Unity gain with tube buffer?

Does anyone make a preamp with unity gain and a tube buffer? Seems like First Watt's B1 is like this with SS device - I'm interest in a similar concept but with a tube buffer stage.
Prometheous (spl?) does it
All The Best
Hi. If Promethius makes what I'm looking for, Idon't see it on their website.
Pubul57, we're working on one that will be offered through Ultra Violet Audio. Probably not a lot of help to you right now though...
Ralph, assuming enough gain (I don't seem to need any based on my previous experience with passives)is there a reason that an active stage with gain would sound better? It seems to me that less is more if it is enough.
I think the reference to Promitheus was for the Apollo preamp, but that uses the TVC with a gain stage (6 or 12db) which is not what you are looking for. I'm sure Nicholas could custom build what you wanted but that might be a bit risky.

It's possible that Jeffrey Jackson at Experience Music could help you. He has a lot of experience with the Intact Audio autoformers and incorporates them into his active preamp designs. Jeff is a big fan of passive linestages and if I were to have something along the lines of what you're looking for custom built for me he'd be near the top of my list.
Hello Pubu57

The simplest thing is to ask Nicolas at Promitheus directly. Of course they use TVC - and thus why their volume control is so good (at least for money there is no equal)!!!!! Gain of 6 dB will not kill you since my translation of what you asked - "can I have a tube preamp without gain stage" and answer is yes, you can.

On other hand, if Atmasphere will build one - this probobly will be the best around

All The Best
If Ralph builds one I will definitely be interested, especially since one of my amps is a pair of Atma-spheres and I assume it will have balanced connections. Clio9, I also spoke with Roger Modjeski who said he is looking into building just such an amp as well, and wood matched with my RM9SE -- so I may very well end up with an Atma and Music Reference version of these "tube buffer" amps. The Pass B1 Buffer pre we saw at RMAF was pretty impressive with the F5 amp. As an aside (the more I hear about your Kinesis speakers the more interested I am, they souned fantastic with the Atma-speheres at the show)
Talk to Ralph about the Audio Kinesis speakers. He has some interesting things to say about them. My Jazz Modules should be here in the next couple of days. Looking forward to getting rid of speaker stands.

I read up a bit more on the B1. Seems pretty interesting and makes me wonder why more manufacturers haven't done this.
It just seems to me (complete electornic laymen) that if passives are better than actives in those areas where they are better, that a passive with buffer (Placette Active for example)would be better than active in those areas as well -especially if the buffer is battery powered (less distortion with no gain stage circuitry, and great S/N being off the grid). Ralph's argument for the active seem to be generally based on the ability to control and drive the interconnect - I'm not sure why this buffered approach would serve that purpose without the need for gain that is not generally needed for digital sources.
With resistive passives controlling the interconnect is more critical. TVCs and AVCs less so (Ralph has this thing about transformers too - so that probably wouldn't be a convincing argument to him). However John Chapman's new design (6 input version) incorporates a buffer stage that can be turned on/off for each input. He comments that using it would be in extreme cases where a source could not drive the passive. No buffer on the output though, which the B1 incorporates in its resistive passive design (along with the input as well). Interestingly enough John chose to just make his TAP resistive passive mini modules with short pigtails that you place near the amp, eliminating the long cable on the output. Not sure how this sounds, but it's similar to the concept of the EVS nude attenuators which you just plug into the amps inputs (I have a pair which I should revisit using).

I'd have to say Nelson Pass's design is interesting and could be worth a try. It's certainly priced right. Just wish it had balanced inputs and outputs. Also, noticed that Nelson commented that a regulated power supply would be better than battery.
Pubul57, the AudioKinesis speakers are designed and built by Duke of AudioKinesis.

Although I prefer an active linestage **designed and built properly**, I do not question for a moment that TVCs and even a properly set up passive can do better than most linestages out there. IMO its a statement about how bad most linestages actually are.

John Chapman has a remote system that allows you to put the passive control right by the amp which with passives is really the only way to do it. The remote solves the issue of having to get up and adjust the volume on both channels every time you want to change the volume.

FWIW we offer a passive control option in our amplifiers...
Ralph, does your comment about TVCs and I assume ATVCs as well apply to pure attenuators passives (resitor-based) as well, or are they hopelessly compromised in terms of getting impedance matching optimized in most systems?

Can you elaborate more on the passive control option for your amps?

Since I have Duke's Jazz Modules coming (have the Stormbringers now) I have been considering the M60s (although the S30 was what I believe Duke voiced the with) as an option.

Clio09, I have a customer using Stormbringers with our MA-1s. He is delighted with them- gave up a set of Carver Silver Amazings. He thinks Duke's speakers are better in every way. In having heard his system, I agree.

We can install a volume control in the M-60 and MA-1. It is similar to the type that we put in the MP-1 preamp.

Pubul57, I am of the opinion that TVCs if done right can offer better performance than a passive, unless the passive is at the input of the amplifier. The best TVCs rival many good line sections, but the best line sections so far are still better IMO/IME and offer greater flexibility.

Thanks for the response. The volume control in the M-60 is an interesting option. Does this have to be done with a new unit or can used one be upgraded?

You comments on TVCs are also interesting. I had been leaning towards getting the new Bent TAP AVC (balanced version) but that will now depend on if I decide to move to the M-60s.
Clio09, only the newer Mk.IIIs can get the volume control option. The earlier units don't have the panel space.
If you desing a unity gain buffered preamp, what difference might there be between a tube buffer versus a SS buffer - are they both equally effective, does a tube buffer create a tube like preamp sound? What is the difference between the buffered approach and TVC/AVCs?
In this case the tube is driving an output transformer and the step down of the output transformer is why there is little if any gain. The output side can drive 50-100 feet of cable, balanced or single-ended. Yes, it will sound better than a semiconductor system- that does not change. The advantage of this system is that the transformer can be properly terminated so there is no ringing or frequency response anomalies, and at the same time the position of the volume control will not act as a tone control since it is buffered.
Sounds like an elegant solution for digital sources - less complexity should be better, or at least the idea of simplicity appeals to me.
my Red Wine Audio Isabella tube preamp has a switch
that allows it to run on 0dB or 12dB. in 0dB it is a tube buffer because it is not adding voltage gain. it is a seriously good sounding battery tube preamp and my version has the built in isabellina dac and it is a pleasure to listen to every day. not cheap but worth every penny, imo!

- Nate
How does using the Isabella without gain compare with using it with gain? I'm working on the assumption that the process of gain can only damage the source signal and if you avoid gain stages, you do yourself a favor assuming a proper impedance match between source and amp -- with or without a buffer. I just don't understand how adding gain to a signal, only to attenuate can possibly sound better than a signal that does not go through all that gain - how it can it possibly help matters assuming sufficient volatage form the source to drive the amp to full power. I've heard arguments regarding the controlling of various ICs which can present a capacitive problem for certain equipment, but isn't that addressed by having a buffer (tube or SS)?
hey pubul57,

the sound with the 0dB or 12dB setting is awesome but for my system, i do not need the extra gain and vinnie recommended that if i don't need it, use 0dB. some power amps do not have much gain, so using the 12dB setting is needed in order to get the music to play loud enough. or some sources dont have enough output voltage, like some phono stages when using MC catridges. but fi you can get the music loud enough with the 0dB setting as is the case for me, i see no point of using the higher gain setting.

I'm going to continue this thread on the Poll Active versus Passive thread to avoid duplication.