Peavey vk100 into some bassman like amp

[bea]

Indeed, Enzo, and indeed, my suggestion explicitly and intentionally means to reduce the level of the deep fundamentals a bit (6dB / octave is a weak reduction, even at 30 Hz).

Reasons:

a) the tone of an electric bass guitar is dominated by it 1st harmonic, not by its fundamental. This holds even for extremely bassy instruments like the Gibson EB-0. Too much energy in the lowest registers will lead to mudiness and to conflicts with the bass drum.

b) most bass cabs are tuned to something around 55Hz. The majority of the bass drivers are not suitable for lower tunings, except of course, specially designed drivers. But those drivers are reduced in efficiency (unavoidably - the lower a speaker can go the lower its efficiency).
With a relatively small amp like this it is (IMO) preferable to use drivers with a good sensitivity.

c) the lowest registers eat up a lot of energy - with many bass cabs that energy is simply wasted to silently move air around (vented cabs driven below their Helmholtz resonance). Not good for the speaker and it reduces the headroom of the amp.

If You d not believe me - simply try it out. It'll cost You a few ct for one or two capacitors of a few nF.

[Enzo]

Such filters are not brick walls. A rolloff under 70Hz does not mean that 69Hz won't come through. A 6db per octave slope means that if the rolloff starts at 60Hz, then 30Hz is only down 6db.

[überfuzz]

Correction
According to the all knowing internet the frequency of a standard tuned A-string is 55 Hz, B-string is 29 Hz. This would suggest that I shouldn't filter out these frequencies, i.e. the highpass filters you addressed should be as low as < 29 Hz. Right?

[überfuzz]

I would suggest to make C22 and C8 switchable to some smaller value yielding a 1st order high pass filter at around 70 Hz. That would reduce musically less important deep fundamentals.

I think 70 Hz is higher than the lowest bass note on a normal 4-stringed bass. A 5-string with a low B string even lower. The highpass filters you refer to was designed to pass frequencies rendered by somewhat normal basses.

Thanks for the input! I'll double check all high-pass filters.

[bea]

I would suggest to make C22 and C8 switchable to some smaller value yielding a 1st order high pass filter at around 70 Hz. That would reduce musically less important deep fundamentals.

[überfuzz]

I asked around in a bass players forum. They encouraged me to build an Ampeg like channel... Here's a first draft, please comment on faults or just weak spots in general.

[überfuzz]

Yes, this is a head.

This amp seems to be all about über-distortion. I'm not into that kind of sound.

[Jazz P Bass]

Have you 'checked out' the amp?

I had one in recently that sounded really bad.
It was a 2x12.

Half of the solder joints were 'crappy'.
I resoldered the whole amp.

Truly, I thought it sounded great.

Is this the head version?

[überfuzz]

Jazz P Bass - It's my way of gently saying, my crapper sounds better. :-)

[Jazz P Bass]

From the first post: "I have a Peavey vk100 that I don't really like.".

What do you 'not like' about this amp?

[überfuzz]

I think I coughed up something like 235$ for it. Not sure what I'll get if I try to sell it, i.e. the hardware is worth more to me than the cash I think I can get is I sell it... I have loads of knick-knacks in my stash so I could probably build it more or less with what I got...

[km6xz]

I would suggest selling the VK, it is at its peak value right now unmodified. The money from it would allow a better chassis and transformers, one of the keys to the Bassman style sound. You can get some great turret boards for those classics for a modest price from Hoffman that would be easier to tinker with than modding the thing trace pc board of the Peavey. You would get what you wanted with fewer compromises than if re-purposing the VK parts.
If you strip out the VK you lose 100% of its value and still might not like the result. Better to get the proper parts and build it as you would want.

[überfuzz]

Seems Ampeg is very popular. I was suggested to look into a some schematics. These suggested amps uses some James like EQ. Maybe I should have two preamps, a Fender and a James styled.

[überfuzz]

All those sleepless nights over Silver Faces turned into Black Faces. At last I will have revenge...

I know that Bassman generally is looked upon as a guitar amp. I've used a Bassman SF as studio and rehearsal bass amp for a while and liked it a lot, in addition to this I've often use AB763 amplifiers, while recording bass. But as I stated higher up n this thread I don't know much about different Bassman models. As of now I think I'll go for a Bassman 100Watt circuitry.

[Jazz P Bass]

What a shame.

Those VK100's are awesome amps.

Sell it.