Dav BG1

[matta]

Lagoausente it is nice to see that you are still on the quest for your 'illusive' DAV-1 'high end' mic pre :grin:

Frank thanks for the pics. I hope you are well my friend, miss our chats, all the best for 2007!

I do have to laugh through as the DAV-1 topology is VERY similar to the Green Pre, but uses AD chips instead of TI. I recommended the Green, as did others, to lagoausente back in this thread: http://www.groupdiy.com/index.php?topic=216156

Which he kind of blew off as not being high end enough, calling it 'mid-level'.... go figure...

Lagoausente, take a look at Franks's photo's and compare them to the Green, if the Green isn't proffesional enough, I doubt that the DAV will be any better :?

Cheers

Matt

 

[skipwave]

[quote author="SALSA"]The combination SSM2017 - OP275 reminds me of a ELEKTOR design from '97. They used half of the OP275 as buffer on the output of the SSM and the other half as servo for the buffer.[/quote]

In the Mic Pre Meta you'll find a transformer-balanced version with the same complement of ICs:
http://www.groupdiy.com/index.php?topic=18939

 

[lagoausente]

[quote author="matta"]Lagoausente it is nice to see that you are still on the quest for your 'illusive' DAV-1 'high end' mic pre :grin:

Frank thanks for the pics. I hope you are well my friend, miss our chats, all the best for 2007!

I do have to laugh through as the DAV-1 topology is VERY similar to the Green Pre, but uses AD chips instead of TI. I recommended the Green, as did others, to lagoausente back in this thread: http://www.groupdiy.com/index.php?topic=216156

Which he kind of blew off as not being high end enough, calling it 'mid-level'.... go figure...

Lagoausente, take a look at Franks's photo's and compare them to the Green, if the Green isn't proffesional enough, I doubt that the DAV will be any better :?

Cheers

Matt[/quote]

I´m not sure how could calificate your actitude. Seems like the kicks to the newbies at school. I really find sometimes mockery as pathetic.
The situation of "unknown" is diferent of be "idiot", but simetimes seems the newbie situation like a perfect "temporal idiot guy here".
But I not against of it, if you enjoy... be happy man.
I just quote what I told:

Green seems a mid level preamp, and quite easy to build.
Is here any clone here of the Universal Audio preamps?

and the reason I tell "seems" is because I was not sure, and as tell along the thread, I had no references, wavs, comparisons, and so was quite lost, situation I have never hiden, and as repeated often on the thread, wanted opinions, references..
About the "DAV illusion", as you tell,first, I didn´t tell the DAV as a "high-end" pre. What i told is that on many blind comparisons was voted over recognized "high-end" pres, what it´s not just the same. And I think haven´t afirmed nothing against, and none in favor of ones and others, just told a about opinions/references from other forums, users etc.
I think you labeled my posts without knowing me at all.
To make you realize of it, note that before I started this thread, I was told by an engeneer that the DAV is a good "mid-range" pre. So you mistake again when you tell me about I´m coming again with the "DAV illusion". Not at all. I started this thread for one reason. I was known it´s based on a IC like the Green, and also that total cost of the components are like the Green, but that´s not the issue. The issue is the blind comparisons made on 3daudioinc, and Gearslutz, where for any reason, the DAV are prefered over the others.
If you go to the 3daucioinc link I posted at start of the thread, you can see on the end one post I made, where I expressed my suspects about any posible compression or something extrange on the dinamics that make people prefer it. So I´m not at non illusion. Just trying to learn theory, surprised? Yes, man, I´m not wanting building the DAV for now, and none the Green for now, but would like to build both on the future when I´ll have some more time. For now, I´ll be upgrading my Mp20 with new opamps, and transformers, while continue searching about electronic/sound.
I write electronic/sound for one reason. Seems sometimes that electronic designers, don´t have the same opinion as sound engeneers, and so my searching will continue on both fields. In this case I was , and I´m looking for a electronic analisis of the DAV (not only what IC uses), and try to find if has any relation with what some people are hearing, because I suspect there is something that makes a subjective preference for the DAV, and much on Classical music recorders. Not that is better, but something that makes people feel as better, something like an added suggar.
And so Matt, if you have light there, I´ll be happy you to switch it on. If you just want be "loughing", then you´ll be happy. :thumb:

 

[babyhead]

Lighten up, Francis. :roll:

 

[skipwave]

[quote author="lagoausente"]For now, I´ll be upgrading my Mp20 with new opamps, and transformers[/quote]

Doesn't the MP20 used Jensen transformers? No upgrades from those. Different colors, but not more hi-fi. Also, the first stage is FET, the ICs might just be line drivers and not impart much to the sound of that design. Admittedly, I've done lots of mods that promised little improvement or even change, since the lure of upgrading is powerful.

Just a thought.

EDIT: Ah, I see what their ploy is now: "FET, Class-A discrete input buffers." Hmmm, buffers. I prefer a FET design like the Hamptone, but that is not a clean and sterile sounding pre.

Sorry for the off-topic.

 

[lagoausente]

Doesn't the MP20 used Jensen transformers? No upgrades from those. Different colors, but not more hi-fi. Also, the first stage is FET, the ICs might just be line drivers and not impart much to the sound of that design. Admittedly, I've done lots of mods that promised little improvement or even change, since the lure of upgrading is powerful.

The first Mp20 units was shiped with Jensen transformers, but they ended this for financial reasons. I´m not sure what transformers come with mine, how can now it?
Regarding to the opamp, there is a huge diference, I could notice on a thread on Tapeon.com, a guy upload some somples, and I could apreciate the diference just through my laptop speakers, haven´t to use good monitors.
As guy told, the Mp20 it´s near just those opamp+this transformers, there are not much more there, so changing this, change near the hole preamp.
And I quote a text from Jim Williams from a forum:

The presonus does have a rather dirty biased jfet pair off the input transformer, removing that circuit would certainly improve the preamp's clean spec.

The BurrBrown OPA627 is the most over-rated opamp out. Way too much money for these things, they sound rather lifeless to me.

I once talked to Glenn Meadows in Nashville and they had spent $15k on these turkeys for the SSL's. I asked how it went, he didn't even want to talk about it!

Do try the LT1357 in there, it may surprise you.

Are you sure about the transformer being a JT-11? Thats a 600/600 ohm line input transformer, not a mic transformer. It wouldn't impedance match so would be noisy. The JT-16 is a 150/600 ohm mic input transformer designed for very low noise front ends, the presonus would be better with a JT-13, besides, a JT-16 is large and wouldn't fit too well.

The DAV pre's are just a BurrBrown INA217 mic pre chip followed by a AD OP-275 opamp. Build yer own for around $25 or so. They benefit from using either the AD SSM2019 or the THAT 1510 preamp chips, all pin compatible. Just pop in a 8 pin socket to play around with them.

Does mean the first line removing the transformer input ciruit?

 

[madriaanse]

in this picture:
http://techtalk.te.funpic.de/coppermine/albums/userpics/10001/IMG_0046-14.jpg

What are those six little gray squares - four with 470nJ on them? Not talking about those trimpots.

Thanks!!

Martin

 

[SALSA]

These are Evox-Rifa metallised polyester capacitors

Cheers,

Mike

 

[skipwave]

[quote author="lagoausente"]

The first Mp20 units was shiped with Jensen transformers, but they ended this for financial reasons. I´m not sure what transformers come with mine, how can now it?
Regarding to the opamp, there is a huge diference, I could notice on a thread on Tapeon.com, a guy upload some somples, and I could apreciate the diference just through my laptop speakers, haven´t to use good monitors.
As guy told, the Mp20 it´s near just those opamp+this transformers, there are not much more there, so changing this, change near the hole preamp.
[/quote]

Thanks for the details Francis. I had read they used the JT-13k7, but apparently not anymore. JW mentions the dirty biased jfets, and that seems not much different from throwing a toob into a sterile IC design to "warm it up." You could re-bias those JFETs, but that would take some careful consideration.

[quote author="lagoausente"] Does mean the first line removing the transformer input ciruit?[/quote]

If the DAV is transformerless input, use Kev's schem, linked to earlier in this thread.

 

[madriaanse]

What strikes me as odd is that no one's made an exact schem, PCB layout and BOM for this preamp. I mean you got folks cloning Neve, Amek, 1176's, LA2A's etc. but not this simple yet effective box. What gives? Too new maybe? I can guarantee you that if I had one I'd be crawling under the hood and taking notes!! :green:

Later,

M.

PS, Mike thanks for that info!! :thumb:

 

[nrgrecording]

I sent the original pcb layout to kubi, he will maybe make a schematic. I myself thought about making a new pcb layout without the psu so you can put more of them in one box easily.
Iam not sure about if its legal or not to copy a pcb layout or a schematic... at least its not that fair? And...I don't want to be involved in any conflict. :wink:
Amek, 1176,LA2pcb have all different pcb layouts for example. The 1081 is somehow very close to the original. :roll:
I remember dramastic audio who used/copied Jakobs pcb layout and he sells his ssl clones for 3000 dollar. It doesn't seem to be that illegal because mr. dramastic is not in prison or so... :wink: but at least it was not the coolest idea.
And.. what strikes me as odd is if someone knows whats legal or not and whats fair or not regarding pcb layouts and diy projects?
I have a bunch of diy projects but iam curious about publishing them. Either they're close to the original but converted for easier diying or they have the same features than the original ones.
Iam sure one of the experienced DIYers can say more about this?

Frank.

 

[lagoausente]

Iam sure one of the experienced DIYers can say more about this?

I hope so. Just need waiting they come over the thread.

 

[rodabod]

I'm not sure if it's very fair - the company still sells these things, and it's their property.

If the design is so simple with an INA127 front-end, then I'm sure we could all look around and design/build something similar ourselves.

 

[lagoausente]

[quote author="rodabod"]I'm not sure if it's very fair - the company still sells these things, and it's their property.

If the design is so simple with an INA127 front-end, then I'm sure we could all look around and design/build something similar ourselves.[/quote]

I think that there is no much diference between getting the schematic, and redesign a new pcb, that directly take the pcb as it is. i agree that seems more unfair the direct copy, but at least, the result would be just the same, unless the position on the components. Also, I don´t think can exist a law that prohibits building a device that has the same schematic as other, if were, most preamps DIY here would be ilegal.
This issue makes me remember some P2p discussion. At what I know, and have read on a mp3 web, several tribunal senteces have told that there can´t be dissaprovaled copies of mp3 unless it is for business, and so, only that business would be ilegal, not the copy itself.
In this case I think we would unlink the pcb or schematic from the comercial name, like it´s on the thread tittle. Just like any other new project. Realize that a DIY project, not often it´s worth to save money, and who make this projects usually is for learning and discussing. In the other hand, all designs must be treated the same. I think there are over there many other projects coming from comercial devices still on the market.

 

[matta]

I'm in agreement with Frank and Roddy why shaft the little guy by cloning his design?

Almost all, if not all the DIY designs here are for designs that are not currently in production, even projects like the 1176 and LA-2A are not 'part for part' clones of the originals or reissues but all inspired by them with designer revisions and new alternative layouts/changes to the circuits. I don't think we should stoop to copying/cloning an in production model, but hey you might differ...

Lagoausente , like I've shared before the Green Pre will get you in the Ball Park of the DAV1... why reinvent the wheel? The Green is pretty well documented, PCB's are available, heck even a complete kit from Ptown etc if you want the 'paint by numbers' option.

You just seem to think this unit has some kind of voodoo, which seems to have been picked up trawling through various websites etc.

Suggestions have been offered up by many fellow DIY'ers, myself included, so not much else can really be said on the issue, you will not be happy until he has cloned a DAV1, simple ;-)

And to respond to previous post....

I´m not sure how could calificate your actitude. Seems like the kicks to the newbies at school. I really find sometimes mockery as pathetic. The situation of "unknown" is diferent of be "idiot", but simetimes seems the newbie situation like a perfect "temporal idiot guy here".
But I not against of it, if you enjoy... be happy man.

It is not a mater of 'picking' on the newbie 'kicks to the newbies at schools' as you call it.

I was once a newbie myself, and still am in so many aspects and if you bother to read my post will notice many of them are helping other newbies, and even not to newbies troubleshoot and fix problems that crop up DOING DIY.

All you seem to be doing is latching onto the IDEA of DIY and are wanting to be spoonfeed and have everything laid out on a sliver platter, and sadly that isn't going to happen, this is Group DIY, Do It Yourself, not DIFY, Do It For You.

Learn the basics, understand electricity and electrical components, read the META's, grab a soldering iron and build a project.

I'd suggest, as have other, starting with the Green Pre. It is obvious that you need/want a mic pre so why not start there, a couple $$$ and some manual labour and you will have a mic pre that rivals the DAV1 in terms of sonics and design.

and the reason I tell "seems" is because I was not sure, and as tell along the thread, I had no references, wavs, comparisons, and so was quite lost, situation I have never hiden, and as repeated often on the thread, wanted opinions, references.

Well that isn't true, I've posted comparisons, with Wave Files between the Green and my 002R pres and the difference is night and day, others have posted a few clips as well. Yes no one has done a direct comparison between 10 or 20 pres, but I getting the feeling we are not that kind of Forum.... within the Forum there are hints of what you will get out of a Green Pre.

And so Matt, if you have light there, I´ll be happy you to switch it on. If you just want be "loughing", then you´ll be happy.

I'm not sure what the heck that means :?

I understand that english is not your first language and that is cool, I'm appreciate you are making the effort to write in english, it isn't easy, but if you want to write it in Spanish (which I think is your native tongue) I'm sure someone will translate it better.

All that is left to be said is that DIY is fun, but it is a hands on kind of thing best enjoyed on the front line, forget the Forums and what others are saying/doing, get in there and BUILD something and learn a new skill, who knows one day you may even end up building something new and unique that you think out performs the DAV1, seems like you are making an effort already modding the Presonus.

Cheers

Matt

 

[rodabod]

lagoausente, this may interest you:

http://www.celestial.com.au/~rosswood/diy/KDMP/kdmp.htm

http://www.celestial.com.au/%7Erosswood/diy/dualmicpre/dualmicpre.htm


Roddy

 

[KarlH]

lagoausente,

If the DAV really is based on the 2017 family of chips, you should try kev's pre. here's 2 channels built on perfboard out of leftover bits. It is easy to do on perf, not a lot of cutting traces, not a lot of parts. I built it because we just closed the studio so I need some pres. The D&R Orion's pres that we have are the same design, clean and quiet.
http://twin-x.com/groupdiy/displayimage.php?album=lastup&cat=10071&pos=0


Along the same lines, check out the thread here http://www.groupdiy.com/index.php?topic=19888 Mikkels small mixer using the THAT1510/2 preamp design straight from the app notes with various improvment suggestions for RFI rejection.

Buena suerte tio y feliz año nuevo,

Karlos

 

[HarryH]

I would like to hear a DAV in person and figure I will make a preamp with those chips to see what it sounds like,but I agree that a direct clone wouldnt be something I would do.I am glad he gets a great rep for his products,and that they are selling well.I dont think there is anything magical there though.My Greens sound great,and I have a bunch of high end stuff to compare it with.
We are not Behringer,and dont want to be.
Harry

 

[madriaanse]

point well taken guys - you'd never want to do anything to hurt anyone's livelyhood - especially a cool small company like DAV. I am just really curious what makes a BG1 so good, whereas supposedly there other preamps, using these same chips, that are not so good (what are the "bad" ones btw? Behringer? Tapco? :grin: )

I've seriously been considering buying one just to see what it sounds like myself. If I keep hearing these rave reviews I definitely will.

All the best,

Martin

 

[mikep]

[quote author="madriaanse"]what makes a BG1 so good, whereas supposedly there other preamps, using these same chips, that are not so good ?[/quote]

since the whole darn micpre is on a chip there isn't much you CAN do, good or bad. other than feed it clean power and provide a nice ground. oh, and dont get excessive with the lead length from the chip to the gain control. these chips have been used in countless preamps and consoles. the earthworks pre is one "good" one. one ubiquitous one that comes to mind is the lower-end joemeek stuff, although admittedly TF wasn't going for super-clean with those designs. the Grace preamps are a similar design, but with slightly better instrumentation amps (INA103 IIRC).

I found this mumbo jumbo:

"The BG1 is said to be derived from Decca circuits dating back to the late '70s, benefiting from the careful development afforded to Decca's specialist electronic designs."

um, ok.

mike