Distortion
There are many types of distortion but in this "White Paper" we will be discussing three specific types of distortion.
They are the classic power tube distortion (ptd) pre amp distortion involving a master volume control (mv) and distortion by a distortion pedal BEFORE the guitar amp.
Power tube distortion (PTD) is the distortion type that most of us are trying to emulate. This is the distortion that all the classic rock records had. Hendrix, Cream, Black Sabbath, Deep Purple and Led Zeppelin all had PTD. Unfortunately PTD is extremely loud in the previous acts as they all started with 100 watt Marshall stacks. (Ritchie Blackmore quickly went to the Marshall Major amps 200 watts) The 100 watt Marshall driving 2 4*12 cabs is capable off 160 watts full output. (All wattage reference are in RMS ratings.) So how did this power tube distortion develop you ask? Guitar amps have been around since the 1940's and guitar players where a more off a supportive role with the odd sole here and there. Not until the early 1960's would we see amplifiers being turned up to get louder. With the development of Rock festivals such as Woodstock the guitar now had to cover large area with inadequate P.A's. The only answer was to turn the amps up louder. When this was not loud enough they added more amps. So how does this relate to me, well I do not think you can turn your 100-watt Marshall up to 8 in the house or small gig without been told to turn it down.
The invention of a Master volume circuit was developed, this allowed the guitar
player to turn the pre amp part of the amp up to full volume but keep the over
all volume down with the MV. Great now I have got all the distortion I want
but it does not sound the same. First of all with the MV turned down to 1 or
2 you will notice two things present 1: no bottom end 2: a fuzzy kind of distortion.
This is apparent in most amps not only Marshall's but also Fender Twins (silver
face with MV) the bottom end starts around 2-3 on the MV volume control and
the fuzzy kind of distortion fades to a very good distortion around 3-4 on the
MV control. Unfortunately again the volume is starting to get loud even with
the 50 watt amps. Not as loud as the amps with no MV but enough that small club
owners will start asking you to turn it down. So now where left with stomp boxes, not necessarily a bad thing. We have tube
screamers, tube emulators, stomp boxes with tubes in them to produce tube distortion
along with versus fuzz units. Some of the best distortion tones have been actually
created with stomp boxes. The Dallas Arbiter Range Master, (Tony Iommie - Rory
Gallagher) Ibanez tube screamer (Eric Johnson - Stevie Ray Vaughn) The Boss
Distortion orange box(Joe Satriani) the combinations are numerous. Speaking
of numbers one of Eric Johnson's tricks is to use a TS9/808 to drive an old
fuzz face that's how he gets the long Hendrix sustain. The one thing stomp boxes
have going for them is they are affordable. You can have a couple set to different
grades off distortion you don't have to have the amp cranked up so that your
flooding the area with sound to get your tone. Set the amp for a good clean
sound at a pre determined level with your band and then set the stomp boxes
to match or ride just above that level. The form of distortion that you require
will dictate what kind off distortion box you use. It would be recommended to
check with other players, artist you respect and guitar magazines. Try to find
pictures of pedal boards some artists will not always tell (Eddie Van Halen
- Billy Gibbons) the secrets for there magical tone at all. Best of all experiment
try different pedals some times one stomp box will work or you might need two.
Stomp boxes sound great when used with an amp that is been pushed a bit. You
might want to go to a smaller amp that is been pushed like a tweed Deluxe and
then put a tube screamer in front of that. I've seen this set up many times,
2 amps one for a clean sound one for a dirty sound use an A-B box. A Tweed Deluxe
or some small 20 watt amp set at about 6-8 on the volume and a Deluxe Reverb
with an E.V.- JBL or Altec for a clean sound. Substitute a high power Celestion
if you do not like E.V.- JBL or Altec speakers. Stomp boxes of choice and you
can have multiple sounds from screaming Heavy Metal guitar to clean snappy country
just by turning on or off a couple of stomp boxes.
So that isn't your cup of tee, still want the big amp sound with a four twelve
cab? Find a twenty-watt head and put it on 8-9 and this will give you true PTD.
There are enough boutique amp makers now along with some of the old classic
amps that you should be able to find some things to fit your budget and sound
requirements. The first time George Thorogood played the El Mo Combo in Toronto
he was using an old Gibson amp cranked up and miked through the P.A. Small wattage
amps cranked up with distortion pedals will give you a very convincing big sound.
This is one of the oldest recording tricks, set small amp cranked up to get
that big sound on to tape without blasting ones self and everybody else out
off the room. I have actually had people's jaws drop when I set little amps
up this way. By disconnecting the internal speaker and hooking up a closed back
2*12 or 4*12 cab this will give some distortion to lots depending on the amp
design. Then mild distortion is good for that old Stones, Black Crows sound.
If its got a lot off distortion you can get a good early Black Sabbath, Aerosmith,
classic rock type sounds. None of the old amps will generate enough distortion
for the 80's -90's type distortion styles. You will defiantly need a distortion
pedal to replicates that sound, unless you go for one of the custom boutique
amps. One of the best sounds I have heard was a Gibson 18-watt amp with a Celestion
Greenback 25 with a tube screamer simply amazing. Sounded like wall an of Marshall's
and was not all that loud. It was usable with a band and you could mike it through
the P.A. for larger gigs and that would thicken up the sound that the audience
would hear. This would also keep the stage volume down and allow the band to
play better as there is no volume battles.
Unfortunately the day off the 100-watt amp is gone for most of us. We are regulated to playing small clubs 50-300 seats and even these gigs are getting harder to find. Bar owners are requesting bands to play quieter than back in the 70's and 80's. In most cases most of us are better of with some form of the small amp scenario and investing the money in a high quality P.A. with monitors. This way you get the best of both worlds. True power amp distortion at a controlled volume for any gig. If your playing any hockey arena or football type stadium gigs pull out the Marshall stacks...... all 8 4*12s and 4 *100 watt heads... ha ha I didn't think so! What? Your playing Joe's Bar on the corner?....60 seater that place?
There are 2 options to this dilemma, stomp boxes or attenuates. Let me say that there is only two attenuators that I would trust are The THD Hot Plate, and The Trainwreck Air Break. I've seen problems with The Marshall Power Brakes and The Scholtz Power Soak. Both of these units cause tubes to red plated after about ten minutes of use. There is no compensation for the loss of high frequency as the volume is cranked down. The loss of highs is noticeable after about 9-12db. I would caution anyone using attenuators to very closely monitor there power tubes for red plating, as once this starts it can lead to catastrophic failure up to and including blown output transformers.
Now where did I put that schematic for that Gibson Falcon amp????
Rob Fowler
Classic Amps
©1998 /2003
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