phatt's Schemo Collection

[phatt]

The Schematics Stuff I've posted has gone missing but not to worry I'll repost a few here :tu:

The DDC (Dynamic Distortion Control) by itself won't blow your mind but by implimentation of the *PhAbbTone* circuit *in front* of this will reap some classic guitar tones from a bygone era.
(All these clipping circuits distort,,,, but this is very touch responsive.)

The addition of a simple cheap Graphic Equalizer *After* the DDC will deliver more tonal options than most music shops have Amps.
Yes I use these circuits in my setup and I play live gigs (although not to much these days)

So I can vouch for their ability to deliver. :tu:
Phil.

[rodriki1]

Hi Phill,

Thanks for a refresh on your ideas here phill.

I am interested in asking you if you know a cheap circuit
for me to try in a way that i could "feel" the so called
tube compression...
sometimes i think i have some sort of problems with my ears!!!
after i did the presence control that is a cheaper version of
a cab sim... i think that 80% of the sound of the tube amp
is caused by filtering effect of output more the kind of wood
box (usually huge and expensive)...
the best stompboxes outthere uses cabsim...
WHAT I MEAN IS:
THE TUBES ARE NOT RESPONSIBLE FOR EVERYTHING IN THE SOUND OF TUBE AMPS.
Why people still keep believing that tube is so important???
besides it is not that cheap to make a real good vintage tube amp.
thanks

[bry melvin]

Actually "tube compression" is most pronounced when it is done with OUTPUT tubes. Also it is very apparent when the amp uses a tube rectifier and it creates a "sag". This can happen with a solid state rectifier but not as pronounced.

You ARE right that the "vintage" tube sound has other factors. These are sometimes deliberate as calculated resonant frequencies of good cabinets. Quality wood in the cabinet and type of speaker materials used.

Some of the "vintage" sound is actually due to deterioration in the type of components used.

You CAN change the sound some by using different capacitors of the same value. Orange drops , oil filled. polyesters all have a slight sound difference. Even Carbon composite resistors contribute toward that.

Some of the vintage sound was due to QUALITY of the tubes. Modern tubes are not manufactured to the same tolerances, and usually use different materials. The most apparent example of this is the 5881. Originally a milspec type there is negligible difference today between that and a "regular" tube.

That all said some of the tube sound stuff is hype. It usually is applied to a 12ax7 preamp. 12ax7s make good preamps, but the BEST tube sounds are from a hard driven OUTPUT 6l6 6v6 el34 7591 etc which is played through a speakers that handle but just barely the power that the amp puts out. Vintage tube amp speakers were designed to just barely handle the amps output. I remember how many I blew apart in the 60s.

When I play live in a large place using rig that includes Peavey Hybrids, Marshall JCMs etc. it ( output tube compression) is apparent. At low levels it really isn't.  In the recording studio I actually use more Solid state with the exception of a couple of 5 watt tube amps. To drive the high power amps into compression would produce sound levels unusable to record. I actually have a work table full of 5 watter experiments to get a tone I want on the album I'm working on.

FWIW I have a Carvin SX amp that can sound more like my (favorite) 64 Guild Thunderbird amp cranked than any of the modern tube amps I own. Of course the Guilds Fenders Sunns and Marshalls are always on stage. Even if the Carvins are doing most of the work

By the way there is a caveat with output tube compression:  If the amp is driven to that point you also have lag. The rectifier tube can't recover quick enough and you lose the beginnings of notes if your playing fast. Some amps start producing notes in there that you didn't play too!

Anyway look for that perfect tone that is in your mind...Don't care if it's from a tube or chip or transistor. If you have to go to a music store and play everything there.  Then if you have to find the schematic and make one

[teemuk]

I agree, tubes in the power amp do make a difference but each day I'm getting more and more convinced that the difference actually comes from the various distortion mechanisms and frequency response non-linearities, inherent to generic output transformer coupled tube power amp circuits, rather than from actual use of tubes. Solid-state amps emulating these mechanisms (e.g. Pritchard, Peavey TransTube, Vox Valvereactor, H&K Dynavalve etc.) do a pretty convincing job and the output waveforms of the circuits they employ can be tweaked to be pretty much identical to those of generic tube amps in overdrive conditions .

...Then again the whole definition of a "tube amp" is very broad and I've seen plenty of them distort quite differently than what the usual presentiment would make you expect. e.g. This is scope capture of a clone of one of those $$$ Trainwreck boutique amps driven to distort:


Kinda different from that "sweet soft clipping" prejudice. Hard, square waveish clipping and awful amount of crossover distortion. Yet, some people would sell their mother to get that tone. Most Class-AB Fender tube amps perform about similarly.

[phatt]

Hello Teemu,
                  Have a look at the dreadful *cutoff at V3* on the TW circuit.
Experts seem convinced that saturation is much smoother than cutoff,, yet as you note it maybe of little concern.

In My (limited) Experience, TW and really old Marshalls also,, The OT's have a very low primary winding and this (I believe though I can't mathamatically explain it)
Makes one hell of a difference to the end result.
I don't know the TW OT primary winding but I do know that some early Marshalls had very low primary.  ie; 1700 Ohms pp.
This I think you will find forces limiting of bandwidth (under load) and definitly accentuates the *Second harmonic*.
BTW, Obsolete Electronics had a whole blab about this but the site is now ,,,well Obsolete

I have built a 6V6 Amp with a 6k6 pp OT and it was very harsh.
short story;
Went down to 2k6 pp and the difference was staggering.
Absolutely the sweetest sound.

Taught me a lot and opened my eyes as to what can be done.
As you may be able to tell I've learnt to train my ears a lot and I pay a lot of attention to the tone shaping,, SS or Valves.
Phil.

[phatt]

Hi Phill,

Thanks for a refresh on your ideas here phill.

I am interested in asking you if you know a cheap circuit
for me to try in a way that i could "feel" the so called
tube compression...
sometimes i think i have some sort of problems with my ears!!!
after i did the presence control that is a cheaper version of
a cab sim... i think that 80% of the sound of the tube amp
is caused by filtering effect of output more the kind of wood
box (usually huge and expensive)...
the best stompboxes outthere uses cabsim...
WHAT I MEAN IS:
THE TUBES ARE NOT RESPONSIBLE FOR EVERYTHING IN THE SOUND OF TUBE AMPS.
Why people still keep believing that tube is so important???
besides it is not that cheap to make a real good vintage tube amp.
thanks

Heck I don't think that you can get it much cheaper than what I've given here. 

How on earth do I explain it?
Tubes/bananas/transistors/fets, all of em distort.
The sound that you *Likely* refer to is power tube compression Which comes mainly
from power stage quirks of some famous valve amps. (*bry melvin* has covered some
already)
The only difference between Valves and SS is the simple fact the valves tend to
compress rather than just distort/clip.
The output of a SS power Amp will not do the soft compress trick so you have no
choise but to make it happen in the preamp stages by using some circuit tricks.
I choose to do it the tried and tested way,, only twist is I impliment the tone
circuit and add a cheap GEQ.
(I'll never win awards for it but it gets some great sounds)


Worth a mention;
(This is why a Tube screamer will sound quite stunning through an old valve amp from
yesteryear but plugged into a all SS Amp it may well sound harsh/fizzy,,very different to say the least. Some Classic tube circuits rip off a lot of high freq hash in the output stages whereas SS amps do the exact oppisite,,so you tend to get all the high freq crap which destroys any smoothness)

Once you can grasp that tube amps work very differnt from SS you will see how darn
important the tone shape is.
Tone is everything if you are trying to extract specific sounds of certain genes of
music.

Forget Wood, Valves and PU's and all the hype, Understand this simple observation.

Tone is just the shape of the frequencies amplified,,, more importantly the ones
that *Are Not Amplified* deliver better results.

*****It's about what you don't hear that makes for fantastic guitar tone*****

Some classic tube amps did this tone shaping by design so when designing SS gear you
have to be very aware of this point.

(my favorite setting with above circuit is a big deep notch CUT @ 300/400hZ *Before distortion* and then cut again *after dist* at 800/1000hZ)
In other words you achive vastly better results by cutting certain frequencies then boost the gain.
Then you get far less circuit noise which means you have heaps more head room before
the dreaded noise/hiss of stupid hi gain stuff.

And that is how you get great distortion sound even with simple cheap SS gear.
If you have access to a *parametric EQ* then use that in front of a dirt box/TS99999,(Pick a model) Then use a graphic after it.

Again The trick with paraEQ is to *CUT,,,NOT boost*.
The Graphic; try a flat setting and just full cut at 1khZ.
Even without the Cabsim this alone will make a big difference.

Worth a mention is Speakers.
I'll tell you a little story;
My friend of many years came to me with his Teck21 Trademark60.
He simply asked if there was any way to make it sound like my gear.
I won't bore you with details but he was stunned at the result.

I simply replaced the speaker with a far *LESS Efficent* speaker.
***Remember***
Modern Amp makers use very high SPL drivers simply because the louder it sounds in
the shop the better chance of a sale.
(apparently young minds only respond to loud sounds)

High SPL drivers are ALWAYS Highest output in the 3khZ freq range and this makes the

amp sound a heck of a lot louder but you pay for it in tone,,,Harsh as all hell.
If you are chasing the sweeter tones of older amps then use of freaky slick named drivers is likely to seriously impair your progress.
The older less efficient drivers generally deliver a sweeter sound,,Hint.
Have fun,
Phil

[phatt]

Just adding this mud map showing how the 3 units are linked.
True Bypass on everything really helps when using different Amps/gear as you often need to find out the response of what you plug into.
Makes for a more versitile setup.

The other though here is that all 3 could be housed in a floor unit if you so wished but you will need a stomp GEQ for that.
I've housed it in a small rack and I tend to leave it set to one sound as it's so dynamic I don't need to keep changing it.

I use a small fet signal booster stomp pedal if I need a little more drive.
Just giving some ideas for you all to kick around.
Phil.

[teemuk]

Tone shaping... YES. That's where it's at!

Just to add, if you study just about any modern hi-gain amp you most likely find plenty of drastic hi-pass filtering before the overdriving stages. Usually many high-gain amps start to cut low frequencies heavily already at about 1 kHz, which is kinda counter-intuitive at first considering that frequency of low E is about 82 Hz. And that's pretty much the trick that separates muddy, fuzzy and farting distortion tone from creamy smooth distortion or snappy, ear-piercing treble. Too little: you get muddy, fuzzy tone (e.g. Laney Klipp amps). Too much: ear bleeding treble and nice bluesy clarity but not really enough balls to strum those heavy metal palm muted riffs. Low frequencies can really kill the distortion tone. Rest of the frequency shaping is pretty much just killing the "fizz" or voicing the distortion tone in various different manners.

If you wonder why people used treble boosters with tube amps it's just because of this: Drastic low frequency cut by boosting gain of higher frequencies - as a side effect it really helped to overdrive the tube amps (which at the time were mostly designed to produce the signal cleanly). The Tube Screamers were practically the same story: Many used them as a rather "clean boost" (with distortion dialled to minimum) - but in fact, the term "clean" in that case is somewhat misleading because those pedals happened to boost mid-range quite drastically by cutting low frequencies as well as highs. So, it wasn't a mere boost, it was once again important tone shaping for overdriving stages to follow.

[J M Fahey]

Kinda different from that "sweet soft clipping" prejudice. Hard, square waveish clipping and awful amount of crossover distortion.

+1
I don't know why that old wive's tale of "tubes clip rounded, SS clips square"  and "tube has even harmonics, SS has odd ones" is still being sickeningly repeated over and over, zillions of times, specially by people who should know better, I mean famous name factories, boutique builders and "tube gurus".
Just for kicks, scope the output of a Plexi when overdriven by 10/15dB , loaded by a real world speaker, 4x12" welcome.
It will be like nothing you ever imagined; "complex dirt" indeed.
"Rounded sinewave" my 4ss !!!

[rodriki1]

thanks again for the ideas here.

I just think here in my country is very expensive to buy a famous tube amp.

I like to know that some of you are willing to share the ideas and impressions.

as you mentioned there is a video of Brian May showing (in his opinions) how vox sound
bad without treble booster...
http://www.youtube.com/watch?v=nHEwL-Tqo7M&feature=related

very interesting
regards

[rowdy_riemer]

Worth a mention is Speakers.
I'll tell you a little story;
My friend of many years came to me with his Teck21 Trademark60.
He simply asked if there was any way to make it sound like my gear.
I won't bore you with details but he was stunned at the result.

I simply replaced the speaker with a far *LESS Efficent* speaker.
***Remember***
Modern Amp makers use very high SPL drivers simply because the louder it sounds in
the shop the better chance of a sale.
(apparently young minds only respond to loud sounds)

I like the sound of my little 5W amp, but I sure wouldn't mind a less efficient speaker if for no other reason than to make it quieter. When my wife is across the street at her grandmother's house, she can hear what I'm playing, and practicing with the amp after the kids go to bed is out of the question. I also do not like the way it makes my ears hurt when I've got the master volume cranked. I use a little sh#tty digitech RP-70 as a headphone amp for quiet practice, and it's just not the same as playing through a real amp. I think I might start looking for some old speakers to see how they sound. I added an external speaker jack to my amp, so experimenting with different speakers should be fairly easy.

BTW, next time I go to a thrift store, I think I'll pickup whatever old eq they have. :tu:

[phatt]

thanks again for the ideas here.

I just think here in my country is very expensive to buy a famous tube amp.

I like to know that some of you are willing to share the ideas and impressions.

as you mentioned there is a video of Brian May showing (in his opinions) how vox sound
bad without treble booster...
http://www.youtube.com/watch?v=nHEwL-Tqo7M&feature=related

very interesting
regards

Hi Rodriki1,
              Yes everyone knows about the famous treble booster,,, but it's kinda useless unless you plug into the *Correct input* on a Vox Amplifier.

Remember there are *6* inputs on the Vox.
normal x2
bright x2
Trem   x2

****Opps, No one ever mentions which one he used?****

The *Normal Channel High* is the one to use as it bypasses any tone stacks.
If you care to follow the signal path of the *Normal Ch* you will see that there is ONLY 1 preamp stage > volume pot > into PI and powerAmp setion.
Only the *top cut* control effects the tone while using Normal Ch.
Use of the other channels will NOT deliver the BM sound.

Take note that Brian demonstrates the sound without the TB engaged and it's very muddy indeed. (trained ears can tell there is no tone stack)
Still very dynamic, as evidenced by simply rolling of the volume on the guitar.

But this is exactly what you want to happen,, the raw dist sound is all there you just need to wipe off some bass. (Tone Shaping again)
This delivers the full midrange sing song effect of His sound.

(Interesting to note that the raw sound of my DDC circuit sounds just like the raw sound of the Vox normal ch.

The problem with chasing exact tones is Most guitarist don't play all Queen music and what happens if You need another type of sound? 

It's fine when you are rich you can have any gear you wish but when you exist on a very strict budget (Like Me) you can't afford to waste money on a one trick pony.
You need something a lot more versitle and not to complex to setup.

My thoughts on the B May signal path.
Note that there is only One half of an AX7 before the PI and power tubes. 8|

Does make you wonder why so many Valve amps today have so many preamp tubes yet a lot of those Amp's still can't quite capture any meaningful tone  :loco
Cheers, Phil.

[phatt]

Worth a mention is Speakers.
I'll tell you a little story;
My friend of many years came to me with his Teck21 Trademark60.
He simply asked if there was any way to make it sound like my gear.
I won't bore you with details but he was stunned at the result.

I simply replaced the speaker with a far *LESS Efficent* speaker.

I like the sound of my little 5W amp, but I sure wouldn't mind a less efficient speaker if for no other reason than to make it quieter.
BTW, next time I go to a thrift store, I think I'll pickup whatever old eq they have. :tu:

Hi, Can I enquire if the little 5Watt Amp is a Valve unit?
If so you can do some tricks by ReAmplifying it and then run it through the cheap Graphic (you will no doubt find at a junk sale) then into a second amp.
I've done that trick to a simple Valve Amp, with great results.
No one wants those old HiFi type EQ's anymore so they tend to sell dirt cheap. :tu:
Phil.

[phatt]

Kinda different from that "sweet soft clipping" prejudice. Hard, square waveish clipping and awful amount of crossover distortion.

+1
I don't know why that old wive's tale of "tubes clip rounded, SS clips square"  and "tube has even harmonics, SS has odd ones" is still being sickeningly repeated over and over, zillions of times, specially by people who should know better, I mean famous name factories, boutique builders and "tube gurus".
Just for kicks, scope the output of a Plexi when overdriven by 10/15dB , loaded by a real world speaker, 4x12" welcome.
It will be like nothing you ever imagined; "complex dirt" indeed.
"Rounded sinewave" my 4ss !!!

I read somewhere that half wave clipping followed by square wave compression is what happens.
In my limited building of Valve gear
Triode preamps do deliver the aysimetrical wave but it's the power stage square wave thing that is most usefull.

As I've just been revisting B May it 's interesting to note that with just a simple one triode preamp (which by itself can't do very much distortion) You only need to send the thing a bigger signal swing and Presto! all the magic power tube stuff just jumps straight out.
Phil.

[rowdy_riemer]

Quote from: rowdy_riemer on 16 May 2010, 22:27:13
Quote
Worth a mention is Speakers.
I'll tell you a little story;
My friend of many years came to me with his Teck21 Trademark60.
He simply asked if there was any way to make it sound like my gear.
I won't bore you with details but he was stunned at the result.

I simply replaced the speaker with a far *LESS Efficent* speaker.

I like the sound of my little 5W amp, but I sure wouldn't mind a less efficient speaker if for no other reason than to make it quieter.
BTW, next time I go to a thrift store, I think I'll pickup whatever old eq they have. Thumbs Up

Hi, Can I enquire if the little 5Watt Amp is a Valve unit?
If so you can do some tricks by ReAmplifying it and then run it through the cheap Graphic (you will no doubt find at a junk sale) then into a second amp.
I've done that trick to a simple Valve Amp, with great results.
No one wants those old HiFi type EQ's anymore so they tend to sell dirt cheap. Thumbs Up
Phil.

It is a valve unit. It's a Peavey Valveking Royal 8, with a few mods. I may do the re-amping thing. It sounds like a good idea. But I definitely would like to keep the setup as simple as possible for practice. I might try one of the various power attenuator projects out there, but I know they've got to have some effect on tone. I guess intentional impedance mismatching could also maybe help. Do you have any suggestions for a re-amping setup?