[BUILD] TBDD

[fazeka]

There is a chance that metalwork will be available but I don't want to promise anything there yet.  If not, there will definitely be at least an fpd for people to work from with the proper dimensions.

OK, fair enough.  ;D Thanks!

 

[horvitz]

OK, TBDD-500 now shipping!  Check the 1st post in my WM thread for info:
http://www.groupdiy.com/index.php?topic=47094.0

 

[kante1603]

Hello Brian,

received your mail with the guide,thanks a lot!
Even without having the kit may I say that the guide looks fantastic?
Everything so properly layed out and clean,I love that (I´m german ;D).
Excellent idea to put sorting sheets in there!
My deepest respect is with you.
And my thoughts:How is your house going,is it heavily damaged?

All the best to you,

Udo.

 

[rob_gould]

I'll second that - the assembly guide looks fantastic.  Many thanks.

 

[horvitz]

Thanks so much, guys.  Although, I did rush more than I would have liked to get the guide done so by all means, please let me know if anything needs clarification or if you find any mistakes or whatever.  I would normally spend a lot more time editing but I thought it was better to get you something quickly rather than nothing at all!

And thanks for asking, Udo.  The house will be fine.  Nobody got hurt and that's all that matters.  Lost 8 trees total and 5 hit the house.  It was neat watching the crane picking up these 100+' trees yesterday and moving them over my house in one piece.  I'll always act like a little kid around big machinery!

 

[kante1603]

I'll always act like a little kid around big machinery!

Hahaha....yes,I know what you mean:My father used to be a senior engineer in machine construction,especially for maintaining those super-big caterpillar machines used in open cast coal mining.So I know how that feels ;D

Have a nice day,

Udo.

 

[horvitz]

Oh I wanted to ask too, for you guys who are not using a 51x rack, could you report back on what kind of rack you are using and whether or not you had to modify the card edge to fit?  Thanks!

 

[spneca]

Just got my kit today.  There goes my weekend.  It looks great.  Can't wait to build it.

I have a 51x rack, so sorry that I won't be helpful.

 

[horvitz]

I was able to replace the sound clips on page 1 if anyone has been looking for them.

You guys having fun sorting resistors?  :

 

[rob_gould]

I forgot to say - package received in the UK at the weekend. Haven't started it yet though...

 

[horvitz]

Boy, things have been a little slow getting to Europe!  It's not just you, Rob.  Thanks for letting me know.

 

[pidah]

Got my kit last week, looking forward to assembly!
Will be the week before Krismass, at the earliest :'(

Thanx for making this kit available Brian!

Cheers
Pieter

 

[rob61]

Finished my build tonight. Using in a 51X rack. I have a "weak" right channel, about 12 db down from the left and lots more hiss. I fed each side one at a time using the same cable to eliminate any problems here... put it in "off" (jumper is on so this should be soft bypass), with mix set to dry. I think its in the input stage, as the TBDD input meter is also down when I feed the right side only. (I have Input set to "stereo").

I do get chorus, but as stated the right side it weak and noisier. I set the BBD bias with my multimeter, but had to use the alt method for the clock as I don't have an oscilloscope. The fact that soft bypass gives me a weaker input meter reading as well would seem to indicate its something in the input of the right channel. Does this sound right?

Any ideas on where to start looking?

 

[horvitz]

OK, so that's not completely awful

First just a few points to note (this will be helpful for everyone).  The meter is on the output, not the input, so a low meter would not really indicate much in terms of where a problem might be.

The good news is that the problem exists in soft bypass.  That means that a very significant portion of the circuit is bypassed, so we don't need to look at very much.  This includes the whole BBD section and all, so you don't need to worry about any of the calibration.

Here is the flow of what we need to look a (applies to soft bypass mode only!):
First thing it hits the THAT1246 on each side.

From there, it goes to the input select, which will take either the right signal and send it to both channels (mono mode) or the left goes left and the right goes right.  This is handled by IC5.

Next is the blend.  The important thing to note is that the bypass is just removing the wet signal from the wet path.  The full wet signal is actually made up of a portion of the dry signal, so remove that wet portion and we have just dry left over going to the wet side of the blend.  The blend is handled on the left by IC213 and on the right by IC113.

The signal splits after the blend and goes one way to the meter and the other way to the output via THAT1646.

So now that we have all that, what do we make of your symptoms?

- First we want to check the input and the stereo/mono assign.  Send a signal just to the right channel and put the unit in mono mode.  If you do this and still get a good signal at the output on the left side, then we know that both the right input and stereo assign are working.  If not, try swapping THAT1246 from one side to the other.  You could also swap IC5 with something like IC104 since 104 isn't really being using in our testing right now.  Since we know your left output is good, we want to get that mono input from the right working on the left output so we can eliminate the whole input section.

- If in soft bypass, you get the same bad result on full wet and full dry at the blend, again try swapping those TL074s from one side to the other and see if the problem follows.

That will be a good start.  The good news about a stereo unit, is that we can swap things from side to side and see if the problem follows.  If none of this helps, we'll have to start following the signal though.  We can easily start looking at the outputs of each of the op amps in the path and see where it is/isn't getting to, but let's get though this much first and take it from there.

  Brian

 

[rob61]

Thanks Brian, I found the problem and now its working great! I found that IC101 (That1246) had one pin that was bent up and not fully inserted in the socket. I pulled the chip, straightened the pin and reinserted. And now its working great. Thanks so much for your help!

One question... For calibrating the meter, I'd like a quick and dirty way using my DAW that just let's me know I'm in range. Iin Nuendo, at 0db you are at digital max before clipping. So should I send out a sine wave at -6db and set so the TBDD shows 0db?

Thanks again, great product!

 

[rob61]

Finished with my build.

 

[horvitz]

Great news!  I've certainly done that myself and it's easy to miss.  Glad it's working now, though.

For real nasty fast cal, it will depend upon converters and calibration within Nuendo and whatnot, but 0 on that that scale should be somewhere around -14dbfs.  If you want to be more accurate at some point, the method in the build guide will get you there.

Nice pic, btw  8)  Great clean work.

 

[baadc0de]

Finished mine too.. waiting for a pic from my friend who has there with his phone to prove it

sounds awesome.. on some things it's like WHOA

 

[horvitz]

Glad to hear it!!  Really happy that you like it.  Try putting it in back of a reverb or delay for extra WHOA  ;D

And yes, pics please!

 

[baadc0de]

I did that for some swirly sounds and loved it. It can make real spaces (like a sampled cathedral) sound different in a good way, sounds unique. Dialled in just right (thank you so much for the brilliant idea of dry/wet) it sounds so great. Also, one thing I liked very much was when I accidentally shorted the left output to the right input on the patchbay, in mono (right) mode. You get these neat synthy sounds.