Promitheus TVC passive preamp anyone?

Whitese · « **Reply #1920 on:** 27 Jun 2007, 02:44 am »

I know about the adapters, but I thought it would sound better with true xlr..

Randy · « **Reply #1921 on:** 27 Jun 2007, 03:01 am »

He!!, you just got that tremendous amp. Spend a little bit more and get a balanced TVC. Mine's balanced, and I would never consider going to unbalanced RCAs. In addition, there's something very satisfying about the click you get when you plug in the cables. At least you know you have a firm connecton.

Whitese · « **Reply #1922 on:** 27 Jun 2007, 03:07 am »

Quote from: Randy on 27 Jun 2007, 03:01 am

He!!, you just got that tremendous amp. Spend a little bit more and get a balanced TVC. Mine's balanced, and I would never consider going to unbalanced RCAs. In addition, there's something very satisfying about the click you get when you plug in the cables. At least you know you have a firm connecton.

I had a Ref TVC, sold it, then got this older one w/o xlr...maybe its time to order another Ref/ebony/xlr and sell this one. ( i just wont tell my wife)

tanchiro58 · « **Reply #1923 on:** 27 Jun 2007, 06:14 pm »

Quote

maybe its time to order another Ref/ebony/xlr and sell this one. ( i just wont tell my wife)

To satisfy your wife why don't you buy a Neutrik XLR and a switch to install in your TVC. I bet your wife would vote for that idea.

Whitese · « **Reply #1924 on:** 27 Jun 2007, 06:29 pm »

Quote from: tanchiro58 on 27 Jun 2007, 06:14 pm

Quote
maybe its time to order another Ref/ebony/xlr and sell this one. ( i just wont tell my wife)

To satisfy your wife why don't you buy a Neutrik XLR and a switch to install in your TVC. I bet your wife would vote for that idea.

expand on that please? you mean add an xlr out? that was my original question...

F-100 · « **Reply #1925 on:** 27 Jun 2007, 06:31 pm »

Quote from: Randy on 27 Jun 2007, 03:01 am

He!!, you just got that tremendous amp. Spend a little bit more and get a balanced TVC. Mine's balanced, and I would never consider going to unbalanced RCAs. In addition, there's something very satisfying about the click you get when you plug in the cables. At least you know you have a firm connecton.

Correct me if I'm wrong but I don't believe the TVC is a true balanced preamp. When I removed the top cover, I saw both RCA and XLR ouputs are connected to the same wire.

Furthermore, a balanced line has three wires, two carrying signal and one ground wire. I see only 2 wires going into the volume pot and 2 coming out (signal & ground) so I'm very sure that the TVC is not a true balance preamp.

Whitese · « **Reply #1926 on:** 27 Jun 2007, 06:36 pm »

Quote from: F-100 on 27 Jun 2007, 06:31 pm

Quote from: Randy on 27 Jun 2007, 03:01 am
He!!, you just got that tremendous amp. Spend a little bit more and get a balanced TVC. Mine's balanced, and I would never consider going to unbalanced RCAs. In addition, there's something very satisfying about the click you get when you plug in the cables. At least you know you have a firm connecton.

Correct me if I'm wrong but I don't believe the TVC have a true balanced preamp. When I removed the top cover, I saw both RCA and XLR ouputs are connected to the same wire.

Oh, interesting observation...but anyway, I am using RCA with some homemade shorting pins...check these out!

tanchiro58 · « **Reply #1927 on:** 27 Jun 2007, 06:58 pm »

Quote

Correct me if I'm wrong but I don't believe the TVC is a true balanced preamp. When I removed the top cover, I saw both RCA and XLR ouputs are connected to the same wire.

Derrick and Whitese,

I do remember when I bought the first stereo TVC with XLR ins and outs. The previous owner told me he used it with his BAT amp and was okay. If I am not wrong I think in a passive preamp XLRs and RCAs act the same since only the signal goes through not like in the amplifier with true balanced 110Ohm required.

For your information you should check out this site

Quote

http://hometheaterhifi.com/forum/archive/index.php/t-2279.html

Tan

guest1632 · « **Reply #1928 on:** 27 Jun 2007, 07:39 pm »

Quote from: F-100 on 27 Jun 2007, 06:31 pm

Quote from: Randy on 27 Jun 2007, 03:01 am
He!!, you just got that tremendous amp. Spend a little bit more and get a balanced TVC. Mine's balanced, and I would never consider going to unbalanced RCAs. In addition, there's something very satisfying about the click you get when you plug in the cables. At least you know you have a firm connecton.

Correct me if I'm wrong but I don't believe the TVC is a true balanced preamp. When I removed the top cover, I saw both RCA and XLR ouputs are connected to the same wire.

Furthermore, a balanced line has three wires, two carrying signal and one ground wire. I see only 2 wires going into the volume pot and 2 coming out (signal & ground) so I'm very sure that the TVC is not a true balance preamp.

Hi all, I am trying to figure out how to get rid of the humm that is being caused by the TVC. This is not a proximity problem. I have tried moving it away from the amp and no difference. I have tried it on two different amps, and still I have the humm. It is originating inside the TVC, but don't know where to start. The humm is a very low level one. It's just loud enough to where if you stand close by the speakers, you can hear it.

By the way, some cables make it worse, like the Anticables.

Ray

F-100 · « **Reply #1929 on:** 27 Jun 2007, 08:00 pm »

Ray,
Is the hum coming from both channels??

tanchiro58 · « **Reply #1930 on:** 27 Jun 2007, 08:04 pm »

Quote

It is originating inside the TVC, but don't know where to start. The humm is a very low level one. It's just loud enough to where if you stand close by the speakers, you can hear it.

Ray,

Your hum problem might be coming from inside the trannies. Try to get some ERS sheets and wrap around the trannies. If the problem is not solved read this link

Quote

http://www.avsforum.com/avs-vb/showthread.php?t=322698

Good luck.

F-100 · « **Reply #1931 on:** 27 Jun 2007, 08:25 pm »

Quote from: tanchiro58 on 27 Jun 2007, 06:58 pm

Quote
Correct me if I'm wrong but I don't believe the TVC is a true balanced preamp. When I removed the top cover, I saw both RCA and XLR ouputs are connected to the same wire.

Derrick and Whitese,

I do remember when I bought the first stereo TVC with XLR ins and outs. The previous owner told me he used it with his BAT amp and was okay. If I am not wrong I think in a passive preamp XLRs and RCAs act the same since only the signal goes through not like in the amplifier with true balanced 110Ohm required.

For your information you should check out this site
Quote
http://hometheaterhifi.com/forum/archive/index.php/t-2279.html

Tan

Hi Tan,

I bought that stereo TVC with XLR & RCA inputs/outputs from you and then sold it to another AC member.

But I recall on that TVC, both XLR & RCA inputs are all wired directly to a selector switch. The selector switch has only 2 wires going into the transformer. The XLR inputs are not true balanced in this case.

"If the input is not true balanced, the advantages of the balanced cable are canceled." - JEJ - Editor

Randy · « **Reply #1932 on:** 27 Jun 2007, 09:08 pm »

"If the input is not true balanced, the advantages of the balanced cable are canceled." - JEJ - Editor

Using the balanced inputs for the TVC allows me to use the balanced output of my CDP, providing a 4.8 v output level as opposed to the 2.4 v of the RCA output, undeniably a huge advantage when using a passive pre like the TVC. Those of you who use CD players might want to look into models that do something like this next time you are in the market.

jonners · « **Reply #1933 on:** 27 Jun 2007, 09:27 pm »

I may be able to help with the questions about balanced connection, since I bought a pair of TVC transformers from Nicholas and put them into boxes and wired them (true balanced) myself. The advice from Nicholas was to wire them as autoformers, with the upper winding for the + signal and the lower for the - signal. In an autoformer the output is a tapping off the same winding as the input. So, one end of the upper winding goes to the +input, the other end goes to earth, and the tappings go to the switch and thence to the + output. Similar for the lower, -ve winding.
A single-ended RCA output can be derived from a balanced out by simply using the + signal and earth (and optionally earthing the - signal).
I have only seen pictures of an actual Promitheus TVC, so I don't know if the above corresponds to the way ther real thing is wired or not. I got the impression from Nicholas that his method of wiring them has changed over time.
Hope this helps.

gooberdude · « **Reply #1934 on:** 28 Jun 2007, 04:23 am »

Hey Ray,

make sure any unused inputs are shorted. this never caused hum but did result in a weird noise once when i set an IC onto top of my amp that was conected only to the TVC. Also, keep all other sources OFF when using the TVC..if multiple inputs are plugged in.

1000a · « **Reply #1935 on:** 28 Jun 2007, 05:23 am »

Quote from: gooberdude on 28 Jun 2007, 04:23 am

Hey Ray,

make sure any unused inputs are shorted. this never caused hum but did result in a weird noise once when i set an IC onto top of my amp that was conected only to the TVC. Also, keep all other sources OFF when using the TVC..if multiple inputs are plugged in.

do i run a (rca) with wire from the Right input to the left imput? not sure I get this part, my TVC should be here soon. thanks

input(RT)____wire____input(LT)?

PromitheusAudio · « **Reply #1936 on:** 28 Jun 2007, 12:24 pm »

Quote from: F-100 on 27 Jun 2007, 06:31 pm

Quote from: Randy on 27 Jun 2007, 03:01 am
He!!, you just got that tremendous amp. Spend a little bit more and get a balanced TVC. Mine's balanced, and I would never consider going to unbalanced RCAs. In addition, there's something very satisfying about the click you get when you plug in the cables. At least you know you have a firm connecton.

Correct me if I'm wrong but I don't believe the TVC is a true balanced preamp. When I removed the top cover, I saw both RCA and XLR ouputs are connected to the same wire.

Furthermore, a balanced line has three wires, two carrying signal and one ground wire. I see only 2 wires going into the volume pot and 2 coming out (signal & ground) so I'm very sure that the TVC is not a true balance preamp.

The balanced tvc are true balanced. On the transformer you would see a same identical amount of wires but double the wires. For the single ended version there is 24 wires per transformer for the balanced version it is 48 wires. So each set of winding handles + or - phase only. The RCA and XLR are sharing pin2 but pin3 is separate. Because RCA is a single ended its a + signal.
The ground wire is not going into the volume pot as the ground wires is already made so only 2 wires go into the phase.

Randy · « **Reply #1937 on:** 28 Jun 2007, 04:20 pm »

Nick, thanks for clearing up the balanced question on the TVC.

Matt, I have to top off the TVC. Have you ever come up with an alternate top? Brass, as you talked about before? What do you think about plexiglass? The bare wires on top certainly touch the cover when it is put on, but apparently it doesn't hurt anything.

gooberdude · « **Reply #1938 on:** 28 Jun 2007, 04:57 pm »

Hey Randy,

i never did get any brass tops made, but that seems like a good alternative if you intend to leave the top screwed on...or just damp that top a little. i leave the top off mine, its tucked under a shelf & doesn't accumulate dust. once i began fiddling around it became obvious my tvc sounded better with the screws all removed - lid, source switch, trannys. i'm adventurous though.

sandwiching the transformer with a tonewood lid sounds good too. damping the transformers, while also isolating them, seems to be beneficial.

F-100 · « **Reply #1939 on:** 28 Jun 2007, 05:31 pm »

Quote from: PromitheusAudio on 28 Jun 2007, 12:24 pm

The balanced tvc are true balanced. On the transformer you would see a same identical amount of wires but double the wires. For the single ended version there is 24 wires per transformer for the balanced version it is 48 wires. So each set of winding handles + or - phase only. The RCA and XLR are sharing pin2 but pin3 is separate. Because RCA is a single ended its a + signal.
The ground wire is not going into the volume pot as the ground wires is already made so only 2 wires go into the phase.

Nick, thanks for clarifying my mistake.

I didn't know that you also offer a balanced TVC. Now, I see it on your website.

Promitheus TVC passive preamp anyone?

guest1632