Amp Misconceptions

[headcrash]

If I may resurrect this thread...

One misconception I often encounter: gain pots with bright cap(acitor)s (ok, not an amp, but part of an amp..).

Many amps have bright caps on their gain pots.
This results effectively in cranked gain for a large travel of the gain pot, but with shifting the frequency of the onset from high to low, by turning it from zero to ten.

In other words: the bright cap pulls higher notes from before the gain pot to the next stage, thus bypasses the gain pot, with the pitch/frequency of the notes depending on where the knob is set (and of course depending on the value of the cap).
Still in other words: with lower gain settings, and only highs and high mids are bypassed and pulled through to the next stage.
Only with gain fully cranked, the bypassing of the gain pot is effective for all frequencies (simplified).


In some amps the sorrunding circuit diminishes the effect by a certain degree (for example SLO and its derivatives).
This can help us "tightening" our sound in these higain amps.
In many amps though the effect is very apparent, for example Marshall's Jubilee or 2203. Here we are often confronted with a rather thin sound on lower gain settings.

I think manufacturers should explain this to their users. This might help them to be able to shape their sound better, or also to decide or not on buying a specific amp.

Of course many amps don't have bright caps across their gain pots, such as ENGLs, many Friedman's,...


One thing, since the SLO has been discussed quite a lot here: if you like to tinker try substituting the R-C combination 470k || 2n2 before the gain pot of the lead channel with only a 470p cap. Works wonders for tightening up the bass, especially when using higher output, bass heavy pickups.
This is actually the main reason, why the Peavey 5150II lead channel is tighter than the 5150I lead channel.


What do you think?

 

[Bruce]

One thing, since the SLO has been discussed quite a lot here: if you like to tinker try substituting the R-C combination 470k || 2n2 before the gain pot of the lead channel with only a 470p cap. Works wonders for tightening up the bass, especially when using higher output, bass heavy pickups.
This is actually the main reason, why the Peavey 5150II lead channel is tighter than the 5150I lead channel.


What do you think?

I think I really like my SLO100

Im grateful there are folks out there who can make them sound better/different. Im the guy who wants to hear the final result.

470k I think of the cost of a house
470p looks like a movie file resolution I may have downloaded
2n2 looks like a degenerate ask on a dating website I’m probably better off not knowing what it is.

 

[headcrash]

I think I really like my SLO100

Im grateful there are folks out there who can make them sound better/different. Im the guy who wants to hear the final result.

470k I think of the cost of a house
470p looks like a movie file resolution I may have downloaded
2n2 looks like a degenerate ask on a dating website I’m probably better off not knowing what it is.

 

[headcrash]

Sorry for being so nerdy. The SLO is a damn fine amp, also without modding it

 

[DrewJD82]

I’ve been wanting to take an electrical engineering class so I can understand this stuff (I know there’s free resources, the only way I’ll learn is if I’m in a class environment with this stuff, I‘ve tried). I’m fascinated with it all and would love to learn how to tweak amps and pedals on my own.

 

[ejecta]

I’ve been wanting to take an electrical engineering class so I can understand this stuff (I know there’s free resources, the only way I’ll learn is if I’m in a class environment with this stuff, I‘ve tried). I’m fascinated with it all and would love to learn how to tweak amps and pedals on my own.

Me too. I know you said you like the classroom but have you found good online resources? I’ve several times thought of going Egnater’s class.

 

[Bruce]

I’ve been wanting to take an electrical engineering class so I can understand this stuff (I know there’s free resources, the only way I’ll learn is if I’m in a class environment with this stuff, I‘ve tried). I’m fascinated with it all and would love to learn how to tweak amps and pedals on my own.

Bruce Egnater has a 2 day amp building class but it’s only somewhere in the Midwest. Told him he should license it and sell the lessons. I’d take it.

 

[DrewJD82]

Bruce Egnater has a 2 day amp building class but it’s only somewhere in the Midwest. Told him he should license it and sell the lessons. I’d take it.

I’ve wanted to do that for a long time now.

 

[DrewJD82]

Me too. I know you said you like the classroom but have you found good online resources? I’ve several times thought of going Egnater’s class.

Well, none of them held my attention enough that I stuck with it. I’ve done several online courses now and had no issues but I think because I was doing those for work I had a different mindset. My company is willing to pay for my education, but the timing has yet to work out where I wouldn’t be killing myself to go to a physical school while maintaining my normal job. They’re going to start pushing on it again soon and it will actually be a major benefit to my job, I just need a proper staff in place before it can happen.

 

[Whizzinby]

Bruce Egnater has a 2 day amp building class but it’s only somewhere in the Midwest. Told him he should license it and sell the lessons. I’d take it.

That’s actually really cool. I’d like to take that and I have no intention of ever building an amp. Would just be cool to learn all the ins and outs, especially from someone like him.

 

[Bruce]

That’s actually really cool. I’d like to take that and I have no intention of ever building an amp. Would just be cool to learn all the ins and outs, especially from someone like him.

Me too. Even if just to learn to properly solder.

 

[Baba]

Me too. Even if just to learn to properly solder.

this for me too. I mean, I could practice soldering, but, I don't.

I only need to do it like, once a year, if that, so . . .

 

[MirrorProfiles]

People think you can buy a Diezel VH4, switch to channel 3, copy Adam Jones' settings, and immediately sound like Tool.

No. You can't. There's more to it than that, and his Marshall that he stacks with the Diezel is doing a lot of the heavy lifting. I love the VH4, but if you want that tone, you've gotta run two amps at once, and get your pickups and pedals right.

To add to this point, I think the same can be said for any of the amps AJ uses.

Even within the same song there can be different amps providing the bulk of the tone at any given moment. There is no single tone, it just depends on the song and the specific riff as to what it could be.

Intolerance’s bridge riff for instance sounds totally like a Mesa and nothing like a non-MV Marshall to me. Prison Sex has moments that sound just like a Marshall and nothing like the Intolerance tone.

There’s similar things throughout all of their albums - there are moments when it’s clearly a Marshall/Diezel/Mesa/whatever else and it varies a lot.

I also think that while it’s often a blend of amps, a lot of the time one amp will be the dominating sound. I think the Dual Rectifier is quite overlooked when talking about Adam’s tone, particularly on the earlier stuff where there are sounds that are nothing like a Marshall.

 

[laxu]

I feel like one of the biggest pits people (including me) fall into is putting powertube distortion on a pedestal. Some old school amps can benefit from it, some amps like Trainwrecks can really benefit from it whereas majority of modern master volume amps actually sound worse with anything more than a little bit of compression.

What people actually want is loud volume. You could buy a Fryette Power Station, plug the world's best amp (for your preference) into it and it won't sound that great if you try to run it at a too low volume. You might still have fun with it, but it's not going to sound anything like it sounds at 95+ dB volumes because a lot of that sound is entirely about our perception of sound.

You could record the cab at low volume, then at your "sounds awesome" volume, normalize the tracks and then play them loud through a PA and both would sound good to you and probably pretty similar. If you were to then turn the volume down enough both would sound like crap because how you hear it changes.

That's why I don't really use attenuators for volume reduction anymore and would rather just buy a master volume amp I can get sounding good at the desired volume level.

For actual low volume, I use a digital modeler because having stereo sound, effects etc and all the things I can do to the tone on my Axe-Fx 3 through studio monitors or headphones is better than trying to make a tube amp work through a real guitar cab at low volume.

 

[headcrash]

I feel like one of the biggest pits people (including me) fall into is putting powertube distortion on a pedestal. Some old school amps can benefit from it, some amps like Trainwrecks can really benefit from it whereas majority of modern master volume amps actually sound worse with anything more than a little bit of compression.

What people actually want is loud volume. You could buy a Fryette Power Station, plug the world's best amp (for your preference) into it and it won't sound that great if you try to run it at a too low volume. You might still have fun with it, but it's not going to sound anything like it sounds at 95+ dB volumes because a lot of that sound is entirely about our perception of sound.

You could record the cab at low volume, then at your "sounds awesome" volume, normalize the tracks and then play them loud through a PA and both would sound good to you and probably pretty similar. If you were to then turn the volume down enough both would sound like crap because how you hear it changes.

That's why I don't really use attenuators for volume reduction anymore and would rather just buy a master volume amp I can get sounding good at the desired volume level.

For actual low volume, I use a digital modeler because having stereo sound, effects etc and all the things I can do to the tone on my Axe-Fx 3 through studio monitors or headphones is better than trying to make a tube amp work through a real guitar cab at low volume.

Good point, and to underline that: nobody would seriously take a cranked-into-power-and-PI-stage-distortion Plexi for modern down tuned chugga chugga metal. To my ears this just doesn't sound good for THAT application.

In fact many modern high gain amps' overdrive/distortion sounds are finished in the preamp, and the power stage is there to amplify this, and ideally add some coloration when being driven into mild saturation.

 

[MirrorProfiles]

In fact many modern high gain amps' overdrive/distortion sounds are finished in the preamp, and the power stage is there to amplify this, and ideally add some coloration when being driven into mild saturation.

exactly this. Rectifier's and 5150's sound like shit to me when they are anywhere close to LOUD. Their sweet spot is enough to keep up with a drummer/gig with but once you go past that its a mushy mess that goes to shit. I actually also think some 4 holer Marshall's sound better through a power station than if they're blasting straight through a cab. You can fine tune the response of the load, refine things with the depth and presence and drive the cab however you like. Not the same thing is blasting straight through 4x12's but I don't really care for the ridiculous volume myself. Instant pain on the ears, the whole room is shaking, you have to control feedback etc. Not really fun for very long (and not really my favourite sound either).

 

[James Freeman]

Master < 1 elite club !

 

[Elric]

I’ve been wanting to take an electrical engineering class so I can understand this stuff (I know there’s free resources, the only way I’ll learn is if I’m in a class environment with this stuff, I‘ve tried). I’m fascinated with it all and would love to learn how to tweak amps and pedals on my own.

FWIW: You can get an Electrical Engineering degree and never hear the word "tube" once. You'll learn a lot about the core priciples and science though. I'd like to take Bruce Egnater's build a JCM800 clone class, sometime. I bet that would be a very cool intro if it gets into the theory side at all and I'm sure he would answer questions directly... Just building the amp would be educational I would think if you already have some core knowledge; so I really think it would be cool.

Unfortunately, haven't had a good workspace for that kind of thing since moving in 2012... I think I definitely would have built an amp by now, if I did... Was already doing pedals, etc.

Anyway I love the science talk. Cliff at FAS is awesome for that stuff, BTW. I love how he talks about the internals here and there. Lot of interesting stuff.

 

[Orvillain]

I'd like to take Bruce Egnater's build a JCM800 clone class

That genuinely sounds like it would be a great experience!

 

[DrewJD82]

FWIW: You can get an Electrical Engineering degree and never hear the word "tube" once. You'll learn a lot about the core priciples and science though. I'd like to take Bruce Egnater's build a JCM800 clone class, sometime. I bet that would be a very cool intro if it gets into the theory side at all and I'm sure he would answer questions directly... Just building the amp would be educational I would think if you already have some core knowledge; so I really think it would be cool.

Unfortunately, haven't had a good workspace for that kind of thing since moving in 2012... I think I definitely would have built an amp by now, if I did... Was already doing pedals, etc.

Anyway I love the science talk. Cliff at FAS is awesome for that stuff, BTW. I love how he talks about the internals here and there. Lot of interesting stuff.

Oh no doubt (about the tube thing), but once I have enough understanding of the language and the science behind it I can most likely go down other paths and have a much better understanding of it all. Just understanding what all the components do and how to read schematics would be a huge amount of info to build off of. Amps and pedals are just one aspect of electricity than interests me, I find it fascinating as a whole.

And yeah, maybe I’ll actually understand WTF Cliff is saying one of these days.