Back in 2018 (https://www.ssguitar.com/index.php?topic=4453.0), I was pondering creating a basic SS amplifier that had all my best ideas in one box. Now it's 3 years later and I still haven't built it, but I've been breadboarding! I've re-thought my opinions on 2-channel amps, and eventually came around to a new question... Is the clean channel nothing more than the default when you turn off the dirt? Like the wire that goes straight from input to output when you switch a pedal off? That sounds so boring, but can there be more to it?
I worked up an idea of making the clean channel run through a tone control and then through a single gain stage, which is how tube amps of yore were laid out. I'm not trying to purposefully emulate tube anything, it just struck me as a novel design decision that will alter the response of the gain stage and maybe introduce some pleasing audio anomalies. Or at least, that's what I'm hoping...
What do you folks think are essential elements of a good default clean channel? Squeaky-clean crystal clarity? Just a little grit on the top for flavor? Tone shaping ideas?
Some simple compression/limiting maybe? (Yes, Phatt, I remember your suggestion of the simple compressor.)
Crystal clean clarity? Foo, that would simply be a PA system, and we know that does not make a good guitar amp. What you think of as clean in a guitar amp is not really very clean. It just doesn't have the shrill raspy edges of dirt channels.
Go to DUncan amps and download the tone stack calculator and explore the tone stacks, you will see their response curves are not flat. Putting all the tone controls at center on your old Fender is NOT the flattest setting.
Hi Ed,,Try to keep in mind that there is no one section of a complete system that will reap magic,,
You build the sound/Tone you want out of what is mostly basic circuits most of which have been around for years.
If you want Clean then I take it you are talking about electric guitar?
In that case the clean will benefit from a little edge. (As Enzo just mentioned)
(My Cab sim, compressor, Phabbtone does that for me)
Regards OD and multi channels on amps,,, Been there done that and failed?
Pedals are far easier to get to where you want. It will depend on what styles you want to emulate.
For me it's just older rock and blues which is built from the little rattle of *Mictesters* Comp which is always on.
Then I add a home designed germanium clipper (that is my clean boost with a little more edge and OD) sweet. :tu:
For MORE heavy rock stuff (think ZZtop) I add a Boss OS2.
For all out scream I add a Boss SD1 (not totally happy with that but it does the job)
OK by now the bass and drums are playing louder so I press my Level Shift which just lifts the volume enough to lift it over the top.
Except for the Level Shifter all the added dirt pedals are set at much lower gain than most players I've known.
This helps a lot as with 3 Drive pedals it's way to easy to end up sounding like Mud or buzzing fizz with to much gain on any of those pedals. The Compressor is AFTER those 3 pedals and that keeps it all within a SET SPL of my overall volume,, without that it's a nightmare trying to keep them all within a certain SPL range.
If heavy metal is your taste then you might only need to add the pedal of your desire. 8|
Of course there are many ways to do similar things but this has worked well for me over the last ~10 ish years.
All that is running thru my crappy old Laney which I think I mentioned to you once before is not even a guitar amplifier, :lmao:
To do all that in one amp chassis is a tall order. :-X :-X Once you realise that all that would need many relays and a pedal board with many switches.
AND you are still stuck with a friggin pedal on the floor,,,, Naah xP
As much as I hate pedal boards it's just a lot easier to use pedals.
And if you don't like one you just swap it out,,, you can't swap out things in a complicated amp chassis in a few minutes?? xP
I just read your other posting and it seems I promised you some of my circuits :-[
I'll try and get some up soon,,, life is very busy at the mo but I WILL get something for you. :tu:
Phil.
Quote from: Enzo on February 15, 2021, 06:57:13 AM
Crystal clean clarity? Foo, that would simply be a PA system, and we know that does not make a good guitar amp. What you think of as clean in a guitar amp is not really very clean. It just doesn't have the shrill raspy edges of dirt channels.
Agreed. The problem is, that tube amps have an inherent non-linearity that everybody knows is the bees knees whether clean or dirty, while us SS guys are pretty much stuck with basically a PA powering a Celestion, and I want to do something about that without involving hot glass... ::) Hopefully without going down the tube emulation rabbit hole that many before me have plumbed to its depths already.
QuoteGo to DUncan amps and download the tone stack calculator and explore the tone stacks, you will see their response curves are not flat. Putting all the tone controls at center on your old Fender is NOT the flattest setting.
Yep, done that, and looked up and tried at least 10 or 15 various tone controls trying to find the one that hits my ears just right. Right now, the Brownface Bass/Treble control has my attention for the longest, so I'm sticking with that, but still researching an active Mid EQ to mitigate the -15dB mid scoop. FWIW, it doesn't sound all that scoopy to me, so maybe I'll leave it.
Oh, and look at the response curves of popular guitar speakers.
Quote from: phatt on February 15, 2021, 08:15:47 AM
Hi Ed,,Try to keep in mind that there is no one section of a complete system that will reap magic,,
You build the sound/Tone you want out of what is mostly basic circuits most of which have been around for years.
If you want Clean then I take it you are talking about electric guitar?
In that case the clean will benefit from a little edge. (As Enzo just mentioned)
(My Cab sim, compressor, Phabbtone does that for me)
Regards OD and multi channels on amps,,, Been there done that and failed?
Pedals are far easier to get to where you want. It will depend on what styles you want to emulate.
For me it's just older rock and blues which is built from the little rattle of *Mictesters* Comp which is always on.
Then I add a home designed germanium clipper (that is my clean boost with a little more edge and OD) sweet. :tu:
For MORE heavy rock stuff (think ZZtop) I add a Boss OS2.
For all out scream I add a Boss SD1 (not totally happy with that but it does the job)
OK by now the bass and drums are playing louder so I press my Level Shift which just lifts the volume enough to lift it over the top.
Except for the Level Shifter all the added dirt pedals are set at much lower gain than most players I've known.
This helps a lot as with 3 Drive pedals it's way to easy to end up sounding like Mud or buzzing fizz with to much gain on any of those pedals. The Compressor is AFTER those 3 pedals and that keeps it all within a SET SPL of my overall volume,, without that it's a nightmare trying to keep them all within a certain SPL range.
If heavy metal is your taste then you might only need to add the pedal of your desire. 8|
Of course there are many ways to do similar things but this has worked well for me over the last ~10 ish years.
All that is running thru my crappy old Laney which I think I mentioned to you once before is not even a guitar amplifier, :lmao:
To do all that in one amp chassis is a tall order. :-X :-X Once you realise that all that would need many relays and a pedal board with many switches.
AND you are still stuck with a friggin pedal on the floor,,,, Naah xP
As much as I hate pedal boards it's just a lot easier to use pedals.
And if you don't like one you just swap it out,,, you can't swap out things in a complicated amp chassis in a few minutes?? xP
Let me clarify: I've tried a lot of dirt pedals and amps (too many to mention) that never left the music shop in my hands, the few that have I don't have any more, and I am not financially flush enough to do any further experimentation with that, and frankly, I'm not all that interested. If I were to name my dream rig, it would be a Mesa Boogie Mark IIc+ or the Bedrock twin combo I tried out in 1992 or so, but didn't have the cash to swing at the time. I still don't, so that's that, but the point is I'm a "set it and forget it" sort, which means once I find something that makes me happy, I'll likely be happy with it for a while. Right now, I'm on a chase of a good clean tone that's not boring, but not over-complicated either.
What I DO have is a few buckets of spare parts, a little time, and a certain tone I'm chasing. I have designed a solid state dirt circuit that I'm about 99.9% happy with, and further tweaking is getting diminishing returns so I know I'm about done. My ultimate plan is to make everything modular (separate boards with connectors between them), so If I get REALLY unhappy with a preamp or tone control, or if the power amp dies and I can't find a replacement, I can simply swap it out. It might take a couple of days, but I'm not gigging, so I don't mind.
QuoteI just read your other posting and it seems I promised you some of my circuits :-[
I'll try and get some up soon,,, life is very busy at the mo but I WILL get something for you. :tu:
Phil.
No problem, this endeavor has gone on for more years than I'd like to confess, so I'm OK. ;)
So, the concensus so far is a bit of compression and judiciously chosen tone control to add some tone shaping and non-linearity to what would otherwise be no different from a monophonic Hi-Fi or PA.
Anything else?
Quote from: Enzo on February 15, 2021, 05:30:02 PM
Oh, and look at the response curves of popular guitar speakers.
Ya know, I was looking at speaker response charts, and they told me a lot less than what my ears could tell me. I can look at the steepness of the low- and high-end rolloff and judge how bassy or trebly they might be, but beyond that they don't tell me anything about any give speaker's fundamental character that I can't pick up immediately with a brief listen. I have a few ideas for what I'd like in a speaker, but that'll require more money than I have at the moment, and even then it'll probably be a Harley Benton twin cab. Cheapest in their class and they are genuine V30s, you know...
You need to go on a bender:
https://www.ssguitar.com/index.php?topic=3732.0
I brought up speaker curves, not so much for learning about individual speakers, but rather to demonstrate how "unflat" they ALL were, and how that is the major contributor to guitar amp tone. For example it doesn't much matter what the amp does at 8k-10kHz when none of the speakers gets much over 5kHz.
For me the short of it is yes, sparkly clean but with tone shaping. Normally a -10db dip in mids, centered around 600hz. After that it is up to preference if you drop lows or highs.
Quote from: joecool85 on February 16, 2021, 08:53:42 AM
For me the short of it is yes, sparkly clean but with tone shaping. Normally a -10db dip in mids, centered around 600hz. After that it is up to preference if you drop lows or highs.
Hi Joe, Your observation is correct but sadly it is only one piece of a much larger jigsaw puzzle.
If you insert that tone curve into a generic SS amp it won't sound like it's valve equivalent.
I'll try to ezzplain the why/what/how in general terms.
At nearly every stage in valve circuits there is a HPF created by the inter-stage decoupling caps ( this includes the power stages) and miller effect tends to roll off excess top end. If you are using Duncans Tone stack Cal it only shows that tone response as a separate entity which is nothing like what actually happens by the time that shape has been reshaped (or Mangled) by all the other sections of the WHOLE circuit that add or subtract from that curve.
Power stage in most SS power amps circuits is ALL DC (Direct coupled,, no caps) so a SS DC power stage = FLAT response,, while Valve power stage = big response curves adding even more hi pass as well as low pass.
The OT used in most guitar amps is also NOT 20/20 bandwidth Flat. Also as the power in an OT goes up the bandwidth tends to narrow,,Adding even more to that, most OT's can't pass really hi Freq so a lot of unwanted fizz is removed by design.
Sadly not so with SS DC power stages. :grr
A simple sim shows hi freq hash on the Primary side of OT but via the magical limitations of transformers the output side shows a nice square wave with smooth round edges waveform and the harder you push them the sweeter the sound. clever 8|
My guess is that SS passes all the crud,, You may remember that Mr Fahey uses output transformers with his big wattage SS Amps.
I have a SS 120Watt Factory PA here which runs a huge OT and the louder I run it, it never sounds harsh and my PhAbbtone is always bright. ;)
It pays dividends to limit your bandwidth for great guitar tone. Take away the excess crap that just gets in the way,, then UP the treble and it will bite without being brittle,,, That is TONE FOCUS Subtraction Not addition is the key.
So even after you have spent weeks in front of Duncans tone stack Cal trying to find the magic it still sounds crap when you put it together. The tone control is only fine adjustment of the whole SYSTEM TONE. The system tone is defined by all the stages and how each part removes or adds to that basic shape.
Something not often noted;
PSU in SS is rigid.
PSU in Valves is NOT it moves up and down a lot.
In Valve supply just changing voltage nodes can dramatically change how the amp responds as the power rises. AFAIK that does not happen in SS amps.
Regards to speaker tone;
Unless you are in the situation where you have many different speakers in the same room at the same time it's likely beyound the ability of a novice to make any meaning full judgement of any difference.
I'm sure there are others here with vastly more knowledge that might be able to explain it better but this is what I've come to understand after ~40 years of messing with 100's of different bits of gear.
Phil.
Hi Ed,
As promised just some schematics of my gear.
This is my OD pedal which only adds a little sand/grit/edge to the tone which helps the Compressor deliver a little more triode type rattle. the components before U2B are just a bit of extra tone shaping. No reason you can't build this into an amp circuit but you need switching which then makes it much more complicated. :-X
I'll add more soon as I find them all ,, been through a few hard drives in the last few years so I have been trying to retrieve a whole lot of files.
As well as trying to make sure they are up to date cause I've altered a lot of my builds.
As you have plenty of Breadboards you can try some of these out and see if it suits. Again don't judge a circuit on it own use them to build you whole system tone/sound.
Phil.
Duncan's calculator doesn't pretend to cover anything except the tone stack itself. Not the whole amp or any other parts, just the stack itself.
Quote from: Enzo on February 17, 2021, 04:25:07 AM
Duncan's calculator doesn't pretend to cover anything except the tone stack itself. Not the whole amp or any other parts, just the stack itself.
Yes I agree, that was my point. Sorry if I did not make that clear. :tu:
Having read many postings on forums and like I get the impression that quite a few punters get the impression those curves are what they actually hear.
Phil.
Quote from: phatt on February 17, 2021, 01:00:58 AM
Quote from: joecool85 on February 16, 2021, 08:53:42 AM
For me the short of it is yes, sparkly clean but with tone shaping. Normally a -10db dip in mids, centered around 600hz. After that it is up to preference if you drop lows or highs.
Hi Joe, Your observation is correct but sadly it is only one piece of a much larger jigsaw puzzle.
If you insert that tone curve into a generic SS amp it won't sound like it's valve equivalent.
He asked for a clean channel, I figured he meant just preamp. If that is the case, I stand by my argument. Of course, taste/preference is relative.
I do agree about what you said though. I've not tried using a transformer for speaker output, but I've thought about it because I constantly hear about it's magical properties.
One of my favorite stories is about Ken Bran, a designer for Marshall. He went on to design his own line of amps, the NARB amps. He reported once that he had a set of Fender transformers on his shelf and decided to put them in one of his amps instead of the Marshall ones. he said it still sounded like a MArshall.
Can the same be said about some of the more recent Marshalls ? A couple of threads about JCM2000's over at MEF right now. Seems like the quality of transformers used by Marshall has gone down. Has just the reliability changed, or has the sound changed also.
Quote from: joecool85 on February 17, 2021, 11:17:29 AM
Quote from: phatt on February 17, 2021, 01:00:58 AM
Quote from: joecool85 on February 16, 2021, 08:53:42 AM
For me the short of it is yes, sparkly clean but with tone shaping. Normally a -10db dip in mids, centered around 600hz. After that it is up to preference if you drop lows or highs.
Hi Joe, Your observation is correct but sadly it is only one piece of a much larger jigsaw puzzle.
If you insert that tone curve into a generic SS amp it won't sound like it's valve equivalent.
He asked for a clean channel, I figured he meant just preamp. If that is the case, I stand by my argument. Of course, taste/preference is relative.
I do agree about what you said though. I've not tried using a transformer for speaker output, but I've thought about it because I constantly hear about it's magical properties.
Per my (admittedly limited) knowledge, since it's SS, much of the "magic" has to happen in the preamp. If one wants to mimic power supply 'sag', or speaker reactance, it's gotta go before the power amp because that thing is linear all the way, toots...
Transformer output is particularly intriguing, because in my mind, it promises to deliver just a little of that non-linear "magic" we hear so much about with tubes. I am leaning toward a MOSFET power amp due to MOSFET designs being relatively simple to build, but I think it might also be a little easier to design around a transformer output. However, I don't doubt I may be plenty wrong about that. Searching around the internet, the general consensus reaction to the idea of transformer output on a Solid State amp is "But why?", and I guess they kinda have a point, I mean why use a transformer if the chips can drive a speaker directly? MOJO, that's why! :trouble
That said, if anybody has any MOSFET-with-transformer circuits, send them my way, especially if it uses one of those 70-volt PA system transformers; I have one, and they are pretty cheap as far as audio transformers go if I want another.
IM Experience, the easiest way to get close to what a transformer output can do is a Compression and Cab
sim circuits.
A cab sim is not hard to make as anyone who has built 9volt pedals can do it. It's a whole lot easier to do that than trying to work on the hardest part of the Amp where there are high currents and any mistakes can be expensive. A SS driven OTx won't give you the distorted PI like a real Valve circuit and SS PA uses Very stiff Power rails while Valves PSU is loose,, Hence the SAG/Compression.
And remember this;; Valve amps only really sound good when driven at higher volumes as that is when all the mojo they talk about really happens, at lower volumes it's not so obvious. No SAG. A lot of Valve rigs now come with a master volume but many will tell you that it tends kill off the magic of the power valves and OT compression magic.
Here is the circuit for my Phatt Box which is the mictester Compressor and a cab sim all
in one box. Cab sim is loosely based on the Nobels SST1 which is similar to the old Rockman.
If I was to build this again I would change a few things so feel free to experiment.
Without the Cab sim the guitar sound is ok but you will never be able to cut through (as they say) when you need it. This is where relying on your tone controls is not enough.
Even a bright switch will add way too much hi freq hash,, especially if the bandwidth is already too wide for OD guitar sound. Yeah you might cut through but you will sound like crap. :-X
Listen to some Santana,,, 90% of that magic smooth sound is actually under 1khZ
I worked out long ago that if you insert a compressor after distortion then you get close to what happens inside a Valve Power stage. Run that through a limited bandwidth (Cab sim) then even into an average guitar amp can sound quite slick.
I have a few Valve amps and yes they are very good at the magic compression at high volumes but my setup is light and can do a fairly convincing impression of an overdriven guitar sound,, as well as crystal cleans. And it's the same at any level.
I play with other people who might want to sing ballads then next up someone wants to play ZZTop.
Not a problem for me. 8|
There are plenty of proven SS power amp circuits that will do the job and super clean PAmps can be an advantage.
Take EVH as example, early on he used a Valve head driving a power resistor then tapped a line signal from that into a couple of 400Watt SS power amps which drove the massive speakers. So if you analyze that for a while it's really the same as an OD pedal driving into a SS power amp. The advantage with EVH idea is that ALL the tone/Bwidth/compression is done by design in the Valve head, he just needed a clean power stage at the end.
All I have done is used pedal circuits to replicate the Valve head dynamics,, It won't win prizes but does a good job.
Doing the tricks in preamp circuits can give you much more feel at lower volumes even with the most basic SS power chip Amp.
Also a pic of my main rig the pedal board is mostly DIY as runs from a Computer PSU which gives me 18V and regulated down for 9V. Although the Lappy PSU is not Earthed I've added an earth to the Secondary output as I've found that does help keep the humbugs away.
This whole setup is extremely quite even with all 3 dirt pedals on, helped by the fact that I don't use Dirt pedals with the Gain up high.
You could build this all in a head if you don't like pedals,, but you will still need a control pedal,, winky ;)
Phil.