V-Stack Valve Stack Simulator

[analogmike]

Hi,

I have not seen this topic brought up here (tried a search too).

http://www.v-stack.com/tech.htm

"State-of-the-art circuit design, based on an exclusive proprietary analog custom microchip, makes it the ideal self-contained and portable vintage guitar tone solution for recording, practice, or performance alike.

The signal processing stages of the V-Stack consist of a treble booster section followed by a valve amp simulator consisting of three stages: preamp, tone network, and output stage.  The final processing stage is a guitar speaker simulator, which rounds out the amplifier tone and adds an extra degree of realism for direct-in recording.  Due to the large amount of available signal gain, a special high-isolation audio multiplexer circuit is required to handle the bypass function.   The V-Stack is based on a proprietary analog custom microchip (Fig. 2), which combines state-of-the-art high performance analog signal processing techniques with low power circuit design.  The low power consumption of the resulting circuitry allows the V-Stack to operate for typically 500 hours or more using a 9V alkaline battery."


I have been enjoying the posts about the runoffgroove tube tube amp emulations. I wonder if V-STack did something similar but burned it into a single chip w/speaker emulator to make production simple?

Has anyone tried the v-stack and/or looked inside? Sounds like a cool thing for practice and recording.

[bobbletrox]

good golly.  

from google:

The AC7303 custom chip was named in recognition of the 30 years of evolution represented by these two designs, although the design of the chip itself is flexible enough to have potential applications beyond its first use as the core processing engine of the V-Stack

[Gary]

I have been enjoying the posts about the runoffgroove tube tube amp emulations. I wonder if V-STack did something similar but burned it into a single chip w/speaker emulator to make production simple?

Wow.  I didn't know this existed. This had to be around for awhile, since they have a proprietary chip.   I hope they used jfets internally.  I really think they are key to a better sound.
Nice link, Mike.

[Doug H]

I first saw this thing sometime last year. First boutiquer I've seen use an ASIC. It's an interesting approach, but you can see it's not really that far off from the amp emulation ideas that have been tossed around here for years. We've just been doing it with discrete components and without all the options for different "flavors". The switchable treble booster is a nice idea too. I think I first saw that idea a few yrs ago on the "Ballz Booster" which isn't posted anymore.

Doug

[R.G.]

If I had to bet, I'd say that this is our friend Stephan Moeller's Vox AC30 emulator "printed" into an analog master slice or one of the field programmable analog arrays. The timing, description, and even naming is too fortuitous to be otherwise.

Customization of an analog programmable chip does not imply proprietary chip, other than what fuse links got burned. It's in the same category of complexity as programming a PIC.

[petemoore]

To the next interesting 'old' theory to explore...
 Rangemaster INTO Vox...using todays available components to emulate this...
 For starters an interesting test would be to try a Rangemaster into a Matchless Type Jfet circuit...into-something.
 Suggested goal: A great sounding Sim, to get you close Rangemaster into Vox AC30 type sound.

[Tony Forestiere]

Has anyone hit the home page and checked out the sound clips? Some good, some... :?
They also have a "Brian May" setup.
Let us know what you think.

[Ed G.]

The clips sound pretty damn good for recording direct. Just the circuit for the speaker simulator could be handy.
Overall, I like it better than any POD product I've heard.

[MarkB]

You know, RG...  you may be right.
Since there is the BHM Edition - designed to sound like a Vox.. hmmm

Coincidence?

Anyone compare the sound clips with Stephan's?  
"-)

[changes]

where can i find a schem for the Stephan Moeller's vox emulator?

[MarkB]

I think he took it offline... he used to have a schematic up (without some values), and you could email him and sign an NDA to get the rest.

We're not sure - but we think he sold the design, since he stopped responding to the emails.. and took the schematics down.

Not sure if Stephan lurks here at all anymore, but if he does - perhaps he could enlighten us..
"-)

[RDV]

I'll just be damned!! That thing rocks!! Those samples are really good. The Led Zep one gave me chills, so did the Queen one. I may actually buy one(rare for me, I'm cheap).

I've been finding that when I build something with lots of gain & EQ options that it's not interfacing well with my live rig. If I buy one of these, to get it to sound good me thinks I would have to totally kill any kind of preamp distortion in the amp channel. I've run into this problem with my Heavy Meatal Pedal I just designed(w/ a great deal of A. Hermida's help & one of R.G.'s articles). It rocks the casbah when you run it into a clean amp or direct, but is really compressed & lacking dynamics when run into a moderately overdriven amp channel. I guess that's why Tube Screamers & Fuzz Faces are so great, cause they work so very well running into some preamp grind...

Regards

RDV

[analogmike]

I've been finding that when I build something with lots of gain & EQ options that it's not interfacing well with my live rig. If I buy one of these, to get it to sound good me thinks I would have to totally kill any kind of preamp distortion in the amp channel. I've run into this problem with my Heavy Meatal Pedal I just designed(w/ a great deal of A. Hermida's help & one of R.G.'s articles). It rocks the casbah when you run it into a clean amp or direct, but is really compressed & lacking dynamics when run into a moderately overdriven amp channel. I guess that's why Tube Screamers & Fuzz Faces are so great, cause they work so very well running into some preamp grind...
RDV

Yes, I don't think the V-Stack will work really well through a guitar amp that already sounds "good", i.e. a vintage tube amp. Plug it into a keyboard or PA and it would probably sound it's best.

[Brian Marshall]

I vowed a couple years ago never to buy a direct recording type thing again.  I had a pod, and sold it, and have never found anything better, but the damn thing was annoying.  the shape of it made it very akward to use.  I have been using a boss gx700 and a red box pro.  the combonation actually sounds pretty good.

I am however working on my own right now.  A two channel (possibly with a booster, we'll see if there is room) with a direct out, and amp out.

I have found two things to be of key importance..... multiple gain stages, and watch the upper harmonics.  My newest pedal, the Liquid Sunshine, was actually a byproduct of this project.

Brian