IVP Instrument Voicing Preamp... emulation?

[nordine]

hi guys,
i have a maybe difficult task, hope some of you can help me..

i REALLY like the sound of the "tube" setting in the IVP.. i know its a somewhat weird tube emulation, but i absolutely love it

is there a way to emulate it?
for what i know, in mark hammer's site theres this "Device" mag, in which the IVP is reviewed.... there one can see that the "tube stage" is comprised (obviously it has previous filtering stages, but i'm talking about its core) by just an IC, a 4558 i think

anyone?

[Ian]

I'm delurking now just to add that I'd also like to get a better idea what's making this particular sound. I've long coveted the IVP for its unique distortion, but my attempts at locating one of them on eBay have so far been fruitless, so I'm hoping someone with firsthand knowledge may chime in. I was actually looking at that issue of Device just last night, trying to get a better idea of what might be inside.

[George Giblet]

The secret is:

As I recall it was quite simple: A transistor differential amplifer driving a small transformer in push-pull mode, no EQ or anything else.

[Mark Hammer]

So wait a second, you're telling me that the secret weapon in a "tube-type" overdrive is transformer distortion?  Ain't that the most irony (no pun intended; well....maybe) I've seen in weeks.  All these years of trying my damndest to remind people that there is a whole lot more to what people think of as "tube sound" that the tubes.  If your comments about the IVP are accurate, I feel supremely vindicated.  I imagine RG would feel the same.

[George Giblet]

Put it this way, I have no  doubts about the general configuration.

To me there are a number of factors which create tube power amplifier distortion, not just one in particular - for example, changing the output tubes is noticeable so tubes cannot be removed from the equation entirely.

I wish someone could measure the DC resistances of the windings on IVP and perhaps the width or size  of the transformer - that would be a start.

I remember a  power transformer and a balanced line-out transformer on a PCB at the back of the unit  and a the small silver transformer on the main PCB, ie. the PCB with all the pots.

[Bluesgeetar]

Well hello!  Long time no hear from me.  I have now gotten into building tube amps and not so much into effects anymore.  But Nordine sent me a private since I own an IVP.  All I can say is wow you guys asked the wrong person.  I am totally stupid when it comes to complex circuitry stuff.  Even back when I was into the effects thing here, all I was interested in was simple 60s pedals clones.  FF RM MK2 etc.  Tube amp stuff is easy cause of layouts and such.  The guys over at Metroamp have turn building a Marshall clone into a no brainer.  Sock her together bias and rock. 

The most I can do is send someone here some digital photos of the insides.  It is chock full of little BBDs and all.  I wouldn't mind.  This forum was good to me when I was into this stuff and put up with my smart ass mouth.  Learned alot here.  So let me know. 

[Mark Hammer]

BBD's?  Since when was there delay on the IVP?  I'm confused.  Is this the same beast written up in DEVICE?

[Bluesgeetar]

I never saw that thing in device.  I know mine is big with a shit load of potentiometers.  It's a rack job.  black

[nordine]

I never saw that thing in device.  I know mine is big with a shit load of potentiometers.  It's a rack job.  black

here?: http://ampage.org/hammer/files/Device1-2.PDF

[leigh]

Thread Resurrection:

Has anyone ever found a schematic for the Intersound IVP? If so, I would love to see it!

Thanks,
Leigh

[christianbird]

Hi! I have IVP information on my blog - http://projectivp.wordpress.com/

I'm looking for help on the project (a clone / pedal), and would appreciate any thoughts or suggestions! Thanks!

Has anyone tried the SkreddZog circuit? Looks fun

[Mark Hammer]

Thanks!  A lot of good info there.

[teemuk]

Ok, sorta offtopic but let's give it a shot:

While peaking at the schematics I happened to notice that one of the designers of these things is "P. Hartley". Now I know that in the same time frame (that is from late 1970's to early 1980's) in Sheffield, UK there was a guy called Peter Hartley who ran Hartley Electric Music shop that not only performed amp repairs but also built the famous Hartley Thompson amps. Coincidentally those also feature a very similar transformer coupled tube emulation circuit, which was also patented.

Seems a bit too much to be a mere coincidence. Are these guys the same person? Anyone know the story behind this? There's not much written history about Intersound or Hartley Thompson amps.