Millenia hv 3

Anyone familiar with one of these and the circuitry. I am wondering how the transparency is achieved and what we have that is close in a diy format

[quote author="josan"]Anyone familiar with one of these and the circuitry. I am wondering how the transparency is achieved and what we have that is close in a diy format[/quote]

Hmmm I use one very often...To much work keeps me from getting deeper in to this HV-3D 8 #ch baby. Only thing is everything that seems important does not have any numbers..(sandpapered away), or something else..*GGG* yes it´s been open..*he-he*

I only knows how it "sounds"..

Kind regards

Peter

...

I was going to post pics of the guts of this thing but never got around to it. Can you?

Anyone have an idea how they implement the 130V supply for B&K mics? Voltage tripler?

Michael

thanks for the replys I didn't realise that Fred had designed for Millenia
so I read the disclaimer on his site. The double balanced pre does look interesting I wonder if anyone has done one and got the trimmer values for the middle stage.

I also have only heard one and not used one so i have not been able to see the guts of it.
I 'll keep this one one the burner

[quote author="Winston O'Boogie"]Fred Forrsell has a schem on his site that is, I believe, a double-balanced pre. It's the basic circuit that Mr. LaGrou adapted somewhat and then claimed it as his own.[/quote]

Hi Winston (er, John),

Thanks for taking an interest in the HV-3. I'm not sure I've ever "claimed as my own" the HV-3 topology. The HV-3 "Double Balanced" topology was conceived by Graeme Cohen at Philips in Australia in the early 1980's. I can send you a copy of the original white paper, if you wish. On the Millennia web site, I give full credit to Mr. Cohen's brilliant work.

http://www.mil-media.com/docs/articles/preamps.shtml

In my recent mic preamp lecture at AES NY, I passed out Graeme's original white paper to those in attendance. I gave a similar lecture a few weeks ago at AES Berlin, but unfortunately did not have any papers to give out. My original design efforts circa 1990-1991 found the "Double Balanced" topology to be ideal. I tested scores of iterations with countless active and passive component and layout -- along with a few subtle design variations. My test criteria can be found here:

http://www.mil-media.com/docs/articles/design.shtml

I later focused on power supply, layout, grounding, and electro-mechanics, making the HV-3 as sonically neutral and dynamically stable as I could. I?m honored and somewhat overwhelmed to say that we're now approaching 16,000 channels shipped. Moreover, the HV-3 user list has grown to be a who's who in professional recording, with a strong weighting in classical and critical acoustic music -- engineers whom I consider to have the most discriminating ears.

I would be surprised if you found an HV-3 schematic on Fred's web site. I understand he has quite a grudge against me personally, but I don't think he would do something that petty. You know, a number of preamps sold today follow the Cohen topology, so I wouldn't be surprised if Fred has recently developed his own "Double Balanced" micamp design.

What I can tell you is that the HV-3 front-end is a collection of large-geometry, tightly matched discrete bipolars with monolithic comparators. Cohen used LM394 transistor arrays, but I didn't like the sound of the 394 in this application. In fact, I've never heard a 394 application that sounded musically correct. The HV-3 output stage is class-A into most loads, and based on monolithic FET topology. Except for phantom blocking, the HV-3 is entirely DC-coupled without servos, including a DC-coupled output stage.

In my opinion, the benefits of Cohen's "Double Balanced" mic amp design outweigh every other mic amp topology I've encountered, to date. WRT accurate performance, DB has many advantages and few tradeoffs. If color and personality are the goal, I would certainly be looking elsewhere, such as transformers and creative actives. Speaking of which, are you still at UA? What are you up to these days?

Best wishes,

[quote author="mfilter"]Anyone have an idea how they implement the 130V supply for B&K mics? Voltage tripler?

Michael[/quote]


Michael,

The HV-3 130VDC supply is derived via a separate transformer winding, FWBR, regulated, and well filtered at both source and destination. More information here:

http://www.mil-media.com/docs/products/bk.shtml

Best,

[quote author="josan"]thanks for the replys I didn't realise that Fred had designed for Millenia
so I read the disclaimer on his site. The double balanced pre does look interesting I wonder if anyone has done one and got the trimmer values for the middle stage.

I also have only heard one and not used one so i have not been able to see the guts of it.
I 'll keep this one one the burner[/quote]

Josan,

The original Double Balanced topology is two-stage (gain and driver), so there is no "middle stage." There are two single-turn trimmers on an HV-3B PCB and a single 20-turn trimmer on the HV-3D board, used for concurrent DC and CMR trim. Trimming is realized in the output stage.

Best,

...

Thanks for the info John, errrr.... Johns

:thumb:

Michael

[quote author="JohnLaGrou"] The HV-3 "Double Balanced" topology was conceived by Graeme Cohen at Philips in Australia in the early 1980's. I can send you a copy of the original white paper, if you wish. On the Millennia web site, I give full credit to Mr. Cohen's brilliant work.[/quote]

:grin:
yes, another very cool Australian fellow.
I'd love to have a copy of that if it's possible.

Hi John,
and good to see you out and about.

Just nice people here! JohnLaGrou, Kev...

Thanks for the info!

the links are gone... :'( :'( :'(