Promitheus TVC passive preamp anyone?

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gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #1060 on: 19 Feb 2007, 09:02 pm »
Good to hear TVC users are playing around with difft configurations and tweaks. 

This weekend I had the opportunity to check out Tim Babbs place & the Klipsch museum in his basement, his 2 channel set-up is simply amazing.  Huge Cornwall speaks, loads of tube gear and paul speltz's cabling...i had no clue 7 watts TOTAL could sound like that...pushing 15" woofers no less.   :o


Tim has a week old Dual volume control Reference TVC, the waxed finish with the Ebony knobs looks great Nick.   it wasn't possible to compare our TVC's accurately, but i do think the latest dual volume TVC's has better stereo separation than my version, which is a single volume control made 10/06.   the overall image seemed wider on Tim's, musicians more spread apart.  We had 3 preamps to compare: 2 TVC's and Tims Wright tubed preamp...the tubed pre bested the TVC's handily.   Keep in mind his preamp and tubed monoblocks (and tube phono pre) are from the same mfgr though - synergy.   

In my solid state system, the TVC has body and weight and soul and all that but in Tim's its quite difft, the TVC's both sounded a bit anemic in comparison.    This is my 1st experience with the TVC and tubed gear though...

My recent TVC tweaks:     After checking out Tim in the 'burbs I installed a set of Nick's Ebony knobs, and also placed some EAR Isodamp in between the chassis bottom and the L shaped Source Selector knob mount.  The Ebony knobs are at least twice the weight of the originals and feel great.  Also, there were 8 indiv screws in the bottom chassis, yet only 6 were in use, so I removed 2 screws and nuts.    Since i did these tweaks at the same time, i can't say what did what...but the overall presentation has more body, weight and warmth.  i'm extremely pleased...   If you have an early TVC with the Source Selector knob on the front, open the top cover to see if there's an L mount inside.  Adding isolating material between the L mount and the chassis does good things.  Vibrations from the transformers are messing with the selector switch, and our heads!

I received a 7" x 5" piece of this free from the mfgr:  EAR Isodamp C-1002-01     I cut 6 pieces about 1" square, laid them ontop of one another (1/8" thick) & then in the TVC.  Place the L bracket back in place I used a tiny allen wrench to pop holes in the Isodamp for the chassis screws to fit through.   This Isodamp is the thinnest EAR makes, thicker would be better so you don't have to make a sandwich like mine.    If you call, tell them you want to isolate a transformer for an audio project...and be real nice! 

This was the 1st time i'd opened up my TVC - the simplicity is really cool to me.  All the internal wiring coming out of the trasnformers look to be copper, and the buss wiring for the all RCA's looks to be silver.

A previous post mentioned substituting a wooden rod for the aluminum one on the Source Selector knob...I think this would be worthwhile as well.   isolating the L mount should be done prior to a wooden rod though.

The new Ebony knob would not fit on the Source Selector rod initially, but a few seconds with a 1/4" drill bit opened the hole so the rod slipped right in.   I figured this post would get dirty at some point!!

anyways, both the knobs and damping the L bracket from the chassis should be seriously considered for the early TVC's made... IMO



Hey Randy, Tim mailed out your knobs earlier in the week... don't force the Selector Knob.  Its a slightly larger diam than the Volume knob, which slid on with no problem.


matt   


Mike B.

Re: Promitheus TVC passive preamp anyone?
« Reply #1061 on: 19 Feb 2007, 11:57 pm »
Rollo, I did a couple mods at a time. The blackhole pad made a big difference in  stabilizing the burn-in changes I first noted. The knobs are larger and add more mass. Didn't compare to the old knobs. If nothing else, the larger diameter looks and feels better to me. For some reason the sound became better just removing the steel top plate. The plexi did not add nor subtract from that improvement. The silver wire I use is the Cardas silver wire sold by Michael Percy. I think they claim 6/9's purity, but I have heard it is extremely difficult to go past 5 nines with silver. I like the present weight of the sound but I don't sense bloom. I have 95db line source speakers and yet I still need to get the volume up to 12 to feel like the thing is coming alive. I am missing a emotional connection. Just my 2 cents.

rollo

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Re: Promitheus TVC passive preamp anyone?
« Reply #1062 on: 20 Feb 2007, 12:27 am »
Mike B,

          We are of the same opinion.I also thought it sounded better with the top removed.Bloom, well tube bloom will always win out.That is why I strongly feel the Promitheus tubed pre [or buffer] will give us all the best of both worlds.
          After experimenting with my active as a buffer I see tremendous potential here.I trust that Promitheus strives for the presentation that we desire and has admitted that the TVC alone just can't do it all."the only time I will use the TVC alone is when I want to save electricity",pretty bold I must say.Actually very honest.
          There are many happy campers out there with the TVC as it is a hell of a piece to begin with.It will be a great piece with the active and also provide proper gain for different phono setups with out a step up transformer.
          As a vinyl guy this is a blessing.Very good stepups are hard to find for a reasonable price.Forget about the synergy issues,it could get very frustrating.
this active just simplifies matters.
rollo

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #1063 on: 20 Feb 2007, 12:56 am »
Hey Mike B,

Did you remove the stock damping material under the trannies before adding the Black Hole pads?

i'll try listening without the top on...





guest1632

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Re: Promitheus TVC passive preamp anyone?
« Reply #1064 on: 20 Feb 2007, 01:25 am »
Mike B,

          We are of the same opinion.I also thought it sounded better with the top removed.Bloom, well tube bloom will always win out.That is why I strongly feel the Promitheus tubed pre [or buffer] will give us all the best of both worlds.
          After experimenting with my active as a buffer I see tremendous potential here.I trust that Promitheus strives for the presentation that we desire and has admitted that the TVC alone just can't do it all."the only time I will use the TVC alone is when I want to save electricity",pretty bold I must say.Actually very honest.
          There are many happy campers out there with the TVC as it is a hell of a piece to begin with.It will be a great piece with the active and also provide proper gain for different phono setups with out a step up transformer.
          As a vinyl guy this is a blessing.Very good stepups are hard to find for a reasonable price.Forget about the synergy issues,it could get very frustrating.
this active just simplifies matters.
rollo

Hi Rollo,

I do have an alternative. If you go to:

http://www.diyhifi.org/amplifierguru/guru_001.htm

and get the SKpre stuffed, and add a small transformer which should fit neatly in to the TVC. Each board could be stuck on each inside end of the TVC. Just juse one of the outputs, and wire it to the input of each board. I'm seeing if I can get Greg to remove the volume pots, and put a little toggle switch there for 0, and 6 DB. That whole thing is about $120. If you go to this website:

http://www.diyaudio.com/forums/showthread.php?postid=1126264#post1126264>

 You can read a review. Each board is about 2x3 inches.

Regards,
Ray

PromitheusAudio

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Re: Promitheus TVC passive preamp anyone?
« Reply #1065 on: 20 Feb 2007, 12:30 pm »
Ray,
        This version is a dual mono single box ref. model with 2 inputs and two outputs.The wiring is single run silver with buss for pos. and neg.
         I changed only the single output at this time only.I am trying one step at a time.I also do not want to modify completely until the new two box dual mono with copper wiring and no buses arrives for comparison.For demo purposes in the end I will have a silver version and a copper for those who may prefer either.
          Hopefully by next week the two box will arrive.Can't wait, it should prove interesting.
rollo

This is what Rollo's going to use once i ship this out


I made this with no Buss and copper wiring for the signal. I used silver for the ground to balanced the sound. I really like it this way. The dual box is better, thanks to Rollo for the tip. The copper wiring is the 7N Neotech. Really good.

Once i get more of this i will offer them in the future.

PromitheusAudio

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Re: Promitheus TVC passive preamp anyone?
« Reply #1066 on: 20 Feb 2007, 12:36 pm »
Good to hear TVC users are playing around with difft configurations and tweaks. 

This weekend I had the opportunity to check out Tim Babbs place & the Klipsch museum in his basement, his 2 channel set-up is simply amazing.  Huge Cornwall speaks, loads of tube gear and paul speltz's cabling...i had no clue 7 watts TOTAL could sound like that...pushing 15" woofers no less.   :o


Tim has a week old Dual volume control Reference TVC, the waxed finish with the Ebony knobs looks great Nick.   it wasn't possible to compare our TVC's accurately, but i do think the latest dual volume TVC's has better stereo separation than my version, which is a single volume control made 10/06.   the overall image seemed wider on Tim's, musicians more spread apart.  We had 3 preamps to compare: 2 TVC's and Tims Wright tubed preamp...the tubed pre bested the TVC's handily.   Keep in mind his preamp and tubed monoblocks (and tube phono pre) are from the same mfgr though - synergy.   

In my solid state system, the TVC has body and weight and soul and all that but in Tim's its quite difft, the TVC's both sounded a bit anemic in comparison.    This is my 1st experience with the TVC and tubed gear though...

My recent TVC tweaks:     After checking out Tim in the 'burbs I installed a set of Nick's Ebony knobs, and also placed some EAR Isodamp in between the chassis bottom and the L shaped Source Selector knob mount.  The Ebony knobs are at least twice the weight of the originals and feel great.  Also, there were 8 indiv screws in the bottom chassis, yet only 6 were in use, so I removed 2 screws and nuts.    Since i did these tweaks at the same time, i can't say what did what...but the overall presentation has more body, weight and warmth.  i'm extremely pleased...   If you have an early TVC with the Source Selector knob on the front, open the top cover to see if there's an L mount inside.  Adding isolating material between the L mount and the chassis does good things.  Vibrations from the transformers are messing with the selector switch, and our heads!

I received a 7" x 5" piece of this free from the mfgr:  EAR Isodamp C-1002-01     I cut 6 pieces about 1" square, laid them ontop of one another (1/8" thick) & then in the TVC.  Place the L bracket back in place I used a tiny allen wrench to pop holes in the Isodamp for the chassis screws to fit through.   This Isodamp is the thinnest EAR makes, thicker would be better so you don't have to make a sandwich like mine.    If you call, tell them you want to isolate a transformer for an audio project...and be real nice! 

This was the 1st time i'd opened up my TVC - the simplicity is really cool to me.  All the internal wiring coming out of the trasnformers look to be copper, and the buss wiring for the all RCA's looks to be silver.

A previous post mentioned substituting a wooden rod for the aluminum one on the Source Selector knob...I think this would be worthwhile as well.   isolating the L mount should be done prior to a wooden rod though.

The new Ebony knob would not fit on the Source Selector rod initially, but a few seconds with a 1/4" drill bit opened the hole so the rod slipped right in.   I figured this post would get dirty at some point!!

anyways, both the knobs and damping the L bracket from the chassis should be seriously considered for the early TVC's made... IMO



Hey Randy, Tim mailed out your knobs earlier in the week... don't force the Selector Knob.  Its a slightly larger diam than the Volume knob, which slid on with no problem.


matt   



I thought the dual mono's where much better than the single volume anyway. but once you go dual box its a different story all together. I believe even GHM has heard the difference between dual mono and single volume and prefered the dual mono.

Yes, once you hear a good active preamp, the tvc can sound aneamic with the wrong setupworse once you hear the active preamp and the tvc. You realise how much you are missing. I have always believe what you don't know can't kill you, once you have tasted the forbiden fruit, it is hard to go back.

Hence i keep on striving to acheive the better sound but instead of going all out on the tvc and i decide to go for an active partner to complement the tvc. Best of both worlds.

Pacio

Re: Promitheus TVC passive preamp anyone?
« Reply #1067 on: 20 Feb 2007, 12:50 pm »
Hello everybody,
I'm Marco and perhaps I'm the first future owner of the newly developed Promitheus Active Preamp! I've just placed my order to Nick and maybe you can call me naive, but once I got the reviews from Nick himself and Rollo on the use of the TVC paired to an active preamp, I could not resist..
I already have the TVC and I'm very happy with it, but you know the "upgradeitis" is terrible..and if I can find a way to make no non-sense upgrades, why not?
Let's see, I will keep you informed..
Cheers,
Marco

PromitheusAudio

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Re: Promitheus TVC passive preamp anyone?
« Reply #1068 on: 20 Feb 2007, 12:56 pm »
Would the active pre as standalone pre, be suited for my modified SB with only 1 volt output?   And what level of performance should I expect from this pre?  I mean , tubed power supply and transformer coupled does not ring any bells:P
   

Robert

For the active preamp standalone, i can install a volume control and yes it can be suited for the modified SB.

For the tube active preamps there are 3 schools of thought here
1) transformer coupled-AudioNote, Kondo, Supratek
2) normal - Bat and other conventional preamps in the market

WIth a transformer coupled preamp what you have is the transformer stepping down the gain as while as provide a "almost" constant loading for the tube. This type of preamp excel at needing minimal parts at the same type provide transparent and low output impedance. THe use of a single tube is enough to drive any loads. Output impedance of 30-600 ohms are easily achievable with a single tube. because of the single tube, the strenght of a transformer coupled preamps are good bass, transparent, good highs and good mids. One  and only drawbacks of the transformer based preamps is actually only (to my ears) is COST. On the list Supratek is the cheapest so far i have seen retailing at USD2.9K i believe. AN and Kondo is really not afforable more the latter. AN and KONDO stuff brand new is around USD10K++ and above. COst of a output transformer for preamp is around USD250+ and above for the transformer only. Cost only.

Normal preamps on the other hand, have either high output impedance 2K and above or low output impedance by the use of negative feedback or multiple tubes(bat) to lower output impedance. Cheaper to implement
IN short both types of preamps have their own cult followings and fans.

Tube power supply on the other hand is often used by both groups of preamp. THey offer a queiter power supply and the allow the swapping of tubes to tune the sound.

If you ask if the preamp should suite your SB the answer is yes.

Cheers
Nicholas

PromitheusAudio

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Re: Promitheus TVC passive preamp anyone?
« Reply #1069 on: 20 Feb 2007, 01:01 pm »
i wonder if Nick does trades??  aai think his tubed and phono would be good... :thumb:

Sadly no.

Our prices are low to keep this hobby fun and afforable


robert1325

Re: Promitheus TVC passive preamp anyone?
« Reply #1070 on: 20 Feb 2007, 02:05 pm »
WOW,  thanks for the long and clear answer :thumb:        This must be a very good pre then  :D

EDIT:   is it 500 including shipping?     And how much is your balanced powersupply? ( the small one),  Drop me a pm if you don't want to tell it on the boards...    I'll have to save up some money, your  products look very good!!!!!

GHM

Re: Promitheus TVC passive preamp anyone?
« Reply #1071 on: 20 Feb 2007, 03:19 pm »
Nick is correct. I have been listening to a dual mono version. It does seem to have an edge on the stereo version.

Strangely I find body and soul just fine in my system. I normally listen on the volume settings at 10 or 11 O'clock. Sometimes even 9 O'clock on some formats. My speakers are known to have a richness to them all by their lonesome. The tubed NOS DAC and and Promitheus TVC just compliment it. My speakers are 89dB sensitive.

My friend could really use the tubed gain stage. He normally runs his knob at 2 O'clock. So we're back to matching the equipment up. It is a balancing act. My amplifier was designed to run with a TVC. The builder also makes TVCs. This maybe the reason I'm not having any issues in the areas mentioned. I do love what tubes do for the system. That's why the tube DAC is in the chain. It gave me the meat on the bones I was looking for.

I may just buy one of Nick's active stages to play with. It will probably be more for my friend though as I know he could use it to its full potential.

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #1072 on: 20 Feb 2007, 03:41 pm »
Last night i removed the metal cover from my TVC, there wasn't any sort of shocking change.   As the night went on though, i might have detected a smoother presentation, i'll report back after more listening.

One thing that struck me though is that one group of tiny wires coming from 1 transformer actually runs across the top of the tranny to get to the volume knob, and when the metal lid is in place it touches those wires...maybe keeping the lid from touching the bare wires makes a difference?

one thing is certain though, removing the lid had no ill effects whatsoever.

Now that i've had a chance to get used to the Ebony knobs and isolating the Selector knob mount, i will state again these are really, really worthwhile tweaks.   The stereo separation is better, sound is smoother and richer...more fun to these young ears.    I'll start looking for a 1/4" dowel rod to replace the Selector switch's metal rod inside the TVC.

One thing i didn't consider was unscrewing the L mount and swinging it sideways...maybe that L mount can be screwed into the side wall of the TVC...or better yet held in place with heavy duty double sided tape, removing 2 more screws from the chassis.    anyone???

matt

rollo

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Re: Promitheus TVC passive preamp anyone?
« Reply #1073 on: 22 Feb 2007, 12:30 am »
Gooberdude,
                  Did you try using the albums under the TVC for isolation as you mentioned in the tweaks thread? You try the albums and I will try the 1/4" TH. cardboard[8 layers].
 rollo 

P.S.  You might want to try an ebony pen blank for the rod replacement in lieu of a wood dowel.

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #1074 on: 22 Feb 2007, 12:37 am »
I haven't yet, but last night i a pair under my cdp...same result.   :D  had not listened to my cdp in some time, its fun with the sub.

i plan to stick 'em under the isoblocks under the TVC and TT soon.  the TVC will get them 1st since its an easy set-up to dismantle.

Been flippin' through a box of LP's..hardest part is finding pairs w/the same thickness.

a few Eddie Harris LP's made the cut & fit dandy under the cd player.

next, place some on top of the TVC.

just kidding.

Have you been listening w/a tube pre in line with the TVC??

rollo

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Re: Promitheus TVC passive preamp anyone?
« Reply #1075 on: 22 Feb 2007, 01:05 am »
Gooberdude,
       I have been listening with both for a few days now. It is beginning to grow on me since I was able to find a volume level on both pieces that is acceptable.
       I can wait to hear Nicholas' active pre with the PROPER GAIN for my configuration. The new unit should be here soon and then I can fine tune the system to include the active.

stereohifi

Re: Promitheus TVC passive preamp anyone?
« Reply #1076 on: 22 Feb 2007, 01:43 am »
Hello to all, since  Nicholas products are from Malaysia, does somebody can share with us what customs fees, if any they had to pay, particually in Canada or US.
I,M looking for the whole pakage, balanced TVC + tube buffer, all to replace a very well known name tube amp.
Regards.

rollo

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Re: Promitheus TVC passive preamp anyone?
« Reply #1077 on: 22 Feb 2007, 02:35 am »
Hello to all, since  Nicholas products are from Malaysia, does somebody can share with us what customs fees, if any they had to pay, particularly in Canada or US.
I,M looking for the whole package, balanced TVC + tube buffer, all to replace a very well known name tube amp.
Regards.
 

I live in US no fees or duty.We have a free trade agreement with Malaysia.
rollo

Pacio

Re: Promitheus TVC passive preamp anyone?
« Reply #1078 on: 22 Feb 2007, 11:09 am »
Hello everybody,
sorry if I'm going slightly off thread, but speaking about Nick's TVC this seems to me the best place to post my issue.
I have my Ref. 3 TVC dual mono sounding too loud at the lowest level. I mean, during the day I can listen to it easily at 10 o'clock (maybe I can push it even at 12, but not much more than this..), but when it comes to late listening, I cannot simply listen to it not even at the first step. At complete attenuation I hear no sound at all but once I turn the knobs to the first step, then it's too much. This prevent me from listening while I do some "homework" at night or simply from letting my new set up to break in during the night.
Have you experienced this with your own TVC? What do you suggest?
I heard about Rothwell In-Line Attenuators, which should attenuate about 10 db the sound. The attenuators have some drowbacks like loosing some "life like" sound, some trebles smoothened, some lacks here and there but I would use them only at night and they would be removed for normal listening. (about 70 USD/pair RCA)
Any comments or suggestions on that will be much appreciated.
Thanks,
Marco

gooberdude

Re: Promitheus TVC passive preamp anyone?
« Reply #1079 on: 22 Feb 2007, 03:01 pm »
hey marco,

Try not to to use those attenuators.  i owned them, they are a good product, but several Elec Engineers warned me about their use...they could hurt your source in the long run.  i bought them to use in-line with my ipod and an old Marantz integrated but sold them soon after the dire warnings.  i did not use these with the TVC though...

Would it be possible to adjust the gain on your amp, or the output of your source?

Funny 'cuz many TVC users, inlcuding myself, have issues getting enough volume, not the other way around!


Rollo,

My TVC is now pulped.  I couldn't get the LP itself to fit, its a tight squeeze with the isoblocks and 3" maple board already.   But, i fit one empty LP cover under the Isoblocks, and the sound is fantastic... a smidge smoother in the hi-frequencies.

Honestly, my rack looks pretty cool now with album covers spread about...


For weeks my sub has been sitting on a set of the 2" MS footers w/o points (Heavyfeet) and when i disassembled my TT to install the covers, i decided to 'take from peter to pay paul' and installed the pointed 2" footers under the sub and listened with my cdp.  these damn sub tweaks!   the change is ridiculous, the speed of the sub increased bigtime and its control of the lowest registers is way more pronounced.  so bizarre that improving the subs performance can affect the entire spectrum of sound.   even the teeniest bass guitar string plucks are deep and visceral now, totally adding to the 3-D weirdness.  i listened to Jimmy Smith's 'Root Down' CD (re-issue on Impulse) twice last night.   the room where the recording took place kinda comes alive now - too much fun!