VBITNGC building & comment

[wim]

Thanks a lot Walter, it is clear. I did not notice yoy are from Belgium, thats why i mailed you in English. Sorry.

Now waiting and hoping that Zang (Digi01) aswers my mail with a positive result (that he has boards to sale).

 

[uvodee]

indeed

hij heeft nog boards ter beschikking..
heb hem enkele dagen geleden nog een vraag gesteld daarover


M vr. gr.

Jean-Pierre

Federal Way, WA

 

[wim]

Now, that sounds positive! Thanks uvodee.

 

[troystg]

Quick question.. Can the output grounds of the chips be tied together here?

I would like to put a switch on the output and switch between the rear binding posts and a front panel headphone jack with resistors in series. But I am unsure if the three(3) terminal headphone jack is compatible wit hthe seperate chips. To my knowledge the chip output grd is equal to pwr ground but I wanted to check and be sure.

 

[VT67]

Troy

All the separate grounds are connected to the HC groundplain via wires. I think if you lead the gnd wire from your headphone jack to this central ground point everything will be O.K.

Regards

 

[troystg]

That's what I needed, thanks...

So now when are boards going to be available? PLEASEEEE... Pretty please.. With sug... Awe not that again...

Happy Friday!

 

[VT67]

And this is the correct routing of the wires!!
Sorry, but In the previous image I also connected the -HC to ground.

Regards

 

[wim]

GeWa, do you mean that all the wires that you draw in your previous post have to be made with wire by hand? If so, good that this subject is on the forum. If not, i schould not know about it (the BOM do not speak about it too).

So for everyone who is going to build this amp, take good care off the photo from GeWa, a view posts ago.

 

[VT67]

GeWa, do you mean that all the wires that you draw in your previous post have to be made with wire by hand?

Yes.

Also the HC and LC power supply has to be wired manualy. This is one of the disadvantages of a single layer board and the fact that it's only a euro card format (couldn't place the parts idealy). It all sounds a bit dramatically but it isn't. I will post a picture of how it all has to be wired.

Regards

 

[VT67]

Attached a picture so you can see how the power supply wires have to be connected. For those who are interested, I slapped a small 3 page manual together which includes a parts list and some images and explanation of how to wire the amp. If you want one just send me an email. (to big in size to post it here, 375kb)

Regards

 

[wim]

I agree with you GeWa, it is not dramatically, but good to know about it.

Thanks for your wirediagram and your manual!

 

[Sir_John]

Hello everybody. Well this is my first post to the forum. I've been watching this thread for some time as I liked the concept of the VBITNGC. I would like to give it a try myself.

Can I also get schematics and a manual, also files needed to make a pcb?

Thanks in advance.

Ah, yes, where can I get more information about the following:

Inverted configuration: In national's datasheet there's only noninverted conf described. How do I design things (formulas, etc) when I want to do it with Inverted topology? Where can I find resources for this?

T-Network: theory, why it works, calculations...

Is it possible to put 3875 in parallel mode? Resources? Schematics? Anybody tried it so far?

Uhhh. 🙂

I hope I did not put so many questions in one post....

 

[Franz G]

T-Network: theory, why it works, calculations...

Here, you will find everything about the t-network. In the first post, you can download an excel sheet for the needed calculations.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=40664&highlight=

Kind regards
Franz

 

[Sir_John]

Franz, thank you very much for the link. Lots of very useful data.

Now, what is the present stage of the VBITNGC project? As I understand, there is a pcb that can be purchased but I dunno how. Also I am not quite sure of the full up to date schematics that is used for pcb. Can anyone post the full schematic please?

Also, is there any listening impresions of the project so far?

And yes, can I get files to make pcb myself? I mean, here in Belgrade we have nice small companies that make pcb's from files you bring'em on the disc. I believe that the pricing can be reasonable too.

My email is sir_john@bitsyu.net

Thanks everyone

 

[VT67]

Project update

Sir John, I sent you a PM with all the info you need 😉

Attached a picture that shows you how I placed the LC wires.

Regards

 

[VT67]

And this is a picture with the HC and GND wires in place. I used 1,5mm² (16 AWG) solid core wire for this.

Regards

 

[troystg]

So fire it up and let her rip!!!

And then order some boards for us to buy... 😀

It looks very nice so far.

 

[VT67]

Troy

Just send you a PM.
Have you already tryed to contact Zang, because he had boards made?

Regards

 

[Sir_John]

WoW GeWA!!!

Looks VERY nice!

I am looking forward to hearing first listening impressions!

Where did you buy parts?

And yes, thanks for PM, it was more than usefull!!

 

[falcott]

Hi all - and you thought this thread was laid to rest!

Franz, if you are still listening 😉 - or anyone else! - I am finishing off a VBIGC based on Joe Rasmussen's schematic that I started building 2 years ago (yes, and I'm a slow house renovator too 🙄 ). Point to point on perf board.

I'm thinking about the power-up delay. In your opinion, is it preferable to ground the input pin (8) on the LM3875 chip, or to switch the chip's power input?

Thanks! 🙂