CE-2 question

[mike_a]

Hi,

I'm starting to build a Boss CE-2 clone with the tonepad RTS PCB.
I wanted to ask if anyone knows what would be the best replacement IC for the TL022 (the LFO IC), as I can't find it where I live.
I saw some people reported LFO ticking and I assumed it has something to do with maybe a wrong LFO IC replacement.
I've also seen people use a TL072 but it seems to me that the very big slew rate difference between them might cause problems.  Am I wrong?
Have anyone had a good experience with any other IC?

Thanks,
Mike.

[Fuzzy-Train]

I used a TL072 on mine and haven't had any problems thus far.

Just in case you need to do some de-bugging, here's some voltages:

[miqbal]

Actually, TL022 is used due to low current draw. Due to that reason, It have bigger chance that TL022 would produce less tick compare to a larger current draw TL072. There are some thread (I forgot where it is) that Marty has suggested an LF356 to replace the TL022. Well actually, I have  built CE-2 from Tone pad, I use a TL 022, and have some spares TL072. I'll let you know the result if I use the TL072 (just need a liitle spare time.... )

IQB

[mike_a]

Actually, TL022 is used due to low current draw. Due to that reason, It have bigger chance that TL022 would produce less tick compare to a larger current draw TL072.

Maybe I wasn't clear but that is what I meant as well (the TL022 is the original chip so it's supposed to be ok).
Which current draw are we talking about BTW?  I checked the datasheets and the only current that is lower on the TL022 is the supply current.  Is that it?
I would appreciate it if you got a chance to experiment with other IC's and could tell us about it.

EDIT: I just noticed that the LF356 is a single opamp.  do you know how he managed to use it?
maybe it's an LM358, like in the small clone?

Thanks again.

[Mark Hammer]

Yes, it should be an LM358, which IS designated as a low-current dual op-amp.  You will frequently see either the TL022 or LM358 as the dual op-amp used for LFOs.  The less current the LFO draws, the less susceptible it is to audible ticking, and the less additional effort the manufacturer has to go through to reduce the ticking.

[mike_a]

Thanks Mark.

But there is something which I can't quite understand: In the datasheet of the TL072 I can see that it's supply current draw is in fact a lot bigger than that of the TL022 (1.4ma vs. 130ua in the TL022).  The LM358's is stated as 0.7ma and the TL062 is 200ua.  Judging from these figures it would seem that the TL062 is more suitable than the LM358 for LFO uses.

Am I missing something here?

Mike.

[Mark Hammer]

Thanks Mark.

But there is something which I can't quite understand: In the datasheet of the TL072 I can see that it's supply current draw is in fact a lot bigger than that of the TL022 (1.4ma vs. 130ua in the TL022).  The LM358's is stated as 0.7ma and the TL062 is 200ua.  Judging from these figures it would seem that the TL062 is more suitable than the LM358 for LFO uses.

Am I missing something here?

We're probably both missing something.  The current draw is presumably one of those things that is not fixed, in spite of the circuit itself.  Just what happens to a TL062 and LM358 when the circuit produces a sudden current draw when on the leading edge of a square wave is beyond the perimeter of my expertise.  People have reported good results with an 062, though I can't tell you what their standards were or if it was as good as or better than a TL022 or LM358.  I'm pretty much relying on a) what I see looking at scads and scads of schematics using a traditional 2-opamp LFO, and b) what it says in the specs for op-amps in catalogs.  There ARE ways of reducing audible ticking with "regular" and nonrecommended op-amps.  Using low-current ones simply means you're not depending on one approach alone.

[Fuzzy-Train]

I believe you could also us a NE5532. I have one in my rebote 2.5.. it's a low noise OP as well.

Just another suggestion for ya'.

[miqbal]

EDIT: I just noticed that the LF356 is a single opamp.  do you know how he managed to use it?
maybe it's an LM358, like in the small clone?

Thanks again.

I'm sorry for putting the wrong chip code, I really forgot the chip code that Marty has posted in one of the thread here.
Thanks for Mark's correction.

Anyway, I already have some spare time today to test all the dual opamps I have in my arsenal. TL022, TL072, JRC4558. I also have the M5218L but it SIP (Single In-line Package) in the package so I can't use it. And guess what..., I have one LM358 in my junk box!!

Well, after putting them all in my CE-2 clone, this is my conclusion: NO big difference..., NO difference actually. All opamps produce NO tickle (not audible maybe; according to my ears).

I only heard a very very thin wavy sound when the guitar sound is decaying.
I have recorded all the 'sound' of the opamps, but don't know where to post it. Maybe I can send them by email, PM me.

Note: I build my CE-2 clone based on Tonepad. I created my own (but still the exact copy of Tonepad's) because I use the original transistor(need to turn the pin), 2SC732 for Q1-Q3, and 2SC945 for Q4-Q5, and can easily implementing all the mod described by Tonepad. Tonepad use 2N5088, really hard to find and more expensive in my country.

[miqbal]

Hi Mike,

Thank you for your suggestion on putting my files on the gallery.

Here you go:
http://aronnelson.com/gallery/v/membersonly/sound_clips/

No sound editing.

Lets see what you think.

IQB

[mike_a]

Thanks for posting the files!

They are indeed very similar.
If it's not too much trouble, I would appreciate it if you could add some details on your build, such as:
Did you use shielded cables?  If so, where?
What power supply did you use?  Battery?  Wall Wart?
Was the circuit a stock tonepad circuit or did you make modifications to it?

Thanks again,
Mike.

[MartyMart]

From my CE-2 build report :

SUBS:
R52 - 47r all i had
C5/10/14 47n as I had no 33n's
C9/C17 - 1uf poly caps
IC1-NE5532an / IC2-TL072cp
D1/2/7 1n4148

MODS:
Added the vibrato switch
Added the 250k blend pot ( linear, so bunched up but works fine to allow more clean gtr through)
Changed C22 (47pf) to a 68pf for more depth ( not switchable )
Changed R32, the 1M to the rate pot to a 470k for much faster top end rate

Marty.

[miqbal]

Thanks for posting the files!

They are indeed very similar.
If it's not too much trouble, I would appreciate it if you could add some details on your build
Was the circuit a stock tonepad circuit or did you make modifications to it?

No problem.

There are some modifications, but no technical reason behind them, I think.
what I do:

• Changed the transistor pads formation, from in-line to a triangle-shape, so any pin arrangement can easily be accommodated.
  On the stock layout, you can easily put any transistor which has an E-B-C (Emitter-Base-Collector) pin arrangement. It would be harder if you want to install a transistor with different pin arrangement, E-C-B for example.
  Actually, I use 2SC732 for Q1-Q3, and 2SC945 for Q4-Q5, they are all E-C-B (Emitter-Base-Collector).
• Add a 2nd (latest) version millennium bypass (millennium 2).
• Add some components to accommodate all mods as suggested by Tonepad (1 cap for intensity selector, 1 cap for wet bass, 250k pot for effect level, and 3 SPDT switch).
• Change C2/C9/C17 electrolytic cap to wima type (I don't have the elcos on my box)
• Haven't put the C4/C16 ceramic cap (same reason with no.4)

I have put my CE-2 layout, check this out:
http://aronnelson.com/gallery/v/membersonly/sound_clips/
I wish I could post the picture of my populated board, I have no camera around.

Did you use shielded cables?  If so, where?

No shielded cable. Actually it has not been boxed yet (I have two more, still waiting for the enclosure, no Hammond distributor in my country .

What power supply did you use?  Battery?  Wall Wart?

Standard DC adaptor. It is adjustable, 1.5 to 12V, 650mA. I have check the inside, it use standard LM317 adjustable regulator circuitry.

Note:
My millenium II bypass is still problematic. The led is always on, even I connect the fx-out to the millenium 'check' pad.
Someone has put a thread that he had made his millenium 2 alive after his 4th trial on 4 BS170 mosfets.
Better you use the first version (millenium 1).

Hope it may help.

IQB

[mike_a]

Many many thanks Marty and Muhammad for your replies!

I hope to start building this weekend.

Mike.

[Joe Kramer]

The TL062 is an ideal LFO chip for 9V stompboxes.  Low power, and interacts very little with the PS lines.   I've used it many times with great success.  FWIW, it will give you a slightly wider voltage swing/LFO sweep than the TL022 also.

Regards,
Joe