Promitheus TVC passive preamp anyone?

NewBuyer · « **Reply #140 on:** 9 Oct 2006, 03:31 am »

Hey GHM, would you perhaps be willing to please post a picture of the internals of your TVC? I would really like to see what the balanced transformers look like in there... I think the lid is held on by 4 hex-head screws?

GHM · « **Reply #141 on:** 9 Oct 2006, 08:30 am »

Quote from: NewBuyer on 9 Oct 2006, 03:31 am

Hey GHM, would you perhaps be willing to please post a picture of the internals of your TVC? I would really like to see what the balanced transformers look like in there... I think the lid is held on by 4 hex-head screws?

Hi New Buyer when I get home from work today. I'll see what I can do. I wouldn't know the difference myself... But maybe you would. Nick mentioned he upgraded the trannies twice..not quite sure where I fall in at. Greg and mine should be a like..I think? Randy may have been the one with the first fully balanced trannies?

Good listen

denjo · « **Reply #142 on:** 9 Oct 2006, 10:27 am »

GHM
Read your listening comparisons between the Bent NOH and Promitheus with great interest! I had a hunch they would sound more similar than dissimilar. Because of the transparency of TVCs, I would surmise that differences would generally boil down to cables used for the trannies. The Bent uses AudioNote silver wires (not sure which ones). It would be interesting to find out what silver wires Nick uses with the Promitheus, probably Neotechs? Would be interesting to know.
Happy listening!

Dennis

PromitheusAudio · « **Reply #143 on:** 9 Oct 2006, 10:45 am »

Guys

THanks for the review, it really helps us to further improve on our product

As you know we are starting out fresh in this field.

At the momemt the new rev 3 transformers are better than the rev 2 units like what gymane compared with the bent. The rev 3 units address some of the review points mention in the earlier units we have shipped. This new version features a better focus and channel separation and more open highs. If i am not mistaken the bass definition has improve. This is the version that is to be shipped from now on. I believe Laurence and Randy's balanced unit sounds better and comparable to the Music first is because of this newer unit design.
here the new link Laurence just mail me
http://www.zerogain.com/forum/showthread.php?t=13988

Also bear in mind our tvc and all our products requires carefully footing. Hence the wood cones we supply together are voice as a complete unit. Gymane when you compared did you compared with the cones together?

Also just to let you know we are starting work on our own "non-oversampling dac" which would feature balanced outputs
THe dac will feature
1) separate power supply box. so it will be a 2 box approach
2) pre-regulator stage in the power supply box.
3) dedicated shunt regulator (for each ic) for lower noise
4) Our own nickel pulse transformer (this separates the ground thus resulting in a quieter music)
5) An output stage to convert se into Balanced and buffers the output voltage

Our estimated selling price with shipping included will be around 320-350usd. What do you guys think?

studley · « **Reply #144 on:** 9 Oct 2006, 12:13 pm »

Hi Nicholas

This is Ian in the UK (we normally converse by emails). Is my TVC that you shipped today the rev 3 transformer version?

The DAC sounds really interesting. Have you thought about a USB input, preferably with a direct conversion to 12S i.e. leaving out the spdif step?

Rgds
Ian

Randy · « **Reply #145 on:** 9 Oct 2006, 04:26 pm »

Nicholas,
I had an nonupsampling DAC for a while that ran on batteries made by a guy who was then a doctoral student at Northwestern University. I can't think of his name or the name of his DAC, but it had a great sound. It didn't offer balanced connections, however, which, as you know, I am partial to. Have you considered battery power for your DAC?

GHM · « **Reply #146 on:** 9 Oct 2006, 10:24 pm »

Looks like Nick has answered the question for me NewBuyer. Denjo, I can see why you like your TAP so much. If it is better than the NOH in sound quality..you have a stellar preamp!!

Nicholas I used the cones when listening to the Promitheus. I haven't had a chance to do much listening lately..work has taken my time. I still only have 50 or 60 hrs on the Promitheus. Your Dac by the description sounds KILLER!!! You need to hook me up with some of those monoblocks!

I plan to try the weather seal dampening this week. I'm curious to hear if it makes any differences.

Randy I envy you!

Good listening

PromitheusAudio · « **Reply #147 on:** 10 Oct 2006, 09:23 am »

Ian

All trannies are a rev 3 types. We stop making rev 2. I believe there were better and I actually scrap about 6 pairs of rev2 to change all to rev3

THe silver wires we used are no-brander but from germany. Really good sound at a very afforable cables. I believe the cables is pure (4n). This is the same pure silver that we used for our interconnects

Cheers
Nicholas

LordCloud · « **Reply #148 on:** 10 Oct 2006, 01:34 pm »

I currently have a non over sampling dac that I am in love with as well as a TVC linestage that I am even more in love with. If you can do the dac with a simple design and balanced outputs for 320-350 usd I will be one of your first customers. Throw in battery power and I will be in absolute heaven.

xsb7244 · « **Reply #149 on:** 10 Oct 2006, 06:30 pm »

anybody tried Promitheus Audio phono preamp, interconnect cables, and balanced power supply. also
new dac is a good thing. Will the new dac be able to compete with the Liteaudio DAC-60?

marvda1 · « **Reply #150 on:** 10 Oct 2006, 08:49 pm »

What specs do you look for in your power amp, source, speakers and a passive preamp to know if the passive will be compatible in your system?

marvda1 · « **Reply #151 on:** 10 Oct 2006, 09:29 pm »

How does the tvc compare to the sonic euphoria?

NewBuyer · « **Reply #152 on:** 10 Oct 2006, 09:56 pm »

Quote from: PromitheusAudio on 9 Oct 2006, 10:45 am

...we are starting work on our own "non-oversampling dac" which would feature balanced outputs
THe dac will feature
1) separate power supply box. so it will be a 2 box approach
2) pre-regulator stage in the power supply box.
3) dedicated shunt regulator (for each ic) for lower noise
4) Our own nickel pulse transformer (this separates the ground thus resulting in a quieter music)
5) An output stage to convert se into Balanced and buffers the output voltage

Our estimated selling price with shipping included will be around 320-350usd. What do you guys think?

This DAC looks quite promising. My questions (just at the moment):
- Will it have both se and balanced outputs, or just balanced?
- Will the output stage use output transformers?
- Does the design allow for passive I/V, and/or for multiple DAC chips in parallel?
- Can everything run in Class A mode?

By the way GHM, are you still willing to post pictures of your TVC internals? No big deal, just a strong curiousity about what these new trannies look like - If you do post pictures of them, I think these would be the only net-pictures of the new ones at this time(?)

GHM · « **Reply #153 on:** 10 Oct 2006, 10:09 pm »

Hi Newbuyer..mine are the version 2s like Greg's. I can post pics no problem. I figured you may have seen Greg's as he posted them in this thread several pages back. As soon as I finish watching this movie with it at the moment..I'll post some pics.

marvda1, not sure how it compares to the Sonic Euphoria. Which is a Autoformer type volume control not like the TVC. Maybe someone that owns one will test it out and give us a review?

PromitheusAudio · « **Reply #154 on:** 10 Oct 2006, 10:53 pm »

Hi
here's the new pics of the new tvc

Notice now its has the dual chamber of wires. Double the wires out

Coming back to the DAC

We are going to offer 2 versions one is the
1) solidstate output with xlr output and se output
2) valve output with output transformer(xlr and se output)

The design will used passive I/V and will run in Class A. Will be running with a single chip dac at the moment. Our reference for our design is the Audio Note Dac something we would like to bench mark with as i heard it perform a well balanced sound.

CHeers
nicholas

PromitheusAudio · « **Reply #155 on:** 10 Oct 2006, 10:58 pm »

Forgotten about this one

For the specs to look into, is your output impedance of your onix cdp and your input impedance of your power amp. That’s all

Considering it will have like most cdp an op-amp output then it is fine

best regards
nicholas

NewBuyer · « **Reply #156 on:** 11 Oct 2006, 12:08 am »

Ah sorry GHM, yours are version 2's - again sorry, my bad - I thought yours were the version 3 trannies! No worries, I can see the pics of those in Greg's post.

GHM · « **Reply #157 on:** 11 Oct 2006, 12:18 am »

Quote from: NewBuyer on 11 Oct 2006, 12:08 am

Ah sorry GHM, yours are version 2's - again sorry, my bad - I thought yours were the version 3 trannies! No worries, I can see the pics of those in Greg's post.

No problem Newbuyer.. even though I personally don't hear any short comings from the version 2. Come November I may take Nicholas up on the offer and send my unit in for the balanced trannies or just order another one.

NewBuyer · « **Reply #158 on:** 11 Oct 2006, 12:52 am »

Quote from: PromitheusAudio on 10 Oct 2006, 10:53 pm

...Coming back to the DAC
We are going to offer 2 versions one is the
1) solidstate output with xlr output and se output
2) valve output with output transformer(xlr and se output)
The design will used passive I/V and will run in Class A. Will be running with a single chip dac at the moment...

Thanks for posting these pics, what nice looking trannies! If they are driven by roughly 2k ohms or less, what would you say is the usable bandwidth of these trannies (say, within approximately +/- 1 db)?

About the DAC, can the solid state version have output transformers? I think this would be great for isolation between DAC and preamp. Both its se and xlr outputs could run through the output transformers. Poth audio uses Jensen output transformers mounted externally (yes, externally!) on their se DAC mod.

Will the DAC be filterless? No filter = no phase shifts. Interesting discussion at DIY here. Warning - that thread is over 100 pages long!

PromitheusAudio · « **Reply #159 on:** 11 Oct 2006, 10:12 am »

On the frequency response will look into that with the 2k loading. Normally bandwidth is 20khz to 50khz -1db with 1 k as i recall i can rescope it later today with the 2k load.

Yes the opt on the solidstate version will be a good idea. Will look into that

The DAC will be filterless so its receiver and DAC with a passive I/V and then output stage and then OPTS

Thanks for the tip

Anyway i just upload the method on how i made my own homebrew room lenz and my homebrew garrard 401 plinth. Check them out
http://www.promitheusaudio.com/garrard.htm for garrard
http://www.promitheusaudio.com/roomlenz.htm for the room lenz.
I was writing an email to matt and i thought i just stored it and lets others see

Cheers
nicholas