4069 (or 4049) clean boost?

[Dragonfly]

Yeah, yeah, that's right, it's a bunch of mosfets, but you're are wrong!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! THEY'RE 6 Cmos BASED INVERTER BUFFERS, that means, there are 6 op-amps! Not discrete Mosfets. Maybe you were refering to the 4007... anyway, I preffer a discrete booster than an IC based one.

BTW, 4049U and UBE means "unbuffered"... they are the same.

You should use more exclamation points. 

And yes, a 4007 may be better suited for use similar to discretes...

Anyway, here are a few things that may pertain to what the OP is trying to do here....

http://www.diystompboxes.com/smfforum/index.php?topic=56838.0
http://www.diystompboxes.com/smfforum/index.php?topic=61605.0
http://www.vt52.com/diy/diypage/aren/fet/aren.html
http://engr.nmsu.edu/~etti/spring97/electronics/cmos/cmostran.html

[gez]

Although an individual CMOS inverter comprises a p-channel MOSFET stacked on top of a n-channel MOSFET, it behaves in a very different way than a discrete MOSFET when used as an audio amplifier.  Inverters have lower transconductance than discrete MOSFETs and this is partly the reason why you get the compression that inverters are well know for - do some work with a scope and you'll see that the signal starts to compress/distort long before it approaches the rails.  The result is limited headroom, and that's why a (well designed) discrete common-source amp, for example, will give you more headroom.  Totally different beasts.

Personally, I don't understand why people don't use op-amps for clean boosters.  It just seems a no-brainer to me...

[puretube]

Yeah, yeah, that's right, it's a bunch of mosfets, but you're are wrong!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! THEY'RE 6 Cmos BASED INVERTER BUFFERS, that means, there are 6 op-amps! Not discrete Mosfets. Maybe you were refering to the 4007... anyway, I preffer a discrete booster than an IC based one.

BTW, 4049U and UBE means "unbuffered"... they are the same.

not an opamp at all, such an inverter: it misses a noninverting input
(to compare inputsignals with the inverting one...)
http://www.diystompboxes.com/smfforum/index.php?topic=59383.0

[earthtonesaudio]

Personally, I wouldn't use a CMOS inverter for a clean boost.  Wrong tool for the job.

For pristine clean, I couldn't agree more.  However, with the input cap lowered to 1nF, Tim's CMOS Boost is "clean enough" for me.  I am working on something that will use the other 5 inverters, and needed some extra gain.  It just seems like a shame to let that last inverter sit unused.

[Renegadrian]

Is the pin 8 of 4049 dedicated to ground only or can it be used with pin 7 for other applications???

[gez]

Is the pin 8 of 4049 dedicated to ground only or can it be used with pin 7 for other applications???

If you look at the following data sheet, you can see how the individual inverters 'fit in':

http://www.datasheetarchive.com/pdf/347001.pdf

Pin 7 is the input of an inverter and pin 8 is the Vss pin.

[Renegadrian]

As I understood...Thank you very much, Sir! 

[slideman82]

Personally, I don't understand why people don't use op-amps for clean boosters.  It just seems a no-brainer to me...

Maybe because it's simpler, and, you know, theirs natural low order harmonic distorition sounds really nice, quite warm... these discrete boosters sound perfetc in solid state amps.
I think op amps sound quite cold (or the opposite of warm!). Have you ever listened to some Peavey Rage 15W?

[gez]

Personally, I don't understand why people don't use op-amps for clean boosters.  It just seems a no-brainer to me...

Maybe because it's simpler, and, you know, theirs natural low order harmonic distorition sounds really nice, quite warm... these discrete boosters sound perfetc in solid state amps.
I think op amps sound quite cold (or the opposite of warm!). Have you ever listened to some Peavey Rage 15W?

There are only two reasons to build a booster that I can think of: to amplify weak, single-coil pickups to get a louder clean sound from your amp, or to drive the hell out of a tube amp.  With the latter, there's a case to be made for driving the amp with a dirty sound, but for the former I'd want low distortion ('transparency'), low noise, high z in and low z out.  Enter the op-amp. 

As for simpler, there's virtually nothing it in if you do a head count of components.

PS  No self-respecting guitarist uses a solid-state amp (joke!)

[slideman82]

Well, just a mosfet as booster, then a buffer... and voila! But you're right, op amps sound cleaner, really good with single coil.

[Sack Puppet]

SS amps?

Intelligent self respecting guitarists know how heavy and temperamental a Valve amp can be

S.

[gez]

WIMP!