DS-1 FANS !!!...OPA2604AP in a DS-1 ***pics***

[jschwalls]

I was REALLY bored today so i decided to mod another DS-1 and also swap the chip with something different...

The result is a much quieter pedal, bottom is a little saggy now.. i will need to remedy that...
overall it sounds much better, the highs are very nice and mids are really punchy.

This is a great lead tone pedal...

i tried different chips before settling on this one.
JRC4558, ti4558, TL072N, and the OPA2134PA.. I like the OPA2604AP the best...nothing really exciting about the other mods.


Still this pedal isn't even close to my beloved BD-2 which i  will discuss in another post.






note.. hahaha if you look at last picture you can see my Tubescreamer collection.. hahaha

[ayayay!]

The cap right above r36, what's that for?  Isn't that a diode placeholder? 

And the 3 resistors in series on r13? 

[jschwalls]

the cap above r36 is just upgrading the old crappy cap...

Jon Schwalls
DS-1 mods

C1.-----0.1 uf
C2.-----1 uf tant
C3.-----0.1uf
C4.-----470pf
C5.-----0.1 uf
C7.-----220pf SM
C8.-----1uf tant
C9.-----1uf tant
C10.----0.047uf
C11.----0.047uf
C12.----0.1 uf
C13.----0.1uf
C14.----1uf tant

R1----1k
r33---20k
R14---1.5k
R13---2.4k
R16---6.8k
R2----470k
R35----1.1k

D4-----3mm red LED
D5-----3mm red LED + original diode series

nothing original about the mods... basically a Keeley rip-off..

the new opamp sounds alot better.

[sevenisthenumber]

Ive been using these for a while. A burr brown in a blues driver is sweet!!!!   their cheap too!

http://cimarrontechnology.com/index.asp?PageAction=VIEWPROD&ProdID=34

[jschwalls]

thanks for the link.. i was wondering if somebody made these...

Happy new Year
JON

[Jobet]

That's a cool way to install DIP IC's. I do those by attaching a small daughterboard.

I'm partial to TL0X2 series though. The Burr Brown 2604's just sounded too clean and sterile for a dirt box in my ears.



The daughterboard is that thing wrapped in masking tape.

[Jobet]

Hey...wanna try something awesome ?

Try stacking an NE5532 with a TL072 !

[jschwalls]

Hey...wanna try something awesome ?

Try stacking an NE5532 with a TL072 !

I stacked a TL072 and a 4558 in a recent TS9 and loved the results.... i need to order some NE5532, you guys seem to love them..... thanks.

[Jobet]

Yeah.


And if you want more "breath", use a TL082 instead. The punchiness of the NE5532 combines with the tube-sounding "breath" of the TL082. Gawd, nobody needs a tube amp with this combo .

[Paul T]

The Burr-Brown OPA2604 is a very special opamp: Fet inputs( very high input impedance), it works in Class "A" mode (which is why the IC always gets a little warm), it accepts a maximum supply voltage of +/- 25V, gives 35ma max. output current and the unit-gain bandwith is 20Mhz (compared to 4Mhz for a TL072). It can give you a high, ultra clean output signal at a very broad frequency range (very high output with no harmonic distortion)...even TIDE can't give something this clean !!!

For a clean booster, this would be the perfect op-amp, provided you like a clean, untainted signal. It's been my op-amp of choice for a long time, and yet, it can give very subjective results...you either love it or you don't, depending on how it reacts to the circuit attached to it.

Putting IC sockets in your pedals (to swap different ics) is a very good idea, and the OPA2604 is a major contender.

Try it; you will be surprised.

[Nuts]

Thanks, I have to try it, It always needed more mids.

[Jobet]

The Burr-Brown OPA2604 is a very special opamp: Fet inputs( very high input impedance), it works in Class "A" mode (which is why the IC always gets a little warm), it accepts a maximum supply voltage of +/- 25V, gives 35ma max. output current and the unit-gain bandwith is 20Mhz (compared to 4Mhz for a TL072). It can give you a high, ultra clean output signal at a very broad frequency range (very high output with no harmonic distortion)...even TIDE can't give something this clean !!!

For a clean booster, this would be the perfect op-amp, provided you like a clean, untainted signal. It's been my op-amp of choice for a long time, and yet, it can give very subjective results...you either love it or you don't, depending on how it reacts to the circuit attached to it.

Putting IC sockets in your pedals (to swap different ics) is a very good idea, and the OPA2604 is a major contender.

Try it; you will be surprised.

Well, first off, the difference between a 4MHz and 20MHz bandwidth will be generally inaudible for our uses. 

Anyway, I found that the OPA series chips are ultra high-quality things, which could find a better place in microphone preamps and clean boosters, albeit their value in dirt stomps is very limited IMHO. I mean, isn't it a tad frivolous to put in an ultra-clean chip only to dirty up the signal in a clipping stage ? In a clean booster, these chips are simply irreplaceable and are sparkly, crystal clear. In an overdrive or a distortion unit tho, IMHO, they are wasted.

[km-r]

Hey...wanna try something awesome ?

Try stacking an NE5532 with a TL072 !

you mean soldering another dual op amp on top of one??? 

[Jobet]

Hey...wanna try something awesome ?

Try stacking an NE5532 with a TL072 !

you mean soldering another dual op amp on top of one??? 

Yup.

[km-r]

OMG that is soooo cool! ima try that NOW!

hey, seriously?

[Jobet]

OMG that is soooo cool! ima try that NOW!

hey, seriously?

Yup. Make sure the IC's are aligned, meaning pin 1 to pin 1, pin 2 to pin 2 etc etc.

[petemoore]

   I lost mileage stacking...never worked at it that much after overheating a couple OA's..
  getting the heat to the inside oa lugpin, when piggybacking, without overheating the 'top' opamp...kinda tricky.
  OT: One way to do it would require 2x board space, but then you'd have 2 sockets and could try all the piggyback opamp configurations using a much smaller count of OA's, no burnt ones [not so good for modding available dS-1 boxes].

[Jobet]

   I lost mileage stacking...never worked at it that much after overheating a couple OA's..
  getting the heat to the inside oa lugpin, when piggybacking, without overheating the 'top' opamp...kinda tricky.
  OT: One way to do it would require 2x board space, but then you'd have 2 sockets and could try all the piggyback opamp configurations using a much smaller count of OA's, no burnt ones [not so good for modding available dS-1 boxes].

You can make a small veroboard daughterboard with the 2 sockets wired in parallel then down to the mainboard using a ribbon cable.

Anyway, when stacking, what I do is piggyback the chips first. Then with a fine point soldering iron, I apply solder where the pins meet.

Never missed a beat nor burned anything yet. Just be careful and don't use anything hotter than a 30 watter, with 20 or 25 recommended.

[Paul T]

Well, first off, the difference between a 4MHz and 20MHz bandwidth will be generally inaudible for our uses. 

Anyway, I found that the OPA series chips are ultra high-quality things, which could find a better place in microphone preamps and clean boosters, albeit their value in dirt stomps is very limited IMHO. I mean, isn't it a tad frivolous to put in an ultra-clean chip only to dirty up the signal in a clipping stage ? In a clean booster, these chips are simply irreplaceable and are sparkly, crystal clear. In an overdrive or a distortion unit tho, IMHO, they are wasted.


[/quote]

You are absolutely right !

Working with guitar pedals, this feature does seem "over-kill", however, because the OPA2604 has such a broad frequency range, you will get much more higher harmonics content when pushing it into the overdrive/distortion zone (precisely because it can reach higher frequencies). This gives more sparkle to your sound, but can lead to bad oscillations, if there is too much gain, unless you tame the signal by putting a higher than normal value capacitor in the feedback loop.

This IC just has a different sound: it's easier to get more harmonics with less gain.

Like I said, you either like it or you don't. I still think the OPA2604 can be used to compare with other opamps, as a reference point or just to see if your circuit is prone to bad oscillations.

(...my humble opinion !)

[km-r]

i also sometimes use alligator clips as heatsinks so that the pins dont overheat when soldering...