PhAbbZone pedal

[phatt]

Sounds great Phil, good job!

**edit**
Maybe I missed it, but what opamp did you use for that?

Hi Joe and thanks for the vote.

Arrh good point?? opps

yeah some TL074, simply because they take up less space.
Some LM883 and a mix of a few spare parts bin stuff 5448.

The first opamp is a single NE5534.

I built it mostly in stages,, so while the Valve preamp was mounted a lot of the rest was still on the breadboard.
Hence a lot of buffer stages may well be not needed but having been caught out with big losses by not having them I left it all as it was tested,, cause It worked,, so don't keep messing just throw all the boards into the box and hope like hell I've not missed something.

I did fluff up one board,, etched it wrong way round but who is going to know? 
Phil.

[phatt]

Now that is a nice sounding box of tricks you have made.  :tu: :tu: :tu:
I am tempted to scrap my ideas and just build a PhAbbZone pedal.....
something to aim for...

Kevin

It's a lot of work :duh but at least you have heard it and have some idea of the outcome. :tu:
Phil.

[QReuCk]

Thanks QReuCk and Roly,,
I guess my reply would be, ok try it suck it and see?

Yes you can up the Z if you want but you will likely run into trouble trying to balance the clean sound which will then have the hump as well as a lot more treble ,,which is EXACTLY what you Don't Want for this type of sound.

This mismatch is what sends the novice round the twist (did for me ) because quite obviously a lot of modern amps have way more bandwidth than is needed for rock guitar tone and finding the balance between the clean sounds and OD sounds is hard to balance even for professionals.

Disclaimer: I do play with multi chanel amps that have separated EQ for each chanel...

And as far as bandwidth is concerned I do think you can have a big part of the benefits of presenting a high input Z to your PU's without suffering all the troubles: I don't know exactly what physical phenomenon it is linked to, but if you allow your PU's to resonate and filter out the excessive high end, you will still have the rich sound of the attack (heard cause these harmonics are on a very different octave than the root so they don't need to be at the same amplitude) rapidely decreasing into a more filtered sound (high order harmonics from the instrument do fade pretty quick). I won't say it sounds amazing with very high gain, but for clean or for moderate crunch I think it sounds pretty cool, especially if you attack quite heavily with the right hand (oh and don't set the pick ups too close to the strings, nor the strings too close to the frets, these things need some air to vibrate).

Well that's what I came up with after a few tests with commercially available boxes, but it might not fit perfectly another player. Trouble is: you have to think your tone from one end to the other. One of these ends being the player himself, it's not easy to come up with a do-it-all solution.

[phatt]

Hi QReuCk,

Well sounds like you are like myself,, still learning,, lol.
But we are all on a learning curve and We share our findings. Good stuff :tu:

FWIW,, here is some of what i have learned;

Ok take that screen shot of Hi Z/Low Z input comparison that Roly has so kindly shown to us.
Now if you have a Parametric EQ available to You then try this test out on your ears to try and capture the concept of how reso boosting will impair the ability to reproduce a good sound/tone result.

OK,, Select Mid bands, Narrow Q and Boost the hell out of it and maybe sweep the freq knob (if available).

If you find anything useful then fine I accept that as we all have different ideas on tone. (munsons curve stuff)

Now try the INVERSE of the above.

Cut the Boost/Gain knob to full Cut. (delivering the inverse of what you previously heard, a Deep notch CUT)

My bet is that most folks will find the second tone shaping effect (Deep narrow cut) much more rewarding while trying to extract a decent sound from most audio equipment. (Especially Guitar gear)

A boosted Para Eq with narrow Q will deliver a tone shape not unlike what Roly's Screen shots show.

In My Experience this is a Nightmare to work with and you will have a hell of a time trying to find a good result.

I doubt even the novice will take long to grasp that narrow Q tone BOOSTING is problematic by design and will frustrate them at least until they have emptied their bank accounts on fancy pants addon pedals or other gimmicks that get sold like french fries at Macca'z.

In this Mad world where everything that says/implies MORE of anything is better than less has a long way to go before they understand the intricate details of sound.

It may well prove that what is NOT heard is what makes great sound.
Well that is my take on it all BUT I reserve the right to be Wrong and if shown how so I will bow
gracefully.  8|

With some of those old Valve Amps from a long ago era I can give you more USEABLE
Treble for Guitar from the *LOW* input (68k/68k voltage divider) than any other High Z input ever devised. It will cost you about 20 cents for the trick,, lol
Phil.

[QReuCk]

Thanks for the answer.
Rest assured I do think I have more to learn from you than you from me. 
Interesting point you have... and presented like this I fully agree with it: I do think as a general rule high Q band cutting is often better than high Q boosting.

But:
My preamps setting are often around the onset of clipping and as a consequence I try to maintain the other rule of thumb in my thinkings: Every filtering before the preamp (or first clipping stage) serves only the purpose of shaping the response of the clipping. Predicting how this will affect the clipping is very difficult as highs ride on lows (the assumption that pretend we can treat each frequency separatedly when thinking about it is an over simplification that might not work very good). Currently, even if this oversimplification works a bit to grasp the concept, it doesn't replace to me fiddling with any possibility before the clipping stage and hearing what happens. And my hears tell me both my guitars sound better (especially for clean to moderately overdriven tones) when buffered at a 3Mohm input than straight into the amp (which are more like 1Mohm if I remember correctly).

Well, as you say, I still got a lot to learn, and I really appreciate your views on this. Confronting different views does help learning things.

[QReuCk]

Oh and back on topic, you published a schematic of something that according to the sound sampled you put does work great. So even if I am always tempted to digress and ask for details that are not always relevant to the point (best way I found to learn things), you must be doing something right even if I don't fully understand how you do it.

And by the way I did some more testings and found out that exacerbating this resonant peak doesn't sound very pleasing when dealing with a higher gain setting that what I'm used to (I can live with that though as I very rarely use this kind of tone).

[phatt]

You might find it interesting if you care to go back in time when guitar amplifiers were rather sad affairs with terrible distortion figures and poor bandwidth, driving crap speakers.

Yet a vast majority of younger folks ask how to attain those old sounds.

They will struggle with modern equipment because the New world of hiteck digital everything claims to give you more than you will ever need.  :duh

I've found that word MORE to be most of the problem. wink.

you actually need less and in my humble experience works so much better and gives far better note definition.
Remember the fundamental freq of 90% of every note /chord you can play on guitar is hardly ever going above 1khZ.

With modern higain monster pu's and one Amp may contain more Amplification than a 60's rock concert,, well it's all just getting in the way.

Why just last Sunday I heard 2 guitar players. One chap playing one of those fancy Line 6 combos with more patches than a hells angels convention. A Great player with a lot of technical style but his tone just disappeared into one big pile of crap noise.
Frankly it sounded like a cheap bit of gear and I would never wish to own such gear.
The other player also very good,, but I heard every note he played and enjoyed it even with a couple of mistakes.

I can only assume the line 6 has all that digi efex stuff built in and has high spl drivers which I know can get nasty at hi levels. so it's harsh and the excess bandwidth can easy destroy higain sound.

The other guy had far less bandwidth,, I should know,, I built it for him. 8|
sorry if I'm blowing my own trumpet but it's a great buzz for a little backyard tinkerer to hear his own ideas up against some of the big brands like that. <3)

Tone focus is what gets the job done and that is very hard to get your head around and likely harder to impart in writing.

You need to hear these differences in real time, A/B testing.
Phil.

[QReuCk]

I agree that tone focus is key for the following reason:
- high order harmonics do sound bad, and some of them are even not hamonically correct (especially those from 7x fundamental frequency and higher). Filtering them out both before and after clipping is a good idea, especially after heavy clipping (square wave signals contain a lot of them). Before clipping they usually are a lot less prominent due to the natural behaviour of a guitar.
- when playing several notes (chords, double stops, etc), you will generate some intermodulation distortion, which is not bad in powerchords (the only case where the intermodulation actually adds harmonically related frequencies), but will be dissonant for most other intervals. The more clipping, the more intermodulation. You can filter some of it with low end filtering after clipping but the best way to limit that is to reduce the bandwidth before clipping, especially lowest end, cause you want to avoid clipped-generated harmonics of the lowest notes of your chord with the same amplitude as the fondamental of higher notes of your chord (especially considering a major third will be generated as the 5th harmonic... not that good in a minor chord...).
- highs ride on lows. Clipping apply to the overall signal. So your highs will be asymetrically clipped (here comes the south after even harmonics) with a modulation of this clipping. To me it sounds quite good, but applies only when a) your clipping device sees some harmonics that are there already b) you do not squash them by changing the whole thing into a square wave anyway (ie clipping the lows so hard you don't even let any room to still have the original highs in the signal). So this applies more in the region between clean with a bit of warmth and slight crunch.

It seems your device uses just these concepts, and it sounds good, so you must be doing something right. What I'm more interested in these days is the last of the conceptual aspects I detailed above. Accoustically, an electric guitar will have a lot of harmonics, but with a lot less amplitude than the fondamental and first octave. Put some low input impedance stompboxes and a long guitar cable with capacitance problems after a passive pickup and you have very few harmonics to enhance your "warmer clean" tone.

[phatt]

You are a better man than myself if you can grasp all that. xP
so good on you :tu:

I just stick to simple stuff to explain it.
The best explanation of distortion I read,, (so long back can't remember who/where but likely one of the guitar focused sites)
Went simply thus;
*Half wave distortion followed by Square wave dist.*
If you simulate some of those old famous Valve rigs that is indeed what happens. 8|
the triodes produce the rattle and the power stage squares it off at higher power.

The rest is tone shaping.
The trick is getting the signal swings to line up at each stage if you want the dynamics to happen.
Of course if all you want is fuzz with no dynamics then throw away that idea and turn everything up as far as you can and start playing around with tone shaping.
Phil.

[QReuCk]

I'm not a better man than any one here, i'm just someone who happens to have been teached some engineering and math stuff a long time ago and have a tendency to overthink sometimes  :lmao: :duh

Regarding your approximate concept of tube tone, we do agree:
Tone shaping (guitar pickup, guitar tone and volume circuit, even picking technique, guitar cable, components that might be added/set before the first buffer; then if you put it in pre-clipping EQ/tone tweaking stage) - half wave clipping - tone shaping circuit - half wave clipping - tone shaping circuit - (repete those two for the number of triod stages you have) - tone stack - symetrical clipping (push pull stage) - tone shaping device (guitar speaker).

In my opinion, chosing between high input impedance or not is a choice (I do not pretend one is "better" than the other) impacting the first tone shaping stage of your rig even if it's not the one you would think you act on if you are working on *an amp* or *a stompbox*. Good on you if with your choice you make a good sounding overall rig, which is the case here. And I've heard a lot of people make good use of very low input impedence devices (old school fuzz boxes for instance), I just can't get my head around it as it implies some dynamically changing tone shaping. That doesn't mean it's not right to do so.
And according to Hartley Peavey, the output transformer of tube amps could very well perform also some dynamically changing tone shaping, which is hard to perfectly emulate, but also very hard to understand in for me.