http://www.musiciansfriend.com/stupid/
 
I was reading about it and along with the standard listed stuff I found this in a post on the GS forum, re: the "Starved plate voltage. Seems it has a high voltage mode. I guess this model has been out for about a year so. It looks like a pretty good deal... as deals go.
 
As I promised more into:

"Hello Stephen,

Here is a promo sheet for the model. The main differences are tighter screening on tube selection, the gold plated connectors, and the cosmetic changes.

I hope this information is useful, please let me know if I can help further."

Nice to know some details....Then I asked about the ever looming question about starved plate design. This is what Thom had to say:

"Hello Stephen,

No, we think the 50 volts we send to the plate is perfect for the sound we are hoping for! Since it's appropriate to the circuit, I would say it's just enough. But yes, some people would call that starved.

The MPAII, and this new reference series version also offers choice for people though; the overload qualities are like the ProMPA in the "NORMAL" voltage mode. There is also a "HIGH" voltage mode has more headroom. Also, in the "HIGH" voltage mode there is a sharper transition to saturation/clipping than the "NORMAL" mode so, personally, I still prefer "normal", but it's good to give people options."

Sincerely,
Thom Davis
***************************************************
Technical Services
Applied Research and Technology

A division of Yorkville Sound

I'm of the opinion that it is the iChips surrounding the tube that define this preamp's sound and that it really doesn't matter how many volts are on the tubes plate.

Most tube preamps use the tube stages for voltage gain.

The tube in the ART adds very little voltage gain the solid state stuff surrounding the tube does most of that. The tube is used in a cathode follower differential circuit that negates or filters most of the tasty tube like harmonic distortion added by the tubes 1st stage. 

It doesn't really matter what sort of power supply is on the tube, you'll be listening to the sound of the very same iChips that are found in Mackie and Behringer mixers and most of the cheap I/O boxes on the market.

At $399 it seems like a very expensive way to fill 2 rack spaces and end up with the VLZehringer sound... but people love it!!! 

At $199 the VU meters are starting to look pretty darn cool for the money.



best regards,
mike

what exactly are the "iChips"?

Slang for integrated circuit chips.



best regards,
mike

ah. 

I have been interested in this unit simply because it has the high voltage selection.  but what you're saying is that the "high voltage" is not really high voltage at all (50V is NOT high voltage for a tube) and that the gain is not really affected by the tube, that it only adds distortion like any other starved plate design?

I'm curious what the "high voltage" selection actually does then?  marketing?

Reece,

the art unit seems a bang for the buck item.  Won't replace your tube tech gear, but it has a good reputation.  I'd get one but don't really have a need for it.

I got the single channel mP DI/Preamp unit.  It didn't work on arrival- very little signal.  Until I opened 'er up and resat the tube which had shaken out during shipping (it hasn't come out since).  I drag it to live shows since it works well on bass and is a nice splitter unit, too.

What Mike is saying is that it is a basic IC preamp like in any interface.  The signal then goes through the tube.  The MP gets very ... fluffy when driven.  It can be a good sound.  I don't know how the full plate sounds - I've never even played with them.  I don't imagine it would work as well as an expensive tube preamp with high quality electronics surrounding the tube.  And starved plate units (I've got an old presonus interface w/ such tubes) tend to ... sound distorted when driven hard.  Not the nice hair of saturation you get on a high end unit, but spikey stuff.

But as a preamp that is solid and has some flavor by driving the tube (a little) many people like it.  A stereo preamp that is probably a half step up or more from your interface's preamps with some "tube flavor" on output is a good deal if you need more preamps.  As replacements you probably aren't going to see a night and day difference in sound, unless you use the tube and that is a judgement call on your part.  It could work very nice on some things like the mp on bass (there was a funny gearslutz thread where people like it more than a high end bass DI until they found out it was ART).  Anyway, you aren't going to do better for $100 a channel.

@

Basically what AT said.

The starved plate lowers the headroom... which isn't a big problem because the circuit doesn't need much headroom there. Increasing the voltage on the plate may add headroom... but it's not a huge benefit because the circuit doesn't use it very much there.

Most plain old tube preamps get by with a fraction of the parts found in the ART. Many old tube preamps sound clean and smooth. Like regular old preamps doing a good job. 

In fact that's why I stop by to make comment because I find it interesting that some companies can sell the sound of a strained 4558 iChip (or some similar item) and find an audience that considers that sound to be associated with the tube seen inside the box. It's the same solid state iChip sound you get in an Ibanez Tube Screamer pedal.

If you are after a sound like that the ART will get you some.


best regards,
mike

so the extra voltage on the plate is only supposed to add "headroom" in the gain circuit of the starved plate design?

I think the guy quoted above says it best.

They had a circuit that they liked... it was pointed out that it was starved plate.

They made an option to put something like 200 volts on the plate.




Very few people get to the point of asking how a differential circuit adds any useful distortion to the sound.




I wouldn't try to make sense of it... it's a complicated sold state preamp with a tube sitting in there.

People love it.



best regards,
mike 

[shrugs]
I'm not sure I understand the usefulness of adding extra voltage to a starved plate design.

my interest in this unit is a lot lower now.  I have a TPS II, which is a starved plate design and it's not a bad unit for the price, as I'm sure this is as well as AT says, but I'm not sure that the extra voltage is as appealing as I would like for it to be.