Promitheus TVC passive preamp anyone?

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gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #2060 on: 30 Jul 2007, 02:44 pm »
Dynamat is killer for cars....no doubt.     If anyone watches the Hot Rod shows like Pimp My Ride or Chip Foose's show Overhaulin'  its evident that Dynamat has a place on all chassis metal.    


For the Europe guys, why not buy say 5 sheets of BHP and then split all the shipping costs??       Its silly for us in the states to buy just one sheet & have it mailed, so I bought 3.    Only ended up paying about $5 more for 3 than i would have if I ordered just 1 sheet.

Damping the TVC trannies will require about 1/4th of a sheet of BHP.  If not even less than that.


Ray, i wouldn't get Dynamat anywhere near my TVC.     If anyone is interested, i have a huge roll of Dynamat Extreme to hand out...    Dynamat really is a brute... it kills whereas BHP enhances.


tanchiro58

Re: Promitheus TVC passive preamp anyone?
« Reply #2061 on: 30 Jul 2007, 06:15 pm »
Quote
as far as i know, there's no other audio specific material like BHP avail...is there????   damping material designed for trannies???

gooberdude,

If you have a chance to get the Ebony wood (sold on ebay for knives handles) you will be surprised too. I have used them to lay on top of trannies of my amp and preamp and got good results.  :thumb:

guest1632

  • Guest
Re: Promitheus TVC passive preamp anyone?
« Reply #2062 on: 30 Jul 2007, 06:22 pm »
Quote
as far as i know, there's no other audio specific material like BHP avail...is there????   damping material designed for trannies???

gooberdude,

If you have a chance to get the Ebony wood (sold on ebay for knives handles) you will be surprised too. I have used them to lay on top of trannies of my amp and preamp and got good results.  :thumb:

Hi, There is some soubathane stuff for dampening, but it doesn't work as well as BHP.

Ray

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #2063 on: 30 Jul 2007, 07:06 pm »
It seems like Ebony is the new Maple.   i think all the tonewoods deserve experimentation...they ain't called Tone wood for nuthin!

ferenc_k

Re: Promitheus TVC passive preamp anyone?
« Reply #2064 on: 30 Jul 2007, 08:06 pm »
Check Yamamoto PB-22 ebony base out. Really, really cheap. looks beautiful and usually works very well. You can use it svereal ways, 3 or 4. I have quite a few.

http://www2.117.ne.jp/%7ey-s/PB-22-e.html

1000a

Re: Promitheus TVC passive preamp anyone?
« Reply #2065 on: 31 Jul 2007, 08:52 pm »
Boy is Speaker City ever slow to ship the BHP, as has been mentioned before!

Quote
Check Yamamoto PB-22 ebony base out. Really, really cheap. looks beautiful and usually works very well. You can use it svereal ways, 3 or 4. I have quite a few.

http://www2.117.ne.jp/%7ey-s/PB-22-e.html

I am in the US is there another link to this product?

thanks

tanchiro58

Re: Promitheus TVC passive preamp anyone?
« Reply #2066 on: 31 Jul 2007, 09:28 pm »
1000a,

That was my question to Ferenc. So this is the website

Quote
http://www.venushifi.com/products/yamamoto_audiobases.shtml

Tan

1000a

Re: Promitheus TVC passive preamp anyone?
« Reply #2067 on: 1 Aug 2007, 02:15 am »
Thanks Tan

just what I was hoping for.  I am about to buy various inexpensive wood cabinet knobs, wood knife planks, wood plugs made of various woods; cherry, ebony, oak and spruce to dig in and try lots of different tonewoods (maybe not the purist grade at first) with out spending a fortune just to see what they might do.  I am also gonna try cork just for fun since someone uses it in iso blocks.  just gonna play around with lots of options see what I can learn and maybe get lucky.

On this same thought process seeing the Altman DAC on wood chassis and other gear and reading up on such it seems worth while.

So this is a question I meant to ask a long time ago

Does anyone know why the basic TVC's have metal tops and bottoms - was it an economics decision? :scratch:  or do they impart a better sound to the device? :scratch:

I got the impression the statement series would be all wood?  If this is true I am guessing and only guessing a wood bottom might be a better choice for the basic and Ref TVCs?  Or maybe the improvements are so small the expense over-road the improvements in the basic TVCs?  Nick?

Anyone been bold enough to try replacing the bottom steel with a wood plank they think would aid the presentation of music? (i know some have mounted the trannies on ebony blanks and so on)

or even a large piece of BHP under the bottom plate with a selected wood under it covering the whole area of the metal plate?

just wondering if the metal is not the ideal choice? :scratch: 
Might some of us try some other alternatives.
With all the wood being talked about and used in audio chassis's I hope its not a fad but a worthwhile effort.

guest1632

  • Guest
Re: Promitheus TVC passive preamp anyone?
« Reply #2068 on: 1 Aug 2007, 02:45 am »
Thanks Tan

just what I was hoping for.  I am about to buy various inexpensive wood cabinet knobs, wood knife planks, wood plugs made of various woods; cherry, ebony, oak and spruce to dig in and try lots of different tonewoods (maybe not the purist grade at first) with out spending a fortune just to see what they might do.  I am also gonna try cork just for fun since someone uses it in iso blocks.  just gonna play around with lots of options see what I can learn and maybe get lucky.

On this same thought process seeing the Altman DAC on wood chassis and other gear and reading up on such it seems worth while.

So this is a question I meant to ask a long time ago

Does anyone know why the basic TVC's have metal tops and bottoms - was it an economics decision? :scratch:  or do they impart a better sound to the device? :scratch:

I got the impression the statement series would be all wood?  If this is true I am guessing and only guessing a wood bottom might be a better choice for the basic and Ref TVCs?  Or maybe the improvements are so small the expense over-road the improvements in the basic TVCs?  Nick?

Anyone been bold enough to try replacing the bottom steel with a wood plank they think would aid the presentation of music? (i know some have mounted the trannies on ebony blanks and so on)

or even a large piece of BHP under the bottom plate with a selected wood under it covering the whole area of the metal plate?

just wondering if the metal is not the ideal choice? :scratch: 
Might some of us try some other alternatives.
With all the wood being talked about and used in audio chassis's I hope its not a fad but a worthwhile effort.


Hi,  The reason for the metal as opposed to wood was partly due to toughening up the TVC during shipping. A lot of times, the TVC's are tossed around. Those trafos aren't lightweights. So they would come loose and because the wood is soft, the screws holding the trafos would break through the wood. When I got my first TVC, it had a wooden base and was damaged.  It did originally come with the wooden bottom and a steel plate on the top. Some have tried brass, and it's supposed to be really good. The Ebony wooden knobs do smooth things out a bit. They also ten to dampen the switches and the controls used for the volume.

Now the major problem with the steel plates is that they ring. So here's where the BHP comes in to play. i actually wonder if say an inch square of the Dynamat on the top and bottom would do the same as opposed to using a 6.25 x 2 running in between the trafos from front to back on both the top and bottom. So that's all I know for now.

Ray

1000a

Re: Promitheus TVC passive preamp anyone?
« Reply #2069 on: 1 Aug 2007, 04:45 am »
Thanks Ray

That's exactly what I was hoping to hear I think- so off we all go and continue our ear research- the thing is ridiculously good without touching it- :drool:

knowing we can squeeze more for small audio change is just great fun :lol:

Again Nick congratulations on a fantastic piece of gear.

maybe its just good luck and synergy but I am having none of the sonic sacrifices  some have mentioned using strait to an amp and desiring the active pre.

Below box are some of Scott Faller's (Enjoy the Music) comments on my amp:

Quote
As you can see from the pic above, there is a volume knob on the front of the unit. Don't be misled by that picture, this unit is not a true integrated. What this volume knob does is attenuate the incoming signal. This allows you to directly connect a source to the amplifier. Not a bad option for those who either a) don't have room for a separate preamp b) don't want to spend the extra money for a preamp c) don't want the coloration often associated with a preamp. Oh, the pot for the gain control is an Alps.

Do I understand this not really- anyway works fantastic with Nick's TVC

« Last Edit: 1 Aug 2007, 04:58 am by 1000a »

guest1632

  • Guest
Re: Promitheus TVC passive preamp anyone?
« Reply #2070 on: 1 Aug 2007, 06:07 am »
Thanks Ray

That's exactly what I was hoping to hear I think- so off we all go and continue our ear research- the thing is ridiculously good without touching it- :drool:

knowing we can squeeze more for small audio change is just great fun :lol:

Again Nick congratulations on a fantastic piece of gear.

maybe its just good luck and synergy but I am having none of the sonic sacrifices  some have mentioned using strait to an amp and desiring the active pre.

Below box are some of Scott Faller's (Enjoy the Music) comments on my amp:

Quote
As you can see from the pic above, there is a volume knob on the front of the unit. Don't be misled by that picture, this unit is not a true integrated. What this volume knob does is attenuate the incoming signal. This allows you to directly connect a source to the amplifier. Not a bad option for those who either a) don't have room for a separate preamp b) don't want to spend the extra money for a preamp c) don't want the coloration often associated with a preamp. Oh, the pot for the gain control is an Alps.

Do I understand this not really- anyway works fantastic with Nick's TVC



Hi 1000A,

All I can suggest is to beg, borrow, and don't steal heheh, a TVC,, and see for yourself. Just for kicks the other day, I hooked up my DVD player directly to my amp. It has a builtin volume control from the remote. It didn't sound to bad at all.

What the TVC does, besides the electrical explanation on Nick's site is to sonically give you better overall sound by matching everything up.   

So I hook back up my TVC, and everything sounded nicer. That's kinda it in the nutshell.

Yes, your amp would work AOK with a TVC. Just turn the volume all the way up, and let the TVC do all the work. What amp is it?

Ray

1000a

Re: Promitheus TVC passive preamp anyone?
« Reply #2071 on: 1 Aug 2007, 03:44 pm »
Hi Ray

my amp is the biggest Jolida integrated 100watts (PP tube el34) per channel. (jd1000a)

I do finally have my TVC Ref2

got it 3 weeks back, but unfortunately my amp needs a repair so I am currently having to use my $300 av receiver for music and I am leary of placing the TVC in front of it.

so I am on board but then Murphy showed up! :lol:

Gaara

Re: Promitheus TVC passive preamp anyone?
« Reply #2072 on: 1 Aug 2007, 04:30 pm »
Assuming you can get it.  Anyone else try to order some Black Hole Pad recently?

I order June 19th...still apparently out of stock.

Hi Gaara,

I have a sheet sitting here. I can precut you some enough for all four sides of each transformer. PM me your address, and I'll see what I can do for you. Hey, someone helped me out, so I am just paying it forward. Glad to do it.

The 6.25 by 22, 2 strips one on the top underside and one on the bottom in between the two transformers, don't know I have enough for you there. But covering the frames of the trafos and especially underside, will go a long way to make this baby sing.

Ray Bronk



Ray,

I appreciate the offer but I will pass.  I have a large amount coming (7 sheets) as I need enough to do 3 TVCs, and some other components.  I am going to call today to try and figure out what happend.

On a side note, does anyone know what happened to the C-Cores?  Rollo talked alot about them and the statement line then Nic said to disregard what Rollo said...so I have no idea if these are still being made and when (if) to expect them.

Nic are you out there, any news on these?

Jared

tanchiro58

Re: Promitheus TVC passive preamp anyone?
« Reply #2073 on: 1 Aug 2007, 05:55 pm »
Quote
On a side note, does anyone know what happened to the C-Cores?  Rollo talked alot about them and the statement line then Nic said to disregard what Rollo said...so I have no idea if these are still being made and when (if) to expect them.

Jared,

Check Promitheus Audio website. I think Nicholas Chua offers only for the Apollo tube preamp with an extra $300.00. Therefore, the Apollo preamp with C-cores cost $1300.00 plus shipping.

Tan

anubisgrau

  • Full Member
  • Posts: 386
Re: Promitheus TVC passive preamp anyone?
« Reply #2074 on: 1 Aug 2007, 09:21 pm »
Thanks Tan

just what I was hoping for.  I am about to buy various inexpensive wood cabinet knobs, wood knife planks, wood plugs made of various woods; cherry, ebony, oak and spruce to dig in and try lots of different tonewoods (maybe not the purist grade at first) with out spending a fortune just to see what they might do.  I am also gonna try cork just for fun since someone uses it in iso blocks.  just gonna play around with lots of options see what I can learn and maybe get lucky.

On this same thought process seeing the Altman DAC on wood chassis and other gear and reading up on such it seems worth while.

So this is a question I meant to ask a long time ago

Does anyone know why the basic TVC's have metal tops and bottoms - was it an economics decision? :scratch:  or do they impart a better sound to the device? :scratch:

I got the impression the statement series would be all wood?  If this is true I am guessing and only guessing a wood bottom might be a better choice for the basic and Ref TVCs?  Or maybe the improvements are so small the expense over-road the improvements in the basic TVCs?  Nick?

Anyone been bold enough to try replacing the bottom steel with a wood plank they think would aid the presentation of music? (i know some have mounted the trannies on ebony blanks and so on)

or even a large piece of BHP under the bottom plate with a selected wood under it covering the whole area of the metal plate?

just wondering if the metal is not the ideal choice? :scratch: 
Might some of us try some other alternatives.
With all the wood being talked about and used in audio chassis's I hope its not a fad but a worthwhile effort.


any metal is certainly to be avoided next to the unshielded trannies.

brass sounds better than steel but still worse than wood - especially if it is the one with good acoustic behaviour, a quality spruce or maple. never tried ebony.

promi's first units with a thin wooden bottom were prone to a transport damage. i've seen and heard one whose trannie was badly lose with a nasty crack in the wooden bottom.

i would expect that a thicker wooden bottom would be a solution.

we've made a full naked version of a double-C core dual mono TVC screwed directly into the oak platform, no lid, no sides, no output connectors - directly soldered to the trannies.

if you have any possibilites to live with something like this in your room, you shouldn't think twice.

steel lid parts congest the sound of promi, IMHO.

guest1632

  • Guest
Re: Promitheus TVC passive preamp anyone?
« Reply #2075 on: 1 Aug 2007, 09:39 pm »
Thanks Tan

just what I was hoping for.  I am about to buy various inexpensive wood cabinet knobs, wood knife planks, wood plugs made of various woods; cherry, ebony, oak and spruce to dig in and try lots of different tonewoods (maybe not the purist grade at first) with out spending a fortune just to see what they might do.  I am also gonna try cork just for fun since someone uses it in iso blocks.  just gonna play around with lots of options see what I can learn and maybe get lucky.

On this same thought process seeing the Altman DAC on wood chassis and other gear and reading up on such it seems worth while.

So this is a question I meant to ask a long time ago

Does anyone know why the basic TVC's have metal tops and bottoms - was it an economics decision? :scratch:  or do they impart a better sound to the device? :scratch:

I got the impression the statement series would be all wood?  If this is true I am guessing and only guessing a wood bottom might be a better choice for the basic and Ref TVCs?  Or maybe the improvements are so small the expense over-road the improvements in the basic TVCs?  Nick?

Anyone been bold enough to try replacing the bottom steel with a wood plank they think would aid the presentation of music? (i know some have mounted the trannies on ebony blanks and so on)

or even a large piece of BHP under the bottom plate with a selected wood under it covering the whole area of the metal plate?

just wondering if the metal is not the ideal choice? :scratch: 
Might some of us try some other alternatives.
With all the wood being talked about and used in audio chassis's I hope its not a fad but a worthwhile effort.


any metal is certainly to be avoided next to the unshielded trannies.

brass sounds better than steel but still worse than wood - especially if it is the one with good acoustic behaviour, a quality spruce or maple. never tried ebony.

promi's first units with a thin wooden bottom were prone to a transport damage. i've seen and heard one whose trannie was badly lose with a nasty crack in the wooden bottom.

i would expect that a thicker wooden bottom would be a solution.

we've made a full naked version of a double-C core dual mono TVC screwed directly into the oak platform, no lid, no sides, no output connectors - directly soldered to the trannies.

if you have any possibilites to live with something like this in your room, you shouldn't think twice.

steel lid parts congest the sound of promi, IMHO.

Hi, Yeah, the possibilities of using wood aren't bad, but you then have to do some routing to get it to match up with the rest of the TVC. There's also the painting or whatever the process that Nick uses. You could probably redo the box and veneer it with a different color. Posibilities are endless here. .

Ray

anubisgrau

  • Full Member
  • Posts: 386
Re: Promitheus TVC passive preamp anyone?
« Reply #2076 on: 1 Aug 2007, 10:28 pm »


Hi, Yeah, the possibilities of using wood aren't bad, but you then have to do some routing to get it to match up with the rest of the TVC. There's also the painting or whatever the process that Nick uses. You could probably redo the box and veneer it with a different color. Posibilities are endless here. .

Ray

my point is that once you throw the steel top & bottom, you should find yourself a decent wooden board and screw the trannies directly into in, leaving everything open. just make a front side so you can install your volume switchers. if you are confident in your selection of ICs, just solder them direct at the inputs/ouputs of the trannies.

if worried about dust & dirt, make yourself an acrylic cover you can simple move everytime you plan to use the TVC.

i don't know what nicholas uses to varnish wood, is it some acoustic treatment or just a sealer/colour.

it should be either done properly, with a top quality varnish aimed for instruments that resonate such as violin or guitar, or it should be left without anything. many modern coats based on plastic are not any beneficial to the sound.

it doesn't have to be hyped and expensive C37. there are other, cheaper manufacturers of good wood treatments for the instruments that don't cost a fortune and do a practically similar job. google, you'll find them.

guest1632

  • Guest
Re: Promitheus TVC passive preamp anyone?
« Reply #2077 on: 1 Aug 2007, 10:48 pm »


Hi, Yeah, the possibilities of using wood aren't bad, but you then have to do some routing to get it to match up with the rest of the TVC. There's also the painting or whatever the process that Nick uses. You could probably redo the box and veneer it with a different color. Posibilities are endless here.

Ray

my point is that once you throw the steel top & bottom, you should find yourself a decent wooden board and screw the trannies directly into in, leaving everything open. just make a front side so you can install your volume switchers. if you are confident in your selection of ICs, just solder them direct at the inputs/ouputs of the trannies.

if worried about dust & dirt, make yourself an acrylic cover you can simple move everytime you plan to use the TVC.

i don't know what nicholas uses to varnish wood, is it some acoustic treatment or just a sealer/colour.

it should be either done properly, with a top quality varnish aimed for instruments that resonate such as violin or guitar, or it should be left without anything. many modern coats based on plastic are not any beneficial to the sound.

it doesn't have to be hyped and expensive C37. there are other, cheaper manufacturers of good wood treatments for the instruments that don't cost a fortune and do a practically similar job. google, you'll find them.

Hi, I think Nick discusses that process on his site. The problem with soldering direct is that nick uses a buss for both the ins and outs. So you still have to mount them all on something to hold everything in place.   If youu have ever looked inside of one of these TVC's, it a nightmare in there.

Ray

Cincy_bob

Re: Promitheus TVC passive preamp anyone?
« Reply #2078 on: 2 Aug 2007, 11:20 pm »
Guys, I'm new to this forum, and I am thinking about joining your Promitheus club.  (I know, I'm late to the party...)  I have been an audio freak for many years, but I am a newbee when it comes to passive preamplification.  I had always steered away from it because my audio systems have always involved a long (15 to 20 foot) pair of interconnects between the preamp and amp(s).  I had understood that there are issues with capacitance that tend to roll off high frequencies and potentially cause other problems when a passive pre is used with anything other than a short interconnect run.  I am not very knowledgeable when it comes to the technical aspects of electronics, so I could use some help here.

Can anyone help me to understand whether a Promitheus Audio TVC would be a good match to a second system I am assembling?  I am building the system around a pair of Morrow Audio 300B SET monoblocks (10wpc, 100K input impedance, 0.25V input sensitivity) and 98dB efficient single point source crossoverless speakers.  The source will initially be a CDP and will eventually grow to include an analog rig as well.  The room calls for the sources to be connected to the TVC using short (1-meter) runs and the TVC to be connected to the monoblocks using a long (6 to 7 meter) pair of interconnects.  While it is possible I could reposition the TVC closer to the monoblocks, that would require a bunch of long runs from the source components to the TVC - which would be an ugly mess of wire that would likely score low on WAF.  (I am putting this second system into a living room with the promise that it will be a small scale system that will not impose itself on the room...)

Any input you can offer would be much appreciated!

Gaara

Re: Promitheus TVC passive preamp anyone?
« Reply #2079 on: 3 Aug 2007, 12:47 am »
I remember reading back in the day about Ric Schultz's Ultimate Attenuators, a type of passive pre.  He said there were a few key things that should be in place to be able to use passive pres, and the more the better.  They included:

A source with higher output then the amps input sensitivity
A high input impedance on the amp
Efficient speakers
Short cable runs

You seem to have plenty of gain, a very high input impedance, and very efficient speakers.  The only issue would be the long cable runs...which is less of an issue with a TVC.

From my understanding of it normal passive pres add their own capacitance to the line, which can cause the attenuation of the highs and other issues.  Adding a normal passive pre would cause the over all capacitance to rise, this would be worsened with your long interconnects and the higher the capacitance the more the roll off.

Well the beauty of a TVC is that it actually drastically reduces capacitance, making your longer interconnect runs a non issue.  There is a good amount of info on it here but the jist of it is that the lower the volume setting on a TVC the lower the output impedance.  With a input sensitivity that low and speakers that efficient you would probably never get even halfway up the volume scale of the TVC, meaning that your amp would always see a very low input impedance.

The only thing I would be worried about in your situation would be that it would be to loud with such efficient speakers, but your amps don't put out much power so I don't see it being a problem.  What would you be replacing?

Jared