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Old 19th October 2004, 12:04 AM   #21
amz-fx is offline amz-fx  United States
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The circuit is a soft-knee type of clipper that rounds the wave instead of doing a fairly sharp clipping like with a pair of diodes.

A good tube simulation needs more of the 'feel" and sag than just rounded clipping for a good simulation...

regards, Jack
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Old 25th October 2004, 09:47 AM   #22
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to me that amp didn't sound that great
something about it just didn't do it for me
almost sounded like it was just like a soft fuzz effect then any real tube amp sound.
sure it is more mild and smooth then heavy gain ss distortion but it still is missing that creamy sound to it and also has some sound in the distortion that is like a staticy sound.... almost reminds me of my preamp pushed too far where the protective circuitry kicks in just in a more mild way
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Old 25th October 2004, 10:41 PM   #23
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Default My opinion as a Tone Guru.....

I've found there is a way to simulate EVERYTHING a tube amp does with a well designed solid state combined with digital modeling but one thing is very very hard to do.
Simulate the graceful signal clipping of tubes in the preamp section.

Many think it's the overdriven power tube section which after a couple years of exstenvie research, I had believe too. UNTRUE.

I've noticed that I can clone any tube amps tone with my solid state head by combining it with about any modern modeling processor. Key is using my amps gain and the amp modeling to voice it. I have a Crate head that has a fuzz distortion that is a bit grainy or chizzley sounding as many would describe it.

What I wasn't achieving was the low gain setting sustain tube preamp based circuits achieve.
I'd get the tone of any artist dead on but it was a bit of a challenge smoothing it over do to most of them using tube amps.

You can have the same level of say a moderate amount of distortion in a solid state amp and a tube amp, but 90% of the time the tube will give more sustain

I recently added a Behringer DSP2024 processor to the loop and was VERY surprised to find I was able to drop my gain down to FIVE!
All the ronch of metal yet the smooth everlasting sustain just like a tube amp.

Without using ANY effects, the processor gives me this result. The only downside is I am experiencing feedback which was NEVER an issue before.......hmmmm just like tube amps are known for doing!

ANYWAY, I'm not sure if this will help but I suspect this is why I am getting this major increase of sustain and sonics.
The input impedance is 80 k ohms balanced and the output is
80 ohms balanced. Both analog of course.

I suspect that high output impedance is giving enough clean gain to match the gracefully clipped sustain tubes are known for.

I'm not sure what you can do with this data, but I'm betting a S.S. preamp with this input and output rating that utilizes a fuzz gain that can be driven into ronchy metal tones will prove to be VERY successful in recreating that graceful tube clipping.

I'd build the damn thing myself but I just don't have the knowledge to do so yet.

I have however found a VERY simple method of simulating over driven power tubes in an all S.S. amp....this circuit it so simple and so sweet I am dumbfounded no S.S. builder is using it.
Sorry guys but I can't share this one....not justyet at least. This circuit is so beautiful you can even choose the level of power tube saturation emulation you want in the output signal.

Anyway, someone build a pre with those input and output impedance levels I was mentioning and let me know how it goes........
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Old 27th October 2004, 12:54 AM   #24
amz-fx is offline amz-fx  United States
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There is a lot going on in a cranked amp beyond just the performance of the active circuit elements... the speaker cone is bottoming out making a honky sound, the loud audio is driving the guitar body/strings to create sustain/feedback and the output transformer is reaching some degree of saturation. None of these items are modeled in the typical stompbox circuit.

The clipping performance of the tube gain stages can be replicated fairly easily with the proper solid state equivalents but the aspects of the whole amp that I describe above are missing, as is the dynamic interaction of the gain stages and those factors. This leaves you with a circuit that may sound good but still misses the mark by a slim margin.

The Mini-Tubes Preamp on my cd-rom is a good solidstate emulation of a Marshall tube amp circuit:

http://www.muzique.com/amz-cd.htm

regards, Jack
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Old 27th October 2004, 04:39 PM   #25
Nasse is offline Nasse  Finland
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Hey Jack thanx for quick delivery I recently ordered your cd

But damn post broke the cd in two pieces. IŽll collect some money and maybe try again with better luck, I believe it is worth it. Some other stuff I ordered earlier were super.

Someone say that bubble packing is great for posting cds but I think maybe thin plywood or something...

That minibooster circuit is very very nice. I have tried some cmos inverter stuff too which has something similar but is different animal, but anyway I believe it and minibooster has some very nice sounding and "feeling" properties, "plays" like good tube amp


Listened that Bluetone Amp demo on their page and turned it off before halfway, did not like it, they said on another forum they should really redo the soundclips. No high voltage is big plus imho but of course you can debate ad infinitum about "real tube sound"
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Old 27th October 2004, 07:17 PM   #26
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Quote:
Originally posted by amz-fx
There is a lot going on in a cranked amp beyond just the performance of the active circuit elements... the speaker cone is bottoming out making a honky sound, the loud audio is driving the guitar body/strings to create sustain/feedback and the output transformer is reaching some degree of saturation. None of these items are modeled in the typical stompbox circuit.


regards, Jack
Yes but these elements are not just singular to tube amps. They occur in S.S. just the same.

As far as a speaker bottoming out.....I feel this is just one more myth of terminallogy.
A speaker has a given Xmax that a mere 5 watts will push it to reach full excurrsion or even bottom out, which in the world of audio I know, means your voice coil is smacking your magnet. YIKES!

I'm no expert in electronics by any means, but this honking is likely coming from the high impedance output of tube circuits. In all the research I've done, this is one of the two factors that seperates tube from S.S. emulating tube. The high impedance output, which is about 10 decibels greater than that of all guitar speakers responce curve, and the graceful clipping of tube distortion circuits.

Crank that volume and you overdrive the speakers responce curve more and more.

I recently added a Behringer DSP2024 which greatly increased my signal output post EQ/gain but pre amplification stage. I can crank the amps volume which gives me this same honking effect but at low volume levels. My processors control my overall volume.

I think generally emulation circuits and amps won't get you the same results without very cleverly figuring out where you need to alter your signal and how/why. I've got a really simple preamp design I think is at the same time ingenius and will give dead on tube results.

Bottom line is, tube circuits in comparison to S'S' emulation circuits are VERY simple. I think this is where S.S. emulation amp builders/designers are going wrong. Things need to be kept simple while still covering all the basses.
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Old 23rd November 2004, 11:52 AM   #27
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just look at my posts
Make it sound tubey !!!
note: my foult - caps values in nF (not pF)
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Old 24th November 2005, 01:16 AM   #28
dimitri is offline dimitri  United States
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Default http://patft.uspto.gov/netahtml/srchnum.htm

4439742 Mar., 1984 Sondermeyer
4809336 Feb., 1989 Pritchard
4937874 Jun., 1990 Pittman et al.
4995084 Feb., 1991 Pritchard
5032796 Jul., 1991 Tiers et al.
5131044 Jul., 1992 Brown, Sr. et al.
5133014 Jul., 1992 Pritchard
5434536 Jul., 1995 Pritchard
5524055 Jun., 1996 Sondermeyer
5619578 Apr., 1997 Sondermeyer et al. .
5636284 Jun., 1997 Prichard 381/61.
5668499 Sep., 1997 Albert et al.
5789689 Aug., 1998 Doidic et al.
5805713 Sep., 1998 Pritchard
5909145 Jun., 1999 Zimmerman
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Old 19th December 2005, 02:09 PM   #29
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Default Re: WHA????

Quote:
Originally posted by MrGuitardeath
You can't be serious......

I mean I bet you know more than me but the cheapest op amp out there?

eh , if it works well for you cool.....I have doubts

I've gone out and used cheap ol' tl082 amps from radio shack with decent luck and comming up with something that worked.
or tried using again cheap j201 jfets or mpf102 jfets from radio shack. sure they all can give a little different sound and clipping but a lot also has to do with the rest of the circiut, like others said the tone shaping, as much of as the transistors/ic's you use.
main thing I would look for if building a high gain preamp/distortion pedal is low noise though. noise though through lots of gain could cause some issues.
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Old 20th December 2005, 07:44 PM   #30
rodriki is offline rodriki  Brazil
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Default what sound to be good

Hi,

the guys (a LOT OF them) i have discussed this question
a time ago sound not to believe it is possible to get
a tube clipping type of distortion outside of anything diferent
from tube.

The arguments are always beating the same key:
The best thing about tube clipping are output tube distortion and
the "so called compressing" or sag effect (coming from energy source).

(I must remember the most desirable tube distortion comes from really expensive stuff.)

I insist in thinking about what is the tube compression.
And now, how can this be recreated without tubes??????
(so hard to find were i live ...)

At least how can we get those SCREAMING guitar i use
hear from my home stereo???? Not having a tube amp of course.

The use of fet in place of tubes sound not to be the answer yet.
The tipical output frequence response of tube amps, because of output transformer is the main argument for the greatest diference in COLOR of tube amps.

I still hope some expert guy will find some tricks to help.
And share....like LIKE YOU always did

Thanks.
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