madbeanpedals::forum

Projects => How Do I? Beginner's Paradise. => Topic started by: Aleph Null on August 29, 2018, 09:53:53 AM

Title: CD4049UB. Y Tho?
Post by: Aleph Null on August 29, 2018, 09:53:53 AM
The snark doodle, red llama, and all such similar call for the CD4049UB, but use only two of the gain stages. It's always seemed strange to me that the other four are just wasted. Is there something special about the Hex CMOS buffer? Couldn't you get similar results by slamming the output of one TL072 stage into the input of another? Please school me.
Title: Re: CD4049UB. Y Tho?
Post by: jkokura on August 29, 2018, 10:02:33 AM
Have you ever used one?

No more than 2 stages are needed.

Jacob
Title: Re: CD4049UB. Y Tho?
Post by: Scruffie on August 29, 2018, 10:28:00 AM
CMOS as opamps both soft clip and have limited bandwidth which can both sound nice.

No more than two are normally used as they're quite hissy and that gets worse the more stages of amplification you have in series.
Title: Re: CD4049UB. Y Tho?
Post by: Aleph Null on August 29, 2018, 11:20:24 AM
CMOS as opamps both soft clip and have limited bandwidth which can both sound nice.

No more than two are normally used as they're quite hissy and that gets worse the more stages of amplification you have in series.
So the quality of distortion is different than something like a TL072. That makes sense.

Having used a red llama, I get that two gain stages is enough. But why use a Hex CMOS instead of a dual CMOS? Is that sort of part jut not commonly available?

Sent from my SM-G920V using Tapatalk

Title: Re: CD4049UB. Y Tho?
Post by: alanp on August 29, 2018, 11:21:44 AM
4049 is a relatively common part, that longtime DIY'ers are likely to have in their stash. Simple as that.
Title: Re: CD4049UB. Y Tho?
Post by: Scruffie on August 29, 2018, 12:12:09 PM
There's no dual CMOS I know of, the lowest is 3 and it's still a 14-Pin DIP, plus different chips will exhibit different behaviours based on their specs as they're not designed for audio purposes in the first place.

That and as Alan says, it's a common part most people have access to and is useful for various applications.
Title: Re: CD4049UB. Y Tho?
Post by: jubal81 on August 29, 2018, 01:08:34 PM
Spotted this mosfet H-bridge a while back and was wondering if it might be fun to try out. The internal schematic looks about the same.


https://www.mouser.com/datasheet/2/115/ZXMHC6A07N8-94256.pdf (https://www.mouser.com/datasheet/2/115/ZXMHC6A07N8-94256.pdf)
Title: Re: CD4049UB. Y Tho?
Post by: Aleph Null on August 29, 2018, 01:52:39 PM
Spotted this mosfet H-bridge a while back and was wondering if it might be fun to try out. The internal schematic looks about the same.


https://www.mouser.com/datasheet/2/115/ZXMHC6A07N8-94256.pdf (https://www.mouser.com/datasheet/2/115/ZXMHC6A07N8-94256.pdf)
That could be fun.

I was thinking of going the other direction: use another gain stage for recovery after a baxandal eq, use another as an output buffer after the volume, us one or two more for extra gain for maximum fuzz...something like that.

Sent from my SM-G920V using Tapatalk

Title: Re: CD4049UB. Y Tho?
Post by: jubal81 on August 29, 2018, 02:05:57 PM
Spotted this mosfet H-bridge a while back and was wondering if it might be fun to try out. The internal schematic looks about the same.


https://www.mouser.com/datasheet/2/115/ZXMHC6A07N8-94256.pdf (https://www.mouser.com/datasheet/2/115/ZXMHC6A07N8-94256.pdf)
That could be fun.

I was thinking of going the other direction: use another gain stage for recovery after a baxandal eq, use another as an output buffer after the volume, us one or two more for extra gain for maximum fuzz...something like that.

Sent from my SM-G920V using Tapatalk
You could do that for sure. Check out the Ubescreamer at Runoffgroove.

That's not commonly done, because like Scruffie said, these are used for their distortion characteristics and they are noisy. Better to use FETs for opamps for those things. If you hate wasting the other stages, you can do different gain setups with them and switch them into the circuit like the ROG Double D.
Title: Re: CD4049UB. Y Tho?
Post by: gordo on August 29, 2018, 08:47:57 PM
That's an effect I hadn't thought of in ages. Sounded pretty cool and a singer buddy of mine that played guitar every few tunes loved it for his crunch and distortion tones. Gave it to him and ended up being his only pedal.
Title: Re: CD4049UB. Y Tho?
Post by: stringsthings on August 29, 2018, 11:44:34 PM

... But why use a Hex CMOS instead of a dual CMOS? ...


from "Electronic Projects for Musicians", Craig Anderton, 1980

"IC1 is a 4049 hex CMOS inverter/buffer that was never really intended for
audio use.  It's a digital IC (the type used in computers), and is generally
grouped with lots of other digital ICs to implement some type of digital
function (microcomputer, industrial control, and so on). But as it so happens,
each inverter of the IC may be modified to run as a linear (audio) IC,
and because these inverters are based on FET circuitry, distorting them
gives a tube-type distortion sound."

The 4049 is so inexpensive that it was probably never manufactured with less than 6 inverters.
The chip designers had 14 pins to play with.  6 inverters + 2 power = 14 pins.

It's still an extremely inexpensive chip.  Mouser will sell them to you for $0.141/chip
( 2,275 minimum )





joke of the day:   don't ask me how I know the minimum price.
( does anyone want to buy 2,273  CD4049 chips?  I ordered extras  ;D )

bonus joke:
they shipped them to me in packs of 8.
I'm thinking of opening up a retail store: 

 CD4049s 'R' us

open mon-fri -  noon to 8:00pm
closed on weekends and holidays for inventory control

Title: Re: CD4049UB. Y Tho?
Post by: jubal81 on August 29, 2018, 11:51:12 PM
Article on EDN a while back had an opamp made from 4 of them, so that should use up a few.
https://www.edn.com/design/analog/4424461/A-true-op-amp-made-from-inverters
(https://m.eet.com/media/1201661/DI5442f1.png)
Title: Re: CD4049UB. Y Tho?
Post by: Aleph Null on August 30, 2018, 09:43:14 AM
This thread has turned out to be more interesting than I was expecting.

Now I'm thinking it might be fun to experiment with two or three pairs of inverters in parallel with a high pass, band pass, or low pass filters before each pair. There's enough in the 4049 to make a two or three band eq with tunable saturation for each band.

Might be time to try and breadboard something...
Title: Re: CD4049UB. Y Tho?
Post by: lrgaraujo on August 30, 2018, 08:01:03 PM
This thread has turned out to be more interesting than I was expecting.

Now I'm thinking it might be fun to experiment with two or three pairs of inverters in parallel with a high pass, band pass, or low pass filters before each pair. There's enough in the 4049 to make a two or three band eq with tunable saturation for each band.

Might be time to try and breadboard something...


One of my idols in this forum, Vallhagen, has a project called the "The Ble Monster" in which he does pretty much that. And he manages to use all 6 inverters. I'm not much of an electric guitar player myself, much less a metal player, but his demos sound quite nice
Title: Re: CD4049UB. Y Tho?
Post by: storyboardist on September 05, 2018, 08:55:46 AM
I always felt wasteful only using 2 of the inverters with a Red Llama too. I came up with a 2-in-1 pedal that uses 2 inverters for a Red Llama, and the other 4 to make simpler/stripped down version of the ROG UBE Screamer Jason mentioned. It's in the same vein as a Way Huge Camel Toe, but fewer parts.

Title: Re: CD4049UB. Y Tho?
Post by: Aleph Null on September 05, 2018, 10:25:54 AM
I always felt wasteful only using 2 of the inverters with a Red Llama too. I came up with a 2-in-1 pedal that uses 2 inverters for a Red Llama, and the other 4 to make simpler/stripped down version of the ROG UBE Screamer Jason mentioned. It's in the same vein as a Way Huge Camel Toe, but fewer parts.
That's really cool. I like the name too.
Title: Re: CD4049UB. Y Tho?
Post by: storyboardist on September 05, 2018, 08:43:19 PM
I always felt wasteful only using 2 of the inverters with a Red Llama too. I came up with a 2-in-1 pedal that uses 2 inverters for a Red Llama, and the other 4 to make simpler/stripped down version of the ROG UBE Screamer Jason mentioned. It's in the same vein as a Way Huge Camel Toe, but fewer parts.
That's really cool. I like the name too.

Thanks. I got the idea around the time Top Petty passed and remembered that he and Mike Campbell were big fans of Way Huge stuff and that there was almost a Mike Campbell signature version of the Camel Toe (the Campbell Toe or Tone or something). Anyway, I named if after the band.