Promitheus TVC passive preamp anyone?

denjo · « **Reply #1720 on:** 21 May 2007, 09:42 am »

GHM wrote:

"FWIW I spent several hrs over two days listening to the active stage. It was mediocre the first day. The 24 hour warm up made quite a difference. It made the music a tad more rounded and fuller.It was also very quiet...no hum or hiss. I find I prefer the sound without the unit in the chain here however. It was pleasant to listen too,but didn't make a staggering difference in my system. Gain was basically the same with or without it in the chain. As I stated previously, gain isn't a issue in my system.Maybe if I had more time with it things would have changed more. The unit looked to be used..I assume it was burned in.

I can see where the unit could benefit the right system. If you have a thin sounding system or a hot top end..it is just what the doctor ordered."

Like many TVC owners out there, I have often wondered if an active pre might be the panacea to a fuller, sweeter, rounder sounding system - the general premise being that TVCs can be thin sounding. Quite by accident, and while my amplifier was away for repairs, I tried another amplifier which reputedly had a lot more power and was quite surprised to find that my TVC sounded much more full bodied with the extra oomph of power than before. Previously, I found that my system with the TVC could do with a bit more bass and presence in the lower registers. I thought it was my speakers that lacked the ability to go low. I now know that it was not my speakers or preamplifier or cables or tweaks but the solution lay with simply having more power to drive the TVCs. Not only is my volume control on the TVC cranked lower to achieve comparable SPLs, the bass which my speakers pump out is just incredible. Don't let it be said that TVCs are thin or bass shy, it is not! As I discovered for myself, if you are not getting the fullness of sound from your TVC and before you rush to add an active gain in the chain, it could be that there is not enough power to allow the TVCs to reach its full potential.

I hope no one misunderstands that I am against an active gain. I am not, I am just suggesting that before you take that step and add another component into your system, you might want to look within your system and for some, you might find the solution lies with the power amplifier.

GHM · « **Reply #1721 on:** 21 May 2007, 01:04 pm »

Denjo,
I understand where your coming from. You state quite well what I was thinking. The source plays a role in this as well. The NOS Dacs are known for their fullness.They may not be as extended in the upper frequencies as the upsamplers or oversamplers,but fullness isn't a problem. Fred and I both use the same Dacs. He called me this morning to let me know at the present He prefers the sound without the active unit. Essentially our Dacs have a built in tube buffer, so adding another buffer to the chain doesn't make much sense here.
I wonder if your more powerful amplifier has more of a sensitive input.

gooberdude · « **Reply #1722 on:** 21 May 2007, 04:14 pm »

Denjo, you hit the nail on the head...

Over the weekend I sold a really cool pair of ASL tube monoblocks and as I was flipping back & forth between them and a belles 150A hot rod during the sales demo the biggest change was the bass....the tiny WAVE 8's have much better bass when compared directly A-B.

sources, amps, acoustic treatments, cables, quality AC current, speakers, etc...will all have a critical part in how we perceive the TVC.

For a while i've been contemplating getting the Active pre. I'm pretty sure i'm gonna hunt down a good tube amp instead...

rollo · « **Reply #1723 on:** 21 May 2007, 04:52 pm »

denjo,

Very well said. The Buffer/ Pre was designed to provide added warmth and that old tube magic to the mix. Is it for everyone? No it is not. With over 750 Hrs on the Pre. it is more than broken in. I have noticed as well that the Buffer adds fullness and a little more flesh on the bone presentation with a slight mellowing of the sound . What the Buffer adds to the mix is a better portrayal of the sound stage in depth, height and size. More lifelike. So its a trade off, like everything else in our hobby. The 6Db of gain the Buffer provides can be a blessing for your phono section if needed.
The TVC is as neutral as it gets. Sometimes a blessing sometimes not. The TVC will show you what your CDP is capable of for the first time. As you have pointed out, your amp as well.
So if you are looking for a straight wire with gain then its the TVC as is. If you prefer a little tube coloration go with the Buffer. As we can see from some who have posted comments on Buffer have mixed feelings.
Now you guys know I cannot leave things alone. With Nicholas' guidance I substituted the Aerovox and Phillips caps in the Buffer with V-cap Teflon caps. A major improvement. So why are they not stock? They cost mucho dinero, that's why. The Buffer is built to a price point and is well executed for what it cost. Actually it is a tweakers delight. So few parts to play with you can have some fun and obtain the synergy you are looking for.
It will be interesting to hear the comments from the Georgia tour. IMO it is a brave thing to do for a Manf. Actually quite smart, as the input from the end user will be incorporated in future product. Any negative observations will not kill the Buffer, it will help in making it better. Since there are so few parts inside any parts that are revised are easily user replaceable for previous owners. Can the Buffer be improved? probably but it will cost more.
Not for anything but at $500 for a buffer with point to point wiring , separate power supply, NOS parts, in a wood enclosure and easy top tweak it is a bargin IMO. Even the $10,000+ Preamps are tweaked, go figure.
So in essence what we have here is a TVC as a stand alone piece or a complete Preamp without phono [ combo ], two ways to go. So the choice is yours. Different strokes for different folks. It is wrong to say everyone will benefit from the Buffer.
It is good to see that Promitheus is covering all the bases for our choice in our systems, how refreshing. So play away buckaroos, that's what its all about.
Nothing in this hobby is carved in stone as we all know. Just nice to see we have alternatives. I am keeping mine.

rollo

GHM · « **Reply #1724 on:** 21 May 2007, 05:09 pm »

Well said Rollo..I find the active unit and it's power supply VERY well built. Certainly well above the $500 price point. I was amazed at how transparent this combo is. If I had to choose a tubed buffer ..this would be it. It makes the Musical Fidelity tube buffer unit look like a toy!
This is a hefty little combo! I'm sure it will be the missing puzzle for some. Hopefully EarlyB will get a chance to try it out next and post his comments.

Good listening

Say · « **Reply #1725 on:** 22 May 2007, 04:22 am »

Reference Dual Box Mono TVC: 40 hour report.

After a brief vacation I'm back to burning in the TVC.
In general an audio component's burn in takes up to a month or more of regular playing. I'm not only running in the Promi but a couple of new additions as well. The added components are a Marantz SA15-s1 cd/sacd player and Nordost Valhalla interconnects. Glady, the intial shock and awe of newly added components is beginning to settle into normalcy. Thats definitely a good thing. The usual tizzyness and hype has mellowed already.

This mini review is not only about the TVC but the break in period of the above mentioned three components. I already had a baseline to judge the cd player for about two weeks beforehand. Very good clarity top to bottom. Base is sharp and quick. Not too deep as of yet though, as this was veryfied by playing it with the Conrad Johnson Premier 14 linestage. The Valhalla ic's are loaners from my brother and have already been broken in. Yet they could use a dose of father time too. Now onto the Promi.

This Dual mono TVC sits on the accompanying ebony footers. I was surprised and pleased that they were of moderate girth. The picures do not do them justice. Regarding the Promi both mono units share space on the top shelf of my rack. Little Mpingo disks resonate on top of each unit. Being made of ebony, it seems like a decent match.
For starters, this system is the real deal. It throws a huge soundstage back to my neighbors house! The depth is amazing. I didn't think this could be the case. Not after a very good soundstage by the CJ unit. Not only that but the presence is magical. Cymbols, snares, bells and fast strings are all there in abundance. A palpable mid bass is beginning to bloom. I have a hunch that this vital area of musical pleasure will only grow in abundance with more time on the system.
Onto another important part. After briefly trying the TVC with Anti-IC's and Kimber KCAG's I moved onto the Nordosts. The Anti's are pure silver with Bullit silver plugs. They are the definition of detail. Yet they let in RFI to the point of picking up extra noise. The single-ended Kimber's are balanced through and through. However, I was really bowled over by the improvement that the Viking afterlife provided. Two sets of single ended Valhalla interconnects brought my system to a level previously never reached. (The speaker cables are Highwires as I was too ashamed to ask my brother to also borrow his Valhalla speaker cables).

40 hour details. Bass is getting more profound. Still some minor wandering. Yet more tasty mid bass is already showing, especially after placing four pulsar points under the Monster power conditioner. Go figure. A definite improvement over the little brass footers from audiopoint.

The midrange and above is of pure unadultrated beauty. Vocals are there in your room with you. Clear as a whistle. Background details from any disk is picked up with clarity. Perhaps this has to do with the lack of a noise floor from the TVC. Wherever it "doesn't" come from I'll take it! The TVC just lacks noise. It doesn't color the sound. It let's in all the good stuff. Assuming you give it some TLC. Nice, TLC for the TVC. lol!

Expectations with more burn in? I expect more of the same. Thats about it really. I'll have to report once again with more time spent.

One more thing. The musical decay that a few have talked about needs a revisit simply because it's top notch. If it's on the disk it will reverberate to silence as intended.

Now aint this an exciting hobby?

daz_bike · « **Reply #1726 on:** 22 May 2007, 04:42 am »

Say,

Thanks for your initial thoughts. I have a dual box mono that I am burning in. I'm at the 250hrs mark, however I will wait for the full 400hrs before being critical. It is good to get a blow by blow of the burn in process if you feel like posting this.

Do you have the double Silver wire? I presume that this is a standard option now? I have plenty of body from top to bottom so I attribute a large part of that to the double wire option.

I have had my TVC's on Tuneblocks from day 1 (Graphite with Tungsten Carbide bearing) and I haven't really tested how they affect the sound. Partly because I know they work very well and secondly the preamp is sounding very good even though only just over half way toward the 400hrs +. I will evaluate that after burn in.

Another thing I want to look at is separating the boxes a bit further apart than I have at the moment to see if that has any effect. One thing you can only do with double box. Some mention that taking the top cover off improves the sound. Anyhow there are a few more things to evaluate once the unit is broken in.

Finally if you have multiple inputs I suggest to uses shorting plugs in any vacant RCA sockets as the vacant inputs pick up a lot of noise in my system.

Cheers

rollo · « **Reply #1727 on:** 22 May 2007, 03:18 pm »

Say,
Good news. Now go get some Black Hole Pad and install on the three exposed sides of each trannie and fasten your seatbelt. This is a must tweak the bass and soundstage improve dramatically. Its just a no brain-er. Try the ebony cones without the brass cups and see what it does for you. You may be surprised.
Well another happy camper, enjoy!

rollo

gooberdude · « **Reply #1728 on:** 22 May 2007, 03:53 pm »

I can back-up Rollo's claim with the Black Hole Pad on the tranformers 100%. best TVC tweak i've done...

Say · « **Reply #1729 on:** 22 May 2007, 05:56 pm »

Quote from: daz_bike on 22 May 2007, 04:42 am

Say,

Thanks for your initial thoughts. I have a dual box mono that I am burning in. I'm at the 250hrs mark, however I will wait for the full 400hrs before being critical. It is good to get a blow by blow of the burn in process if you feel like posting this.

Do you have the double Silver wire? I presume that this is a standard option now? I have plenty of body from top to bottom so I attribute a large part of that to the double wire option.

I have had my TVC's on Tuneblocks from day 1 (Graphite with Tungsten Carbide bearing) and I haven't really tested how they affect the sound. Partly because I know they work very well and secondly the preamp is sounding very good even though only just over half way toward the 400hrs +. I will evaluate that after burn in.

Another thing I want to look at is separating the boxes a bit further apart than I have at the moment to see if that has any effect. One thing you can only do with double box. Some mention that taking the top cover off improves the sound. Anyhow there are a few more things to evaluate once the unit is broken in.

Finally if you have multiple inputs I suggest to uses shorting plugs in any vacant RCA sockets as the vacant inputs pick up a lot of noise in my system.

Cheers

daz_bike, I haven't removed the steel tops of the units as of yet. I don't intend on tweaking anything other than footers till the 400 hour burn in is complete. However, I did order the top of the line dual monos. So whatever Nick put in there is probably the latest standard stuff (balanced and unbalanced). I didn't short the plugs but I did put on some cardas caps I have laying around. Would shorting be a better thing? I don't know cause the darn units are dead quite.

I also tried some ERS paper to see how it may effect the nasties from the transformers. It did remove a bit of noise but too much so so, in effect, it's not necessary.

Thanks for the added advice rollo and gooberdude! The black hole pads are damping material. Such items do tend to tighten things up. Being that you guys are tweak-a-holics I will take your experienced word and order me some.

This is one tweak that I'll order now and place onto the transformers once the testing period is over.

Big Red Machine · « **Reply #1730 on:** 22 May 2007, 06:15 pm »

Any Apollo user reports yet?

1000a · « **Reply #1731 on:** 22 May 2007, 09:02 pm »

where does one get this black hole pad?

gooberdude · « **Reply #1732 on:** 22 May 2007, 09:04 pm »

Search on-line for it... I have ordered some from Speaker City in California but i don't think it was in-stock, been waiting a few weeks now.

If you can't get it local, consider a group buy. Its only $7 per sheet but shipping is $12, so it makes sense to buy a few sheets and share.

rajacat · « **Reply #1733 on:** 22 May 2007, 09:27 pm »

Quote from: gooberdude on 22 May 2007, 09:04 pm

Search on-line for it... I have ordered some from Speaker City in California but i don't think it was in-stock, been waiting a few weeks now.

If you can't get it local, consider a group buy. Its only $7 per sheet but shipping is $12, so it makes sense to buy a few sheets and share.

I think that the Black Hole pad is the same as mass loaded vinyl offered at http://www.soundproofing.org/infopages/flooring.htm.
They have the adhesive backed pad also.

Raj

gooberdude · « **Reply #1734 on:** 22 May 2007, 09:49 pm »

Its not even close! Black hole pad is difft than simple mass loaded vinyl.

The soundproofing.org site is great though, those guys helped me design a 3500lb soundproof barrier between me and my neighbors... they are a 70 year old couple who have been owners in my bldg for 30 years & sleep a few feet away from my stereo. thanks to the guys at soundproofing.org, and a hell of a lot of 5/8" drywall, i haven't had a complaint from them in almost 4 years & i play it loud often enough, especially late night.

Before 'the wall' went up i could hear the sheets slide off their bed...

the most interesting part of my wall is that the final 5/8" layer is suspended via the generic Isoblocks that the site sells. 3500 lbs, 3 separate layers, not a single screw...

rajacat · « **Reply #1735 on:** 22 May 2007, 09:57 pm »

How is it different?

pardales · « **Reply #1736 on:** 22 May 2007, 11:39 pm »

Whoever is the first to get one of the new Promithues DAC's should begin a thread about it. Maybe call it....."Promitheus DAC anyone?" Just a suggestion.......

I am looking forward to hearing about it.

dgotlse · « **Reply #1737 on:** 23 May 2007, 05:38 am »

Quote from: gooberdude on 22 May 2007, 03:53 pm

I can back-up Rollo's claim with the Black Hole Pad on the tranformers 100%. best TVC tweak i've done...

Hi, could you provide us with some pictures of your mod?

1000a · « **Reply #1738 on:** 23 May 2007, 06:24 am »

Quote from: pardales on 22 May 2007, 11:39 pm

Whoever is the first to get one of the new Promithues DAC's should begin a thread about it. Maybe call it....."Promitheus DAC anyone?" Just a suggestion....... I am looking forward to hearing about it.

its already started:

http://www.audiocircle.com/index.php?topic=41093.0

Who has ordered (if you'd let us know) and are waiting for a Promi DAC to arrive either SS ot tubed? Are we (and me) all waiting each others feed back and no one has ordered one?

1000a · « **Reply #1739 on:** 23 May 2007, 06:40 am »

Rollo, seriously just how big a foot print do you speculate this GM70 will have?

Did anyone not get a laugh out my commentary on rollos post below, humor my trifling insecurities.

Anyway I thought it was funny.

Quote from: 1000a on 21 May 2007, 06:23 am

Quote
Hey Guys,
Well trip to Malaysia was delayed to 6/12 due to getting a passport. It sucks but I am still going. Nicholas invited me over for a listen. Should be fun. He will have his personal GM70 amp with"C" cores ready for a spin. He said the power supplies are 27"x 13" alone. Wow!.

rollo

Well I finally figured out how to do a quote on the forum, but this amp is really starting to vex me. Hmm lets see 27" x 13" for the power supply, OK that would make the jabberwalkie about Hmm? What the.........., how in ........, well lets see I must of calculated wrong, if the skyhook part is 37.7" the plutonium mixer-black hole deconstruct-er must be ah 98" by say.........?, Oh I was afraid of that, dam the bad luck!

Yep, I gotta buy a different house first!