A Review of My Custom Designed Promitheus Transformer Buffer

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Early B.

About six months ago I sold my Promitheus TVC due to the gain issue that typically plagues all TVCs. Of course, I really missed the TVC sound, so I contacted Nic and asked him to custom build for me a transformer buffer which is essentially a TVC without the “VC.” I wanted the TVC sound and the ability to use the volume control (with remote) of my preamp. It's the best of both worlds.

The Promitheus Transformer Buffer (TB) arrived last week and I placed it between my CDP and pre/pro. It only has one set of inputs and outputs. It also has a separate digital input and output in case I decide to run a DVD player through the buffer or use a DAC or whatever. It also has a switch on the back to "turn off" the transformers. That way, I can toggle back and forth to determine the effect the transformers have on the music.

Below are my initial impressions of the Promitheus Transformer Buffer, but first I’ll quote from a review I did last year on the Promitheus TVC because all of it is applicable to the TB:

The TVC brings out all of the subtle nuances of the music. I like how it presents the music at very low volumes. Even at whisper quiet levels, the TVC has the bass and transient attack of a good active preamp.

The TVC has great tonality. Instruments sound natural and balanced. Equally impressive is the decay of instruments. In many solid state systems, decay is usually truncated, but the TVC creates a very natural decay that would make many tube amps envious.

The best aspect of the Promitheus is a lush midrange with no harshness whatsoever.

The Promitheus TVC is the best audio purchase I’ve ever made.


The equipment used with the TB are a pair of VMPS Tower II SE speakers, Bada HD-22 tube CD player (modified), Emotiva LMC-1 pre/pro, and Emotiva LPA-1 multichannel amplifier, along with DH Labs and MAC cables.

OK, so what was the before & after effect? Well, the sonic improvement was substantial, especially the decay of instruments as noted earlier. I can now decrease the volume on many of my CDs and still hear the dynamics and clarity. Most impressive is the accuracy of cymbals and bells. Also, live music is tremendously life-like. When the audience claps, it sounds like you’re right there clapping along with them.

I should add that the emotional impact of the music is absolutely breathtaking. Listening to female vocals is startling. The TB literally allows you to experience more music, not just hear it. Also, the sound is thicker and richer than the TVC I owned before. It has a lot more body and weight to it. The chassis for the TB is larger than the TVC in order to accommodate much larger and heavier transformers, which is the reason for the fuller sound. And I really appreciate the new honey–colored wood Nic is using. For my tastes, it’s more attractive than the reddish stained merbau wood used on the TVC.

The Promitheus TB is precisely the sound I wanted. I heard it before when I owned the Promitheus TVC, now it’s back and even better due to changes I made in my system. I also like the fact that the TB was very cost effective, especially for a custom made component. I like the plain brown box, although it needs a small logo or something on it. 

I experimented with the switch that turns the transformers "on" and "off." Yeah, it works fine. It's nice to have because you can choose what type of sound you want.  I'll experiment with the digital input with my DVD player soon and post the effect the transformers have on the sound of my HT system.

Final thoughts – the Promitheus Transformer Buffer creates an awesome, emotionally-involving sound quality. Keep in mind that I’m using an HT pre/pro and multichannel amp! A muscular two-channel amp is coming in the next month or two, and my system will likely sound even better. I’ll probably keep the pre/pro in the loop until I can snag a separate 2-channel preamp. I’m very satisfied with the buffer’s performance and look forward to listening to all of my favorite CDs again and again.
 

P.S. -- I'll post pics if someone can PM me and explain how to do that on this forum. Thanks.

munosmario

  • Jr. Member
  • Posts: 191
Re: A Review of My Custom Designed Promitheus Transformer Buffer
« Reply #1 on: 20 May 2008, 06:32 pm »
Early B, great review, actually excellent. How cost effective is this solution? Also, I assume you asked for the digital I/O option (not something that Nick threw in), what exactly did you had in mind? Right now you are using the TB as a buffer in the analog path between your CD player and Emotiva pre/pro. Does the digital I/O mean that TB can be used as a buffer (isolation transformer/impedance matching) in the digital path between two digital components? What would that mean (desirability and sonic benefit versus using TB in analog path) and could you please give a practical example of such usage you had in mind (type of digital equipment and connecting sequence)?

Cheers........................munosmari o

Early B.

Re: A Review of My Custom Designed Promitheus Transformer Buffer
« Reply #2 on: 20 May 2008, 09:35 pm »
Early B, great review, actually excellent. How cost effective is this solution? Also, I assume you asked for the digital I/O option (not something that Nick threw in), what exactly did you had in mind? Right now you are using the TB as a buffer in the analog path between your CD player and Emotiva pre/pro. Does the digital I/O mean that TB can be used as a buffer (isolation transformer/impedance matching) in the digital path between two digital components? What would that mean (desirability and sonic benefit versus using TB in analog path) and could you please give a practical example of such usage you had in mind (type of digital equipment and connecting sequence)?

Yes, the digital I/O is meant to be used as a buffer in the digital path between two components. I plan to place the TB between my DVD player and pre/pro and see if I'll benefit from any sonic improvement for home theater. I'll probably hook it up this weekend and report back.

NewBuyer

  • Full Member
  • Posts: 612
Re: A Review of My Custom Designed Promitheus Transformer Buffer
« Reply #3 on: 21 May 2008, 02:54 am »
I'm confused what the transformer unit you are using, is actually doing... is it just acting as a simple step-down transformer before your existing preamp, and thus attenuating source volume and reducing source impedance? Does it have a ground-lift switch? Was your CDP seeming weak in impedance previously and needing corrective measures? Etc... (you see what I mean)

Thanks in advance for any explanations you can give - my curiousity is driving me here! :)


Early B.

Re: A Review of My Custom Designed Promitheus Transformer Buffer
« Reply #4 on: 21 May 2008, 03:51 am »
I'm confused what the transformer unit you are using, is actually doing... is it just acting as a simple step-down transformer before your existing preamp, and thus attenuating source volume and reducing source impedance? Does it have a ground-lift switch? Was your CDP seeming weak in impedance previously and needing corrective measures? Etc... (you see what I mean)

Thanks in advance for any explanations you can give - my curiousity is driving me here! :)



Nic designed it, so he's probably the best person to respond to your question. I explained my rationale for pursuing the buffer and the results I obtained, so I'll leave the discussion about how and why it works to the techies.

 

munosmario

  • Jr. Member
  • Posts: 191
Re: A Review of My Custom Designed Promitheus Transformer Buffer
« Reply #5 on: 31 May 2008, 01:32 am »
Early B., no techies to the rescue yet. Hope Nick can at some point step in and clarify the full nature of this new child of his. The way a I see it, conceptually, Promitheus line stage product offering is as follows:

1) A TVC used instead of a conventional preamp.

If you have low gain problem you can use

2) a TVC connected to a Promitheus Tube Active Preamp (a two box solution plus the Preamp’s external power supply), or

3) an Apollo TVC Tube Preamp, which is the combination of a TVC and a Tube Active Preamp (a one box solution plus the external power supply), or

4) a TVC with the +6 dB option Nick started to offer recently (another transformer inside the TVC to perform the necessary additional voltage amplification); this is a cheaper solution that 2) or3), or

5) this new Transformer Buffer, which is a TVC without the volume pot(s) but with some number of optional inputs/outputs, connected to a conventional preamp (into any of the preamp’s line inputs, I assume); this is the cheapest solution if you already own a quality conventional preamp (basically, my personal case since I already own two high-end preamps, one tube and one solid state, the reason for my interest in this thread).

Early B., you say that the transformers in the T Buffer are “huge” (compared to those inside of your previous TVC, I gather). Did you ask for a C-Core option or those are conventional but more larger transformers required by the buffer (so the T Buffer is not exactly the equivalent to a regular TVC without volume pots)?
I look forward to hearing more about your experiences with the T Buffer.

Cheers,

Munosmario

Early B.

Re: A Review of My Custom Designed Promitheus Transformer Buffer
« Reply #6 on: 31 May 2008, 03:08 am »
Early B., no techies to the rescue yet. Hope Nick can at some point step in and clarify the full nature of this new child of his. The way a I see it, conceptually, Promitheus line stage product offering is as follows:

1) A TVC used instead of a conventional preamp.

If you have low gain problem you can use

2) a TVC connected to a Promitheus Tube Active Preamp (a two box solution plus the Preamp’s external power supply), or

3) an Apollo TVC Tube Preamp, which is the combination of a TVC and a Tube Active Preamp (a one box solution plus the external power supply), or

4) a TVC with the +6 dB option Nick started to offer recently (another transformer inside the TVC to perform the necessary additional voltage amplification); this is a cheaper solution that 2) or3), or

5) this new Transformer Buffer, which is a TVC without the volume pot(s) but with some number of optional inputs/outputs, connected to a conventional preamp (into any of the preamp’s line inputs, I assume); this is the cheapest solution if you already own a quality conventional preamp (basically, my personal case since I already own two high-end preamps, one tube and one solid state, the reason for my interest in this thread).

Early B., you say that the transformers in the T Buffer are “huge” (compared to those inside of your previous TVC, I gather). Did you ask for a C-Core option or those are conventional but more larger transformers required by the buffer (so the T Buffer is not exactly the equivalent to a regular TVC without volume pots)?
I look forward to hearing more about your experiences with the T Buffer.

Cheers,

Munosmario


I believe your assessement of the five options you outlined is correct.

Yes, the transformers are much larger and heavier than the TVC I used to own. In fact, the chassis is nearly twice as tall to accommodate them.

I'm really enjoying the TB right now. It's still breaking in, but the sound is very robust. I really like the flexibility to unit affords (i.e., I can still use a remote!). Last week I hooked my DVD player to the digital input of the TB and gota slightly cleaner and clearer sound.