[BUILD] TBDD

[Biasrocks]

Okay, I had -15V on one side of the resistor and -11.8 on the other side with IC's in place.

Pulled IC206, no over heating and the voltages returned to normal. -15.18 and -14.96.

Voltages on IC206 socket are as follows.

Pin
1 -004.5mV
2 -7.42V
3 -242.4mV
4 -.700mV
5 -14.95V
6 -7.42V
7 002.3mV
8 32.2mV

Bad chip??

Regards,
Mark

 

[horvitz]

Quite possibly bad.  I tested a good portion of the BBD chips, but not all of them.  That being said though, I'm only aware of one bad one so far out of the whole batch.  You can certainly find out by swapping with the other side.

As for you voltages, they actually don't seem to quite line up.  5-8 look right except I think you have them backward.  8 is opposite 1 and 5 is opposite 4.  Those aside though, I'm worried a bit about 3 and 4. 

3 is the bias voltage that you should also be seeing at TP22.  Do you actually have nothing there?
4 goes down to pin 8 on IC207.  Does that read the same?

I get the following:
1  0V
2  -7.42V
3  -7.5V
4  -13.9V
5  -14.9V
6  -7.4V
7  0V
8  0V

 

[Biasrocks]

Sorry, had Pins 5-8 reversed. I'll check out Pin 3 & 4.

 

[horvitz]

Oh, did you have the boards separated when you tested?  If so, you would get nothing on those pins as you indicated.  The bias for the left goes upstairs to the trimmer on the other board and back down before it hits the IC.

 

[Biasrocks]

Yes, other board disconnected on those first set of numbers.


Measured again with RIGHT board connected.

1  low mv's
2  -7.42
3  -7.48
4  low mv's
5  -14.96
6 -7.45
7 low mv's
8 low mv's

Looks like PIN 4 is not healthy.

Yes, PIN 8 on the other IC is a similar reading.

Mark

 

[horvitz]

Yeah, I think that's all good.  Regarding your pin 4 being different from mine, I think I was reading a charged up C225 which hangs off of there.  It rolls down to 0 if you watch it for a sec.  So, I'd say those all look good.  Try swapping in the MN3007 from the other side and see if it's cool.  If so, I'll have to send you another one.

 

[Biasrocks]

Okay, looks like the problem is solved.

I think I had a marginal solder joint on the IC206, fixed it and put the alternate chip back in and no BBQ.

Put the original chip back in and the BBQ started again, so it looks like I may have fried the chip.

Looks like I'll be needing one from you Brian.

Mark

Yeah, I think that's all good.  Regarding your pin 4 being different from mine, I think I was reading a charged up C225 which hangs off of there.  It rolls down to 0 if you watch it for a sec.  So, I'd say those all look good.  Try swapping in the MN3007 from the other side and see if it's cool.  If so, I'll have to send you another one.

 

[horvitz]

Well, or the solder joint was good all along and the chip fried you.  Anyway, I'll drop you an email.

 

[jplebre]

funniest thing happened - had a bit too much solder on one of the legs of the pot, so I used the solder pump (those cheap $2 ones) and the leg vanished inside the pump

I think I still have connection as I can measure nearly 10k ohm between the back outer lugs, but 5k on the front ones.

Am I on the ballpark or should I procure a new pot? what values?

unit working fine but seems I don't get such a deep effect as in your examples

 

[horvitz]

Oh no!  I think it may be messed up a little.  You should measure 10k across the outer pins on both decks.  If on the front you're only getting 5k, then it will mess up the blend and the unit definitely won't sound right.  Let me know that I'm understanding you correctly, and we'll figure out how to get you a new pot.

 

[jplebre]

I did this in circuit, but yes I measured only 5k let me try it again though

 

[jplebre]

wet= dry completely gone? in stereo = gap in centre?

 

[horvitz]

At full wet, there's still about 50% of the dry signal in there.  Full wet just means that it's operating like an original Dim-D, which is actually a blend of four different things at the output, half of which is a dry signal.

Not sure what you mean about a gap in center.  Setting the input mode to either use just the right (mono) or r+l (stereo) doesn't change how the rest of the unit operates.  Try sending the same mono signal to both inputs and then switch the input mode between  mono and stereo and you should get exactly the same thing on the output.

 

[jplebre]

as in if it went near 100%, the dry would almost cancel out and leave a whole
so, basically, stupid non leaded solder and it's gooiness that..... nvm

I've used a bit of a lead of a resistor and stuck it in the place of the leg, bang! resistor at about slightly less 8k on both gangs (damned manufacturer tolerances) and unit working really close to your samples on page one.

1 and 2 seem to have slightly more depth on your examples. the other ones are almost indistinguishable.

Other than clock spill, does the clock step affect the signal at all?

 

[horvitz]

as in if it went near 100%, the dry would almost cancel out and leave a whole

Ahh.. gotcha.  At 100%, the dry comes through as it should and nothing cancels out there.  The wet signal is interesting, though.  The wet on each side is made up of the wet on that side plus some smaller amount of the wet on the other side.  As the two wet signals wander in a out of phase with each other, it will cancel some.  This is why if you inject a test tone and engage any of the settings, you see the meter going up and down.

I've used a bit of a lead of a resistor and stuck it in the place of the leg, bang! resistor at about slightly less 8k on both gangs (damned manufacturer tolerances) and unit working really close to your samples on page one.

Good!  Sounds like you got the pot sorted.  There's other stuff around there and I haven't tested it in circuit to see what it should actually read, but being down at 8k probably isn't just the tolerance.  These BI pots are pretty good and they are usually very close.  But, just as long as they are the same, we're probably in good shape.

1 and 2 seem to have slightly more depth on your examples. the other ones are almost indistinguishable.

I've found that how much you hear the effect working really depends upon the material.  It's not necessarily that 3 should sound "more" than 1.. they're just all different.  The LFO works twice as fast on 3 and 4, so if you listen to the phasing, you can hear that.  4 should be the most pronounced effect since it turns up the wet level a little bit.  This is definitely not an in-your-face kind of chorus though, it's always going to be pretty subtle.  Hope that helps.

Other than clock spill, does the clock step affect the signal at all?

You're talking about the trimmer to calibrate the clock cancel?  No, it won't affect the signal.  It just helps eliminate the clock residual from the output.  Just make sure that you do the BBD bias and if you don't have an oscilloscope, put the clock cancel in the middle.  Looking at the clock signal on a 'scope however, is a really good way to ensure that the unit is functioning properly.  Any problems tend to boil down to that spot.

 

[kante1603]

Very good explanation Brian!
Yes,it heavily depends on the input signal,personally love it on all kinds of Fender/Rhodes- pianos,in all four settings.Did I mention that I love this thread? ;D

Udo.

 

[fazeka]

Hi,

FYI: I came across this Google doc detailing the technicals of the pushbutton combinations of the original:

http://analogue-heaven.1065350.n5.nabble.com/Dimension-D-It-td101193.html

Credit due to the late Juergen Haible.

Cheers,
Chris

 

[jplebre]

thanks man!!!

 

[rhythminmind]

Just finished mine up. Love it. Quick demo here with an SEM & Bass.

https://soundcloud.com/rhythm-in-mind/sets/tbdd-dimension-d-test

 

[Echo North]

Just finished mine up. Love it. Quick demo here with an SEM & Bass.

https://soundcloud.com/rhythm-in-mind/sets/tbdd-dimension-d-test

Sounds awesome!