DIYstompboxes.com

hi guys



last night i was messing around with a distortion  with a 'passive', just 3 caps/3 resistors
HP..LP...LP..ultra ridiculously simple cab sim...into my DI box/mixer
and it sounded pretty cool.......well promising anyway..
it took the harsh top end off, and fattened the bottom quite nicely....
         
        220n
in.......//........2.2k......2.2k.......out
               /              /            /
               /              _           _
               / 4.7k       _ 100n  _  22n
               /               /           /

i was tweaking it , swapping resistors for pots etc...

this was ok for dirt....for clean i tapped off the 220n/4.7k junction...

needs a buffer...but quite promising...thoughts?

I'll bread it later Mate. Oh so simple pimple too.

yeah worth a bread up... 8)

i'll tack a buffer on it later..see how it goes.

Looks cool.  I'll have to sim it up later.

I have no ASCII art skills but my go as of late has been two LPF's in series like on many other projects but scaled 10x apart to lessen their effect on each other and give a slightly sharper slope.

Ex. 4k7 & 4n7 followed by 47k & 470p.  Works great with a bass fuzz I'm building.  You could scale the R values down further if you're using an opamp but I've only been doing this with MOSFETs and CMOS as of late so I wanted the values high enough so the output impedance from the dirt stages wouldn't skew my math too much.

EDIT: OK I just copied yours with different values:

      10u
in.......//........4.7k......47k.......................buffer
                              /            /                /
                              _           _                /
                              _ 4.7n   _  470p       /1M
                               /           /                /

On mine the output is buffered as well.

cheers bill,

i'll give that a go too...(my ASCII skills are very lame too as you can see..)

what in/out buffer you using?

i was going to go with an opamp....hmmm...

I used an opamp cause I had a spare but anything will work.  I always use a Rat buffer when breadboarding.  It usually sound just fine after a dirt stage.  I don't like them as clean buffers though for lack of headroom.

I attached a schematic for a project I'm building.  I also zoomed in on the passive "cab sim" circuit for clarity.  This cab sim also introduces a heavy emphasis on the low end because the preceding circuit has a emphasis on the mids and highs.  Plus it's designed for bass after all.

cool, nice one bill... 8)

Quoteneeds a buffer...but quite promising...thoughts?

you can buffer BETWEEN the stages too

Quotescaled 10x apart

that's the usual practice, multiply the resistor by ten, divide the capacitor by ten, for each pole

Quote from: garcho on February 12, 2016, 09:55:11 AM

Quoteneeds a buffer...but quite promising...thoughts?

you can buffer BETWEEN the stages too

Quotescaled 10x apart

that's the usual practice, multiply the resistor by ten, divide the capacitor by ten, for each pole

True.  I read it in a book or something many moons ago but I don't see it used often enough in pedals.

heres a clip of how the (ASCII) at the top sounds....just to give an idea..

first clip...straight dist into di /mixer....harsh as hell..

second clip...through the sim..(as top of thread)...no buffers..so had to lift level quite a bit..

https://dl.dropboxusercontent.com/u/7464107/dist%2Bsim.wav

Sounds great!

What were you using for dirt?

hi bill, its a new version of the spitfire that i'm still working on after months :icon_rolleyes: on  breadboards..

with active tonestack...

i was inspired to tinker with cab sims by my poor old multifx korg ax1500g..

if i turn the cab sims off it sounds utter pants, harsh and nasty (DI)...put the cab sim on, sounds cool..
good enough to record with...(i turn the cabs off in an amp obviously)

but i prefer my own dirt..hence the quest to add a relatively simple sim to it...

Quote from: deadastronaut on February 12, 2016, 10:12:00 AM


heres a clip of how the (ASCII) at the top sounds....just to give an idea..

first clip...straight dist into di /mixer....harsh as hell..

second clip...through the sim..(as top of thread)...no buffers..so had to lift level quite a bit..

https://dl.dropboxusercontent.com/u/7464107/dist%2Bsim.wav

I didn't read the explanation of the clip before I listened, so when you first started without the filters I was like "What the hell Rob, this sounds awful!" Then you kicked it on and I was like

(http://www.pipnet.com/eggs/koolaid-large.jpg)

sounds good!

And if it's not too late to weigh in on the buffer issue, if it were me I would put an opamp at the end with a small trimpot in the feedback loop (maybe 1k input resistance and 2k trimpot? I would have to breadboard it) so you can get a little more gain behind the signal if you need it.

Yep thats some sweet sounds.
Awesome chops. Thanks Rob
Now whens this OD gonna make an apperance?

A very good read on speaker tone...
http://www.soundonsound.com/sos/feb12/articles/speakers.htm
IMO, a filter based sim is well worth having, especially for the high cut, despite that it's not doing even half of things a real cab does to the signal. Maybe if your sound is complex enough, you don't notice the missing colouration of a real cab so much?

If you're going thru the problem of buffering the output, you should use a sallen key filter instead and have a better 2pole filter with low output impedance..and for the hpf use the other side of the opamp as an onput buffer

A side note:
- Library with ASCII Art components to copy+paste:
   http://www.retrojunkie.com/asciiart/electron/circuits.htm

- A program to draw ASCII Art circuits. Site is in german, but software is in english:
  http://www.tech-chat.de/download.html

Not really sure what happened to this thread but I was falling asleep in class this morning and this kept me awake for a bit.

(http://i.imgur.com/rSp6Exd.png)

stop falling asleep, you'll miss the tayda coupon.. ;)

cool,  ive been messing with distortions again, i'll give that a whirl..

i do have a rough though not perfect thing on a bb at the mo...tweaky tweak..

i just fancied having something simple i could use to go straight into DI/MIXER...for late night stuff...tame the highs, and boost the lows..not a cab sim per se', etc etc...

heres what i have on BB...

crude as hell quickie but hey..

(https://dl.dropboxusercontent.com/u/7464107/doobydoo.jpg)

well after trying almost every cab sim out there, and not being at all happy

with any of them, i came up with this last night... :icon_idea:

unorthadox but it works pretty well,

the pot acts as a kind of ''air'' freq setting...like moving the mic around a speaker cone

well it does to me anyway ::)...thats the best way i can explain it..

(https://dl.dropboxusercontent.com/u/7464107/cabsimple1.png)

here's a clip ,

signal:  guitar -- distortion, --cab sim on/off,

direct into mixer...(which was the aim.) i turn the 'air' pot gradually towards the end...

https://dl.dropboxusercontent.com/u/7464107/simtest..mp3


its also nice on clean too.... 8)

stick it on ya breadboard and try it with your dirt.. 8)

Really nice, Rob!  Thank you.   

What no biasing Rob?

cheers man,

nope...we need another 36 pages before that happens... ;D

Sounds great :) Looking forward to the next 36 pages. 8)

me too nathan,... ;)

Anyone tried it?

Quote from: deadastronaut on January 13, 2017, 04:24:22 AM
Anyone tried it?

We're all waiting for page 36...   ;)

Might be sooner though... ;)

just for rich i added biasing,

so theres a 47uf, and 2x 10ks...

470k at pin3, and 470k at pin5 to vb ok....

im pretty happy with it,  i,ll be trying a multi fx distortions later, ( without internal cab sims)

And see how this compares.....sounds cool with my distortions,  so we,ll see how it fares with standard
factory dirts...

Here is a thread on passive designs from years ago that might interest you.
http://www.diystompboxes.com/smfforum/index.php?topic=73342.msg1045759;topicseen#msg1045759
j

cheers johan,

but ive tried a few of those too...believe me, ive tried lots, passive, active...to no avail.

i'm kind of almost there with this one i think, i tried other distortions through it earlier

and its pretty cool....

I got a few minutes and threw this together, Rob...sounds a lot better than just line in!  And simple.

1 question - is a touch of distortion normal in the background when playing (clean, no pedal)?  That 2nd stage gain is about maxxed, so I would assume it's not a totally clean thing, or that maybe a pot on the 2nd stage could be used to dial back the 'gain'.  You probably don't notice a thing if using a dirt pedal ;)   Low battery too, which can't help.


Edit:  Yup, popped a 50k pot in Rf position of U2 rather than the 1Meg fixed.  That fixed the overdrive issue, so a knob is going there, perhaps 100k or 250k.  This sounds very good  for clean too!  Played some Clapton Strat stuff like Lay Down Sally into my sound card, and it was very presentable   :icon_cool:

That sounds pretty good Rob! Kinda reminds me of the Stoned Tone Bulldog..

Hi mike, great, glad you tried it,   8)

i had a bit of dist on it, and it kind  of locked up on power down , but when i added the bias it sorted that out... .

Yep its very nice on clean ,  lifts it too....

and yep a smaller R is better.....i just threw what i had to hand on it....


jim, give it a whirl man....i think youll like this,...loves a high gainer.  :icon_twisted:

Yup, really cool with massive distortion too, LOL! 

I like the filter, it gives you quite a big range of sounds for such a simple thing. 

cool...yeah i like that filter too...very cool.

been getting a bit of clipping on clean, (humbucker bridge)

even when dropping value of IC2 FR....hmmmmm.....tinker tinker...

also when hit hard with filter turn up full, goes into screaming, only on clean..
i put a 33k before pot, seems to have tamed that....


edit, trying a similar filter on ic2.... ;)

Mine shrieked like a b@stard at first...I increased the 47p to 68p and decreased 2nd stage's gain...but I'm not discounting the effect of my cheap BB, which must have really odd capacitances.    Thing is unshielded in any way, too, which is bad.

squeeeeelllllllllllllll.... ;D

i put a 100pf on input, as when input was open it squeellllllled..... this sorted it,

heres where i am.... a 1 pot cab sim.  8)

(https://dl.dropboxusercontent.com/u/7464107/WAVES%20FOR%20PELLE/SIMMOID.jpg)


edit, new clip ,  cab sim off....then on.

https://dl.dropboxusercontent.com/u/7464107/WAVES%20FOR%20PELLE/simmo.mp3

All right, now let's get this straight: good to go, in only 3 pages?!  You expect us to believe that?  ???

Nice one, Rob!

Rob,

What is the purpose of R3? What is the anticipated load for IC1B? 600R?

Thanks,

Law

hi law,

just to be more like bypass unity level really...

any suggestions are welcome as always... 8)

I dunno, R3 at 47k should, if the opamp was perfect, be no different than a short = unity gain. Ooo... What chip is it Rob? I mean the -input is really high Z, so high that 47k is not significant.

On breadboard, the extra stray capacitance might be making a filter with the 47k that's just audible - I dunno - but that capacitance will be much reduced when built on pcb.

C5 at 100n is a little skinny for full bass end into a 10k mixer line-in  - but that may be helping to sim the low end roll-off of a real cab 'cause it's around 200Hz. Just saying be aware that 100n into 100k or higher inputs will lose that bass cut. C5 at 470nF at least if you'd wanted full range into 10k.

If you want a fixed low end roll-off no matter what it's driving, add a series cap before R2 and then make C5 wayhuge - 10uF!

Then Lawrence can drive his 600ohm.

Cheerz jim, its an 072..

i,ll try that series cap thingy., 8)

> my cheap BB, ...  Thing is unshielded in any way

Find a rich-person doing copper roof flashing<g>, grab a half a foot scrap, goo it to the bottom of the breadboard, and ground it.

Copper foil tape you can get at Lowes, walmart, HD or the stuff from StewMac is good

Copper clad board screwed or glued to the bottom, and grounded??...

Quote from: PRR on January 15, 2017, 09:45:15 PM
> my cheap BB, ...  Thing is unshielded in any way

Find a rich-person doing copper roof flashing<g>, grab a half a foot scrap, goo it to the bottom of the breadboard, and ground it.

LOL   I do have some scrap.  Good idea! 
However, I'm time-wealthy, money limited!

(http://i.imgur.com/ZIlTj5b.jpg)


Rob - yes, putting a (grounded) sheet under your breadboard can provide a nice ground plane to pick up RF from your environment.  Every little bit helps - even better if you made a Faraday cage and placed your BB inside it, ha ha.  Even aluminum foil will work.

been eyeing up mrs astros tins ;)....

but i'll likely make a dedicated hi gain TB/BB with copper under it.. ;D

anyway..

jim, tried the 470n C5 , and a cap before the 1k..

but it lost the bass somewhat......

(this is going into a passive DI btw)

Quote from: deadastronaut on January 16, 2017, 09:43:00 AM
been eyeing up mrs astros tins ;)....

If you don't fancy eating all those biscuits, treat Mrs Astro to a takeout curry this evening.  Keep the aloominum dish the rish comes in, clean it, trim, ...   ;)

aha...she has some of those too....  :icon_idea: :icon_idea: :icon_idea:

Rob, do you know the input impedance of the D.I. Transformer? Could be 600ohm, then output cap bigger than 470n or you will lose bass.

hi jim, no i dont know...

its this cheapy one, very little info on it... ::)

http://www.staggmusic.com/en/products/view/SDIST

Weird! No data at all for that Stagg D.I. If its transformer, your output cap value is a somewhat different interaction than if it was feeding an active D.I. with resistive input impedance.

Thing is, if you're unlucky, you have something that only sounds as intended with that particular D.I. Although I can't say how much different that would be from an active D.I. with High-Z input or some other make of passive. I'd expect any difference to be in bass response, which might not be a serious problem since there often is tone control on whatever its feeding. Using a High-Z buffer pedal should simulate an active D.I.
If the D.I. or whatever does not have a High-Z input then there will be obviously less bass if the output cap isn't big enough.

cheers jim,

just thought i do have an active DI too..

https://static.bhphotovideo.com/lit_files/84887.pdf

i'll test that and compare...


that stagg does have 2 transformers in it...

well going by the results, it seems best to

add a switch at C5 for 100n and 470n.

depending on whether its into a DI, or straight into a line in.



the active DI was pretty nasty...

Now, you put a cap before R2, Rob?  What value, just 'arbitrarily large'?

A switch might be a good idea, that will cover several possible situations...

hi mike....nope..

but i will tinker... ;)


ive added the switch...just testing.. 8)

and comparing line in and passive DI


edit: yep switch is cool....good for both DI/line.. 8)


PASSIVE DI = 100n nice n bassy...  470n nice n tight

LINE IN  = 100n nice n tight ....470n nice n bassy...

Nearly finished ;)

you know me better than that ha ha,.... ;D


last night i was thinking of adding a mid control just for a laugh....

will try it later... ;)

Quote from: deadastronaut on January 17, 2017, 07:35:42 AM


PASSIVE DI = 100n nice n bassy...  470n nice n tight

LINE IN  = 100n nice n tight ....470n nice n bassy...

Well, you can't beat that, now can you? :) 

It's hard to know when something is "done", isn't it??

yep it certainly is...

its like a painting...do i, or dont i...add a little....hmmmm....

or not.....hmmmm... :icon_mrgreen:

Was bored last night so I tried to make a little 1590A SMD layout for this.. Haven't really made a layout in a while so I did this as practice..  :icon_wink: If anybody wants it I will give a link to the diptrace file. You will probably end up needing it because Rob changes his mind like a woman changes clothes...  :icon_lol:

(https://dl.dropboxusercontent.com/u/11178619/Cab%20Simulation/deadastronaut/top.JPG)

(https://dl.dropboxusercontent.com/u/11178619/Cab%20Simulation/deadastronaut/bottom.JPG)

(https://dl.dropboxusercontent.com/u/11178619/Cab%20Simulation/deadastronaut/1590A.JPG)

oi!.....true though.

;D


your gonna have to change that.......lots of times.. ;)

Quote from: J0K3RX on January 17, 2017, 08:17:49 AM
Was bored last night so I tried to make a little 1590A SMD layout for this.. Haven't really made a layout in a while so I did this as practice..  :icon_wink: If anybody wants it I will give a link to the diptrace file. You will probably end up needing it because Rob changes his mind like a woman changes clothes...  :icon_lol:

(https://dl.dropboxusercontent.com/u/11178619/Cab%20Simulation/deadastronaut/bottom.JPG)

I'll definitely take you up on those diptrace files. I had a brief SMD phase and never got around to using up all my components :P

. "You will probably end up needing it because Rob changes his mind like a woman changes clothes...  :icon_lol:"

Funny hahaha but its true though


Sent from my iPhone using Tapatalk

heres where i am.....after changing my dress over and over ;D

(mike, try this out see what you think....)

(https://dl.dropboxusercontent.com/u/7464107/MY%20CAB%20SIM/ASTROCAB1.png)

(https://dl.dropboxusercontent.com/u/7464107/MY%20CAB%20SIM/ACPCB.png)

I have to say, I'm really excited to try this out. The sound samples sounds fantastic!

I have a Rivera MiniRockRec which works great for recording because I'm using Two Notes Wall of Sound to simulate speakers in my DAW. I was hoping I'd be able to use it for late night practicing too so I don't wake up the family however even though the Mini does have a headphone jack, the speaker simulations don't work with it. They only put a low pass filter on the headphone jack and I think it sounds bad.

Looks like this is a line level signal but could I put this in between the headphone out of the MiniRockRec or would the signal coming from the headphone jack not be enough? Otherwise, I could plug this between the line out of the Mini and into my Interface. I have a headphone out from my Focusrite so I could use that. It would be great because as of now, using the Focusrite, I either have latency if I use WoS or I hear the unfiltered raw signal coming from the line out which also sound like crap of course.

I don't know much about building circuits like this, I literally ordered a cheap breadboard kit on Amazon today. I want to know, i don't see it mentioned, is the pot you have called out a linear or audio taper? Also when I called a small local shop about resistors/capacitors, I was asked if the resistors were 1/4 watt and what voltage the capacitors were. I could not tell from the schematic. I'm sorry if it was somewhere on the post and I missed it. I looked while I was on the phone but couldn't find any references to it.

hi, the 'air' pot is a 1MA   A=LOG.   the 'mid' pot is a B= LINEAR.

1/4 watt resistors are perfect.

electro caps , get 25v-50v and you'll be fine.

yep, i have the same need, where i just want to plug in to a DI box or line in...(mixer)

for late night noodling, and just for convenience as sometimes i leave my amp
at friends /studio etc...but i always bring my pedals home..

i do have a digital multi fx board with cab sim built in, but i prefer my own dirts..


anyway, i'll test this more tomorrow...and see if my ears like it then. my ears change from day to day i find as i get older   ::) 8)

Oooh, a mid control!  FANCY!   I'll check that out soon, Rob...spent the day prepping and painting pine floors in my farmhouse...a little tired and in need of a beer or 4...my elec. room is up here where the floor paint is drying (volatile....ack..).

Nice work on that!  :)

enjoy the beer man, sounds like you earned it...  8)

Quote from: deadastronaut on January 17, 2017, 07:45:01 PM
enjoy the beer man, sounds like you earned it...  8)

Ya, pix later!  ;) 

 I think the cab needs more low end


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You may be right....i,ll listen again later, and post clips... :icon_confused:

get it on ya breadboard, join in... 8)

I don't have breadboard right now, I will buy this week for much more fun . :)


Sent from my iPhone using Tapatalk

Quote from: bluebunny on January 13, 2017, 05:02:08 AM

We're all waiting for page 36...   ;)

Os this the title of a Syd Barrett song,?


here be .sig

I'm trying to put this together. I have little experience with bread boarding. I've built two pedals from kits but that's it so far. Any chance you could post a shot of how this circuit looks on the bread board? I tried doing a tutorial which helped some but I have many questions of how this should work.


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Did I ask for something that's totally gauche? This forum thread stopped completely after my last post asking about a picture of how to put this together on a bread board... Very sorry if this was out of turn.  :-\

Yes,  it was highly offensive lol.... ;D

hopefully i,ll get back on this today....been busy.

Im notorious for changing, testing,  etc....hence the 36 page jokes...

so hang in there.... :icon_wink:

You're not notorious until at least page twenty-two...  ;D

22 , your having a laugh, 

Even the burst box thread is shorter... :icon_mrgreen:

Quote from: deadastronaut on January 25, 2017, 02:42:43 AM
Even the burst box thread is shorter... :icon_mrgreen:

Not one of yours then, Rob.   ;D

2manygadgets - just feed him some sausages, he'll do most anything then.

yeah, pretty much...

i can buy a house, and dance on ice whilst making cakes and lip syncing...i learned that from the bbc..
well worth 145 quid a year.. :icon_rolleyes:

anyway..

i ripped out the mid control...

am going to try a few basic tone controls...the essence of it is still there.. :)

heres where i am...ive ended up with a spare opamp...but i'll try a few other things later
got other stuff to do today...

plenty of bass now...getting there, sounds pretty good, only another 28 pages to go.. ;)

(https://dl.dropboxusercontent.com/u/7464107/WAVES%20FOR%20PELLE/ASTROCAB2.png)

I think R3 is redundant due to the DC coupling.

cheers ducky, well spotted... 8)

You can get rid of IC1B by moving the LPF of R2/C4 to the output of IC2A (either side of C10 will work).

cheers sam..

this?.

(https://dl.dropboxusercontent.com/u/7464107/WAVES%20FOR%20PELLE/astrocab3.png)

Yes,
On further reflection, you will probably want to make C10 bigger too - ideally 10x or more bigger than C4.

Also, having now had a proper look at this, I have a few more thoughts.
Your 'Air control' gives you a frequency response a bit like a wah. It's an interesting design, but is probably quite sensitive to loading and if you feed it a high impedance signal, you could get a lot of gain at > 10 kHz, which could clip the rails. What happens if you go straight from a guitar into it or put 10-100k resistance in series with the input?

Hang on a second. Wasn't it ridiculously simple? ;D

However, keep going it looks great.

You might want to add 'astro cab' to the title. It could make searches difficult. I would not expect it to be under a title saying simple cab sim

Quote from: samhay on January 26, 2017, 09:04:30 AM
You can get rid of IC1B by moving the LPF of R2/C4 to the output of IC2A (either side of C10 will work).

IC1B could be an inverter for a ballanced output...

here be .sig