a # of ok actives & resistor based passives.
Does this TVC not have a sonic signature - if that's what the seller was describing?

GD

GHM · « **Reply #376 on:** 16 Nov 2006, 07:55 pm »

Quote from: gooberdude on 16 Nov 2006, 07:52 pm

GHM & ebag4, what do you think of the ads description of the TVC's 'non-sound'?

I've not heard another TVC, just a # of ok actives & resistor based passives.
Does this TVC not have a sonic signature - if that's what the seller was describing?

GD

I laughed at the description

. It definitely has a sound. NON sound..I don't think so. If compared to a lush and overly bloated tube pre..then I can understand.

gooberdude · « **Reply #377 on:** 16 Nov 2006, 08:06 pm »

yeah, i'd say mine definitely has a sound too. a good sound gosh darn it! aa

have any Promitheus TVC owners played with difft weights on top and footers on bottom?
playing with difft set-ups changes the 'sound' of mine quite a bit...

when the pointed brass footers are underneath & the pointed weight is on top, no music flows directly outta the speakers, there's a complete disconnect. i always figured i'd need newer speakers to get this sort of holographic, tripped out soundstage. its evident even with mediocre sources like my cable tv box & cheap-o Sony cd changer. to my ears, this effect is getting more pronounced as it breaks in.

GD

GHM · « **Reply #378 on:** 17 Nov 2006, 01:41 pm »

Quote from: gooberdude on 16 Nov 2006, 08:06 pm

yeah, i'd say mine definitely has a sound too. a good sound gosh darn it! aa

have any Promitheus TVC owners played with difft weights on top and footers on bottom?
playing with difft set-ups changes the 'sound' of mine quite a bit...

when the pointed brass footers are underneath & the pointed weight is on top, no music flows directly outta the speakers, there's a complete disconnect. i always figured i'd need newer speakers to get this sort of holographic, tripped out soundstage. its evident even with mediocre sources like my cable tv box & cheap-o Sony cd changer. to my ears, this effect is getting more pronounced as it breaks in.

GD

Hey Matt I was checking out the newer reference model on the site. Looks like this unit has a metal top and bottom. It should weight the TVC down pretty good. I listened to the Paradisea Dac with the TVC yesterday. This is an excellent match! I understand why Greg likes the combo so much now.

Too add we compared it against an Arcam DV27..terrific sounding player. The Paradesia held its own with a player that retailed for 5 times its price! The Paradesia was the fuller sounding of the two. My friend preferred the Dac over his much more expensive Arcam for two channel music.

acd483 · « **Reply #379 on:** 18 Nov 2006, 12:45 am »

Quote

Hey Matt I was checking out the newer reference model on the site. Looks like this unit has a metal top and bottom. It should weight the TVC down pretty good. I listened to the Paradisea Dac with the TVC yesterday. This is an excellent match! I understand why Greg likes the combo so much now.

Too add we compared it against an Arcam DV27..terrific sounding player. The Paradesia held its own with a player that retailed for 5 times its price! The Paradesia was the fuller sounding of the two. My friend preferred the Dac over his much more expensive Arcam for two channel music.

Lovely, as that's the DAC I plan on getting...unless the Promitheus DAC will be an even better match! I emailed Nicholas after buying the latest reference version TVC in order to get some more details on his DAC. I'd get the single-ended, tube buffer version, hopefully with USB and TOSLINK connections. Then, we've got a good match-up for the Paradisea...which have been selling like hot cakes on eBay.