PreAmp Cathode bias Capacitor

[Bruce / Mission Amps]

When ever you reduce this cap the bottom end will be reduced and the amp will sound brighter as the frequency balance across the spectrum has been slanted more toward the top end.
You want to do this (reduce that cap) in 2nd, 3rd, 4th etc. gain stages in a high gain preamp so as to limit the bass energy being passed to the next stage, else the sound becomes muddy.

There is also an arguement about suppressing sub sonic intermodulation products - I don't know how valid that arguement is but it seems to make sense.

Cheers,
Ian
CAUTION: Ian's posts (mine) are based on my own preferences which don't include Marshall Amps (horrible shrill nasty things).

"Balance" being the key word there.... depending on the impedance of the circuit being bypassed, using a bypass cap of 1,360uF will pass the mids, highs and extreme highs as well as the 1.36uF cap. But it also will pass the deep lows, while the 1.36uF will not pass those frequencies as well.
Also, since Ian mentioned it...
although used much more commonly in Radio speak, not audio talk, what are the "sub-sonic" intermodulation products of linear and non linear frequencies found in most guitar inputs? Tricky question.

[J M Fahey]

I can answer that one: many think that since the lowest frequency generated by a string is lightly over 80 Hz, there's no way of having any lower.
And distortion always produces harmonics which are *higher* in frequency than the original one; in fact at least 2X or 3X above, so .... ?????
True .... for single notes.
But in chords you have many frequencies, and not only that, they are not wildly separate but often close to each other.
Now when you hit a non linear stage (the most extreme example being clipping), you generate a whole new set of frequecies which were never there before: the sum frequency ... and the difference.
And there you have a strong, modulating (by definition) frequency lower than any of the original ones.
Maybe not in that same stage but ib a later one, that modulation of useful sound by a low frequency, more often than not harmonically unrelated (since it's neither a multiple nor a submultiple of any of the originals) can sound ugly, muddy, you name it.
Keeping a tight control of lower frequencies minimizes that.
One classic example is early distortion pedals, as, say, an MXR Dist+ or many similar.
When playing single notes they provide sustain and bite, and are quite usable, but with chords they fall apart.
Even worse is the Big Muff.
The better behaved TubeScreamer already cuts frequencies below around 600Hz, go figure.
JM2C

[mooreamps]

Low frequency roll-off is accomplished another way...

-respectfully;
-g

[Chuck H]

Your vague setups are failing to intrigue me anymore. Get to the subject. The only reason I'd even look into what you may have to say anymore is because you've responded to one of my subscribed posts. If all you have to say is 'I know somethig." or 'I know something you don't.' I'm tired of it. Old game. Come up with a new one or come clean. What are you bringing? Why are you posting? Are you participating or just amusing yourself?

[big_teee]

Low frequency roll-off is accomplished another way...

-respectfully;
-g

I am the OP, long ago.
It's been an interesting Thread, and one I personally have learned a lot from.
When I started it, I didn't even know enough about bypass Caps, to even name the thread correctly.
I'm like Chuck, this is supposed to be a place to learn, and share with others.
If you have something to share about Bypass Caps, and high and low frequency, total and partial bypass?
Please share.
No petty Games, we are all Adults here.
I prefer things that can be backed up by documentation like the Merlin Preamp Book.
Thanks, and good luck,
B_T

[Gaz]

No petty Games, we are all Adults here.
I prefer things that can be backed up by documentation like the Merlin Preamp Book.
Thanks, and good luck,

This made me LOL. Clearly Big Teeee has not met Gary yet!

[Chuck H]

This made me LOL. Clearly Big Teeee has not met Gary yet!

Or he has Not that Terry is the type to poke at someone

[diagrammatiks]

The Amp Garage :: View topic - Twin Regulated Filament Power Supply

apparently moore is best at fires.

[Steve Conner]

Maybe that's how he got the sack from NASA?

[mooreamps]

Maybe that's how he got the sack from NASA?

....and this is why I don't publish my schematics on the internet....

-g

[R.G.]

....and this is why I don't publish my schematics on the internet....

In the spirit of channeling Spock and Data, I mean this purely out of curiousity and with all due respect.

Since the internet treats you so badly, why are you here?

It doesn't seem to work well for you. You don't want to participate in ways that the rest of the internet seems to want to work. Although I haven't done any looking, I have read here that your participation was banned at other forums.

What's positive enough about it to make it worth what you clearly regard as abuse?

[Chuck H]

What's positive enough about it to make it worth what you clearly regard as abuse?

Maybe Gary doesn't have a peer group elsewhere. Sort of like those Nat Geo programs where you see the outcast critter of one species or another that keeps hanging around the pack or herd in the periphery. Kind of sad really. Not being too sympathetic. There is a reason that animal isn't allowed to hang with the group.

[R.G.]

I really do wish that Gary could learn to deal on a reasonable basis with the greater "us". A while back I had this idea that he could learn to do that. And it really seemed to be working, because his last several posts were not belligerent, even if a little short on actual participation. I look up his posts here whenever I drop by, just to see how he's doing.

Maybe it's a temporary setback. I keep thinking he has something to contribute, but it doesn't seem to show up. Sad, really. Can't be any fun for him, in the normal sense of things.

[echuta13]

I suspect his idea of normal and yours are not the same.

[diagrammatiks]

....and this is why I don't publish my schematics on the internet....

-g

could not care less about your schematic.

that thread was about something you claimed to have invented, tested, and verified blowing up in something you built.