Promitheus TVC passive preamp anyone?

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PromitheusAudio

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Re: Promitheus TVC passive preamp anyone?
« Reply #300 on: 1 Nov 2006, 09:14 am »
Matt
I have sent your preamp yesteday, also with it a pair of our 1.5m silver cables to test out.

On our phono preamp it has selectable gain settings for
mm
1) 38 db
2) 41 db
3) 44 db
4) 46 db
for mc
1) 58 db
2) 61 db
3) 64 db
4) 66 db
5) 68 db
It also has cart loading for 100R,220,330R,470R,750,1K for resistive and 360pf,1000pf,2200pf,3300pf

This way you have much options for play when trying out various mc carts and mm. On the graham slee i know this preamp very well as this is what my close friends uses with his music maker before he upgraded to our preamp. I ask him about your problem ( he uses the almost the same setup for analog, turntable and cart are the same except he is using schrodder arm. He says he does not have much problem with the gain as he is using passive.

BUt doing some rough calculation, your amp with the phono preamp can only drive you amp with the sensitivity of 0.7 volts to full power for both of your carts

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #301 on: 1 Nov 2006, 03:27 pm »
thanks Nick!    :bounce:

I'll be sure to post my thoughts when i receive the TVC & once i'm able to wipe the drool off my keyboard...  :drool:

Do you still recomend adding some rope caulk to the interior of the metal top?  and its the rope caulk from Home Depot, like for gutters?  I might try permoplast - i have some leftover from the Longhorn tweak.


Your phono preamp looks to be a quality design.   the power supply is beefier than my amps psu...   Can you tell me what type of umbilical (and connector) is used between the chassis?     i'm wondering if Revelation Audio Labs might make a suitable aftermarket umbilical for them.  their little cable lets my VPP-1 sing.    www.revelationaudiolabs.com

If anyone has any experience with the phono preamp, please post some feedback.

er, maybe nick needs his own forum here???    aa      there's 9000 views almost.

GD
 

darkmoebius

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Re: Promitheus TVC passive preamp anyone?
« Reply #302 on: 1 Nov 2006, 04:10 pm »
On our phono preamp it has selectable gain settings for
mm: 1) 38 db, 2) 41 db, 3) 44 db, 4) 46 db,
for mc: 1) 58 db, 2) 61 db, 3) 64 db, 4) 66 db, 5) 68 db
It also has cart loading for 100R,220,330R,470R,750,1K for resistive and 360pf,1000pf,2200pf,3300pf

Very flexible! Did you leave off the standard 47k for loading?

Quote
BUt doing some rough calculation, your amp with the phono preamp can only drive you amp with the sensitivity of 0.7 volts to full power for both of your carts

Actually, I can also use the Denon DL-103D, too. It's 0.25mV output becomes 0.47V after the 65.5dB gain of the EXP+Era. Using the +6dB gain switch on my TVC brings this up to an acceptable ~0.9V for use with the Art Audio PX-25's 0.7V input.

But, that doesn't leave much room for dynamic passages and the frequency extremes suffer when using the +6dB setting. Not ideal at all.

I haven't yet decided which direction to go with the phono preamp. The GS Era sounds absolutely fantastic, far better than the Rogue Stealth, EAR 834P, and Musical Surroundings Phonomena in my system. But, it was designed to be follwed by an active preamp with +12-16dB gain.


PromitheusAudio

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Re: Promitheus TVC passive preamp anyone?
« Reply #303 on: 1 Nov 2006, 04:43 pm »
Sorry left out on this, for mm cartridge the loading is 47 k only. You don't need other loadings for mm.

Matt
Used some of this damping material on the stainless steel will be great.

checking out their webpage on after market cables, sorry our connectors are not the ones listed there.

also guys watch later in this few days, we will be showing off our new wood support platform to be mated with our tvc. 

darkmoebius

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Re: Promitheus TVC passive preamp anyone?
« Reply #304 on: 1 Nov 2006, 04:54 pm »
Sorry left out on this, for mm cartridge the loading is 47 k only. You don't need other loadings for mm.

Aaaaah, that's what I figured. The 47k is so obvious.

BTW, your phono preamp webpage doesn't list 47k loading for MM, either. It seems obvious, but you should probably state it outright just in case.

nodiak

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Re: Promitheus TVC passive preamp anyone?
« Reply #305 on: 1 Nov 2006, 09:00 pm »
Gymane, my current gc does have vol. pot. I have 2 kits (3875 and 3886) and may now have them made into straight amps. Thanks for that info. I'll research the iMod specs. Peter actually offers a buffer kit to match with the gc.
Wow, I don't expect miracles from our audio machines, but it would be nice to rest the neurosis for awhile  :lol: !
Don

GHM

Re: Promitheus TVC passive preamp anyone?
« Reply #306 on: 1 Nov 2006, 09:51 pm »
Gymane, my current gc does have vol. pot. I have 2 kits (3875 and 3886) and may now have them made into straight amps. Thanks for that info. I'll research the iMod specs. Peter actually offers a buffer kit to match with the gc.
Wow, I don't expect miracles from our audio machines, but it would be nice to rest the neurosis for awhile  :lol: !
Don

You're right my friend! I had forgotten Peter offers the buffer kit. From the specs his unit packs a wallop too ..the output impedance of Peter's buffer kit is 6 ohms :o. Yup I hear you on the neurosis..this hobby can be extremely addictive!! Now where did I put those Vicodin? :scratch:  :lol:

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #307 on: 3 Nov 2006, 05:58 am »
 aa

glad to report the TVC arrived in great shape...nick packed the thing ready for a 10' drop.   :beer:

i'm gonna wax poetic about this little box till i'm blue in the face for some time, so i'll keep it brief (yeah right).

fit & finish are exemplary.   i'm praying a wood chassis & wood knobs mean i won't get shocked this winter when crankin it up.

the internal chassis vibrations need to be addressed for the full potential of this tvc to be heard - or believed for that matter.   

the supplied wood cones are good, but not adequate to do this monster any type of justice.  i have 4 difft types of footers avail and difft types of brass weights...a mapleshade test room really.   

i recomend the owners of this tvc look into setting up a vibration draining system from the git go..nick is leaning us towards this too with the plinth & the cones...he's just missing the weight & he's recomended treating the metal lid.  the writing is on the wall    :o   '

the ultimate triplepoint 2" footers from mapleshade do the trick incredibly, knee trembly well.  their maple blocks, which is how i'll be listening for a few more paychecks, are a completely acceptable 2nd though.  the flat top ms footers are not to be considered but are much better than the stock promi ones. 

unfortunately, ms prices have gone up bigtime. blocks were $2, now $5. brass pricing went way up too, the footers i mention are $140 i think.    tonight the set-up went from 'kinda harsh but ok since its new' to a 'fire breathing monster w/1000 hrs under the hood' when going from the maple blocks to the ult triplepoints, same weight on lid.   granted, any set-up like this requires a day or 2 to settle in...but both promi & MS offer 30 day guarantee's.      talking about $600 total.....

we never will get to change a tube or a cord or get a cap replaced, yet this joy is gonna be a tweaker's delight & a science experiment.

this is the ideal situation for MS pointed products. Weighted wood into a spike is ideal for transmitting vibes out of a component & into a plinth, according to Dr. Sprey.  a weight on top of the box is crucial as well.  the small pointed brass weight, small ultimate heavyhat from MS, snaps the picture into focus like a 10 megapixel pro camera.   the flat top small weight sucked, same with the heavier weights.   www.mapleshaderecords.com

the weight + footers + nicks tonewood plinth will create sonic bliss.   

the problem with many current footer designs is they both 'couple & isolate' or 'isolate & decouple' or whatever..or simply of a poor design/material.  the only system that really works to control a components inner vibes is one that drives those vibes from inside the chassis into a tonewood plinth - in a tightly controlled way.   from there, the plinth should be suspended somehow.   sounds like small sheet of the spongy shelf paper should be fine...i use it to suspend my rack mdf shelves.   

i hate pimping mapleshade, their catalog wording is a bit much, but their tech is right for this tvc & other similar applications.     

for those owners who don't know much about the benefits of inner chassis vibrations, you're about to.       :green:

anyhoo, we, the elite few, have something that very few have - something pretty darn special.
take this a step further & make the it sing. 

there is no harshness or even a hint this guy is new...it gets better?????????????????????

buy a few of the 1.5M interconnects from nick, pronto.   i just bought a 2nd anti-IC from paul speltz a month ago, i certainly didn't need the surprice IC.  nick's silver IC, my 1st silver experience, embarrassed the $120 MS Clearview 5 minutes in...which will be for sale soon. bass galore, shielded perfectly though there's no visible shielding.  the Promi on source & anti betwe pre & amp has proved copasetic - to put it lightly.     i'll be ordering a 2nd IC & that tonewood plinth asap.   the IC design is really cool, very well made, nice rca's & skinny.  simple: 2 solid core strands of silver in small clear tubes, braided.  another absolute steal from promitheus.     they are directional. test one cable at a time, easy to discern.

nick knows tone - this little box is amazing.     easily the most polite yet ruthlessly powerful piece of gear i've come across.   i'm gonna have to add a seat belt to my listening chair.

and probably start selling tickets to the show.


not sure if this tvc is a giant killer, or the nuclear winter that killed the giants.




GD

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #308 on: 3 Nov 2006, 06:03 am »
I almost forgot, vinyl is not much fun.   with the knob 90% turned up its just a tad louder than i'd ever listen to it, not tearing the roof off though.     i wil try the VPP-1 at the 60db setting...if not i'm looking for a new phono pre.   the grado gold has 5mv output, should be a healthy signal.    it sounds great, no issues there whatsoever.   seems like 50dg would be perfect though and the VPP-1 has 40 db or 60 db only.

suggestions?

this tvc is sooooooo quiet.  no crosstalk, no hash, hiss or anything.  absolute blackness, at any volume knob setting, until play is pushed or the needle dropped.   

a real thrill so far.

NewBuyer

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Re: Promitheus TVC passive preamp anyone?
« Reply #309 on: 3 Nov 2006, 06:07 am »
I don't know anything about this - so I'll come right out and ask: Why would vibration dampening make a difference, with a couple of large transformers? Sounds interesting, just trying to better understand how technically it could affect anything operationally...

darkmoebius

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Re: Promitheus TVC passive preamp anyone?
« Reply #310 on: 3 Nov 2006, 06:43 am »
I almost forgot, vinyl is not much fun.   with the knob 90% turned up its just a tad louder than i'd ever listen to it, not tearing the roof off though.     i wil try the VPP-1 at the 60db setting...if not i'm looking for a new phono pre.   the grado gold has 5mv output, should be a healthy signal.    it sounds great, no issues there whatsoever. 

Aaaah, you've discovered(like I did) the one drawback to passive preamps - 4mV and up cartridges fall in an "in between" range.  4mV needs +48db to make 1V and 54dB for 2V.  5mV needs +46dB/1V and +52dB/2V.

Quote
seems like 50dg would be perfect though and the VPP-1 has 40 db or 60 db only. suggestions?

Channel Island's current VPP-1 webpage says it's got 40dB/50dB switchable gain.  Perhaps yours is an older version?

+40dB gain with a 5mV cart will only get you 0.5V output, not enough. At the low gain, you are probably losing a lot of potential body, dynamics, and tone. 50dB should be perfect at 1.58V output. 60dB will shoot you right out of the usable ballpark at 7V output. Very little, if any, volume control will be usuable.

I have a similir problem with my 4mV Cartridge Man MusicMaker III. +41.5dB gain of my Gram Slee Era Gold is too little(0.475V) and adding in the +24dB EXP Elevator yields way too much gain at 7V.

Quote
this tvc is sooooooo quiet.  no crosstalk, no hash, hiss or anything.  absolute blackness, at any volume knob setting, until play is pushed or the needle dropped.

You got it. Passive is soo good, so quiet, so real, that it's intoxicating. To me, it seems like notes are more vivid because they stand out against the blackness more. You don't realize how much texture and nuance gets obscured by backgound noise until it's gone.

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #311 on: 3 Nov 2006, 07:03 am »
thanks darkmobeus, i can sleep easy tonight.   the vpp-1 is 40 & 50 db.  i've had it at the
the normal 40 db MM setting since new & was going by faulty memory.    thank you.

the $ spent on oyaide gear was $ well spent.

newbuyer, go towards the light....that's about all i can say.   most of the products available for this type of tweaking will have trial periods or money back gurantee's.     i know zero about the science of what i recomend, only the clear & powerful results.    lots of info on this in the forums, the most viable snake oil i've come across & this tvc is the most receptive piece of gear i've come across.

i won't remove the lid until the unit is fully broken in.  i read that the lid accounts for structural rigidity & is important for the tone....i don't want to change that from nicks design until i know how its supposed to sound.

plus, i know what it looks like in there.    :lol:

GD

darkmoebius

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Re: Promitheus TVC passive preamp anyone?
« Reply #312 on: 3 Nov 2006, 08:16 am »
thanks darkmobeus, i can sleep easy tonight.   the vpp-1 is 40 & 50 db.  i've had it at thethe normal 40 db MM setting since new & was going by faulty memory.

I envy you. Because my Welborne 300B monoblocks need 1.5V for full volume, I need 2V output to allow for dynamic headroom. I have three carts, a 4mV, 0.5mV, and 0.25mV meaning I need 54dB, 72dB, 78dB. With my current +24 dB active stepup, I need a phono pre with switchable between 48dB & 54dB. Not an easy find.

Anyway, I'll bet that 50dB setting is going to make huge difference. If you thought that cart sounded good before....


GHM

Re: Promitheus TVC passive preamp anyone?
« Reply #313 on: 3 Nov 2006, 11:09 am »
WoooHooo!!  :dance: Sure looks like you're having some fun gooberdude. The little red box opens up the recording pretty well huh? Glad you're enjoying the system!! I hope to try out a set of Nick's cables soon...we'll see how it goes!! aa
You know the best insulator for cables is air right? Nick seems to have figured that part out from your descriptions. I use my own DIY speaker wires set up the same way as you described Nick's IC cables.

Enjoy!

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #314 on: 3 Nov 2006, 02:59 pm »
stayed up last night until almost 2am listening - can't wait to get home tonight.

its so weird that a high output MM cartridge is gonna need more gain...i thought issues
like this were only for the LOMC crowd.   i have every confidence that the 50db setting will be a perfect fit.  40 db works, but its evidently not optimal.    according to the manual there may be a slight increase in noise at the higher setting...but does that even matter with this TVC?     not sure if garbage in = garbage out with the red box.     aa


this TVC is the only piece of gear i've owned that could/would build a system around.   other gear is expendable now, and i've never looked at it that way.

GD


bikes and beats

Re: Promitheus TVC passive preamp anyone?
« Reply #315 on: 4 Nov 2006, 03:00 pm »
TVC in the house...
Took out the tube pre I've had for over two years now and I must say, the TVC sounded very similar out of the box. The same bass weight and rounded tone but way more detail. It's been running with CD's on repeat since Wednesday night and I'm still waiting for changes. The lowest volume setting isn't low enough with my NuForce Ref 8.02 amps. I had to install in-line attenuators at the amp RCA's to get truly quiet listening. Of course that casts a slight haze on things but maybe they need to burn in a bit. I really like having a system that sips electricity instead of gulping it. I previously had a monster class-A A/B amp and tube pre and the thing could cause brownouts I swear. Being of an enviromental mindset, I feel my current setup is smart and a wise choice for the future. Previously I'd tried a CI Audio passive pre to get to this point but there was nowhere near the fullsome sound of the TVC. I still need to do more critical listening, but so far nothing untoward stands out at background and even moderate volumes. So If you are considering a TVC and are running new "analog switching" amps, then definitely give it a go.
On construction. The nobs are not quite centered and the wood is rough on mine. the switchers are coarse as well. Perhaps they's smooth out. On the plus, the wood pyramid footers are essential and work well. I'm staining mine to match this afternoon.
Out
MikeO

GHM

Re: Promitheus TVC passive preamp anyone?
« Reply #316 on: 4 Nov 2006, 03:15 pm »
TVC in the house...
Took out the tube pre I've had for over two years now and I must say, the TVC sounded very similar out of the box. The same bass weight and rounded tone but way more detail. It's been running with CD's on repeat since Wednesday night and I'm still waiting for changes. The lowest volume setting isn't low enough with my NuForce Ref 8.02 amps. I had to install in-line attenuators at the amp RCA's to get truly quiet listening. Of course that casts a slight haze on things but maybe they need to burn in a bit. I really like having a system that sips electricity instead of gulping it. I previously had a monster class-A A/B amp and tube pre and the thing could cause brownouts I swear. Being of an enviromental mindset, I feel my current setup is smart and a wise choice for the future. Previously I'd tried a CI Audio passive pre to get to this point but there was nowhere near the fullsome sound of the TVC. I still need to do more critical listening, but so far nothing untoward stands out at background and even moderate volumes. So If you are considering a TVC and are running new "analog switching" amps, then definitely give it a go.
On construction. The nobs are not quite centered and the wood is rough on mine. the switchers are coarse as well. Perhaps they's smooth out. On the plus, the wood pyramid footers are essential and work well. I'm staining mine to match this afternoon.
Out
MikeO

Hey Mike...I'm curious. What's the input sensitivity of your Nuforce amplifiers? Just so I know a head of time when looking at amplifiers to match up with the TVC. The switching will smooth out a little as you use them more.

Thanks

darkmoebius

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Re: Promitheus TVC passive preamp anyone?
« Reply #317 on: 4 Nov 2006, 04:31 pm »
What's the input sensitivity of your Nuforce amplifiers?

NuForce doesn' publish the input sensitivty for any of their amps. Nor, do they state the output voltage for their preamps. Can't find that info in any reviews, either.

It would also be helpful to know the output of his Audio Sector Non OS dac.


« Last Edit: 4 Nov 2006, 04:42 pm by darkmoebius »

nodiak

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Re: Promitheus TVC passive preamp anyone?
« Reply #318 on: 4 Nov 2006, 05:32 pm »
Hi all, my apologies but this morn I don't have time to reread the thread.
Has anyone tried the Charlize with the P. TVC ? I have a kit to build this winter, and 3886 and 3875 gc's. Also interested if anyone's tried it with tube amp? I may look for an ebay el34 or el84 .
Thanks, Don

Steve Eddy

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Re: Promitheus TVC passive preamp anyone?
« Reply #319 on: 4 Nov 2006, 06:04 pm »
NuForce doesn' publish the input sensitivty for any of their amps.

They give enough information that you can extrapolate it, assuming the 8.02's rated power and gain are the same as the 8.

The 8's rated at 100 watts into 8 ohms. That's 40 volts peak or 28.28 volts RMS. Gain is specified as 26dB or a factor of 20. 40/20 is 2 volts peak, or 1.414 volts RMS.

Quote
Nor, do they state the output voltage for their preamps.

No. Though I'd like to think it fairly safe to assume it can at least swing 2 volts.

Quote
It would also be helpful to know the output of his Audio Sector Non OS dac.

You remind me I've had one here for over a year now that I still haven't got 'round to assembling. :roll:

Anyway, it uses passive I/V so its output will depend on the value of the I/V resistors (R8 and R9 unless the boards have changed since I got mine). The larger the value of the resistors, the greater the output and vice versa.

So the solution here would be to remove the attenuators he has on the inputs of his amps and reduce the value of the I/V resistors on the DAC. This will also help improve the performance of the DAC as current output DACs like the TDA-1543 ideally want to see a short circuit.

se