Make a PCB that allows both options. Will be more expensive (more PCB area required!), and will take the longest to design.

13%

[ 7 ]

Not interested. (Who needs a Dim D? And isn't there another Dim D project on the way?!)

3%

[ 2 ]

Total Votes : 51

Author

Message

lexvortex

Joined: May 14, 2008Posts: 155Location: Toronto

Posted: Thu May 21, 2009 9:43 pm Post subject:
Calibration of DimD

Hi JH,

I just powered up my DimD and it seems to function OK How should I calibrate this? There are a number of trim pots but I didn't see any instructions on what to do with them. Right now I've got them all set to mid point.

I just powered up my DimD and it seems to function OK How should I calibrate this? There are a number of trim pots but I didn't see any instructions on what to do with them. Right now I've got them all set to mid point.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

CMR: On the balanced input, feed the same signal to both input wires (the "positive" and the "negative" polarity). Ideally, there should be no signal at the output of the input amplifier. In paractice, set the trimmer to the position where the remaining signal is at its minimum.

Clock suppression: After the first opamp, following the BBD.
Ideally: no high frequency signal from BBD clock.
In practice, set trimmer such that the remaining HF signal is minimal.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

CMR: On the balanced input, feed the same signal to both input wires (the "positive" and the "negative" polarity). Ideally, there should be no signal at the output of the input amplifier. In paractice, set the trimmer to the position where the remaining signal is at its minimum.

If we're not planning to use the balanced input does this stillt need to be set?

jhaible wrote:

Clock suppression: After the first opamp, following the BBD.
Ideally: no high frequency signal from BBD clock.
In practice, set trimmer such that the remaining HF signal is minimal.

So this is with no input or does that not matter - we're just looking at the clock signal, right? How do we distinguish "HF signal"? Will this be the presence of *any* signal or will the trimmer filter out the HF signal and will we see a lower frequency signal present?

If we're not planning to use the balanced input does this stillt need to be set?

For unbalnced signals, you can just ignore the trimmer.

Quote:

So this is with no input or does that not matter - we're just looking at the clock signal, right? How do we distinguish "HF signal"? Will this be the presence of *any* signal or will the trimmer filter out the HF signal and will we see a lower frequency signal present?

No signal applied, just looking for remnants of the clock.
You know it as HF by measuring the period on the oscilloscope.
if you don't have a scope, don't worry. Just leave these trimpots in mid position. Many BBD devices don't use a trimpot for this at all.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

No signal applied, just looking for remnants of the clock.
You know it as HF by measuring the period on the oscilloscope.
if you don't have a scope, don't worry. Just leave these trimpots in mid position. Many BBD devices don't use a trimpot for this at all.

I do have a scope. So I would just trim for the lowest frequency of this signal it sounds like (in other words I will see it slow down rather than diminish as I trim)?

No signal applied, just looking for remnants of the clock.
You know it as HF by measuring the period on the oscilloscope.
if you don't have a scope, don't worry. Just leave these trimpots in mid position. Many BBD devices don't use a trimpot for this at all.

I do have a scope. So I would just trim for the lowest frequency of this signal it sounds like (in other words I will see it slow down rather than diminish as I trim)?

Thanks!

Lowest Level, not lowest frequency.
Put the probe on the wiper of the trimmer first, and you see the offender, unfiltered. There shouldn't be much of it after the first opamp - but if you see something, the trimmer will minimize it. You won't *hear* it, anyway.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

After successful triple chorus and tau builds, the inevitable has struck and I have hit a stumbling block - my dim d build doesnt make a sound when I plug it in......
ouch.
Any hints for a novice troubleshooter?

Ive checked all the component positions and polarity and everything checks out.... except one of the tl072s on the main board was in the wrong way round which ive now sorted (could this have damaged the chip?). But still no sound, even in bypass mode. the led does turn on, however. Where can I start looking for suitable values for testing purposes? I couldnt get the 27nf caps on the main board, so I soldered in 22nf and 4.7nf into the same holes, is this cool?
Any pointers would be massively appreciated, Im a bit lost on where to start. I only have a multimeter, no scope unfortunately.

.. except one of the tl072s on the main board was in the wrong way round which ive now sorted (could this have damaged the chip?).

Definitely, yes.
Replace opamp, check supply voltages at every chip (pins. see schematics).
Then trace signal path with a scope from input to output - the usual procedure.

JH.

(just back from Italy)_________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Thanks for the reply JH...
I will try this. Unfortunately I dont have a scope... will this ruin my chances of diagnosis? Or is there any other way..?
Joe

I hate to say this, but a scope really *is* helpful here. Maybe you have a friend with a scope locally, who will trace signals with you?

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

I have nearly every parts, but I don´t know where to get the BBD-Stuff...

I still need:

-MN3007
-MC14069UB
-NE 570N
-LM13600

I live in Berlin. Where can I get this stuff here in Germeny?

And what about HA1457W? What is the difference between using this and TL071/72 like the footprints on the pcb are saying?

Thanks for this awsome project!

Jonas

LM13600 can be replaced with LM13700. Should be available at www.reichelt.de . Same for MC14069 ("MOS4069" should be the Reichelt number.)

The rest is NOS only. I think Tobias provides kits that include these chips (Tobias?). And there are special music electronics dealers like vintageplanet in NL and small bear in the USA.

HA1457? - I don't hear a difference; others might.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Ok, I got the XLR jacks figured out, but Juergen, could you tell me if heat sinks I have left over extra from the Krautrock Phaser project would also fit the footprint on the Main Board for this project?

Also, on the BOM for the BBD Board, there's a section of components called just "Capacitors", between the polyester section and the ceramic section. Based on the values it seems these could/should be ceramic (150pf, 330pf for example) but wanted to make sure before I ordered parts.

my understanding is that these shouldnt be ceramic, but dont take my word for it.

I thought so too but wasn't seeing film caps with some of those values.

Also regarding heat sinks I finally found my stash of ones I used on the compact phasing so will see how those fit here.

Thanks.

Just try them and then feel if they don't get too hot. (Depends on many factors, mainly on the voltage pre-regulator, and air circulation.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Thanks JH. I found some polyesters in these values, so long as 50V is ok for these particular caps.

jhaible wrote:

numbertalk wrote:

JoeMorris wrote:

my understanding is that these shouldnt be ceramic, but dont take my word for it.

I thought so too but wasn't seeing film caps with some of those values.

Also regarding heat sinks I finally found my stash of ones I used on the compact phasing so will see how those fit here.

Thanks.

Just try them and then feel if they don't get too hot. (Depends on many factors, mainly on the voltage pre-regulator, and air circulation.

JH.

_________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forumYou cannot vote in polls in this forumYou cannot attach files in this forumYou can download files in this forum

Please support our site. If you click through and buy from our affiliate partners, we earn a small commission.