Freight Train said:
You're only really hearing the vintage side if the blend is on 1. You're not blending in the other side.
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The Fender Bassman 100T thread
- Thread starter Tim1
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You're only really hearing the vintage side if the blend is on 1. You're not blending in the other side.
No, the active channel is a totally seperate channel. When blend is on 1, you're getting no gain. Nothing you do on one channel will affect the other. You'd set blend on 1 to do a test between the two tone stacks so the gain/distortion isn't coloring the sound.
Im pretty sure adivin is right on this one. The blend knob (like other blend knobs on fender amps) is mixing the overdrive channel with the vintage channel from a level of nothing to full. At one end of the dial its fully channel one, and at the other its fully channel two, in the middle its an equal blend of both, thus allowing you to variably choose how much clean fundamental you want and how much overdrive ya want. Add in the variable of gain, eq, and respective channel volumes and ya get a smorgasbord of clean/dirty tones.
That aside, im diggin your inquiry into the nature of our new favorite toy.
That aside, im diggin your inquiry into the nature of our new favorite toy.
Freight Train said:
Oh, I thought it blended the channels kinda like a pickup blend. How does it manage to only blend distorted signal when all the tubes are contributing to the overdriven sound?
This can easily be tested by setting up two opposite tones on each channel. 1 should give you the left side and 10 the right side.
Just tried it. Nothing you do on one channel affects the other. Even with blend on 1, the active channel will sound different because at the very least it has the active tone stack. But what I was trying to determine was whether the first gain stage of the two channels are the same circuit design. Reason being, if you look at the numbers I posted, just setting the tone stacks to match with the active stack in center "0" position and starting with the passive stack on all 10's, the active channel volume had to be 1 notch higher to match volume. But if the first stage of the two channels has the same gain (meaning gain of the preamp stage, not the gain/distortion control), in which case you'd set both volumes the same with blend on 1, then the passive tone stack is boosting, not just cutting.
The reason some would like to know where flat is - no matter how good a filter is, it adds more and more phase distortion the more you boost or cut with it. If you're trying to get the most accurate reproduction of the instrument, it's important to know where the flat setting is on any filters in the chain that can't be bypassed. The type of phase distortion that filters can add isn't so apparent when you listen to the instrument by itself, but that is one of the elements that causes an instrument to wash out when mixed with other instruments. Anyone who's spent a good amount of time in a professional recording studio with a real monitoring environment is well aware of this. Even though this would be more noticeable in the studio than live, once you become attune to the problems phase distortion causes you can hear its affects live as well. But most likely only if you're using a straight-wire approach with minimal or no boxes between the instrument and amp.
The reason some would like to know where flat is - no matter how good a filter is, it adds more and more phase distortion the more you boost or cut with it. If you're trying to get the most accurate reproduction of the instrument, it's important to know where the flat setting is on any filters in the chain that can't be bypassed. The type of phase distortion that filters can add isn't so apparent when you listen to the instrument by itself, but that is one of the elements that causes an instrument to wash out when mixed with other instruments. Anyone who's spent a good amount of time in a professional recording studio with a real monitoring environment is well aware of this. Even though this would be more noticeable in the studio than live, once you become attune to the problems phase distortion causes you can hear its affects live as well. But most likely only if you're using a straight-wire approach with minimal or no boxes between the instrument and amp.
Look at the block diagram in the manual. The hi/lo inputs go straight to a tube preamp or buffer stage, v1, and after that the signal splits three ways - on the vintage side it goes to the passive tone stack/bass boost first, then vintage channel volume, then 'bright', which is interesting. On the active side the signal splits and goes both direct and through the gain/distortion circuit, which has it's own tube, v2, and they meet up at the blend knob, which blends between the direct input signal (after v1) and the gain/distortion circuit, then to the active channel volume and then to the active tone stack. But after that v1 buffer or preamp stage, the two channels never cross or blend.
So both channels share v1. but the character of the vintage side is coming more from the passive circuitry in the tone stack. The active channel still sounds quicker even with blend on 1. mostly because of the active filters I would think. But there may be more difference than the simple block diagram shows.
So both channels share v1. but the character of the vintage side is coming more from the passive circuitry in the tone stack. The active channel still sounds quicker even with blend on 1. mostly because of the active filters I would think. But there may be more difference than the simple block diagram shows.
Got to agree with Freight Train on this one, the two channels seem totally independent to me. And by the way Freight Train, I think you missed the point on my earlier post, but that's cool with me 
. It's a great amp either way. Must agree with you also about new neo cabs, they can "bark, grunt, thump, roar" as you say - in fact I am considering letting go of my Bergantino 610 and just running with the Fender (the Berg 215 will go to my grave with me though).
. It's a great amp either way. Must agree with you also about new neo cabs, they can "bark, grunt, thump, roar" as you say - in fact I am considering letting go of my Bergantino 610 and just running with the Fender (the Berg 215 will go to my grave with me though)."Bear in mind that this is all assumption and my settings depend on my bass, the room and my ears as much as anything else." tim1
i tend to agree tim , im interested in how the eqs work and channels compare, but when i set up in a room i just keep turning knobs untill i tune into a sound i like.
i tend to agree tim , im interested in how the eqs work and channels compare, but when i set up in a room i just keep turning knobs untill i tune into a sound i like.
scotch
It's not rocket science!
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Freight Train said:
Admittedly, I'm confused as to what youre trying to determine regarding the indepence of the two channels- but, if it is helpful, keep in mind that those 12ax7 preamp tubes essentially have 2 "halves" which can be used seperately for gain stages or even as drivers for other functions.
Not sure if this helps or not.
I was only trying to determine where flat was on the passive tone stack. May not ever use it there, but it's helpful to know as a reference point. You're right about the 12ax7's Scotch. If you look at the block diagram, it uses one half of v1 as the first preamp stage that the two channels share, and the other half is the 'bright' circuit for the vintage channel. Both halves of the second 12ax7 v2 are used by the overdrive circuit.
Hey guys, I'm only trying to figure out what makes this beast tick and how to get the most out of it. I'm not saying how anyone uses tone controls is wrong - there is no wrong. Whatever gets the sound you're going for is right. But after so many years as a recording and mastering engineer I tend to approach things by finding the cleanest, most accurate settings first and then using that as the canvas to start adding colors.
This is all good stuff and where I hoped this thread would lead now that I have the amp. I want to know how it works and not just blindly turn knobs. Over in the Streamliner thread someone scoped the amp to find various flat settings. The results were helpful. The eq on that amp, especially the mid control was counterintuitive. The eq was very interactive. I wonder what we're dealing with here?
That's the nature of passive filters. My favorite eq in my mastering room is the Manley Massive Passive. It's based on the Pultec eq's from the 1950's, which many say are the creamiest eq's ever made. But what a strange beast the Manley is. Each band affects the others in some way. Even within a band, it's Q will widen and narrow depending on how much you're using it. But I've learned from countless hours with it that it sounds much better if you cut rather than boost (yes, you can get gain from passive circuits. It's called Ohm's Law). And I think most if not all passive filters are that way. So that's why it's good to know where flat is, and then try to get the sound you want by cutting rather than boosting. You know, if you want more mid's, try cutting back on low's and high's and raising the gain rather than boosting the mid's.
Just for grins, I plugged in my iPod and it played fine thru the cab but then the bass guitar was canceled out.oh well. Just thought I'd try it. Still adjusting and trying out the stuff you guys post...
Did the neo cab sound decent with music?
Have we at least established that the vintage channel is cut-only as the manual says? It can't be THAT wrong.
BluesyCat said:Just for grins, I plugged in my iPod and it played fine thru the cab but then the bass guitar was canceled out.
Where did you plug it in on the amp?
Well, not according to what I was hearing last night (look back a page or so at the numbers I posted). With the vintage channel eq's all on 10, it was noticeably brighter than the active channel with the eq set flat. I had to pull the passive high's back to 6 before it matched. And to match the volumes the active channel volume had to be 1 notch higher. That's why I was questioning if the passive stack is boosting, accounting for the difference in volume settings, or if there's other things happening in the active channel that makes the volume settings not relate anyway.
Also, since I can't scope it, maybe the vintage channel is flat with all on 10, and the active channel's high eq is not flat in the center position. But I wouldn't think would be the case.
On the active side the center detents should give you flat response. Freight Train, is that what you were saying in an earlier post? I need to re-read that.
Yes, the center detent on the active channel eq should be flat. So what was happening is the vintage channel is quite a bit brighter with all of its controls on 10 when compared with the active channel's eq's all in the center position. You wouldn't think that the active channel's high band is wack and is cutting high's in the center position, so it must be that either the passive tone stack has gain in the high band, or that all the bands have gain and putting them on 10 is causing an interaction like happens in passive filters like this, or that the bands are so off from one another that that's the tone curve you get when they are in neutral.
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