Proper IC Voltages? For Dual OpAmp DOD 250/Liquid Drive/Dist+

[analog kid]

Ok , I have looked all over and it seems that Phillip's Liquid Drive page is The ONLY place that Voltages are listed for a 250/ROSS/DIST+ clone using a Dual Opamp layout. , ala Liquid drive!
Im not saying that those vltgs are WRONG but thing is  I have built two of these type a ROSS clone and the actual Liquid drive (phillip's pcb changes ) and with both of them I AM NOT getting those voltages for Pins 6 and 7 , which are tied together. He has them listed as  .92V .. I get just a tad under Batt voltage!! Is this wrong??
Anyway here are the vltgs listed at Fuzz Central
IC Pin Voltage Readings (OPA2134PA)  
Vin = 10.01V (!)  1 = 4.47V  2 = 4.47V  3 = 3.89V  4 = 0V  5 = 0V  6 = 0.92V  7 = 0.92V  8 = 8.93V
And here are the voltages I get:
Vin = 9.32 battery   1 = 4.7v  2= 5.1v  3= 4.47v  4= 0  5= 0   6= 8.5  7= 8.5  8= 9.1v
I would ignore it and assume it a typo on the vltgs IF I had been able to get either of my "clones" to sound like most people seem to describe them. They worked ..controls functoin as normal , but just seem to be a real Trebley HARSHNESS or Fizziness to the distortion and also not alot of low end compared to bypass no matter how large I made the input cap so I thought it might be something about the bias AND these pin 6 and 7 voltages. ? ?   Which I have no real way to trouble shoot since theyre NOT CONNECTED to anything.
Any help or someone's voltages on this circuit w/ dual opamp would be great!!

[analog kid]

Bump
(just someones sample vltgs ?)

[Mark Hammer]

Just to be able to rule it out, are you absolutely sure that the right chip or pinout is being used?  The original circuits for the pedals listed only used a single op-amp.  Because duals are often the op-amp of choice for purchase/inventory and can sometimes cost less than singles, some folks have worked out layouts using duals where only one op-amp of the two available is used.  I see that the OPA comes as a single in the 134 8-pin package and as a dual in the 2134, also an 8-pin package.  We are absolutely sure that you have the right chip to suit the pinout of the board you are working on? 

Alternatively, you would join a long and illustrious lineup of people if it happened that you etched a board that was inadvertently flipped around; i.e., you used a pnp layout but did it with photo etch, or vice versa.

Just trying to rule things out, as I say.

[analog kid]

Yes Mark , I did etch a board setup for a Dual Opamp package for both my Liquid Drive and the Ross original model(which was set up to use Dual from the beginning I think)  Let me say thanks for the help first. And also am I wrong or would the circuit most likely just not work or sound at all if I DID use a single op in a dual layout or vice versa?? at least that's been my experience.
And also I have to say again that these effects ARE working, just don't have the sound that I would expect or call "RIGHT". there's a real bad Harshness to the Distortion and an overall lack of low end when the drive is UP no matter how large the input cap.  BUT .. those voltages for Pins 6 and 7 are the thing that makes me suspect something may be wrong the most!
Like I put in my first post , phillip's L.D. reference vltgs for 6/7 show  .92 v , and I'm getting close to supply vltg on them in both pedals. ( ?)
which I don't know how to trouble shoot since they're not connected to anything in the crkt!! and I don't know lot's about Opamp pinouts single/dual

[RickL]

Which layout did you use?

If you used the Tonepad layout, pin 1 and 2 are tied together and pin 3 goes to Vb. This should give you roughly 4.5 volts at pins 1, 2, 3, 5, 6 and 7. If you used another layout where pin 5 was tied to ground, pins 6 and 7 should be around 0 volts (i.e. 0.92 volts). In most opamp circuits configured as amplifiers all three pins of each opamp will be within about 1 volt of each other. Since pin 5 (or pin 3 in the case of the Tonepad layout) is tied directly to ground (4.5 volts tonepad), the other pins should be fairly close to that value.

[analog kid]

If you used another layout where pin 5 was tied to ground, pins 6 and 7 should be around 0 volts (i.e. 0.92 volts

I did use a dual op layout on both the liquid and the Ross(which used a dual always I believe.)   I just wasn't getting that low under 1v for pins 6/7  and could n't figure it out. All other vltgs were almost spot on with the References at Fuzz central's Liquid Drive project. but I kept getting just under P.S. Voltage for pins 6/7
WELL I THINK I GOT IT, And DO I FEEL STUPID!!  I never dreamed that I could have the Opamp oriented wrong , SEEING THAT the circuit has been working properly all except for a bit of harshness to the distortion and less low end AND that most vltgs were correct!!  BUT I GUESS THAT's what IT WAS!!
I FLIPPED the IC around 'backwards' and ALL voltages stayed the same EXCEPT 6/7 dropped to .07v    (I don't know if this is TOO low for proper operation or how to bring that up if so) and though that's not closs to 1vlt it's alot better than 8volts I guess!   I hate to admit it but I actually remember now making a note to myself that I soldered the Socket in backwards when I built this , it's been awhile! Good example for never doing that to avoid trouble down the line!
Anyway thanks and sorry for the uneccesary bother. But please advise me if that should still be closer to .92v for proper operation.

[RickL]

It should work fine. The only point of connecting pin 5 to ground and 6/7 together was to put a stable voltage on the unused opamp so it couldn't interfere with the operation of the other opamp. It would probably even work with 5, 6 and 7 connected to nothing.

You can even use that opamp for something else if you want. Build another gain stage, an active tone control or even another identical (electronically) Ross or Liquid Drive. I've done that several times when I've built a simple one opamp circuit on perfboard. The extra components don't take up much room, it won't draw much extra power and you can have two complete pedals in one box for just the cost of a few extra parts. Since you've already etched a board just use a bit of perfboard to hold the extra components and run wires to the three pins on the board.

[analog kid]

The extra components don't take up much room, it won't draw much extra power and you can have two complete pedals in one box for just the cost of a few extra parts. Since you've already etched a board just use a bit of perfboard to hold the extra components and run wires to the three pins on the board.

Yes that's something I've not tried to tackle yet , and since so many dual layouts don't seem to ever use the second amp, especially in a crkt like this with no TC, adding one using the unused amp is VERY interesting , I may have to ask you a bit more about that as I am sure there's not that much to it...
HOWEVER.. back to the point, I know this shouldn't be happening but "THE PROBLEM IS NOT over!" (I thought I had already tried to improper orientation theory    )        I had popped a Burr Brown OPA2227P dual  in there when I got the Pin 6/7 readings to come down to .06v. SO I assumed I would've got this with any dual I put in ..that I had just had them in reversed before.  WELL , I then tried a RP4580 and then a 4558  only to find that the vltge on Pin 6 and 7 were STILL reading  8volts!!!! How is that possible?  I popped back in the B.B. chip and all other vltg the same , except 6/7 comes down to .06 as well as the sound does come more alive 
What could I be missing or not getting here?  Wish I could post the layout Phillip modded from the Tonepad D+ just to show that it IS a dual layout and find out why these Dual amps I am putting in are doing this.. but  here is a quote he made to me ...

Note that the layout that I used uses a dual IC, like
the 4558, but it only uses one of the amplifiers in
the package...just like the original Ross Distortion
did.

[slacker]

I'd check the voltages on the socket without the opamp installed, that should tell you if your circuit is wired up right.
The pins on 8 pin sockets are numbered like this
   ____
1|       |8   
2|       |7
3|       |6   
4|____|5

So looking from above 8 is top right and 4 is bottom left. Pin 8 should be connected to the powersupply and pin 4 to ground. The voltages without an opamp installed should be something like this.

1 0
2 0
3 4-5 volts
4 0
5 0 should be connected to ground
6 0
7 0
8 9 volts

If you get any voltage on 6 or 7 then it most likely means you've got a solder bridge or something else touching the 9 volt trace.

Hope this helps

[analog kid]

Thanks, I guess I never thought about checking voltages to IC pins, OR EVEN FIRING UP, without the IC in there. I usually just do resistance that way. Anyway'
I am getting Zero everywhere I should  INCLUDING 6/7 (but trust me I do not lie when i tell you I really am getting 8plus volts on 6/7 with most dual op's! then only .06v with a couple of precision BB chips I have. ? ? ?
BUT I DO FIND ONE thing a little fishy when checking this as you described. For pin 8 I am getting + power supply vltg BUT for Pin 3 , even with a fresh battery I am only getting around 1.8volts!!!!  I take it this could be a problem?? But could this side of the chip effect anything with pins 6/7? 
And would it be anything for explaining why mine only sounds defined at MAX GAIN, and flabby and muddy at any lower setting?
I will trouble shoot around Pin 3 and check values for now til I hear back though
Thanks again

[slacker]

The 1.8 volts looks a bit low to me, I think you should be seeing nearer to 4 volts.You seem to be getting about the right voltage with the opamp installed though which is a bit strange.
What voltage do you get if you measure at the voltage divider where the 3 1M resistors and the 1uF cap meet, you should definately get 4.5 volts there.
I can't see how the biasing affects pins 6 and 7 though. Hopefully someone else might have some ideas.

[analog kid]

Check at the 1M bias divider
YEP I was going to do that next after I looked at the schematic .  I am also thinking of trying a "bias stability " mod (if it's NOT close to 1/2v and the parts values are right) that I saw before that Jack Orman recommened for this circuit before.   I think it involved dropping those 1M's down to like 100k , kind of like the noiseless biasing method for MuAmp JFET crkts,  and Upping the 1uf cap to 10uf.   I don't know what would drop that voltage so low so I thought this might be worth trying.

[analog kid]

Yeah I checked and it's not as low as 1.8 there but not more than 3volts at the divider. SO I took out the 1M resistors and tinkered with the values to adjust the Pin 3 voltage (checked w/o IC in ) It ended up being I think 390k pair to bring that Pin3 to exactly 4.5v.
Should I LEAVE it that way , and is it crucia that pin 3 be at 4.5?
Because doing so NOT ONLY didn't change the 6/7 being 8volts with most 4558 type op's , but also brings PIN 1 up pretty high , compared to the reference vltgs. , up to close to 7vlts.    Is that too high       
I think it was 1/ 6.9v 2/ 5.4v 3/ 4.5