Op amp questionaire!!!

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Op amp questionaire!!!

Postby AFF » 20 Jun 2009, 17:13

Okay I know the great people of this site are well capable of helping my latest question.

Who can explain the differences in the most common Op amps and the most common Op amp replacements.

For example I know some places swear that the 4885 is the perfect replacement in your new distortion or overdrive pedal. I have heard the newer Op amps with long number and letter names are more hi fi and better suited.

I have also come across that because the less clean and easier some op amps are the more you would be drawn to place that specific one in the circuit.

The main reason behind my question is a Metal Zone mod. It got me thinking more about the op amps ... the one I am modding has three (mitsu) op amps and I also discovered that Boss has produced 3 versions of the MT-2 and each had a different combination of the three.

I am very interested in the socket that allows you to replace your sinlge inline 8 pin and plug and unplu instead of solder and desolder!!! Great idea by the way ... I would love to start mixing and matching the dual inline pin op amps ... I saw a small board that allows you to place to opamps together and then the board will drop right into the single inline slot. I think Monte Allums offers one of these set ups and I am sure that mouser and other elec suppliers do also.

I know I will have do a little bit of spec research also to know what will and will not work together ... I know some have the 7 pin is hot and the 9 pin if not and then a different op amp is completely backwards.


SO THE QUESTION AT HAND IS : WHAT CHARACTERISTICS CAN BE HEARD FROM THE MOST COMMON OP AMPS AND THE MOST COMMON OP AMP REPLACEMENTS. EXAMPLE : BURR BROWNS DO THEY REALLY ACHIEVE A BETTER TONE THAN THE STOCK TS-9 CHIP? I UNDERSTAND DIFFERENTAPPLICATIONS WILL PRODUCE A SLIGHTLY DIFFERENT OUTCOME SO AGAIN I AM WORKING WITH BOSS PEDALS ONLY FOR RIGHT NOW. THANK YOU ALL SO MUCH!!!!!!!!
-AFF
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Re: Op amp questionaire!!!

Postby Electron Tornado » 22 Jun 2009, 00:30

Have you seen this video?

http://www.youtube.com/watch?v=bpTv2jAree8


If you want to try it yourself in a circuit using single in line chips, you can try making a socket out of a 16 pin DIP IC socket. Actually, that should give you two SIP sockets.
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Re: Op amp questionaire!!!

Postby Crimson » 25 Jun 2009, 13:43

I was courius as you when i first start building this kind of things...
So the second effect i made was a TS style overdrive with a "chip selector", so i was able to change from 3 different IC Chips just turning a knob.
I made some test and: for sure different OP makes HUGE o SMALL change on the sounds (dipends on the tipes of IC you're using) but you must have a quite good set up to hear the difference.
I'll try to explain...
The first thing you need is a VERY good amp and a good guitar.I made my test using a custom Sligo 59 bassman, a Fender Twin reverb '77 (an original one, just refurbished 2 months ago), a dumble-style custom amp and a jtm60 marshall, using a Fender Custom shop "something" strato, a PRS custom 24 and an Epiphone Les Paul...With the marshall and the epiphone (mid-low level setup) the difference were very small...With a serious guitar in a serious amp the differences were starting to caming out...
If you're changing from a TL072 to a TL082 (that are almost the same thing) you will not hear a big changes...If you try for example a Tl072 with an 4558 ( RC4558, JRC4558, MC4558) or a 1458 or a BurrBrown 2127 you really can hear (i repeat if your hears and the rest of the rig are good enough!) the sound that is different...
More "creamy" with the 4558, more focused and "standing out" with the BB, more "dry" and with less bass with the TL...
The main things that where changing are the response on low and mid low freq, the "attack" of the distorted sounds, and something on the mid-high freq that where bringing the sound more "out of the mix" or more "lost in the mix" (i found BB chips have a great attack and the distorted sound sounds better in the mix with other instrument that a TL072 or a RC4558 for example).
Of course, the overall tone, drive-style and other stuff remains the same, with all the OP amps a TS remains a TS, but imho there are some differences...
IMHO if you're modding a pedal for yourself you could buy a couple of different chips and find what is the best with the rest of your setup, but if you're modding mid-low level effect (just like boss ones) only changing IC don't waste too much time...I think a better improvement for that kind of effect is to change the signal caps with good quality film caps, change clipping circuit to find what you like best, than you can try some different ICs...

Crim

EDIT: I have not hear the video posted...But i don't belive too much on the youtube video...I only speak for what i've tried by myself :)
EDIT 2: we have also to remember that all the parts in a pedal are quite important.So maybe IC1 is better than IC2, but in tha same effect with all poor parts they sound the same...Could it be that is not the IC, but simple the "bottle neck" is something else that makes the IC sound the same...
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Re: Op amp questionaire!!!

Postby AFF » 25 Jun 2009, 15:21

Crimson wrote:I was courius as you when i first start building this kind of things...
So the second effect i made was a TS style overdrive with a "chip selector", so i was able to change from 3 different IC Chips just turning a knob.
I made some test and: for sure different OP makes HUGE o SMALL change on the sounds (dipends on the tipes of IC you're using) but you must have a quite good set up to hear the difference.
I'll try to explain...
The first thing you need is a VERY good amp and a good guitar.I made my test using a custom Sligo 59 bassman, a Fender Twin reverb '77 (an original one, just refurbished 2 months ago), a dumble-style custom amp and a jtm60 marshall, using a Fender Custom shop "something" strato, a PRS custom 24 and an Epiphone Les Paul...With the marshall and the epiphone (mid-low level setup) the difference were very small...With a serious guitar in a serious amp the differences were starting to caming out...
If you're changing from a TL072 to a TL082 (that are almost the same thing) you will not hear a big changes...If you try for example a Tl072 with an 4558 ( RC4558, JRC4558, MC4558) or a 1458 or a BurrBrown 2127 you really can hear (i repeat if your hears and the rest of the rig are good enough!) the sound that is different...
More "creamy" with the 4558, more focused and "standing out" with the BB, more "dry" and with less bass with the TL...
The main things that where changing are the response on low and mid low freq, the "attack" of the distorted sounds, and something on the mid-high freq that where bringing the sound more "out of the mix" or more "lost in the mix" (i found BB chips have a great attack and the distorted sound sounds better in the mix with other instrument that a TL072 or a RC4558 for example).
Of course, the overall tone, drive-style and other stuff remains the same, with all the OP amps a TS remains a TS, but imho there are some differences...
IMHO if you're modding a pedal for yourself you could buy a couple of different chips and find what is the best with the rest of your setup, but if you're modding mid-low level effect (just like boss ones) only changing IC don't waste too much time...I think a better improvement for that kind of effect is to change the signal caps with good quality film caps, change clipping circuit to find what you like best, than you can try some different ICs...

Crim

EDIT: I have not hear the video posted...But i don't belive too much on the youtube video...I only speak for what i've tried by myself :)
EDIT 2: we have also to remember that all the parts in a pedal are quite important.So maybe IC1 is better than IC2, but in tha same effect with all poor parts they sound the same...Could it be that is not the IC, but simple the "bottle neck" is something else that makes the IC sound the same...


Great explanation!
I definately understand what you mean about the components. Part of what I was looking for you touched base on also ... I have modded a few pedals now and just changing values with same cheap style of parts is big, upgrading components makes a less drastic change (unless you are changing parts that might have been causing unwanted noise or accepting a lot of interference.) For example ... I feel like I am hearing a difference when I exchange my caps with tantalum caps ... they seem to have a tone (maybe it's just that I am telling my ears to hear it???) but I like that !

So now I am looking at the op amp swapping ... I know some will allow a lot more of the modded sound to pass and some will clip that already clipped signal ... before I tackle the op amps on my MT-2 I want to gather all the info on them I can. MT-2's offer endless mods and I would guess that op amps would make more of a difference in the metal xone compared to my ds-1...

Thanks so much for the great info!!!

Last attachment to this ... I looked at the schematic for one of my Peavey PA mixers and found that it has a bunch of 4558 op amps in it. Along with repairing the inputs I was wondering if there is a better alternative for the 4558's or do you think they will work just as good as any other?


-AFF
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Re: Op amp questionaire!!!

Postby gus » 25 Jun 2009, 15:58

Are you the same AFF http://www.diystompboxes.com/smfforum/i ... ic=77278.0 ?
If so you asked the same type question at the other forum. You got a few good answers what do you want someone to tell you to use a certain opamp? I posted it depends because it really does depend. The circuit around the opamp can have more to do with the sound than the opamp.

Test it yourself most opamps used in effects don't cost that much, read a few good opamp books and/or web sites for what is going on inside an opamp, read the spec sheets, read about gain bandwidth product, input noise voltage and current it goes on...

There is no best there is the part(s) that work giving the sound the circuit was "designed" for.
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Re: Op amp questionaire!!!

Postby Crimson » 25 Jun 2009, 16:24

gus wrote:There is no best there is the part(s) that work giving the sound the circuit was "designed" for.


Or "giving the sound you like" :)
But Gus is right, the only thing that can tell you the right part for the effect is your ear(s).And also IC are so cheap parts...If you need a dual OP amps i suggest to try JRC4558 (i prefer them than RC4558 because i feel the RC less natural and more harsh than the JRC), NE532, TL062 (or 72) and if you cand find easily some BurrBrown dual OP.There is also AD712 that seems to be a very good one and LM833.
I think this 5-6 op could be quite different from the stock and from each other.

Crim
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Re: Op amp questionaire!!!

Postby Electron Tornado » 25 Jun 2009, 21:29

gus wrote:Test it yourself most opamps used in effects don't cost that much, read a few good opamp books and/or web sites for what is going on inside an opamp, read the spec sheets, read about gain bandwidth product, input noise voltage and current it goes on...




Great suggestion.

I really have to be the "man from Missouri" here. While tone is very subjective, and there is a lot of hype and bogus mojo out there about this or that chip, etc. I have yet to see anyone post or publish any real data to back up their claims. Which spec or combination of specs of various ICs contribute to the tone produced by an effect? Are tonal changes very noticeable or are they very subtle? Either way, what sounds "better" will vary from listener to listener, between different guitars, different amps, and different players even using the same guitar and amp.

I like the video by Visual Sound, because it's an actual side by side, blind test with a decent sized group of listeners. Despite what anyone's opinion of the video is, I haven't seen any other pedal maker do a similar test. (It would also be worth checking out who their engineer is.)
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Re: Op amp questionaire!!!

Postby spmonkay » 23 Nov 2014, 01:37

Hi would this be an equivalent chip to the burr brown 2127?
http://uk.mouser.com/ProductDetail/Inte ... Qgy4zus%3d

Thanks

Steve
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