SparkleDrive De-Bug assistance

Started by markm, March 20, 2007, 12:10:53 PM

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markm

Hiya Fellas,
I've been working on getting a layout together for the SparkleDrive circuit and currently have one that is almost finished but, as an issue with the blend pot.
The blend is actually functioning as an additional volume/drive pot and I can't quite figure out why.
Right now, it's dead in the water as I have checked over the layout and the schem and can't seem to come up with a conclusion of what the problem -or- error could be.

Here's the layout;  http://aronnelson.com/gallery/album76/sparkledrive_LAYOUT

And here is the schem;



Now, I know from looking at Torchy's schem that there was no connection to Vb at the blend pot, I tried eliminating this connection from my build but to no avail.
Any ideas from you kind Gents?  ???



dachshund

You mean you're not getting any clean signal coming through, by adjusting the Blend?

markm

Well,
There is signal on both sides of the blend pot however, both are distorted.
I think the 5532 is distorting on the clean side.
Did you hook your blend to Vb?

dachshund

Yes, I did. Maybe something's wrong at the transistor.

markm

I thought that was correct.
Torchy's schem does not seem to show that however.
I double checked all resistor values etc. and still, the issue exists.
It is Very close to working correctly though.....the saga continues!

dachshund

Yeah, I just happened to find this schematic before, from a search, and that's what I used. I don't remember who posted it.
http://home.hetnet.nl/~chrisdus/download/VLSD.jpg

markm

#6
From your schem it seems the resistor on U2a is 3K as opposed to 1K in mine.
Also, I think I may have found it!
In mine, R14 appears to be hooked up incorrectly in relation to the blend pot.  :icon_redface:
......I think........ ::)
But...Maybe not?

dachshund

Hmm... which one is R14? On "mine" it's way out to the right, at the output.

markm

R14 is to lug 1 of the Volume pot.
On second look, it appears correct.

johngreene

Quote from: markm on March 20, 2007, 01:54:08 PM
R14 is to lug 1 of the Volume pot.
On second look, it appears correct.

You probably need to bypass the 4.5V closer to the 2 blend pots. Otherwise you are going to couple the leftover 'blended' signal directly into the non-inverting input of the output volume control 5532.

--john
I started out with nothing... I still have most of it.

Torchy

#10
<Edit> ignore me, IC2 is rotated innit  :icon_redface:

markm

TORCHY!!
Don't go away so fast!  :D
Did you get your Vero build to fire?

Torchy

Yes thank you.  :icon_smile:

BTW, you have Blend Pot B lug 2 (pad S) on the wrong side of R13 - you have it connected to the junction of R12 and R13. It should come off the other side of the 100K (R13), which should NOT connect to U3B pin 6.

Replace R13 with a jumper. Now take a 100K from the top end of R12 to pad S (and cut the trace).

markm


Torchy

No, because now youve got lug 2 connected to IC2 pin 6. Lug 2 ONLY goes to the 100k (R13), the other end of which goes to R12/R14/Pin6.

Like this ...


markm

Okay,
I see what you mean here.
See Torchy, You are still needed and liked around these parts!  ;D


calculating_infinity

Quote from: markm on March 20, 2007, 04:48:52 PM
Okay,
I see what you mean here.
See Torchy, You are still needed and liked around these parts!  ;D

Sorry for the OT but +1!  Long live torchy and down with crp.  If you know what I mean.

newbie builder

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